Effects of weight loss from a very-low-carbohydrate diet on endothelial function and markers of cardiovascular disease risk in subjects with abdominal obesity

Changes in baPWV and the risk of clinical outcomes: a cohort study of Chinese community-based population

It has not been fully investigated whether improved arterial stiffness (AS) can reduce the clinical outcomes risk in community population-based study. In this prospective study, a total of 5247 individuals with abnormal AS (at baseline) and repeated brachial-ankle pulse wave velocity (baPWV) measurement before 2018 years were enrolled from the Kailuan Study. According the second baPWV measurement, we divided the participants into two groups, improved AS (defined as transfer elevated AS status to normal) and persistent AS (defined as maintaining elevated AS status). The outcome was a composite event of stroke, myocardial infraction, and all-cause mortality. We used Cox proportional hazards regression to examine the association between AS status at the follow-up and the subsequent outcome. During a median of 5.2 years follow-up, we observed 413 end point events. After adjusted for potential confounders, comparing with the persistent AS group, individuals in the improved AS group had a 43% (hazard ratio [HR], 0.57; 95% confidence interval [CI] 0.35-0.94) decreased the risk of the primary composite events. We also found a baPWV decrease of 1 m/s was associated with a 3% decreased risk (HR, 0.97; 95% CI 0.94-0.99) for primary composite events. We further demonstrated that younger than 60 years, non-smoker, non-hypertension, and non-diabetes were associated with improved the AS status. In conclusion, improving AS status may reduce the risk of clinical events. In the future, more research should be performed to explore the target for improving the AS status.

Effects of low-carbohydrate diets, with and without caloric restriction, on inflammatory markers in adults: a systematic review and meta-analysis of randomized clinical trials

Low-carbohydrate diets (LCDs) have gained interest due to their favorable effects on health outcomes, such as inflammation. However, further research is needed to ascertain the overall effects of LCDs on inflammatory parameters, but at the same time considering weight loss and calorie intake. Thus, a systematic review and meta-analysis of randomized clinical trials was performed to investigate the effects of LCDs compared with low-fat diets (LFDs), with and without caloric restriction, on inflammatory markers in adults. PubMed, Scopus, and Web of Science were searched through March 2022 to select intervention studies addressing LCDs vs. LFDs, in which the following circulating inflammatory markers were used: C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and interleukin (IL-6). Analyses were conducted comparing LCDs vs. LFDs through weighted mean differences (WMD) or standardized mean differences (SMD) and 95% confidence intervals (95% CIs) using random effects models. The systematic review and meta-analysis included a total of 51 studies with a total sample of 4,164 adults, with or without other chronic diseases. Intervention durations ranged from 2-144 weeks. LCDs, compared with LFDs, significantly decreased body weight [WMD = -1.35%, p = 0.001], CRP [SMD = -0.1, p = 0.03], and IL-6 [SMD = -0.15, p = 0.09]. However, LCDs did not significantly decrease TNF-α [SMD = -0.02, p = 0.7] compared to LFDs. In conclusion, LCDs have a beneficial effect on markers of inflammation by decreasing CRP and IL-6; this effect has an association with weight loss. However, LCDs were not more effective than LFDs in decreasing TNF-α.

The Effect of Diet on Vascular Aging: A Narrative Review of the Available Literature

Early vascular aging is related to various cardiovascular diseases including hypertension, coronary heart disease, and stroke. Healthful lifestyle practices and interventions, including dietary regimens and consistent aerobic exercise, exert favorable modulation on these processes, thereby diminishing the risk of cardiovascular disease with advancing age. The principal objective of this review was to conduct a comprehensive evaluation and synthesis of the available literature regarding the effectiveness of different diets on vascular health, such as arterial stiffness and endothelial function. To conduct this review, a thorough search of electronic databases including PubMed, Scopus, and Web of Science Core Collection was carried out. Based on the existing evidence, the Mediterranean, Dietary Approaches to Stop Hypertension, and low-calorie diets may have a beneficial effect on vascular health. However, more randomized controlled trials with sufficient sample sizes, longer follow-ups, rigorous methodologies, and, possibly, head-to-head comparisons between the different diets are needed to shed light on this topic.

