Short-term effects of a hypocaloric diet with low glycemic index and low glycemic load on body adiposity, metabolic variables, ghrelin, leptin, and pregnancy rate in overweight and obese infertile women: a randomized controlled trial

The Contribution of Precision Nutrition Intervention in Subfertile Couples

BACKGROUND/AIM

Subfertility is characterized by a decrease in reproductive efficiency, which can result in delayed pregnancy, and affects one in six individuals during their lifetime. The present narrative review aims to evaluate the contribution of precision nutrition to changes in fertility in subfertile couples.

METHODS

The literature review was carried out through bibliographic research in the PubMed, Scopus, SciELO and Google Scholar databases. The following search criteria were applied: (1) original articles and narrative, systematic or meta-analytic reviews, and (2) the individual or combined use of the following keywords: "genetic variation", "nutrigenetics", "precision nutrition", "couple's subfertility", and "couple's infertility". A preliminary reading of all the articles was carried out, and only those that best fit the themes and subthemes of the narrative review were selected.

RESULTS

Scientific evidence suggests that adherence to a healthy diet that follows the Mediterranean pattern is associated with increased fertility in women and improved semen quality in men, better metabolic health and reduced levels of inflammation and oxidative stress, as well as maintaining a healthy body weight. The integration of different tools, such as nutrigenetics, predictive biochemical analyses, intestinal microbiota tests and clinical nutrition software, used in precision nutrition interventions can contribute to providing information on how diet and genetics interact and how they can influence fertility.

CONCLUSIONS

The adoption of a multidisciplinary and precision approach allows the design of dietary and lifestyle recommendations adapted to the specific characteristics and needs of couples with subfertility, thus optimizing reproductive health outcomes and achieving successful conception.

Associations of periconception dietary glycemic index and load with fertility in women and men: a study among couples in the general population

BACKGROUND

The dietary glycemic index (GI) and load (GL) reflect carbohydrate quality and quantity, potentially impacting fertility through modulation of insulin sensitivity and generation of oxidative stress. While fertility is influenced by both women and men, reproductive research often emphasizes maternal factors. We first examined periconception dietary intake in both women and male partners, and subsequent associations of dietary GI and GL with fecundability and subfertility.

METHODS

Among 830 women and 651 male partners, participating in a population-based prospective cohort study from preconception onwards, we assessed periconception dietary intake and calculated GI and GL, using a food frequency questionnaire (FFQ) at median 12.4 weeks gestation (95% range 10.9, 18.4). Information on time to pregnancy was obtained through questionnaires, with subfertility defined as a time to pregnancy ≥ 12 months or use of assisted reproductive technology.

RESULTS

In the periconception period, mean energy intake in women was 1870 kcal (SD: 500; 46% carbohydrates, 16% protein, 33% fat; dietary GI 56.2 (SD: 3.5) and GL 141.4 (SD: 67.4)). Mean energy intake in men was 2350 kcal (SD: 591; 43% carbohydrates, 16% protein, 33% fat; dietary GI 56.8 (SD: 3.2) and GL 156.7 (SD: 75.4)). Median time to pregnancy was 4.8 months (IQR: 1.2, 16.4), with 30.6% of 830 women experiencing subfertility. Dietary GI and GL were not associated with fertility outcomes in women. In men, higher dietary GI and GL across the full range were associated with decreased fecundability, after adjusting for socio-demographic and lifestyle factors, as well as dietary GI or GL of female partners [FR: 0.91, 95% CI 0.83, 0.99; FR: 0.90, 95% CI 0.81, 0.99, per SDS increase in dietary GI and GL, respectively]. When assessing the combined influence of dietary GI clinical categories in women and men, both partners adhering to a low GI diet tended to be associated with increased fecundability, but not with subfertility risk.

CONCLUSIONS

Suboptimal periconception carbohydrate intake may be negatively associated with male fertility, but not with fertility outcomes in women. Further studies are needed to assess whether a lower GI and GL diet is a feasible lifestyle intervention to improve couples fertility.

Effects of a culturally tailored low-glycaemic index dietary educational intervention on reducing cardiometabolic risk among Chinese adults with obesity: a randomized controlled trial

AIMS

An assessor-blinded randomized controlled trial was conducted to assess the effect of a culturally tailored low-glycaemic index (GI) dietary educational intervention on body mass index and cardiometabolic risks for Chinese people with obesity in Hong Kong.

METHODS AND RESULTS

A total of 166 Chinese adults in Hong Kong with obesity were randomized to the intervention group (n = 83) or the control group (n = 83). The intervention group received the culturally sensitive low-GI dietary educational intervention based on the health belief model, consisting of an educational booklet, one individual interactive educational session, and three follow-up telephone calls. The control group received general advice on a healthy diet, including a pamphlet, one individual education session, and three follow-up telephone calls. Outcome measures included body mass index, cardiometabolic risk factors, dietary intake variables, and sense of satiety. Data collection was conducted at baseline and post-intervention at 12 weeks. A generalized estimating equation model was used to compare the difference in changes in outcome variables between groups. Compared with the control group, the intervention group exhibited a significant reduction in dietary glycaemic load (β = -6.963, P = 0.026) at post-intervention. No significant effects were found on other outcomes.

CONCLUSION

A 12-week culturally tailored and health belief model-based low-GI dietary educational intervention significantly reduced the dietary glycaemic load and showed the feasibility of the low-GI dietary intervention in Chinese adults in Hong Kong with obesity. A longer intervention period and follow-up might be required to achieve improvements in reducing cardiometabolic risk factors in people with obesity.

REGISTRATION

ClinicalTrials.gov: NCT04152213.

Effectiveness of preconception weight loss interventions on fertility in women: a systematic review and meta-analysis

IMPORTANCE

Weight loss before conception is recommended for women with overweight or obesity to improve fertility outcomes, but evidence supporting this recommendation is mixed.

OBJECTIVE

To examine the effectiveness of weight loss interventions using lifestyle modification and/or medication in women with overweight or obesity on pregnancy, live birth, and miscarriage.

DATA SOURCES

An electronic search of MEDLINE, Embase, Cochrane Library, including Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature was conducted through July 6, 2022, via Wiley.

STUDY SELECTION AND SYNTHESIS

Randomized controlled trials examining weight loss interventions through lifestyle and/or medication in women with overweight or obesity planning pregnancy were included. Random-effects meta-analysis was conducted, reporting the risk ratio (RR) for each outcome. Subgroup analyses were conducted by intervention type, type of control group, fertility treatment, intervention length, and body mass index (BMI).

MAIN OUTCOME(S)

Clinical pregnancy, live birth, and miscarriage events.

RESULT(S)

A narrative review and meta-analysis were possible for 16 studies for pregnancy (n = 3,588), 13 for live birth (n = 3,329), and 11 for miscarriage (n = 3,248). Women randomized and exposed to a weight loss intervention were more likely to become pregnant (RR = 1.24, 95% CI 1.07-1.44; I2 = 59%) but not to have live birth (RR = 1.19, 95% CI 0.97-1.45; I2 = 69%) or miscarriage (RR = 1.17, 95% CI 0.79-1.74; I2 = 31%) compared with women in control groups. Subgroup analyses revealed women randomized to weight loss interventions lasting 12 weeks or fewer (n = 9, RR = 1.43; 95% CI 1.13-1.83) and women with a BMI ≥ 35 kg/m2 (n = 7, RR = 1.54; 95% CI, 1.18-2.02) were more likely to become pregnant compared with women in the control groups. Miscarriage was higher in intervention groups who underwent fertility treatment (n = 8, RR 1.45; 95% CI 1.07-1.96).

CONCLUSION(S)

Pregnancy rates were higher in women undergoing preconception weight loss interventions with no impact on live birth or miscarriage rates. Findings do not support one-size-fits-all recommendation for weight loss through lifestyle modification and/or medication in women with overweight or obesity immediately before conception to improve live birth or miscarriage outcomes.

Relationship between dietary glycemic index and glycemic load and sperm-quality parameters in Iranian men: a cross-sectional study

BACKGROUND

Infertility is a major clinical problem with psychological, financial and medical costs. Male infertility has recently been linked to 50% of childless couples. It is worth mentioning that diet and its components can be manipulated and applied in counseling meetings of infertile men as a modifiable factor. The goal of this study was to determine the correlation of dietary glycemic index (GI) and glycemic load (GL) with sperm-quality parameters in Iranian men.

MATERIALS AND METHODS

In this cross-sectional study which was carried from Aug to Nov 2023, after excluding smokers, 322 men who were attending the IVF clinic of Ayatollah Mousavi Hospital for seminal analysis were enrolled. Dietary intake was completed by an expert dietitian through face-to-face interviews with a validated 168-item food frequency questionnaire (FFQ). In the present study, sperm-quality parameters, including motility, concentration, normal morphology, vitality, DNA fragmentation index (DFI), and chromatin maturation of sperm, were analyzed. The relationship between dietary GI and CL and these parameters was assessed.

RESULTS

Adjusting for the baseline variables, dietary GI and GL showed positive and negative associations with sperm progressive motility, respectively (p = 0.01 and p < 0.001). Higher dietary GI was associated with lower (p = 0.03); however, a higher dietary GL was associated with higher immotile sperm (p < 0.001). A higher dietary GI was associated with a 77% higher sperm count (p = 0.003). In contrast, higher dietary GL was associated with a lower count (p < 0.001). Higher dietary GI and GL were associated with higher and lower percentages of sperm with normal morphology by 70% and 40%, respectively (p < 0.001 in both). A higher dietary GL was associated with an increase in sperm vitality and DFI of 33% and 53%, respectively (p < 0.001). Higher dietary GI showed a significant negative effect on sperm DFI (p = 0.009). Dietary GI and GL showed significant positive and negative effects on SCMA, respectively (p = 0.002 and p < 0.001).

CONCLUSION

A diet with a higher GI showed beneficial effects on more parameters of sperm; however, higher dietary GL showed deleterious effects, except sperm vitality and SCMA. More studies are needed to obtain a concise result.

Low-Glycemic Load Diets and Thyroid Function: A Narrative Review and Future Perspectives

Nutrition and calorie intake are associated with subtle changes of thyroid function tests in subjects with an intact Hypothalamic-Pituitary-Thyroid axis. Iodine deficiency and extreme fluctuations in calorie intake, such as those that occur during periods of starvation or overfeeding could lead to alterations in thyroid hormones. The dietary macronutrient and micronutrient composition could also influence the thyroid function. Recently, Low-Glycemic Load (LGL) diets have become very popular and are effective in the treatment and/or prevention of several medical conditions, including diabetes, obesity, cardiovascular disease, and epilepsy. In this review, we report on the available data from the literature regarding the association between LGL diets and thyroid function or dysfunction. Several studies conducted in this field to date have yielded inconsistent results.

