Does a MediDiet with additional extra virgin olive oil (EVOO) and pistachios reduce the incidence of gestational diabetes?

Effect of olive oil consumption on diabetes risk: a dose-response meta-analysis

BACKGROUND

Diabetes is a common metabolic disease worldwide, is also a global major public health problem. We carried out this meta-analysis to evaluate the effects of olive oil(OO) consumption on diabetes.

METHODS

PubMed, Embase, Scopus, Web of Science and Cochrane Library databases were systematically searched until October 2024. Heterogeneity among studies was examined using Q and I2 statistics. Combined risk ratio (RR) with their 95% confidence interval (CI) were calculated by using a random effects model. Also dose-response analysis and subgroup analysis were performed.

RESULTS

10 studies (4 cohorts and 6 RCT) involved more than 50,0000 subjects and 2,0000 individuals with diabetes were included in the meta-analysis. A 13% (RR = 0.87, 95%CI = 0.83 - 0.92, P < 0.01) decreased risk of diabetes was shown in Cohort study and 22% (RR = 0.78, 95%CI = 0.70 - 0.88, P < 0.01) decreased risk in RCT study for the highest vs. lowest olive oil consumption. Subgroup analysis results showed that there was a better effect on reducing diabetes risk in age > 50 years(RR = 0.77, 95%CI = 0.70 - 0.89, P < 0.01), Europe(RR = 0.81, 95%CI = 0.72 - 0.86, P < 0.01) and extra virgin olive oil ( RR = 0.75, 95%CI = 0.65-0.87, P < 0.01). Dose-response analysis showed a significant nonlinear association of diabetes risk with OO intake(Pnon-linearity < 0.05) and when 10-20 g of olive oil is consumed daily, the effect amount is statistically significant, while more than 20 g there was not statistically significant. Begg's and Egger's regression test results indicated that there was no publication bias and the results were reliable.

CONCLUSIONS

Evidence from this meta-analysis suggested that OO consumption is associated with a decreased risk of diabetes, especially, 10-20 g OO daily may be beneficial for prevention and management of diabetes.

Effective dietary interventions during pregnancy: a systematic review and meta-analysis of behavior change techniques to promote healthy eating

Improving dietary intake during pregnancy can mitigate adverse consequences for women and their children. The effective techniques and features for supporting and sustaining dietary change during pregnancy and postpartum are minimally reported. The primary aims of this systematic review and meta-analysis were to summarise the effectiveness of dietary interventions for pregnant woman, identify which behaviour change techniques (BCTs) and intervention features were most frequently used and determine which were most effective at improving dietary intake. Six databases were searched to identify randomised control trials (RCTs) reporting on dietary intake in pregnant women over the age of sixteen, with an active intervention group compared to a control group receiving usual care or less intensive interventions. The Cochrane Risk of Bias Tool 1 was used to assess study validity. BCTs were coded by two authors using Michie et al.'s BCT taxonomy V1. A random effect model assessed intervention effects on indices of dietary quality and food groups (fruit, vegetables, grains and cereals, meat, and dairy) in relation to the use of BCTs and intervention features. Thirty- seven RCTs met the inclusion criteria. High heterogeneity was observed across intervention characteristics and measures of fidelity. Only half of the available BCTs were used, with eleven used once. The BCT category Reward and threat was successful in improving dietary quality and vegetable intake, whilst 'Action planning' (1.4) from the category Goals and planning significantly improved dietary quality. Interventions delivered by a nutrition professional and those that included group sessions improved dietary quality more than those delivered by other health professionals, research staff, or application-delivered interventions and delivered via other modalities. Future dietary interventions during pregnancy should incorporate and report on BCTs used in the intervention. Successful design elements for improving antenatal dietary intake may include multimodal interventions delivered by nutrition professionals and the use of Rewards and Goal setting.