The effect of a ketogenic diet on inflammation-related markers: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

Despite the important role of inflammation-related factors on the occurrence of chronic diseases, there is still conflicting evidence about the effects of the ketogenic diet (KD) on these factors.

OBJECTIVE

In order to obtain a better viewpoint, this study aimed to comprehensively investigate the effects of a KD on inflammation-related markers.

DATA SOURCES

To find pertinent randomized controlled trials up to August 2023, databases including PubMed/Medline, Web of Science, Scopus, Cochrane Library, and Embase were searched.

DATA EXTRACTION

This study included all randomized controlled trials investigating the effects of a KD on C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-8, and IL-10 levels. Pooled weighted mean difference (WMD) and 95% confidence intervals (CIs) were achieved by random-effects model analysis for the best estimation of outcomes.

DATA ANALYSIS

Forty-four studies were included in this article. The pooled findings showed that a KD has an effect on lowering TNF-α (WMD: -0.32 pg/mL; 95% CI: -0.55, -0.09; P = 0.007) and IL-6 (WMD: -0.27 pg/mL; 95% CI: -0.52, -0.02; P = 0.036) compared with control groups. However, no significant effect was reported for others inflammation marker-related levels. The results of the subgroup analysis showed that, in trials following the KD for ≤8 weeks and in people aged ≤50 years, the reduction in TNF-α levels was significantly higher than in other groups. In addition, in people with a body mass index greater than 30 kg/m2 compared to a body mass index ≤30 kg/m2, IL-6 levels decreased to a greater extent after receiving the KD.

CONCLUSIONS

Consequently, adherence to a KD appears to improve some markers associated with inflammation, including TNF-α and IL-6.

Low-carbohydrate and ketogenic diets: a scoping review of neurological and inflammatory outcomes in human studies and their relevance to chronic pain

Dietary restriction of carbohydrate has been demonstrated to be beneficial for nervous system dysfunction in animal models and may be beneficial for human chronic pain. The purpose of this review is to assess the impact of a low-carbohydrate/ketogenic diet on the adult nervous system function and inflammatory biomarkers to inform nutritional research for chronic pain. An electronic database search was carried out in May 2021. Publications were screened for prospective research with dietary carbohydrate intake <130 g per day and duration of ≥2 weeks. Studies were categorised into those reporting adult neurological outcomes to be extracted for analysis and those reporting other adult research outcomes. Both groups were screened again for reported inflammatory biomarkers. From 1548 studies, there were 847 studies included. Sixty-four reported neurological outcomes with 83% showing improvement. Five hundred and twenty-three studies had a different research focus (metabolic n = 394, sport/performance n = 51, cancer n = 33, general n = 30, neurological with non-neuro outcomes n = 12, or gastrointestinal n = 4). The second screen identified sixty-three studies reporting on inflammatory biomarkers, with 71% reporting a reduction in inflammation. The overall results suggest a favourable outcome on the nervous system and inflammatory biomarkers from a reduction in dietary carbohydrates. Both nervous system sensitisation and inflammation occur in chronic pain, and the results from this review indicate it may be improved by low-carbohydrate nutritional therapy. More clinical trials within this population are required to build on the few human trials that have been done.

Effects of dietary-based weight loss interventions on biomarkers of endothelial function: a systematic review and meta-analysis