The Mechanism of Leptin Resistance in Obesity and Therapeutic Perspective

Leptin resistance is induced via leptin signaling blockade by chronic overstimulation of the leptin receptor and intracellular signaling defect or increased hypothalamic inflammation and suppressor of cytokine signaling (SOCS)-3 expression. High-fat diet triggers leptin resistance induced by at least two independent causes: first, the limited ability of peripheral leptin to activate hypothalamic signaling transducers and activators of transcription (STAT) signaling and secondly a signaling defect in leptin-responsive hypothalamic neurons. Central leptin resistance is dependent on decreased leptin transport efficiency across the blood brain barrier (BBB) rather than hypothalamic leptin insensitivity. Since the hypothalamic phosphorylated STAT3 (pSTAT3) represents a sensitive and specific readout of leptin receptor-B signaling, the assessment of pSTAT3 levels is the gold standard. Hypertriglyceridemia is one of important factors to inhibit the transport of leptin across BBB in obesity. Mismatch between high leptin and the amount of leptin receptor expression in obesity triggers brain leptin resistance via increasing hypothalamic inflammation and SOCS-3 expression. Therapeutic strategies that regulate the passage of leptin to the brain include the development of modifications in the structure of leptin analogues as well as the synthesis of new leptin receptor agonists with increased BBB permeability. In the hyperleptinemic state, polyethylene glycol (PEG)-modified leptin is unable to pass through the BBB. Peripheral histone deacetylase (HDAC) 6 inhibitor, tubastatin, and metformin increase central leptin sensitization. While add-on therapy with anagliptin, metformin and miglitol reduce leptin concentrations, the use of long-acting leptin analogs, and exendin-4 lead to the recovery of leptin sensitivity. Contouring surgery with fat removal, and bariatric surgery independently of the type of surgery performed provide significant improvement in leptin concentrations. Although approaches to correcting leptin resistance have shown some success, no clinically effective application has been developed to date. Due to the impairment of central and peripheral leptin signaling, as well as the extensive integration of leptin-sensitive metabolic pathways with other neurons, the effectiveness of methods used to eliminate leptin resistance is extremely limited.

The influence of lifestyle interventions and overweight on infertility: a systematic review, meta-analysis, and meta-regression of randomized controlled trials

This study aimed to investigate the effect of lifestyle intervention (LSI) on diagnosed infertility in overweight and obese women. A systematic review and meta-analysis were conducted. A literature search was performed on the following databases from September 2022 to December 2022: PubMed, Web of Science, and SPORTDiscus. The inclusion criteria were the following: women between 18 and 45 years of age, BMI over 25.0 kg/m2, diagnosed with infertility, a weight loss intervention, and control group part of RCTs. In total, 15 studies were identified and included. The meta-analysis shows a beneficial effect of LSI on reducing weight, waist circumference, and BMI and increasing infertility. A significantly beneficial effect of lifestyle intervention on weight reduction was observed for participants who initially had a higher BMI, while a non-significant effect was observed for individuals with a BMI above 35 kg/m2. The meta-analysis showed a beneficial effect of lifestyle intervention on ovulation incidence and sex hormone-binding globulin. The lifestyle intervention group had 11.23 times more ovulatory incidence than the control group, which in turn increased the ability to conceive. As robust evidence for the effect of lifestyle interventions on infertility in obese and overweight women was found, it is advised to integrate similar interventions into future infertility treatment processes.

Glycemic index, glycemic load, dietary inflammatory index, and risk of infertility in women

The dietary glycemic load (GL) indicates the quantity and quality of carbohydrates, which can affect ovulation and fertility by controlling insulin sensitivity. Also, past studies confirm the role of the dietary inflammatory index (DII) in many diseases, including metabolic syndrome and cardiovascular disorders, so it may be related to reproductive health. This case-control study aims to study the association between glycemic index (GI), GL, and DII with infertility in women. This study was conducted on 300 infertile women in the case group and 300 fertile women in the control group in Kermanshah, Iran. Food intake was evaluated using FFQ, and using NUTRITIONIST IV software programs, GI and GL values were determined. DII was computed as well using FFQ data. Physical activity was assessed using IPAQ-SF. The association between GI, GL, and DII with infertility was evaluated using a logistic regression test, using STATA version 14 software. The results showed that the DII, GI, and GL were higher in the case group compared to the control group ([p = .009], [p = .0001], and [p = .0007], respectively). The increase in GI, GL, and DII caused an increase in infertility factors, and consequently enhanced chance of infertility ((adjusted odd ratio [OR] 2; 95% confidence interval [CI], 1.16, 3.45), (OR 3.68; 95% CI, 1.99, 6.82), and (OR 1.7; 95% CI, 0.97, 2.95), respectively). The present study indicated that the chance of infertility is higher in women who follow a diet with high GI, GL, and DII. Therefore, a positive association may be present between GI, GL, and DII with infertility.

How effective are lifestyle interventions for overweight women trying to conceive?

PURPOSE OF REVIEW

To summarize and critically review the current knowledge on the effectiveness of lifestyle modifications for overweight women trying to conceive.

RECENT FINDINGS

Overweight is associated with a wide spectrum of disorders, which may directly or indirectly affect fertility [from menstrual cycle irregularities to a lower chance of live birth after assisted reproductive technology (ART) treatment]. Weight loss through nonpharmaceutical lifestyle interventions is achievable. Weight loss can normalize menstrual cycle irregularities and can increase fecundability. Pregnancy-associated risks, such as gestational diabetes can be decreased by preconception weight reduction.

SUMMARY

Weight loss through lifestyle changes (i.e., lower caloric intake and increased physical activity), may increase fecundability and may have a positive impact on the course of pregnancy, delivery, and neonatal outcomes. Accordingly, women should be motivated to reduce their weight before conception. However, the effectiveness of life-style intervention programs for women actively seeking medical support in achieving pregnancy has not convincingly been demonstrated. In the few randomized controlled trials (RCTs), selection bias for trial participation by patient motivation may have been present, yet participant attrition was still high and mean effects were small, casting doubts on the utility of such programs in routine care. Pharmacological and surgical intervention may be more effective or necessary complements to lifestyle intervention programs.

Nutrition, female fertility and in vitro fertilization outcomes

The investigation of modifiable factors that may exert influences on female reproductive health and in vitro fertilization (IVF) outcomes is increasing. Growing attention is being paid to nutrition. The aim of the present review is to recapitulate the current understanding on the effects of nutrition on female fertility and IVF outcomes. In particular, the three main classes of macromolecules have been analysed i.e. carbohydrates, proteins and fatty acids. An increasing number of studies have focused on the potential benefit of whole grain, vegetables and omega-3 polynsatured fatty acids (ω-3 PUFAs) on reproductive outcomes. Controversial results exist regarding the consumption of omega-6 (ω-6) PUFAs and dairy. Overall, nutrition appears to represent a modifiable factor that may play a significant role in the context of female reproduction and IVF outcomes, but the limited number of studies and the discrepancies between the available data call for further research in the area.

Acceptability and feasibility of a planned preconception weight loss intervention in women with long-acting reversible contraception: the Plan-it mixed-methods study

BACKGROUND

Women with overweight (a body mass index of ≥ 25 kg/m2) or obesity (a body mass index of ≥ 30 kg/m2) are at greater risk of experiencing complications during pregnancy and labour than women with a healthy weight. Women who remove their long-acting reversible contraception (i.e. coils or implants) are one of the few groups of people who contact services as part of their preparation for conception, creating an opportunity to offer a weight loss intervention.

OBJECTIVES

The objectives were to understand if routine NHS data captured the pathway from long-acting reversible contraception removal to pregnancy and included body mass index; to identify the suitable components of a preconception weight loss intervention; and to engage with key stakeholders to determine the acceptability and feasibility of asking women with overweight/obesity to delay the removal of their long-acting reversible contraception in order to take part in a preconception weight loss intervention.

DESIGN

This was a preparatory mixed-methods study, assessing the acceptability and feasibility of a potential intervention, using routine NHS data and purposefully collected qualitative data.

PARTICIPANTS

The NHS routine data included all women with a long-acting reversible contraception code. There were three groups of participants in the surveys and interviews: health-care practitioners who remove long-acting reversible contraception; weight management consultants; and women of reproductive age with experience of overweight/obesity and of using long-acting reversible contraception.

SETTING

UK-based health-care practitioners recruited at professional meetings; and weight management consultants and contraceptive users recruited via social media.

DATA SOURCES

Anonymised routine data from UK sexual health clinics and the Clinical Practice Research Datalink, including the Pregnancy Register; and online surveys and qualitative interviews with stakeholders.

RESULTS

The records of 2,632,871 women aged 16-48 years showed that 318,040 had at least one long-acting reversible contraception event, with 62% of records including a body mass index. Given the identified limitations of the routine NHS data sets, it would not be feasible to reliably identify women with overweight/obesity who request a long-acting reversible contraception removal with an intention to become pregnant. Online surveys were completed by 100 health-care practitioners, four weight management consultants and 243 contraceptive users. Ten health-care practitioners and 20 long-acting reversible contraception users completed qualitative interviews. A realist-informed approach generated a hypothesised programme theory. The combination of weight discussions and the delay of long-acting reversible contraception removal was unacceptable as an intervention to contraceptive users for ethical and practical reasons. However, a preconception health intervention incorporating weight loss could be acceptable, and one potential programme is outlined.

LIMITATIONS

There was very limited engagement with weight management consultants, and the sample of participating stakeholders may not be representative.

CONCLUSIONS

An intervention that asks women to delay long-acting reversible contraception removal to participate in a preconception weight loss intervention would be neither feasible nor acceptable. A preconception health programme, including weight management, would be welcomed but requires risk communication training of health-care practitioners.

FUTURE WORK

Work to improve routine data sets, increase awareness of the importance of preconception health and overcome health-care practitioner barriers to discussing weight as part of preconception care is a priority.

TRIAL REGISTRATION

This trial is registered as ISRCTN14733020.

FUNDING

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 27, No. 1.