Association Between the EAT-Lancet Reference Diet and Gestational Diabetes Mellitus: A Mini-Review

Gestational diabetes mellitus (GDM) is a prevalent pregnancy complication that seriously endangers maternal and infant health, posing a medical and economic burden worldwide. Several dietary patterns have been recommended for women of childbearing age, demonstrating a positive role in preventing and managing GDM. However, these dietary patterns may not fully take environmental factors into account when addressing global food sustainability and planetary health. In this context, the EAT-Lancet Commission proposed a diet in 2019 aimed at both health improvement and environmental sustainability, which can potentially reduce the prevalence of diet-related diseases. Nevertheless, the role of the EAT-Lancet reference diet in preventing and managing GDM has not been fully evaluated. Therefore, we conducted a literature search to assess the existing evidence for the association between the EAT-Lancet reference diet components and GDM. Based on the current evidence available in the PubMed database from inception to 31 October 2024, women of childbearing age are recommended to consume whole grains, fish, soy products, olive oil, full-fat dairy products, nuts, and moderate amounts of fruits while reducing red meat and sugar-sweetened beverage intake to lower the risk of GDM. There remains inconsistency regarding the association between tubers or starchy vegetables, vegetables, eggs, and poultry and the risk of GDM. In conclusion, current research on the association between diet and GDM is limited and offers suggestions for methodologies to obtain robust evidence regarding the association between the EAT-Lancet reference diet and GDM.

Introduction of the Mediterranean diet in pregnancy and the incidence of gestational diabetes mellitus: A systematic review of randomised controlled trials and meta-analysis

OBJECTIVES

To determine if introducing the Mediterranean diet in pregnancy reduces the incidence of gestational diabetes.

STUDY DESIGN

Systematic review and meta-analysis of randomised controlled trials (RCTs). A literature search was conducted using the following databases: MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and CINAHL with no language or date restrictions. Studies were deemed eligible if the population was pregnant women, the intervention was the Mediterranean diet, and the outcome was gestational diabetes. Quality assessment was carried out using the Cochrane risk of bias tool. A random effects model using Revman software was used to pool results, generating a summary risk ratio with 95 % confidence intervals (95 %CI).

RESULTS AND CONCLUSIONS

The search identified three eligible studies. Across the trials, 2348 women were included. Two of the three trials defined the intervention as the Mediterranean diet supplemented with extra virgin olive oil (EVOO) and pistachios, with the control group being Mediterranean diet alone. Meta-analysis of these trials found a significant reduction in the incidence of gestational diabetes in the intervention group compared to the control group (risk ratio=0.71, 95% confidence interval=(0.57, 0.88)). In addition, this was consistent with the results of the remaining eligible trial which defined the intervention as Mediterranean diet and the control as a standard UK diet (risk ratio = 0.71, 95% confidence interval = (0.55, 0.90)). At present evidence is scarce regarding whether adopting a Mediterranean diet reduces the risk of gestational diabetes. A large multi-centre randomised controlled trial is needed to definitively determine the impact of the Mediterranean diet in pregnancy on the incidence of gestational diabetes.

Association between the Maternal Mediterranean Diet and Perinatal Outcomes: A Systematic Review and Meta-Analysis

The Mediterranean diet is a global, well-known healthy dietary pattern. This review aims to synthesize the existing evidence on the relationship between the maternal Mediterranean diet during pregnancy and perinatal outcomes, including randomized controlled trials (RCTs) and cohort studies. PubMed, Web of Science, and the Cochrane Library were searched from inception to 10 March, 2023, supplemented by manual screening. A random-effect model was used to estimate pooled sizes with 95% confidence intervals (CIs) for specific outcomes of interest. Data from 5 RCTs and 18 cohort studies with 107,355 pregnant participants were synthesized. In RCTs, it was observed that the maternal Mediterranean diet significantly reduced the incidence of gestational diabetes mellitus [odds ratio (OR), 0.56; 95% CI: 0.34, 0.93], as well as small for gestational age (0.55; 95% CI: 0.35, 0.88). In cohort studies, the highest adherence score to the maternal Mediterranean diet was inversely associated with a lower risk of various adverse pregnancy outcomes, including gestational diabetes mellitus (OR, 0.82; 95% CI: 0.67, 1.00), pregnancy-induced hypertension (0.73; 95% CI: 0.60, 0.89), pre-eclampsia (0.77; 95% CI: 0.64, 0.93), preterm delivery (0.67; 95% CI: 0.49, 0.91), low birth weight (0.70; 95% CI: 0.64, 0.78), intrauterine growth restriction (0.46; 95% CI: 0.23, 0.91), and increased gestational age at delivery (weighted mean difference, 0.11 wk; 95% CI: 0.03, 0.20). Meta-regression analyses did not identify the adjustment for confounders and geographical location as predictive factors for heterogeneity. The results suggest that adherence to the Mediterranean diet during pregnancy appears to be beneficial for perinatal outcomes. Future, larger, and higher-quality RCTs and cohort studies are warranted to confirm the present findings. PROSPERO registration no.: CRD42023406317.