Endothelial dysfunction is closely linked to the development of atherosclerosis. This systematic review and meta-analysis reviewed the evidence on the effect of weight loss, achieved by dietary-based interventions, on biomarkers of endothelial function (EF). Two databases (Medline, Embase) were searched from inception until November 2022 for studies that met the following criteria: 1) adult subjects (≥ 18 years) without exclusion for health status, 2) dietary interventions for weight loss, and 3) measurements of changes in EF biomarkers. Random-effect meta-analysis and meta-regression were performed. Thirty-seven articles including 1449 participants were included in the systematic review. Study duration ranged from 3-52 weeks. Overall, weight loss significantly improved biomarkers of EF [standardised mean difference (SMD):0.65; 95%CI:0.49,0.81; P < 0.001;I2 = 91.9%]. Subgroup analyses showed weight loss significantly improved levels of E-selectin (P < 0.001), intercellular adhesion molecule-1 (ICAM-1) (P < 0.001), vascular cell adhesion molecule-1 (VCAM-1) (P < 0.001), nitrite/nitrate (NOx) (P < 0.001) and vascular endothelial growth factor (VEGF) (P < 0.001). Conversely, there was no significant improvement for von Willebrand Factor (vWF). Meta-regression analysis revealed that changes in EF biomarkers were not affected by age, BMI, quality of the studies or the amount of weight lost. A significant heterogeneity was observed for the effects of weight loss on changes in EF biomarkers. Dietary-induced weight loss may be associated with biomarkers changes indicating an improvement of EF, and it may represent a potential strategy to reduce atherosclerotic risk.

Netrin-1 Promotes Visceral Adipose Tissue Inflammation in Obesity and Is Associated with Insulin Resistance

Netrin (NTN)-1 exhibits pro- and anti-inflammatory roles in different settings, playing important roles in the obesity-associated low-grade chronic inflammation. We aimed to determine the impact of NTN-1 on obesity and obesity-associated type 2 diabetes, as well as its role in visceral adipose tissue (VAT) inflammation. A total of 91 subjects were enrolled in this case-control study. Circulating levels of NTN-1 and its receptor neogenin (NEO)-1 were determined before and after weight loss achieved by caloric restriction and bariatric surgery. mRNA levels of NTN1 and NEO1 were assessed in human VAT, liver, and peripheral blood mononuclear cells. In vitro studies in human visceral adipocytes and human monocytic leukemia cells (THP-1)-derived macrophages were performed to analyze the impact of inflammation-related mediators on the gene expression levels of NTN1 and its receptor NEO1 as well as the effect of NTN-1 on inflammation. Increased (p < 0.001) circulating concentrations of NTN-1 in obesity decreased (p < 0.05) after diet-induced weight loss being also associated with a reduction in glucose (p < 0.01) and insulin levels (p < 0.05). Gene expression levels of NTN1 and NEO1 were upregulated (p < 0.05) in the VAT from patients with obesity with the highest expression in the stromovascular fraction cells compared with mature adipocytes (p < 0.01). NTN1 expression levels were enhanced (p < 0.01) under hypoxia and by inflammatory factors in both adipocytes and macrophages. Adipocyte-conditioned media strongly upregulated (p < 0.001) the mRNA levels of NTN1 in macrophages. The treatment of adipocytes with NTN-1 promoted the upregulation (p < 0.05) of pro-inflammatory and chemotactic molecules as well as its receptor NEO1. Collectively, these findings suggest that NTN-1 regulates VAT chronic inflammation and insulin resistance in obesity.

Could the ketogenic diet induce a shift in thyroid function and support a metabolic advantage in healthy participants? A pilot randomized-controlled-crossover trial

BACKGROUND

The ketogenic diet (KD) has been shown to result in body mass loss in people with disease as well as healthy people, yet the effect of the KD on thyroid function and metabolism are unknown.

OBJECTIVE

We aimed to determine the effects of a KD, compared with an isocaloric high-carbohydrate low-fat (HCLF) diet, on resting metabolic rate and thyroid function in healthy individuals.

DESIGN

Eleven healthy, normal-weight participants (mean(SD) age: 30(9) years) completed this randomized crossover-controlled study. For a minimum of three weeks on each, participants followed two isocaloric diets: a HCLF diet (55%carbohydrate, 20%fat, 25%protein) and a KD (15%carbohydrate, 60%fat, 25% protein), with a one-week washout period in-between. Importantly, while on the KD, the participants were required to remain in a state of nutritional ketosis for three consecutive weeks. Crossover analyses and linear mixed models were used to assess effect of diet on body mass, thyroid function and resting metabolic rate.