Anti-Inflammatory Diets in Fertility: An Evidence Review

Infertility is a global health concern affecting 48 million couples and 186 million individuals worldwide. Infertility creates a significant economic and social burden for couples who wish to conceive and has been associated with suboptimal lifestyle factors, including poor diet and physical inactivity. Modifying preconception nutrition to better adhere with Food-Based Dietary Guidelines (FBDGs) is a non-invasive and potentially effective means for improving fertility outcomes. While several dietary patterns have been associated with fertility outcomes, the mechanistic links between diet and infertility remain unclear. A key mechanism outlined in the literature relates to the adverse effects of inflammation on fertility, potentially contributing to irregular menstrual cyclicity, implantation failure, and other negative reproductive sequelae. Therefore, dietary interventions which act to reduce inflammation may improve fertility outcomes. This review consistently shows that adherence to anti-inflammatory diets such as the Mediterranean diet (specifically, increased intake of monounsaturated and n-3 polyunsaturated fatty acids, flavonoids, and reduced intake of red and processed meat) improves fertility, assisted reproductive technology (ART) success, and sperm quality in men. Therefore, integration of anti-inflammatory dietary patterns as low-risk adjunctive fertility treatments may improve fertility partially or fully and reduce the need for prolonged or intensive pharmacological or surgical interventions.

Effects of preconception weight loss after lifestyle intervention on fertility outcomes and pregnancy complications

It is well documented that obesity decreases natural fertility among men and women as well as pregnancy chances after conventional infertility and assisted reproductive technology (ART)-based treatments. Moreover, pregnancy complications are increased in women with overweight and obesity. General guidelines on the treatment of obesity recommend lifestyle intervention, including diet and exercise as the first-line treatment, coupled with or without medical treatments, such as weight loss medication or bariatric surgery, to reduce complications of obesity in adults. In the context of infertility in various countries and infertility clinics, there is a body mass index limit for public refund of infertility treatment of women with obesity. In this respect, it is important to investigate the evidence of effects of lifestyle intervention preceding infertility treatment on reproductive outcomes. The combined results of 15 randomized controlled trials (RCTs) of the effectiveness of preconception lifestyle intervention on reproductive outcomes documented in the latest systemic review and meta-analysis, together with the most recent RCT performed in 2022 are discussed. The current evidence suggests that greater weight loss and increase in clinical pregnancy, live birth, and natural conception rates after lifestyle intervention compared with no intervention were observed, but it seems no beneficial effect of lifestyle intervention preceding ART was observed on these parameters. With respect to potential harm of lifestyle intervention, there is no significant increased risk of early pregnancy loss, although the most recent RCT (not included in the systematic review and meta-analysis) showed a trend toward an increased risk. Complications during pregnancy, such as early pregnancy loss and maternal as well as fetal and neonatal complications, are underreported in most studies and need further analysis in an individual participant data meta-analysis. Limitations of the studies as well as future perspectives and challenges in this field of research will be highlighted.

Female infertility and diet, is there a role for a personalized nutritional approach in assisted reproductive technologies? A Narrative Review

Female infertility is a major public health concern and a global challenge. It is a disorder of the reproductive system, defined as the inability to achieve a clinical pregnancy. Nutrition and other environmental factors are found to impact reproductive health in women as well as the outcome of assisted reproductive technologies (ART). Dietary factors, such as polyunsaturated fatty acids (PUFA), fiber as well as the intake of Mediterranean diet appear to exert beneficial effects on female reproductive outcomes. The exact mechanisms associating diet to female fertility are yet to be identified, although genomic, epigenomic, and microbial pathways may be implicated. This review aims to summarize the current knowledge on the impact of dietary components on female reproduction and ART outcomes, and to discuss the relevant interplay of diet with genome, epigenome and microbial composition.

Sex-specific effects of maternal dietary carbohydrate quality on fetal development and offspring metabolic phenotype in mice

Objectives

In utero glycemia is an important determinant of fetal growth. Women with gestational diabetes are more likely to deliver large-for-gestational age babies that are at increased risk for obesity. The maternal nutritional state modulates the development of offspring biological systems during the critical periods of gestation and lactation. Carbohydrate typically contributes most of the dietary energy, however, there are very few mechanistic studies investigating the effects of maternal dietary carbohydrate quality on fetal and offspring outcomes. Therefore, we sought to investigate the direct effects of maternal carbohydrate quality on sex-specific offspring metabolic programming.

Methods

Female C57BL/6 mice were fed one of five isocaloric diets: four high-sugar diets based on glucose, sucrose, isomaltulose or fructose (all containing 60% energy as carbohydrate), or a standard, minimally processed, chow diet, and were mated with chow-fed males. Half of the dams were sacrificed for fetus dissection and placental collection, with the remaining giving live birth. All dams were metabolically profiled before and during pregnancy, and pups were similarly profiled at 12 weeks of age.

Results

Overall, glucose-fed dams were heavier and fatter than chow or isomaltulose-fed dams. Female fetuses from glucose and isomaltulose-fed mothers weighed less and had smaller livers, than those from chow-fed mothers, with isomaltulose-fed female fetuses also having decreased placental mass. In contrast, male fetuses responded differently to the maternal diets, with heart mass being significantly increased when their mothers were fed fructose-containing diets, that is, sucrose, isomaltulose and fructose. High-sugar fed female offspring weighed the same, but were significantly fatter, than chow-fed offspring at 12 weeks of age, while glucose and isomaltulose-fed male pups displayed a similar phenotype to their mothers’.

Conclusion

While both glucose and isomaltulose diets constrained fetal growth in females, only placentas from isomaltulose-fed dams were significantly smaller than those from chow-fed mothers, suggesting the mechanisms through which fetal growth is reduced may be different. Female fetuses of isomaltulose-fed mothers were also lighter than sucrose-fed fetuses suggesting the glycemic index, or rate of glucose digestion and absorption, may be an important factor in determining nutrient availability to the growing fetus.

The effectiveness of weight-loss lifestyle interventions for improving fertility in women and men with overweight or obesity and infertility: A systematic review update of evidence from randomized controlled trials

Being overweight or obese can have a negative impact on fertility outcomes. This systematic review updates randomized controlled trial (RCT) findings on the effectiveness of weight loss interventions in reducing weight and improving reproductive outcomes of women and men with overweight or obesity and infertility. Eligible studies, published since the last review, were identified by searching databases from March 20, 2016 until March 31, 2020. RCTs involving any type of lifestyle intervention were considered. Eight RCTs were identified and aggregated with seven RCTs included in our previous review. Meta-analyses revealed that women randomized to a combined diet and exercise intervention were more likely to become pregnant, risk ratio (RR) = 1.87 (95% CI 1.20, 2.93) and achieve a live birth RR = 2.20 (95% CI 1.23, 3.94), compared to women in control groups who received no or minimal intervention. This pattern was not replicated in trials where control groups received immediate access to assisted reproductive technology (ART). No eligible randomized trials involving men were identified. Data were largely obtained from small scale studies. Better designed, adequately powered, robust randomized trials are needed to better understand the effect of weight loss interventions on reproductive outcomes in both women and men.

Dietary Interventions: A Promising Treatment for Polycystic Ovary Syndrome

BACKGROUND

Dietary interventions as a first-line treatment for patients with polycystic ovary syndrome (PCOS) have been evaluated, but the optimal diet has not been determined. Proper diet and the maintenance of adequate nutritional status are of great importance in the prevention of this disorder, and therapeutics and dietary habits play an important role in the recovery of patients with PCOS.

SUMMARY

A range of dietary patterns have been shown to impact weight loss and insulin resistance (IR) and improve reproductive function, including the Mediterranean diet, the ketogenic diet, Dietary Approaches to Stop Hypertension, and other dietary patterns. Key Messages: Diets that can reduce rates of obesity and IR are beneficial to women with PCOS, the status of obesity and IR should be determined at the early stage of the disease, so as to develop individualized and sustainable dietary intervention. The long-term efficacy, safety, and health benefits of diet management in patients with PCOS need to be tested by further researches.

The role of hyperbaric oxygen to platelet aggregation in noninsulin-dependent diabetes mellitus (NIDDM)

OBJECTIVES

Hyperglycemia in diabetes mellitus (DM) could cause rheological disorder, such as platelet aggregation and blood hyperviscosity. Hyperbaric oxygen (HBO) could decrease collagen as platelet aggregation agonist. This study aimed to explore the effect of HBO treatment to platelet aggregation parameters (latency time(LT), aggregation speed, aggregation index, and aggregation percentage) with the collagen aggregator in the noninsulin dependent diabetes mellitus (NIDDM).

METHODS

The number of subjects in this study were 16 for each group normoxia normobaric (NONB) and HBO. NIDDM patients from DM polyclinic in Rumah Sakit Angkatan Laut (RSAL) Dr Ramelan Surabaya which was fulfilled inclusion criteria would receive HBO Therapy. Control Group/NONB were treated with NONB condition (20% O₂ 1 ATA) for 90 min and treatment group/HBO were treated with hyperoxia hyperbaric condition (100% O₂ 2.4 ATA) for 3 × 30 min with interval of 2 × 5 min for inhaling fresh air. Subject has been blood taken for platelet aggregation test before and after HBO Therapy. The length of treatment was 5 days for both condition (NONB and HBO).

RESULTS

The data from both groups, NONB and HBO were tested first by normality test, homogenity test, correlation test, analysis of covariance, and paired t-test. Based on paired t-test, the decrease on platelet aggregation speed, aggregation index, and aggregation percentage after HBO treatment was showed significant difference on the LT and aggregation index while in aggregation speed and aggregation percentage was not significant. NONB group after 5 days was showed a significant difference on the aggregation speed and aggregation index while in LT and aggregation percentage was not significant.

CONCLUSIONS

The utilization of HBO 2.4 ATA 100% O₂ 3 × 30 min, once a day, for 5 days could decrease the platelet aggregation parameters (LT, aggregation speed, aggregation index, and aggregation percentage) in patients with NIDDM.

Preconception lifestyle advice for people with infertility

BACKGROUND

Infertility is a prevalent problem that has significant consequences for individuals, families, and the community. Modifiable lifestyle factors may affect the chance of people with infertility having a baby. However, no guideline is available about what preconception advice should be offered. It is important to determine what preconception advice should be given to people with infertility and to evaluate whether this advice helps them make positive behavioural changes to improve their lifestyle and their chances of conceiving.

OBJECTIVES

To assess the safety and effectiveness of preconception lifestyle advice on fertility outcomes and lifestyle behavioural changes for people with infertility.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, PsycINFO, AMED, CINAHL, trial registers, Google Scholar, and Epistemonikos in January 2021; we checked references and contacted field experts to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), randomised cross-over studies, and cluster-randomised studies that compared at least one form of preconception lifestyle advice with routine care or attention control for people with infertility.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. Primary effectiveness outcomes were live birth and ongoing pregnancy. Primary safety outcomes were adverse events and miscarriage. Secondary outcomes included reported behavioural changes in lifestyle, birth weight, gestational age, clinical pregnancy, time to pregnancy, quality of life, and male factor infertility outcomes. We assessed the overall quality of evidence using GRADE criteria.