Mediterranean diet and female reproductive health over lifespan: a systematic review and meta-analysis

OBJECTIVE

We conducted a systematic review and meta-analysis of the effects of Mediterranean diet on female reproductive health outcomes over the life-course.

DATA SOURCES

We searched PubMed, Embase, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov to identify eligible studies published till February 2022. Eligible references from identified studies and review articles were also considered.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials, prospective cohort studies, or nested case-control studies examining Mediterranean diet and major female reproductive outcomes over the lifespan, including clinical outcomes from childhood to adulthood (menarche, polycystic ovary syndrome, endometriosis, and outcomes related to fertility, pregnancy, and menopause), were included for review.

METHODS

Two independent reviewers screened and performed data extraction and risk-of-bias assessment. We performed random-effects meta-analysis to obtain summary relative risks and 95% confidence intervals for major female reproductive outcomes. Subgroup analyses were performed for several pregnancy outcomes according to timing of the interventions for randomized controlled trials and timing of the dietary assessment for observational studies.

RESULTS

Thirty-two studies (9 randomized controlled trials, 22 prospective cohort studies, and 1 nested case-control study) involving 103,204 predominantly White women (>95%) were included. The pooled relative risk (95% confidence interval) comparing randomization to Mediterranean diet vs a control diet based on 7 randomized controlled trials was 0.74 (0.55-0.99) for gestational diabetes mellitus, 0.45 (0.26-0.76) for preterm birth, 0.71 (0.51-1.00) for gestational hypertension, and 0.82 (0.54-1.22) for preeclampsia; the effect sizes for preterm birth were greater in randomized controlled trials that initiated the interventions in first trimester vs after first trimester (P heterogeneity=.02). We observed inverse associations for all the above-mentioned pregnancy outcomes based on 9 cohort studies. There was suggestive evidence of favorable associations between Mediterranean diet adherence with fertility and gestational weight management. Limited studies suggested associations between higher Mediterranean diet adherence and later time to menarche and fewer vasomotor menopausal symptoms, null associations for polycystic ovary syndrome-like phenotype and pregnancy loss, and positive associations for luteal phase deficiency.

CONCLUSION

Adherence to Mediterranean diet may lower risks of adverse pregnancy outcomes among predominantly White populations. For fertility-related outcomes, available evidence supporting potential beneficial effects is suggestive yet limited. For other reproductive outcomes across the lifespan, data remains sparse.

Metabolic and molecular effects of dietary extra virgin olive oil in blood and placenta of women with GDM

Gestational diabetes mellitus (GDM) increases the risks of maternal, placental, and neonatal complications. Previously, we found that a diet enriched in extra virgin olive oil (EVOO) prevents increased maternal triglyceridemia and placental proinflammatory markers in a cohort of GDM patients. The aim of this work was to evaluate maternal circulating markers of insulin resistance, placental collagen, glycogen and lipid levels, and placental levels of proteins, mRNAs, and a microRNA involved in the endocytic pathway in the same cohort of control women and women with GDM who received or did not receive a diet enriched in EVOO (36 g/day) from weeks 24 to 28 of pregnancy until term.

Results

At term, the TG/HDL cholesterol ratio, fatty acid binding protein 4 circulating levels, and maternal BMI were increased in the GDM patients, alterations prevented by the maternal diet enriched in EVOO. Although there were no changes in placental lipid levels and lipid profile, GDM placentas were thicker than controls and showed increased glycogen and collagen content, alterations prevented by the EVOO enriched diet. GDM placentas showed increases in megalin levels, in the expression of several genes involved in the endocytic pathway, and in miR-199, which targets these genes, alterations prevented by the maternal diet enriched in EVOO.

Conclusions

We identified novel beneficial effects of an EVOO-enriched diet in GDM women, a diet capable of regulating maternal insulin resistance, the structure and metabolism of the placenta, and the placental endocytic pathway, suggesting effects that may be beneficial for fetal development.