RESULTS

Both dietary interventions resulted in significant body mass loss (p<0.05) however three weeks of sustained ketosis (KD) resulted in a greater loss of body mass (mean (95%CI): -2.9 (-3.5, -2.4) kg) than did three weeks on the HCLF diet (-0.4 (-1.0, 0.1) kg, p < 0.0001). Compared to pre-diet levels, the change in plasma T3 concentration was significantly different between the two diets (p = 0.003), such that plasma T3 concentration was significantly lower following the KD diet (4.1 (3.8, 4.4) pmol/L, p<0.0001) but not different following the HCLF diet (4.8 (4.5, 5.2) pmol/L, p = 0.171. There was a significant increase in T4 concentration from pre-diet levels following the KD diet (19.3 (17.8, 20.9) pmol/L, p < 0.0001), but not following the HCLF diet (17.3 (15.7, 18.8) pmol.L, p = 0.28). The magnitude of change in plasma T4 concentration was not different between the two diets (p = 0.4). There was no effect of diet on plasma thyroid stimulating hormone concentration (p = 0.27). There was a significantly greater T3:T4 ratio following the HCLF diet (0.41 (0.27, 0.55), p < 0.0001) compared to pre-diet levels but not following the KD diet (0.25 (0.12, 0.39), p = 0.80).

CONCLUSIONS

Although the diets were isocaloric and physical activity and resting metabolic rate remained constant, the participants lost more mass after the KD than after the HCLF diet. The observed significant changes in triiodothyronine concentration suggest that unknown metabolic changes occur in nutritional ketosis, changes that warrant further investigation.

TRIAL REGISTRATION

Pan African Clinical Trial Registry: PACTR201707002406306 URL: https://pactr.samrc.ac.za/.

Increased levels of VCAM-1 is associated with higher occurrence of coronary artery disease in adults with moderate to severe obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) leads to important vascular abnormalities, including the endothelial dysfunction and the production of endothelial cell adhesion molecules. The adhesion molecules play an important role in the process of endothelial dysfunction in the pathogenesis of atherosclerosis. We assess the relationship between the levels of adhesion molecules and the presence of coronary artery disease (CAD) in Chinese adults with moderate to severe OSA.

METHODS

The cross-sectional study included a total of 189 Chinese adults: 90 patients with moderate to severe OSA (apnea-hypopnea index≥15 events/h) alone, 40 patients with moderate to severe OSA and CAD, and 59 controls without OSA or with mild OSA and without CAD. We used high-throughput Multiplex Immunobead Assay technology to simultaneously test plasma levels of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1). The associations between the levels of circulating adhesion molecules and CAD in moderate to severe OSA patients were evaluated by multivariate logistic regression analysis.

RESULTS

The circulating VCAM-1 levels were significantly elevated in patients suffering from moderate to severe OSA combined CAD compared with patients having moderate to severe OSA alone [853.28 (564.26) vs. 416.61 (301.69) ng/mL, P < 0.001]. Furthermore, circulating VCAM-1 levels were independently associated with CAD (odds ration = 2.113, 95%CI 1.400-2.766, P < 0.001) and showed higher discriminatory accuracy in assessing the presence of CAD (AUC: 0.899, 95%CI 0.849-0.950, P < 0.001) in moderate to severe OSA patients. However, no significant association was found between circulating ICAM-1 levels and CAD in moderate to severe OSA patients.

CONCLUSIONS

The circulating VCAM-1 levels were significantly correlated with the presence of CAD in Chinese adults with moderate to severe OSA. The circulating VCAM-1 may function as a novel biomarker for monitoring the development and progression of CAD in patients with moderate to severe OSA.