MAIN RESULTS

We included in the review seven RCTs involving 2130 participants. Only one RCT included male partners. Three studies compared preconception lifestyle advice on a combination of topics with routine care or attention control. Four studies compared preconception lifestyle advice on one topic (weight, alcohol intake, or smoking) with routine care for women with infertility and specific lifestyle characteristics. The evidence was of low to very low-quality. The main limitations of the included studies were serious risk of bias due to lack of blinding, serious imprecision, and poor reporting of outcome measures. Preconception lifestyle advice on a combination of topics versus routine care or attention control Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.79 to 1.10; 1 RCT, 626 participants), but the quality of evidence was low. No studies reported on adverse events or miscarriage. Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice on a combination of topics affects lifestyle behavioural changes: body mass index (BMI) (mean difference (MD) -1.06 kg/m², 95% CI -2.33 to 0.21; 1 RCT, 180 participants), vegetable intake (MD 12.50 grams/d, 95% CI -8.43 to 33.43; 1 RCT, 264 participants), alcohol abstinence in men (RR 1.08, 95% CI 0.74 to 1.58; 1 RCT, 210 participants), or smoking cessation in men (RR 1.01, 95% CI 0.91 to 1.12; 1 RCT, 212 participants). Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of women with adequate folic acid supplement use (RR 0.98, 95% CI 0.95 to 1.01; 2 RCTs, 850 participants; I² = 4%), alcohol abstinence (RR 1.07, 95% CI 0.99 to 1.17; 1 RCT, 607 participants), and smoking cessation (RR 1.01, 95% CI 0.98 to 1.04; 1 RCT, 606 participants), on low quality evidence. No studies reported on other behavioural changes. Preconception lifestyle advice on weight versus routine care Studies on preconception lifestyle advice on weight were identified only in women with infertility and obesity. Compared to routine care, we are uncertain whether preconception lifestyle advice on weight affects the number of live births (RR 0.94, 95% CI 0.62 to 1.43; 2 RCTs, 707 participants; I² = 68%; very low-quality evidence), adverse events including gestational diabetes (RR 0.78, 95% CI 0.48 to 1.26; 1 RCT, 317 participants; very low-quality evidence), hypertension (RR 1.07, 95% CI 0.66 to 1.75; 1 RCT, 317 participants; very low-quality evidence), or miscarriage (RR 1.50, 95% CI 0.95 to 2.37; 1 RCT, 577 participants; very low-quality evidence). Regarding lifestyle behavioural changes for women with infertility and obesity, preconception lifestyle advice on weight may slightly reduce BMI (MD -1.30 kg/m², 95% CI -1.58 to -1.02; 1 RCT, 574 participants; low-quality evidence). Due to very low-quality evidence, we are uncertain whether preconception lifestyle advice affects the percentage of weight loss, vegetable and fruit intake, alcohol abstinence, or physical activity. No studies reported on other behavioural changes. Preconception lifestyle advice on alcohol intake versus routine care Studies on preconception lifestyle advice on alcohol intake were identified only in at-risk drinking women with infertility. We are uncertain whether preconception lifestyle advice on alcohol intake affects the number of live births (RR 1.15, 95% CI 0.53 to 2.50; 1 RCT, 37 participants; very low-quality evidence) or miscarriages (RR 1.31, 95% CI 0.21 to 8.34; 1 RCT, 37 participants; very low-quality evidence). One study reported on behavioural changes for alcohol consumption but not as defined in the review methods. No studies reported on adverse events or other behavioural changes. Preconception lifestyle advice on smoking versus routine care Studies on preconception lifestyle advice on smoking were identified only in smoking women with infertility. No studies reported on live birth, ongoing pregnancy, adverse events, or miscarriage. One study reported on behavioural changes for smoking but not as defined in the review methods.

AUTHORS' CONCLUSIONS

Low-quality evidence suggests that preconception lifestyle advice on a combination of topics may result in little to no difference in the number of live births. Evidence was insufficient to allow conclusions on the effects of preconception lifestyle advice on adverse events and miscarriage and on safety, as no studies were found that looked at these outcomes, or the studies were of very low quality. This review does not provide clear guidance for clinical practice in this area. However, it does highlight the need for high-quality RCTs to investigate preconception lifestyle advice on a combination of topics and to assess relevant effectiveness and safety outcomes in men and women with infertility.

Effect of Calorie Restriction and Exercise on Type 2 Diabetes

Type-2 diabetes (T2D) is a chronic condition, generally regarded as an irreversible, that is among the top 10 causes of death globally. The hallmark of T2D is hyperglycemia, which results from disturbances in insulin sensitivity, insulin secretion, β-cell dysfunction and insulin resistance. Several clinical and lifestyle factors are involved in the progression of T2D, such as obesity and physical inactivity. A high-calorie diet is the main contributor to the development of obesity, which results in T2D, as obesity or increased intra-abdominal adipose tissue is related to insulin resistance. Technological advances have contributed to individuals having a more sedentary lifestyle, leading to obesity and T2D. T2D can be treated with lifestyle interventions, such as diet and exercise. Herein, we highlight the positive impact of a very low-calorie diet (VLCD) and lifestyle modalities in the treatment and prevention of T2D. An inclusion of VLCD 400-800 kcal/day for 8 weeks and ≥ 150 minutes exercise 5 times a week as lifestyle interventions can decrease glucose levels to normal, reduce HbA1c and improve insulin resistance and sensitivity. Therefore, a potential mechanism in maintaining glucose homeostasis and remission of T2D by VLCD and exercise reduces body weight.

Pharmacological and non-pharmacological strategies for obese women with subfertility

BACKGROUND

Clinicians primarily recommend weight loss for obese women seeking pregnancy. The effectiveness of interventions aimed at weight loss in obese women with subfertility is unclear.

OBJECTIVES

To assess the effectiveness and safety of pharmacological and non-pharmacological strategies compared with each other, placebo, or no treatment for achieving weight loss in obese women with subfertility.

SEARCH METHODS

We searched the CGF Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, and AMED from inception to 18 August 2020. We also checked reference lists and contacted experts in the field for additional relevant papers.

SELECTION CRITERIA

We included published and unpublished randomised controlled trials in which weight loss was the main goal of the intervention. Our primary effectiveness outcomes were live birth or ongoing pregnancy and primary safety outcomes were miscarriage and adverse events. Secondary outcomes included clinical pregnancy, weight change, quality of life, and mental health outcome.

DATA COLLECTION AND ANALYSIS

Review authors followed standard Cochrane methodology.

MAIN RESULTS

This review includes 10 trials. Evidence was of very low to low quality: the main limitations were due to lack of studies and poor reporting of study methods. The main reasons for downgrading evidence were lack of details by which to judge risk of bias (randomisation and allocation concealment), lack of blinding, and imprecision. Non-pharmacological intervention versus no intervention or placebo Evidence is insufficient to determine whether a diet or lifestyle intervention compared to no intervention affects live birth (odds ratio (OR) 0.85, 95% confidence interval (CI) 0.65 to 1.11; 918 women, 3 studies; I² = 78%; low-quality evidence). This suggests that if the chance of live birth following no intervention is assumed to be 43%, the chance following diet or lifestyle changes would be 33% to 46%. We are uncertain if lifestyle change compared with no intervention affects miscarriage rate (OR 1.54, 95% CI 0.99 to 2.39; 917 women, 3 studies; I² = 0%; very low-quality evidence). Evidence is insufficient to determine whether lifestyle change compared with no intervention affects clinical pregnancy (OR 1.06, 95% CI 0.81 to 1.40; 917 women, 3 studies; I² = 73%; low-quality evidence). Lifestyle intervention resulted in a decrease in body mass index (BMI), but data were not pooled due to heterogeneity in effect (mean difference (MD) -3.70, 95% CI -4.10 to -3.30; 305 women, 1 study; low-quality evidence; and MD -1.80, 95% CI -2.67 to -0.93; 43 women, 1 study; very low-quality evidence). Non-pharmacological versus non-pharmacological intervention We are uncertain whether intensive weight loss interventions compared to standard care nutrition counselling affects live birth (OR 11.00, 95% CI 0.43 to 284; 11 women, 1 study; very low-quality evidence), clinical pregnancy (OR 11.00, 95% CI 0.43 to 284; 11 women, 1 study; very low-quality evidence), BMI (MD -3.00, 95% CI -5.37 to -0.63; 11 women, 1 study; very low-quality evidence), weight change (MD -9.00, 95% CI -15.50 to -2.50; 11 women, 1 study; very low-quality evidence), quality of life (MD 0.06, 95% CI -0.03 to 0.15; 11 women, 1 study; very low-quality evidence), or mental health (MD -7.00, 95% CI -13.92 to -0.08; 11 women, 1 study; very low-quality evidence). No study reported on adverse events . Pharmacological versus pharmacological intervention For metformin plus liraglutide compared to metformin we are uncertain of an effect on the adverse events nausea (OR 7.22, 95% CI 0.72 to 72.7; 28 women, 1 study; very low-quality evidence), diarrhoea (OR 0.31, 95% CI 0.01 to 8.3; 28 women, 1 study; very low-quality evidence), and headache (OR 5.80, 95% CI 0.25 to 133; 28 women, 1 study; very low-quality evidence). We are uncertain if a combination of metformin plus liraglutide vs metformin affects BMI (MD 2.1, 95% CI -0.42 to 2.62; 28 women, 1 study; very low-quality evidence) and total body fat (MD -0.50, 95% CI -4.65 to 3.65; 28 women, 1 study; very low-quality evidence). For metformin, clomiphene, and L-carnitine versus metformin, clomiphene, and placebo, we are uncertain of an effect on miscarriage (OR 3.58, 95% CI 0.73 to 17.55; 274 women, 1 study; very low-quality evidence), clinical pregnancy (OR 5.56, 95% CI 2.57 to 12.02; 274 women, 1 study; very low-quality evidence) or BMI (MD -0.3, 95% CI 1.17 to 0.57, 274 women, 1 study, very low-quality evidence). We are uncertain if dexfenfluramine versus placebo affects weight loss in kilograms (MD -0.10, 95% CI -2.77 to 2.57; 21 women, 1 study; very low-quality evidence). No study reported on live birth, quality of life, or mental health outcomes. Pharmacological intervention versus no intervention or placebo We are uncertain if metformin compared with placebo affects live birth (OR 1.57, 95% CI 0.44 to 5.57; 65 women, 1 study; very low-quality evidence). This suggests that if the chance of live birth following placebo is assumed to be 15%, the chance following metformin would be 7% to 50%. We are uncertain if metformin compared with placebo affects gastrointestinal adverse events (OR 0.91, 95% CI 0.32 to 2.57; 65 women, 1 study; very low-quality evidence) or miscarriage (OR 0.50, 95% CI 0.04 to 5.80; 65 women, 1 study; very low-quality evidence) or clinical pregnancy (OR 2.67, 95% CI 0.90 to 7.93; 96 women, 2 studies; I² = 48%; very low-quality evidence). We are also uncertain if diet combined with metformin versus diet and placebo affects BMI (MD -0.30, 95% CI -2.16 to 1.56; 143 women, 1 study; very low-quality evidence) or waist-to-hip ratio (WHR) (MD 2.00, 95% CI -2.21 to 6.21; 143 women, 1 study; very low-quality evidence). Pharmacological versus non-pharmacological intervention No study undertook this comparison.