The Metabolic and Analytical Changes of Healthy Volunteers upon Intake of Portuguese Extra Virgin Olive Oil: A Comparison Study between Pre- and Post-Intervention

(1) Background: Extra virgin olive oil (EVOO) is studied mostly for its health benefits in preventing non-communicable chronic diseases, particularly within a Mediterranean dietary pattern. However, few studies have addressed the effect of EVOO in healthy individuals, prior to an established disease. This study aims to evaluate the impact of Northern Portuguese polyphenol-rich EVOO (NPPR-EVOO) consumption on various important clinical parameters in healthy adult volunteers. (2) Methods: This quasi-experimental intervention study assessed the impact of NPPR-EVOO for a period of 100 days. Serum total cholesterol, HbA1c, HDL-c, LDL-c, and CRP, and anthropometric measures-waist and hip perimeters, hand grip strength, and body fat-were assessed and food logs were analyzed. (3) Results: Serum HbA1c (5.12 ± 0.32%; 4.93 ± 0.24, p = 0.000) and LDL-c (96.50 ± 28.57 mg/dL; 87.41 ± 31.38 mg/dL, p = 0.017) significantly decreased following NPPR-EVOO. Also, daily energy significantly increased, but no changes in other dietary parameters, or anthropometry, were seen. Adherence to the Mediterranean diet did not explain the differences found in individuals regarding serum lipid profile and HbA1c, reinforcing the role of EVOO's effect. (4) Conclusions: NPPR-EVOO lowered the serum levels of LDL cholesterol and HbA1c, providing clues on the effect of EVOO-putative health benefits. These results pave the way for a deeper exploration of EVOO as a functional food.

Oleuropein Attenuates Oxidative Stress in Human Trophoblast Cells

Olive-derived bioactive compound oleuropein was evaluated against damage induced by hydrogen peroxide in human trophoblast cells in vitro, by examining the changes in several markers implicated in oxidative stress interactions in the placenta. Trophoblast HTR-8/SVneo cells were preincubated with OLE at 10 and 100 µM and exposed to H₂O₂, as a model of oxidative stress. Protein and lipid peroxidation, as well as antioxidant enzymes' activity, were determined spectrophotometrically, and DNA damage was evaluated by comet assay. iNOS protein expression was assessed by Western blot, while the mRNA expression of pro- and anti-apoptotic genes BAX and BCL2 and transcription factor NFE2L2, as well as cytokines IL-6 and TNF α were determined by qPCR. Oleuropein demonstrated cytoprotective effects against H₂O₂ in trophoblast cells by significantly improving the antioxidant status and preventing protein and lipid damage, as well as reducing the iNOS levels. OLE reduced the mRNA expression of IL-6 and TNF α, however, it did not influence the expression of NFE2L2 or the BAX/BCL2 ratio after H₂O₂ exposure. Oleuropein per se did not lead to any adverse effects in HTR-8/SVneo cells under the described conditions, confirming its safety in vitro. In conclusion, it significantly attenuated oxidative damage and restored antioxidant functioning, confirming its protective role in trophoblast.

How to Measure Adherence to a Mediterranean Diet in Dental Studies: Is a Short Adherence Screener Enough? A Comparative Analysis

This study aimed to evaluate the Mediterranean Diet Adherence Screener (MEDAS) in a study investigating the anti-inflammatory effect of a 6-week Mediterranean diet intervention on periodontal parameters. Data from a randomized clinical trial were analyzed for correlations between the MEDAS score and oral inflammatory parameters (bleeding on probing (BOP), gingival index (GI), and periodontal inflamed surface area (PISA)) and select nutrient intakes estimated by a food frequency questionnaire (FFQ) and a 24-h dietary recall (24dr). A mixed model, calculations of Spearman ρ, Lin’s Concordance Coefficient (CC), and Mann–Whitney U test were used for the statistical analyses. The MEDAS score was significantly negatively correlated with periodontal inflammation (BOP: CoE −0.391, p < 0.001; GI −0.407, p < 0.001; PISA −0.348, p = 0.001) and positively correlated with poly unsaturated fatty acids/total fat, vitamin C, and fiber intake estimates obtained from the FFQ and 24dr (ρ 0.38–0.77). The FFQ and 24dr produced heterogeneously comparable intake results for most nutrients (CC 0–0.79, Spearman ρ 0.16–0.65). Within the limitations of this study, the MEDAS was able to indicate nutritional habits associated with different levels of periodontal inflammation. Accordingly, the MEDAS can be a sufficient and useful diet screener in dental studies. Due to its correlation with oral inflammatory parameters, the MEDAS might also be useful in dental practice.