The Pros and Cons of Low Carbohydrate and Ketogenic Diets in the Prevention and Treatment of Cancer

Ketogenic diets are low carbohydrate (CHO), high fat diets that are currently very popular for weight loss. Since cancer cells typically consume far more glucose than normal cells, low CHO diets are currently being considered as possible therapeutic regimens to manage cancer. However, our understanding of the safety and efficacy of such CHO-restricted diets in the prevention and treatment of cancer is still in its infancy. In this perspective we provide an overview of the current state of knowledge regarding the use of low CHO diets in the prevention and treatment of cancer. We also highlight the gaps in our knowledge regarding the potential usefulness of low CHO diets in cancer. While pre-clinical rodent studies have provided convincing evidence that CHO restriction may be effective in reducing cancer growth, there has not been sufficient attention given to the effect of these low CHO diets, that are often high in fats and low in soluble fiber, on inflammation. This is important, given that different fats have distinct effects on inflammation. As well, we demonstrate that short chain fatty acids, which are produced via the fermentation of fiber by our gut microbiome, have more anti-inflammatory properties than β-hydroxybutyrate, a ketone body produced during nutritional ketosis that is touted to have anti-inflammatory activity. Since chronic inflammation is strongly associated with cancer formation, defining the type of fats in low CHO diets may contribute to our understanding of whether these diets may work simply by reducing glucose bioavailability, or via modulation of inflammatory responses.

Effect of low-carbohydrate diet on adiponectin level in adults: a systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND

To the best of our knowledge, no previous study has reported findings on the effects of low-carbohydrate diet (LCD) on adiponectin concentration.

OBJECTIVE

The current systematic review and dose-response meta-analysis was carried out to systematically review the available controlled clinical trials about the effect of LCD on adiponectin level in adults.

METHODS

Literature searches of PubMed/Medline, Scopus and Web of Sciences were conducted up to August 2019. Randomized controlled trials (RCTs) which assessed the effect of LCD on the adiponectin level were selected.

RESULTS

Eleven studies, including 1047 participants (LCD = 534 and control = 513), were included in the meta-analysis. Proportion of carbohydrate from calorie was from 4 to 34%. Time of the follow-up varied between studies and ranged from 6 to 152 weeks. LCD intake mildly but significantly increased adiponectin (0.02 µg/ml, 95% CI: 0.01 to 0.03, P < 0.001). Dose-response analysis indicated a nonlinear association between the percentage of carbohydrate and change in adiponectin level from baseline (P = 0.04). After subgroup analysis based on the proportion of carbohydrate from calorie, there was a significant increase in adiponectin concentration in studies that prescribed <30% of calorie from carbohydrates (0.12 µg/ml, 95% CI: 0.07-0.18). In contrast, diets which consisted ≥30% of carbohydrates had no significant effect on adiponectin (0.50 µg/ml, 95% CI: -0.46 to 1.48). Also, meta-regression analysis revealed that age (β = 0.04, P = 0.15), baseline BMI (β= -0.15, P = 0.15), time of follow-up (β = 0.01, P = 0.17), percentage of carbohydrates (β = 0.004, P = 0.90), percentage of protein (β= -0.12, P = 0.08), percentage of fat (β = 0.20, P = 0.61) and baseline adiponectin (β = 0.001, P = 0.97) are not sources of heterogeneity.

CONCLUSION

This systematic review and meta-analysis demonstrated a mild but significant effect of LCD on adiponectin concentration compared to control groups.

Ketogenic Diets and Cardio-Metabolic Diseases

While the prevalence of cardio-metabolic diseases (CMDs) has become a worldwide epidemic, much attention is paid to managing CMDs effectively. A ketogenic diet (KD) constitutes a high-fat and low-carbohydrate diet with appropriate protein content and calories. KD has drawn the interests of clinicians and scientists regarding its application in the management of metabolic diseases and related disorders; thus, the current review aimed to examine the evidences surrounding KD and the CMDs to draw the clinical implications. Overall, KD appears to play a significant role in the therapy of various CMDs, which is manifested by the effects of KDs on cardio-metabolic outcomes. KD therapy is generally promising in obesity, heart failure, and hypertension, though different voices still exist. In diabetes and dyslipidemia, the performance of KD remains controversial. As for cardiovascular complications of metabolic diseases, current evidence suggests that KD is generally protective to obese related cardiovascular disease (CVD), while remaining contradictory to diabetes and other metabolic disorder related CVDs. Various factors might account for the controversies, including genetic background, duration of therapy, food composition, quality, and sources of KDs. Therefore, it's crucial to perform more rigorous researches to focus on clinical safety and appropriate treatment duration and plan of KDs.