AUTHORS' CONCLUSIONS

Evidence is insufficient to support the use of pharmacological and non-pharmacological strategies for obese women with subfertility. No data are available for the comparison of pharmacological versus non-pharmacological strategies. We are uncertain whether pharmacological or non-pharmacological strategies effect live birth, ongoing pregnancy, adverse events, clinical pregnancy, quality of life, or mental heath outcomes. However, for obese women with subfertility, a lifestyle intervention may reduce BMI. Future studies should compare a combination of pharmacological and lifestyle interventions for obese women with subfertility.

An optimal glycemic load range is better for reducing obesity and diabetes risk among middle-aged and elderly adults

Background

Due to the lack of evidence, advice pertaining to glycemic load (GL) can be misleading. Does the excessive restriction of GL, mostly through an extreme reduction in carbohydrate intake, result in a relatively high intake of fat and protein and result in overweight and obesity? This study was performed to initially explore the optimal GL range.

Methods

A cross-sectional study involving 2029 participants aged 40 years or older in Guangzhou, China was conducted. Participants were divided into four groups according to cluster analysis. Dietary data were assessed using a previously validated 3-day food record.

Results

Instead of participants with the highest [cluster 1, median (interquartile ranges) GL was 112(107–119)/1000 kcal] and the lowest GL intake [cluster 4, 90(82–96)/1000 kcal], those with moderate GL intakes [clusters 2 and 3, 93(85–102) and 93(85–99)/1000 kcal, respectively] had a lower prevalence of overweight, obesity and diabetes. In addition, clusters 2 and 3 were more consistent with the macronutrient intake reference with adequate micronutrient intake. Therefore, the optimal GL range was determined to be (85–100)/1000 kcal, rather than “lower is better”.

Conclusions

Reducing the GL intake to prevent diabetes deserves more attention in the context of a balanced diet. An appropriate GL may be better than excessive restriction.

Reducing intergenerational obesity and diabetes risk

To address the intergenerational transmission of obesity and diabetes, strategies promoting the health of women of reproductive age appear to be urgently needed. In this narrative review, we summarise what has been learned from many prenatal clinical trials, discuss the emerging evidence from preconception clinical trials and highlight persistent gaps and critical future directions. Most trials tested prenatal interventions that resulted in a limited gestational weight gain of ~1 kg and reduced gestational diabetes by 20-30%. These interventions also reduced macrosomia by 20-40% but had little-to-no impact on other offspring outcomes at birth or beyond. Far fewer trials tested preconception interventions, with almost all designed to improve conception or live-birth rates in overweight or obese women with infertility rather than reduce intergenerational risks in diverse populations. Preconception trials have successfully reduced weight by 3-9 kg and improved markers of glucose homeostasis and insulin resistance by the end of the intervention but whether effects were sustained to conception is unclear. Very few studies have reported offspring outcomes at birth and beyond, with no evidence thus far of beneficial effects on offspring obesity or diabetes risks. Further efforts to develop effective and scalable strategies to reduce risk of obesity and diabetes before conception should be prioritised, especially for diverse and under-resourced populations at disparately high risk of obesity and diabetes. Future clinical trials should include interventions with high potential for dissemination, diverse populations, thorough maternal phenotyping from enrolment through to conception and pregnancy, and rigorous assessment of offspring obesity and diabetes risks from birth onwards, including into the third generation.

Effects of Dietary Glycemic Index and Glycemic Load on Cardiometabolic and Reproductive Profiles in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Women with polycystic ovary syndrome (PCOS) exhibit cardiometabolic (e.g., insulin resistance) and associated reproductive disruptions. Lifestyle modification (e.g., diet) is recommended as the first-line therapy to manage PCOS; however, a favorable dietary regimen remains unclear beyond energy restriction. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to summarize evidence on impacts of dietary glycemic index (GI) or glycemic load (GL) on cardiometabolic and reproductive profiles to update the International Evidence-based Guideline for the Assessment and Management of PCOS. Databases of MEDLINE, Cochrane, Web of Science, and Scopus were searched through 30 October 2019, and confirmed on 25 March 2020, to identify RCTs (≥8 wk) comparing the effects of diets with lower (LGI/LGL) and higher (HGI/HGL) GI/GL on glucoregulatory outcomes, lipid profile, anthropometrics, and androgen status in PCOS. The primary outcome was HOMA-IR. Data were pooled by random-effects models and expressed as weighted mean differences and 95% CIs. The risk of bias was assessed by the Cochrane tool. Ten RCTs (n = 403) were eligible. Eight evaluated LGI and 2 LGL diets. LGI diets decreased HOMA-IR (-0.78; -1.20, -0.37; I2 = 86.6%), fasting insulin (-2.39; -4.78, 0.00 μIU/mL; I2 = 76.8%), total cholesterol (-11.13; -18.23, -4.04 mg/dL; I2 = 0.0%), LDL cholesterol (-6.27; -12.01, -0.53 mg/dL; I2 = 0.0%), triglycerides (-14.85; -28.75, -0.95 mg/dL; I2 = 31.0%), waist circumference (-2.81; -4.40, -1.23 cm; I2 = 53.9%), and total testosterone (-0.21; -0.32, -0.09 nmol/L; I2 = 8.6%) compared with HGI diets (all: P ≤ 0.05) without affecting fasting glucose, HDL cholesterol, weight, or free androgen index (all: P ≥ 0.07). Some results were contradictory and only described narratively for 2 RCTs that evaluated LGL diets, since inclusion in meta-analyses was not possible. LGI diets improved glucoregulatory outcomes (HOMA-IR, insulin), lipid profiles, abdominal adiposity, and androgen status, conceivably supporting their inclusion for dietary management of PCOS. Further RCTs should confirm these observations and address whether LGI diets improve more patient-pressing complications, including ovulatory cyclicity, infertility, and cardiovascular disease risk in this high-risk population. This review was registered at www.crd.york.ac.uk/PROSPERO as CRD42020175300.

Effectiveness of Non-Pharmacological Interventions for Overweight or Obese Infertile Women: A Systematic Review and Meta-Analysis

Obesity is a well-known risk factor for infertility, and nonpharmacological treatments are recommended as effective and safe, but evidence is still lacking on whether nonpharmacological interventions improve fertility in overweight or obese women. The aim of this study was to systematically assess the current evidence in the literature and to evaluate the impact of nonpharmacological interventions on improving pregnancy-related outcomes in overweight or obese infertile women. Seven databases were searched for randomized controlled trials (RCTs) of nonpharmacological interventions for infertile women with overweight or obesity through August 16, 2019 with no language restriction. A meta-analysis was conducted of the primary outcomes. A total of 21 RCTs were selected and systematically reviewed. Compared to the control group, nonpharmacological interventions significantly increased the pregnancy rate (relative risk (RR), 1.37; 95% CI, 1.04–1.81; p = 0.03; I² = 58%; nine RCTs) and the natural conception rate (RR, 2.17, 95% CI, 1.41–3.34; p = 0.0004; I² = 19%, five RCTs). However, they had no significant effect on the live birth rate (RR, 1.36, 95% CI, 0.94–1.95; p=0.10, I² = 65%, eight RCTs) and increased the risk of miscarriage (RR: 1.57, 95% CI, 1.05–2.36; p = 0.03; I² = 0%). Therefore, nonpharmacological interventions could have a positive effect on the pregnancy and natural conception rates, whereas it is unclear whether they improve the live birth rate. Further research is needed to demonstrate the integrated effects of nonpharmacological interventions involving psychological outcomes, as well as pregnancy-related outcomes.

The role of diet in unexpected poor response to ovarian stimulation: a cross-sectional study

RESEARCH QUESTION

Is there an association between diet and poor ovarian response to ovarian stimulation in women with normal biomarkers of ovarian reserve?

DESIGN

Women eligible for IVF at an Academic Fertility Center were invited to participate in this prospective cross-sectional study. The main inclusion criteria were age 18-39 years, body mass index 18-25 kg/m², preserved ovarian reserve (antral follicle count 10-22 or anti-Müllerian hormone concentration 2-5 ng/ml) and a starting dose of gonadotrophins of 150-225 IU/day. Information on diet was obtained using a validated food frequency questionnaire. 'Unexpected poor ovarian response' was defined as the retrieval of three or fewer suitable oocytes. A logistic regression model was used to adjust for confounders.

RESULTS

Out of the 303 women enrolled in the study, 48 (16%) showed an unexpected poor ovarian response. The frequency of poor responders increased with increasing glycaemic load, carbohydrate intake and fibre intake. When comparing the third with the first tertile (reference), the adjusted odds ratios for these were 3.91 (95% confidence interval [CI] 1.11-13.83, P = 0.04), 4.78 (95% CI 1.23-18.51, P = 0.02) and 6.03 (95% CI 1.18-30.77, P = 0.07), respectively.

CONCLUSIONS

Elevated dietary glycaemic load as well as carbohydrate intake and fibre intake is significantly associated with unexpected poor ovarian response. Future interventional studies should clarify whether dietary modification might restore normal response.

C-reactive protein and ART outcomes: a systematic review

BACKGROUND

A dynamic balance between pro- and anti-inflammatory factors contributes to regulating human female reproduction. Chronic low-grade inflammation has been detected in several female reproductive conditions, from anovulation to embryo implantation failure. C-reactive protein (CRP) is a reliable marker of inflammation that is extensively used in clinical practice. Recent studies quantified CRP in the serum of infertile women undergoing ART and suggested its potential for the prediction of ART reproductive outcomes.