Weight reduction ameliorates inflammatory cytokines, adipocytokines and endothelial dysfunction biomarkers among Saudi patients with type 2 diabetes

Background

Type 2 diabetes mellitus (T2DM) considered as one of the cardiovascular disorders (CVD) principle risk factor as diabetes is associated with abnormal levels of endothelial function, inflammatory and adipocytokines.

Objective

The aim of this study was to measure the impact of weight reducing on inflammatory cytokines, adipocytokines and endothelial function biomarkers among obese T2DM patients.

Methods

One-hundred T2DM patients enrolled in the present study; the age range was 35–55 year. Participants shared in this study were enrolled in group (A) received diet control and aerobic exercise on treadmill, while, group (B) had no intervention for 3 months.

Results

The mean values of body mass index (BMI), tumor necrosis factor -alpha (TNF-α), interleukin-6 (IL-6), leptin, inter-cellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), E-selectin and plasminogen activator inhibitor-1 activity (PAI-1 activity) were significantly decreased and adiponectin was increased significantly in the training group, however the results of the control group were not significant. Also, there were significant differences between both groups at the end of the study.

Conclusion

Weight reducing program modulates inflammatory cytokines, adipocytokines and endothelial function biomarkers among obese T2DM patients.

Caloric restriction in heart failure: A systematic review

BACKGROUND AND AIMS

Nutrition exerts a determinant role in maintaining cardiac function, regulating insulin and mitochondrial efficiency, that are essential to support energy production for contractility. In patients with heart failure (HF), myocardial tissue efficiency is reduced because of decreased mitochondrial oxidative capacity. In HF conditions, cardiomyocytes shift toward glucose and a reduction in fatty acid utilization. Calorie restriction induces weight loss in obese patients and can be beneficial in some HF patients, although this has generated some controversy. This study aims to evaluate the impact of the CR diet on myocardial efficiency in HF patients.

METHODS

On Pubmed and Embase, articles related to the keywords: "chronic heart failure" with "diet," "nutrition," "insulin resistance," and "caloric restriction" have been searched, Studies, including exercise or food supplementation, were excluded.

RESULTS

The retrieved articles showed that weight loss, through the activation of insulin and various kinase pathways, regulates the efficiency of myocardial tissue. In contrast, insulin resistance represents a strong cardiovascular risk factor that reduces myocardial function.

CONCLUSION

CR diet represents the first therapy in overweight HF patients, both with preserved ejection fraction (HFpEF) and with reduced ejection fraction (HFrHF) because reducing body fat, the myocardial function increased. Insulin activity is the critical hormone that regulates mitochondrial function and cardiac efficiency. However, a severely restricted diet may represent a severe risk factor correlated with all-cause mortality, particularly in underweight HF patients. Long-term studies conducted on large populations are necessary to evaluate the effects of CR on myocardial function in HF patients.

The Effect of Low-Carbohydrate Diet on Macrovascular and Microvascular Endothelial Function is Not Affected by the Provision of Caloric Restriction in Women with Obesity: A Randomized Study

Obesity impairs both macro- and microvascular endothelial function due to decreased bioavailability of nitric oxide. Current evidence on the effect of low-carbohydrate (LC) diet on endothelial function is conflicting and confounded by the provision of caloric restriction (CR). We tested the hypothesis that LC without CR diet, but not LC with CR diet, would improve macro- and microvascular endothelial function in women with obesity. Twenty-one healthy women with obesity (age: 33 ± 2 years, body mass index: 33.0 ± 0.6 kg/m²; mean ± SEM) were randomly assigned to receive either a LC diet (~10% carbohydrate calories) with CR (n = 12; 500 calorie/day deficit) or a LC diet without CR (n = 9) and completed the 6-week diet intervention. After the intervention, macrovascular endothelial function, measured as brachial artery flow-mediated dilation did not change (7.3 ± 0.9% to 8.0 ± 1.1%, p = 0.7). On the other hand, following the LC diet intervention, regardless of CR, blocking nitric oxide production decreased microvascular endothelial function, measured by arteriolar flow-induced dilation (p ≤ 0.02 for both diets) and the magnitude was more than baseline (p ≤ 0.04). These data suggest improved NO contributions following the intervention. In conclusion, a 6-week LC diet, regardless of CR, may improve microvascular, but not macrovascular endothelial function, via increasing bioavailability of nitric oxide in women with obesity.