OBJECTIVE AND RATIONALE

The first objective of this systematic review of the available literature was to evaluate the association between pre-implantation circulating CRP concentration and pregnancy rates in women undergoing ART. The second objective was to describe serum CRP concentration changes after early embryo implantation. The changes in circulating CRP throughout the ART cycle, clinical implications of CRP quantification for the management of women undergoing ART, and future therapeutic options will also be discussed.

SEARCH METHODS

The MEDLINE database was systematically searched from inception to March 2019 using the following key words: (C-reactive protein) AND (assisted reproductive techniques OR ovulation induction OR insemination OR in vitro fertilization). Only articles in English were considered. Studies were selected based on title and abstract. The full text of potentially relevant articles was retrieved and assessed for inclusion by two reviewers (S.B. and S.H.). The protocol was registered in the International prospective register of systematic reviews (PROSPERO; registration number: CRD148687).

OUTCOMES

In total, 10 studies were included in this systematic review. Most of these studies reported lower circulating CRP values before the window of implantation and higher circulating CRP values during the peri-implantation period in women with successful ART outcome (biochemical or clinical pregnancy) compared to women without a successful outcome. Several lifestyle factors and/or drugs that reduce the concentration of circulating CRP significantly improve ART outcomes. Subgroup analyses according to female BMI and baseline circulating CRP concentration are highly recommended in future analyses.

WIDER IMPLICATIONS

These findings highlight a possible detrimental impact of preconception high circulating CRP concentration on ART outcomes. However, the biochemical or clinical pregnancy rate endpoints used in the studies examined here are insufficient (there were no data on live birth outcome), and the impact of major variables that can influence CRP and/or ART, for example maternal age, BMI, number of transferred embryos, and use of anti-inflammatory drugs, were not considered in the analyses. CRP quantification may be a potential marker of ART outcome, but its predictive value still needs to be investigated in large prospective studies. In future, the quantification of circulating CRP before starting ART could help to identify patients with a poor ART prognosis, leading to ART cycle cancellation or to preconception treatment to minimize the medical risks and costs.

Dietary Carbohydrate Intake, Dietary Glycemic Load and Outcomes of In Vitro Fertilization: Findings from an Observational Italian Cohort Study

In recent decades, increasing attention has been paid to the influence of diet on reproductive health. Carbohydrates in diet affect glucose metabolism and multiple evidences showed the key role of insulin sensitivity in regulating female fertility. We designed a prospective cohort study to investigate the relation between dietary carbohydrate intake, glycemic load (GL) and the outcomes of assisted reproduction. A population of 494 female partners of couples referring to an Italian Fertility Center and eligible for in vitro fertilization (IVF) were enrolled in the study. On the day of the oocyte retrieval, information on their diet was obtained using a validated food frequency questionnaire (FFQ). We calculated the relative risk and 95% confidence interval of embryo transfer, clinical pregnancy and live birth according to the following dietary exposures: GL, glycemic index (GI) as well as the daily carbohydrate and fiber intake. A multiple regression model was used to account for the confounders. After adjusting for age, college degree, body mass index (BMI), leisure physical activity and previous assisted reproduction techniques (ART) cycles, no significant association was observed between the considered dietary exposures and the IVF outcomes. The roles of GL, carbohydrate intake and GI were assessed in strata of the cause of infertility and body mass index and no relation emerged in this further analysis. We found no clear association between the dietary carbohydrate quantity and quality and IVF outcomes in a cohort of infertile Italian women.

The Effect of Lifestyle Intervention on Pregnancy and Birth Outcomes on Obese Infertile Women: A Systematic Review and Meta-Analysis

Obesity has been associated with negative effects on natural fertility and poor prognosis when assisted reproductive technologies (ART) are performed. Patients attending for fertility treatments are often advised to optimize their weights to improve the outcomes. There is lack of enough information on how weight-loss would be effective for improving fertility in women who are overweight or obese. We conducted a systematic review to evaluate whether weight-loss achieved by lifestyle program improves natural or assisted reproduction in obese infertile women. We searched CENTRAL, MEDLINE, and EMBASE up to March 2018. Two reviews were selected as randomised trials assessing a lifestyle intervention in women with obesity before receiving treatments for infertility and appraised their risk of bias. We extracted data on pregnancy, birth, and miscarriage rates as the primary outcomes and pooled effect estimates using a random effects model. The primary outcome was the live birth rate. We reported summary measures as the relative risk (RR), 95% confidence interval (CI), and percentage of heterogeneity (I2). We included eight randomised trials with 1175 women. Lifestyle programmes, improved pregnancy rates (RR: 1.43, CI: 95% 1.02 to 2.01; I2=60%; 8 RCTs; N=1098) but had no impact on live births (RR: 1.39, CI: 95% 0.90 to 2.14; I2=64%; 7RCTs; N=1034). Our findings suggest that women participating in lifestyle interventions had an increased risk of miscarriage (RR: 1.50, CI: 95% 1.04 to 2.16; I2=0; 6RCTs; N=543). We rated the quality of evidence for these outcomes as the moderate-to-low. Lifestyle interventions slightly increased the pregnancy rate, while it would be uncertain whether it can improve the live birth. Lifestyle interventions can increase the risk of miscarriage. More research is needed to further explore lifestyle interventions on reproductive outcomes in obese infertile women.

Moderate Weight Loss Modifies Leptin and Ghrelin Synthesis Rhythms but Not the Subjective Sensations of Appetite in Obesity Patients

Obesity is characterized by a resistance to appetite-regulating hormones, leading to a misalignment between the physiological signals and the perceived hunger/satiety signal. A disruption of the synthesis rhythm may explain this situation. The aim of this study was to evaluate the effect of dietary-induced weight loss on the daily rhythms of leptin and ghrelin and its influence on the daily variability of the appetite sensations of patients with obesity. Twenty subjects with obesity underwent a hypocaloric dietary intervention for 12 weeks. Plasma leptin and ghrelin were analyzed at baseline and at the end of the intervention and in 13 normal-weight controls. Appetite ratings were analyzed. Weight loss decreased leptin synthesis (pauc < 0.001) but not the rhythm characteristics, except the mean variability value (pmesor = 0.020). By contrast, the mean ghrelin level increased after weight loss. The rhythm characteristics were also modified until a rhythm similar to the normal-weight subjects was reached. The amount of variability of leptin and ghrelin was correlated with the effectiveness of the dietary intervention (p < 0.020 and p < 0.001, respectively). Losing weight partially restores the daily rhythms of leptin and modifies the ghrelin rhythms, but appetite sensations are barely modified, thus confirming that these hormones cannot exercise their physiological function properly.

The Impact of Traditional Medicine-Based Lifestyle and Diet on Infertility Treatment in Women Undergoing Assisted Reproduction: A Randomized Controlled Trial

The problem of infertility is growing rapidly in the world. Traditional medicine with thousands of years of history has claimed that it can treat some kinds of infertility using nutritional and lifestyle modifications and interventions. The purpose of this study was to evaluate the effect of a traditional medicine-oriented diet and lifestyle on infertility treatment. Based on a clinical trial study, 180 infertile women who were 20-40 years old and candidates for in vitro fertilization (IVF) were randomly assigned to 2 groups: an intervention group and a control group. The intervention group used diet and lifestyle recommendations based on Iranian traditional medicine for at least 3 months. The number of ova, mature ovum number, embryo number, embryo quality, and fertilization rate were significantly higher in the intervention group than in the control group (for all items; p < 0.05). Overall pregnancy rate was significantly higher in the intervention group (35.2 vs. 12.4%; odds ratio [OR], 3.8; 95% CI, 1.8-8.3). The intervention group had a higher rate of getting spontaneous pregnancy than the control group (20.9 vs. 2.2%; OR, 11.5; 95% CI, 2.6-50.9). Chemical pregnancy was significantly higher in the intervention group (64 vs. 27.5%; OR, 4.7; 95% CI, 1.9-11.6). Diet and lifestyle modifications based on traditional medicine can contribute greatly to the infertility treatment. Thus, many infertility cases can be treated without the need to use advanced methods. In case of using assisted reproductive techniques, traditional medicine can enhance the efficiency of these methods.

Cumulative live birth rates after weight reduction in obese women scheduled for IVF: follow-up of a randomized controlled trial

STUDY QUESTION

Did weight reduction in obese women scheduled for IVF increase cumulative live birth rate (CLBR) after 2 years?

SUMMARY ANSWER

Weight loss prior to IVF did not increase CLBR.

WHAT IS KNOWN ALREADY

Few studies have investigated the effect of weight reduction in obese infertile women scheduled for IVF. In a recent randomized controlled trial (RCT), including one IVF cycle, we found no increase in live birth rate after weight reduction. Weight regain after obesity reduction treatment often occurs, and children born to obese women have a higher risk of childhood obesity.

STUDY DESIGN, SIZE, DURATION

A 2-year follow-up of a multicenter, RCT running between 2012 and 2018 was performed. Out of 317 women randomized to weight reduction followed by IVF treatment or IVF treatment-only, 305 remained in the full analysis set. Of these women, 90.5% (276/305) participated in this study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Nine infertility clinics in Sweden, Denmark and Iceland participated in the RCT. Obese women under 38 years of age having a BMI ≥30 and < 35 kg/m² were randomized to weight reduction and IVF or IVF-only. In all, 160 patients were randomized to a low calorie diet for 12 weeks and 3–5 weeks of weight stabilization, before IVF and 157 patients to IVF-only. Two years after randomization, the patients filled in a questionnaire regarding current weight, live births and ongoing pregnancies.

MAIN RESULTS AND THE ROLE OF CHANCE

42 additional live births were achieved during the follow-up in the weight reduction and IVF group, and 40 additional live births in the IVF-only group, giving a CLBR, the main outcome of this study, of 57.2% (87/152) and 53.6% (82/153), respectively (P = 0.56; odds ratio (OR) 1.16, 95% CI: 0.74–1.52). Most of the women in the weight reduction and IVF group had regained their pre-study weight after 2 years. The mean weight gain over the 2 years was 8.6 kg, while women in the IVF-only group had a mean weight loss of 1.2 kg. At the 2-year follow-up, the weight standard deviation scores of the children born in the original RCT (index cycle) were 0.218 (1.329) (mean, SD) in the weight reduction and IVF group and − 0.055 (1.271) (mean, SD) in the IVF-only group (P = 0.25; mean difference between groups, 0.327; 95% CI: −0.272 to 0.932).

LIMITATIONS, REASON FOR CAUTION

All data presented in this follow-up study were self-reported by the participants, which could affect the results. A further limitation is in power for the main outcome. The study is a secondary analysis of a large RCT, where the original power calculation was based on live-birth rate after one cycle and not on CLBR.

WIDER IMPLICATIONS OF THE FINDINGS

The follow-up indicates that for women with a BMI ≥30 and < 35 kg/m² and scheduled for IVF, the weight reduction did not increase their chance of a live birth either in the index cycle or after 2 years. It also shows that even in this highly motivated group, a regain of pre-study weight occurred.

STUDY FUNDING/COMPETING INTEREST(S)

The 2-year follow-up was financed by grants from the Swedish state under the agreement between the Swedish Government and the county councils, the ALF-agreement (ALFGBG-70940 and ALFGBG-77690), Merck AB, Solna, Sweden (an affiliate of Merck KGaA, Darmstadt, Germany), Hjalmar Svensson Foundation. Ms Kluge has nothing to disclose. Dr Bergh has been reimbursed for lectures and other informational activities (Ferring, MSD, Merck, Gedeon Richter). Dr Einarsson has been reimbursed for lectures for Merck and Ferring. Dr Thurin-Kjellberg reports grants from Merck, and reimbursement for lectures from Merck outside the submitted work. Dr Pinborg has been reimbursed for lectures and other informational activities (Ferring, MSD, Merck, Gedeon Richter). Dr Englund has nothing to disclose.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov number, NCT01566929.

The Effects of Overweight and Obesity on Assisted Reproduction Technology Outcomes

The aim of the present study was to assess the impact of professional nutrition assistance on assisted reproduction technology (ART) outcomes in overweight or obese patients with polycystic ovarian syndrome (PCOS). The study represents a retrospective analysis of fertilization rates, embryo quality and gestations after ART in seven PCOS patients, five obese and two overweight. The women attended a private Fertility Center in Brazil between the years 2010 and 2016. Out of the seven patients, the three that reached a successful gestation were the ones that underwent comprehensive lifestyle changes, taking care of their diet for a more prolonged period of time and reached an ideal weight loss during the nutrition counseling period.

Preconception management of women with obesity: A systematic review

The prevalence of women of child-bearing age with obesity continues to rise at an alarming rate. This has significant implications for both the short-term and long-term health of mother and offspring. Given the paucity of evidence-based literature in this field, the preconception management of women with obesity is highly variable both between institutions and around the world. This systematic review aims to evaluate studies that inform us about the role of preconception weight loss in the fertility and pregnancy outcomes of women with obesity. Current therapeutic interventions are discussed, with a specific focus on the suitability of weight loss interventions for women with obesity planning pregnancy. There are significant knowledge gaps in the current literature; these are discussed and areas for future research are explored.

Female infertility: which role for obesity?

Obesity is associated with infertility in women through multiple and complex mechanisms. Briefly, the adipose tissue through the production of many factors, such as leptin, free fatty acids (FFA), and cytokines may affect both ovarian and endometrium functions, with a final alteration in oocyte maturation and endometrial epithelium receptivity. In addition, through the development of peripheral insulin resistance obesity produces a condition of functional hyperandrogenism and hyperestrogenism that contribute to produce anovulation and to reduce endometrial receptivity and, therefore participate to cause infertility. Weight loss is able to restore fertility in most cases, but there are no practical indications to guide the clinician to choice the best method among increased physical activity, diet, drugs, and bariatric surgery.

Low glycaemic index diets as an intervention for obesity: a systematic review and meta-analysis

OBJECTIVES

Low glycaemic index (GI) diets may aid in weight loss by reducing postprandial blood glucose excursions, leading to more stable blood glucose concentrations and therefore a reduction in hunger. To test this hypothesis, we conducted a systematic review and meta-analysis of randomized controlled trials comparing low GI diets with other diet types.

METHODS

We included 101 studies involving 109 study arms and 8,527 participants. We meta-analysed the studies using a random-effects model and conducted subgroup analyses and meta-regression based on control diet, blood glucose control, baseline BMI and dietary GI.

RESULTS

Low GI diets resulted in small but significant improvements in body weight, BMI, LDL and total cholesterol overall, although no individual control diet was significantly different from low GI diets. Studies in people with normal blood glucose who achieved a difference in GI of 20 points or more resulted in a larger reduction in body weight (SMD = -0.26; 95% CIs [-0.43, -0.09]), and total cholesterol (SMD = -0.24; 95% CIs [-0.42, -0.05]) than studies that only achieved a smaller reduction in GI.

CONCLUSIONS

Low GI diets, especially diets achieving a substantial decrease in GI, were moderately effective in lowering body weight. However, efforts should be made to increase compliance with low GI diets, in order for them to be effective in people with overweight and obesity.

Glycaemic Index of Maternal Dietary Carbohydrate Differentially Alters Fto and Lep Expression in Offspring in C57BL/6 Mice

Maternal diet and gestational hyperglycaemia have implications for offspring health. Leptin (LEP) and fat mass and obesity-associated (FTO) alleles are known to influence body fat mass in humans, potentially via effects on appetite. We hypothesized that expression of Fto, Lep, and other appetite-related genes (Argp, Npy, Pomc, Cart, Lepr) in the offspring of female mice are influenced by the glycaemic index (GI) of carbohydrates in the maternal diet. C57BL/6 mice were randomly assigned to low or high GI diets and mated with chow-fed males at eight weeks of age. Male pups were weaned at four weeks and randomly divided into two groups, one group following their mother's diet (LL and HH), and one following the standard chow diet (LC and HC) to 20 weeks. Fto expression was 3.8-fold higher in the placenta of mothers fed the high GI diet (p = 0.0001) and 2.5-fold higher in the hypothalamus of 20-week old offspring fed the high GI (HH vs. LL, p < 0.0001). By contrast, leptin gene (Lep) expression in visceral adipose tissue was 4.4-fold higher in four-week old offspring of low GI mothers (LC vs. HC, p < 0.0001) and 3.3-fold higher in visceral adipose tissue of 20-week old animals (LL vs. HH, p < 0.0001). Plasma ghrelin and leptin levels, and hypothalamic appetite genes were also differentially regulated by maternal and offspring diet. These findings provide the first evidence in an animal model that maternal high GI dietary carbohydrates that are digested and absorbed faster may contribute to programming of appetite in offspring.

A study of ghrelin and leptin levels and their relationship to metabolic profiles in obese and lean Saudi women with polycystic ovary syndrome (PCOS)

BACKGROUND

Polycystic ovary syndrome (PCOS) is considered as one of the most frequently encountered hormonal pathologies in women during their reproductive years. Leptin and ghrelin, peptide hormones with adipostatic and orexigenic effect, respectively, seem to be involved in the metabolic changes that occur in PCOS. The aim of this study was to determine serum ghrelin and leptin levels in obese and lean Saudi women with PCOS and to investigate their relationship to the metabolic profiles in these women.

METHODS

This study was conducted as a prospective, observational, cross-sectional, case-control study, at the Department of Obstetrics and Gynecology, Al-Noor Hospital, Makkah, Kingdom of Saudi Arabia. The study population included 252 women [130 women with PCOS (diagnosed according to the Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus, 2003) and 122 normo-ovulatory women as matched controls] attending the outpatient Gynecology Clinic. Demographic details were recorded, blood was extracted following overnight fast and serum was used for the determination of serum ghrelin and leptin levels and other hormonal and biochemical parameters including total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, glucose, and insulin. Insulin resistance and sensitivity were calculated as HOMA-IR and HOMA-S.

RESULTS

No significant differences in ghrelin (P = 0.1830) and leptin (P = 0.8329) levels were detected between the PCOS and control groups. However, ghrelin levels were significantly lower; and leptin levels were significantly higher in obese PCOS patients in comparison with lean patients (P = 0.0001 for both). In the PCOS group, there were significant correlations between ghrelin and leptin levels with Body Mass Index (BMI), waist-hip ratio, total cholesterol, triglycerides, HDL, LDL and insulin levels. Multiple regression analysis demonstrated that insulin was the main determinant for ghrelin (R2 = 0.316) and leptin (R2 = 0.352) levels (P = 0.0001 for both).

CONCLUSIONS

Although serum ghrelin and leptin levels were found to be normal in women with PCOS; yet, there is a relationship, possibly linked to obesity, hyperinsulinemia and insulin resistance between these levels and metabolic profile of Saudi PCOS.

Systematic review and meta-analysis of the impact of preconception lifestyle interventions on fertility, obstetric, fetal, anthropometric and metabolic outcomes in men and women

STUDY QUESTION

What is the impact of preconception lifestyle interventions on live birth, birth weight and pregnancy rate?

SUMMARY ANSWER

Lifestyle interventions showed benefits for weight loss and increased natural pregnancy rate, but not for live birth or birth weight.

WHAT IS KNOWN ALREADY

Evidence on the practice and content of preconception counseling and interventions is variable and limited.

STUDY DESIGN, SIZE, DURATION

Systematic review and meta-analysis (MA). Main search terms were those related to preconception lifestyle. Database searched were Ovid MEDLINE(R), EBM Reviews, PsycINFO, EMBASE and CINAHL Plus. No language restriction was placed on the published articles. The final search was performed on 10 January 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were non-pregnant women of childbearing age intent on conceiving or their male partners. Exclusion criteria include participants with BMI < 18 kg/m2, animal trials, hereditary disorder in one or both partners and trials focusing solely on alcohol or smoking cessation/reduction, micronutrient supplementation, or diabetes control. Anthropometric, fertility, obstetric and fetal outcomes were assessed. Bias and quality assessments were performed.

MAIN RESULTS AND THE ROLE OF CHANCE

The search returned 1802 articles and eight studies were included for analysis. Populations targeted were primarily overweight or obese subfertile women seeking reproductive assistance, with few community-based studies and none including men. MA showed greater reduction in weight (n = 3, P < 0.00001, mean difference: -3.48 kg, 95% CI: -4.29, -2.67, I2 = 0%) and BMI (n = 2, P < 0.00001, mean difference: -1.40 kg/m2, 95% CI: -1.95, -0.84, I2 = 24%) with intervention. The only significant fertility outcome was an increased natural pregnancy rate (n = 2, P = 0.003, odds ratio: 1.87, CI: 1.24, 2.81, I2 = 0%). No differences were observed for ART adverse events, clinical pregnancy, pregnancy complications, delivery complications, live birth, premature birth, birth weight, neonatal mortality or anxiety. Risk of bias were high for three studies, moderate for three studies and low for two studies, Attrition bias was moderate or high in majority of studies.

LIMITATIONS, REASONS FOR CAUTION

Results were limited to subfertile or infertile women who were overweight or obese undergoing ART with no studies in men. The heterogeneous nature of the interventions in terms of duration and regimen means no conclusions could be made regarding the method or components of optimal lifestyle intervention. Attrition bias itself is an important factor that could affect efficacy of interventions.

WIDER IMPLICATIONS OF THE FINDINGS

Existing preconception lifestyle interventions primarily targeted overweight and obese subfertile women undergoing ART with a focus on weight loss. It is important to note that natural conception increased with lifestyle intervention. This emphasizes the need for further research exploring optimal components of preconception lifestyle interventions in the broader population and on the optimal nature, intensity and timing of interventions.

STUDY FUNDING/COMPETING INTEREST(S)

No conflict of interest declared. C.L.H. is a National Heart Foundation Postdoctoral Research Fellow. B.H. is funded by an Alfred Deakin Postdoctoral Research Fellowship. H.J.T. and B.W.M. hold NHMRC Practitioner fellowships. L.J.M. is supported by a SACVRDP Fellowship; a program collaboratively funded by the NHF, the South Australian Department of Health and the South Australian Health and Medical Research Institute.

PROSPERO REGISTRATION NUMBER

CRD42015023952.

A greater glycemic load reduction was associated with a lower diabetes risk in pre-diabetic patients who consume a high glycemic load diet

Few prospective studies evaluating the association between dietary glycemic load (GL) and diabetes have accounted for changes in GL. However, the diet of patients could be modified in response to an awareness of pre-diabetes. The aim of this study was to examine the longitudinal associations between changes in GL and the incidence of diabetes among pre-diabetic patients. We hypothesized that subjects with low and high baseline GL would show different correlations with diabetes. A total of 493 pre-diabetic patients (142 men and 351 women) between 40 and 79 years of age were included in this study. Dietary records and oral glucose tolerance tests were conducted every year. The participants were divided into low- and high-GL groups based on baseline GL. During a median 4 years of follow-up, 108 incident cases of diabetes were identified. Among participants with a high baseline GL, the incidence of diabetes increased with decreasing GL reduction, and the multivariate-adjusted HR (95% CI) was 2.34 (1.27-4.29) when comparing the lowest to the highest tertiles; however, among those with a low baseline GL, no significant association was observed. Regardless of baseline GL status, the incidence of diabetes was higher in individuals with a high follow-up GL than in those with a low follow-up GL, and the multivariate-adjusted HR (95% CI) was 1.64 (1.09-2.45). In conclusion, a greater GL reduction was associated with a lower diabetes risk in pre-diabetic patients with a high dietary GL. In patients with pre-diabetes and a low dietary GL, further reductions in GL did not show any additional effects.

The effect of dietary glycemic index and glycemic load on inflammatory biomarkers: a systematic review and meta-analysis of randomized clinical trials

Background

To our knowledge, there is no study available that summarizes earlier findings on the effect of dietary glycemic index (GI) and glycemic load (GL) on inflammatory biomarkers.

Objective

This systematic review and meta-analysis was conducted to systematically review the available clinical trials that examined the effects of low-GI (LGI) and low-GL (LGL) diets on several inflammatory biomarkers in adults.

Design

We searched for relevant articles published up to June 2017 through PubMed, Medline, SCOPUS, EMBASE, and Google Scholar with the use of relevant keywords. Clinical trials that examined the effect of dietary GI and GL on inflammation in adults were included.

Results

Overall, 28 randomized controlled trials (RCTs) including 2961 participants (59% women, 41% men) were included in this meta-analysis. By combining findings from 14 studies on high-sensitivity C-reactive protein (hs-CRP) concentrations, we found no significant effect of LGI or LGL diets on serum hs-CRP concentrations compared with the control diet [weighted mean difference (WMD) for dietary GI: -0.05 mg/L (95% CI: -0.21, 0.10 mg/L); and WMD for dietary GL: 0.08 mg/L (95% CI: -0.26, 0.42 mg/L), respectively]. After combining effect sizes from 5 studies, we did not find significant changes in serum tumor necrosis factor α (TNF-α) concentrations comparing control diets with LGI (WMD: -0.18 mg/L; 95% CI: -0.43, 0.06 mg/L) or LGL (WMD: -0.20 mg/L; 95% CI: -0.33, 0.07 mg/L) diets. Significant changes were also not seen in leptin and interleukin 6 (IL-6) concentrations after the consumption of LGI or LGL diets.

Conclusions

We did not find any significant effect of dietary GI or GL on serum concentrations of inflammatory cytokines, including hs-CRP, leptin, IL-6, and TNF-α in adults. Additional RCTs-in particular, feeding trials-are required to shed light on this issue.

Association between Dietary Glycemic Index and Knee Osteoarthritis: The Korean National Health and Nutrition Examination Survey 2010-2012

BACKGROUND

Obesity and metabolic abnormalities are important risk factors for knee osteoarthritis (KOA). Recent epidemiologic studies have found that a high glycemic index (GI) and glycemic load (GL) diet are associated with a higher risk for metabolic complications and cardiovascular mortality.

OBJECTIVE

We aimed to examine the association between dietary GI, dietary GL, and KOA among Korean adults.

DESIGN

This was a cross-sectional study that analyzed data obtained from the Korean National Health and Nutrition Examination Survey 2010-2012.

PARTICIPANTS/SETTING

A total of 9,203 participants (5,275 women) aged ≥50 years were included.

MAIN OUTCOME MEASURES

KOA was defined as the presence of radiographic features of Kellgren-Lawrence grade ≥2. Chronic knee pain was defined as the presence of knee pain for more than 30 days during the past 3 months. Dietary information was collected using a single 24-hour recall method.

STATISTICAL ANALYSES PERFORMED

The association between the quintiles of dietary GI and dietary GL and knee conditions was analyzed using a multinomial logistic regression analysis adjusting for age, physical activity, obesity, hypertension and diabetes, serum low-density lipoprotein, and total energy intake.

RESULTS

Among the women, the association between dietary GI and symptomatic KOA was: quintile 1: 1.00 (reference); quintile 2: 1.29 (95% CI 0.87 to 1.92); quintile 3: 1.59 (95% CI 1.11 to 2.28); quintile 4: 1.74 (95% CI 1.21 to 2.51); and quintile 5: 1.77 (95% CI 1.20 to 2.60) (P=0.001). Chronic knee pain without KOA was associated with dietary GI; however, this association was not linear across quintiles. There was no significant association between dietary GI and asymptomatic KOA. Among the men, no significant association was found between dietary GI and any knee conditions. There was no significant association between dietary GL and KOA in both men and women.

CONCLUSIONS

There was a significant positive association between dietary GI and symptomatic KOA in women.

Weight Loss and Appetite Control in Women

PURPOSE OF REVIEW

The aim of this review is to describe and discuss weight loss-induced variations in appetite in women and factors responsible for these changes.

RECENT FINDINGS

Studies have shown postweight loss increases in fasting and postprandial appetite in individuals engaged in weight loss trials, especially in women. Similarly, appetite-related peptides associated to the homeostatic control of feeding, such as leptin, ghrelin and peptide YY, were also found to be altered in way that promotes increased appetite after weight loss interventions. Sustained caloric deficits also drive increases in the frequency and strength of food cravings, food reward and seem to enhance oro-sensory sensations in women who lost weight. The menstrual cycle has also been to shown to influence caloric intake in women, more specifically food cravings. On the other hand, caloric restriction seems to increase cognitive restraint, decrease habitual disinhibition and susceptibility to hunger among women engaged in weight loss trials. Neural analysis corroborates these results, showing increased activation in brain areas involved in food reward and self-control processing. In conclusion, evidence supports that weight loss increases appetite sensations, and promotes changes in homeostatic and non-homeostatic control of feeding, which collectively seem to upregulate appetite in women.

Nutritional approaches for managing obesity-associated metabolic diseases

Obesity is an ongoing pandemic and serves as a causal factor of a wide spectrum of metabolic diseases including diabetes, fatty liver disease, and cardiovascular disease. Much evidence has demonstrated that nutrient overload/overnutrition initiates or exacerbates inflammatory responses in tissues/organs involved in the regulation of systemic metabolic homeostasis. This obesity-associated inflammation is usually at a low-grade and viewed as metabolic inflammation. When it exists continuously, inflammation inappropriately alters metabolic pathways and impairs insulin signaling cascades in peripheral tissues/organs such as adipose tissue, the liver and skeletal muscles, resulting in local fat deposition and insulin resistance and systemic metabolic dysregulation. In addition, inflammatory mediators, e.g., proinflammatory cytokines, and excessive nutrients, e.g., glucose and fatty acids, act together to aggravate local insulin resistance and form a vicious cycle to further disturb the local metabolic pathways and exacerbate systemic metabolic dysregulation. Owing to the critical role of nutrient metabolism in controlling the initiation and progression of inflammation and insulin resistance, nutritional approaches have been implicated as effective tools for managing obesity and obesity-associated metabolic diseases. Based on the mounting evidence generated from both basic and clinical research, nutritional approaches are commonly used for suppressing inflammation, improving insulin sensitivity, and/or decreasing fat deposition. Consequently, the combined effects are responsible for improvement of systemic insulin sensitivity and metabolic homeostasis.

Waist-hip Ratio (WHR), a Better Predictor for Prostate Cancer than Body Mass Index (BMI): Results from a Chinese Hospital-based Biopsy Cohort

To investigate whether waist-hip ratio (WHR) is a better predictor of prostate cancer (PCa) incidence than body mass index (BMI) in Chinese men. Of consecutive patients who underwent prostate biopsies in one tertiary center between 2013 and 2015, we examined data on 1018 with PSA ≤20 ng/ml. Clinical data and biopsy outcomes were collected. Logistic regression was used to evaluate the associations between BMI, WHR and PCa incidence. Area under the ROC (AUC) was used to evaluate the accuracy of different prognostic models. A total of 255 men and 103 men were diagnosed with PCa and high grade PCa (HGPCa, Gleason score ≥8). WHR was an independent risk factor for both PCa (OR = 1.07 95%Cl 1.03-1.11) and HGPCa (OR = 1.14 95%Cl 1.09-1.19) detection, while BMI had no relationship with either PCa or HGPCa detection. Adding WHR to a multivariable model increased the AUC for detecting HGPCa from 0.66 (95%Cl 0.60-0.72) to 0.71 (95%Cl 0.65-0.76). In this Chinese cohort, WHR was significantly predictive of PCa and HGPCa. Adding WHR to a multivariable model increased the diagnostic accuracy for detecting HGPCa. If confirmed, including WHR measurement may improve PCa and HGPCa detection.