Non-Systematic Review of Diet and Nutritional Risk Factors of Cardiovascular Disease in Obesity

Although cardiovascular disease and its risk factors have been widely studied and new methods of diagnosis and treatment have been developed and implemented, the morbidity and mortality levels are still rising-cardiovascular disease is responsible for more than four million deaths each year in Europe alone. Even though nutrition is classified as one of the main and changeable risk factors, the quality of the diet in the majority of people does not follow the recommendations essential for prevention of obesity and cardiovascular disease. It demonstrates the need for better nutritional education in cardiovascular disease prevention and treatment, and the need to emphasize dietary components most relevant in cardiovascular disease. In our non-systematic review, we summarize the most recent knowledge about nutritional risk and prevention in cardiovascular disease and obesity.

Plasma homocysteine after laparoscopic Roux-en-Y gastric bypass increases in the early postoperative phase but decreases in the long-term follow-up. A retrospective analysis

BACKGROUND

Homocysteine is an important independent risk factor for predicting cardiovascular disease (CVD). However, changes in the homocysteine levels after bariatric surgery remain controversial.

OBJECTIVES

Modeling differences in homocysteine after bariatric surgery.

SETTING

University Hospital, Austria.

METHODS

Seven hundred eight consecutive bariatric surgery patients (78% female, 22% male, mean body mass index 41 kg/m² preoperatively) underwent laparoscopic long-limb Roux-en-Y gastric bypass in a 6-year period and were retrospectively evaluated for changes in their preoperative homocysteine levels, at 3, 6, 9, 12, 18, 24, 36, 48, 60, and 72 months postoperatively. Furthermore, a postal and telephone screening for postoperative CVD with a follow-up of 71% was conducted.

RESULTS

Hyperhomocysteinemia was present in 11.8% preoperatively (normal range: <15 μmol/L). The median plasma homocysteine level was 10.4 preoperatively, 12.1 at 3, 11.2 at 6, 10.0 at 9, 9.8 at 12, 8.9 at 18, 8.7 at 24, 8.6 at 36, 9.1 at 48, 9.8 at 60, and 10.0 μmol/L at 72 months postoperatively. After subdividing the study population in morbidly obese (n = 509, body mass index 40-50 kg/m²) and super-obese (n = 199, body mass index >50 kg/m²) patients, the short-term increase into homocysteine levels remained. Overall, newly onset CVD risk was 4.2%. After subdividing the CVD risk into risk for myocardial infarction, stroke, and risk for deep vein thrombosis/pulmonary embolism the distribution was as follows: .2% myocardial infarction, .59% stroke, and 2.97% deep vein thrombosis/pulmonary embolism (median 36 [interquartile range 36-48] mo postoperatively).

CONCLUSION

Laparoscopic Roux-en-Y gastric bypass leads to increased homocysteine levels in the early postoperative period. However, there was no relationship between increased homocysteine levels and CVD event onset.

Relationship between endothelium-dependent vasodilation and fat distribution using the new "imiomics" image analysis technique

BACKGROUND AND AIMS

We investigated how vasoreactivity in the brachial artery and the forearm resistance vessels were related to fat distribution and tissue volume, using both traditional imaging analysis and a new technique, called "Imiomics", whereby vasoreactivity was related to each of the >2M 3D image elements included in the whole-body magnetic resonance imaging (MRI).

METHODS AND RESULTS

In 326 subjects in the Prospective investigation of Obesity, Energy and Metabolism (POEM) study (all aged 50 years), endothelium-dependent vasodilation was measured by acetylcholine infusion in the brachial artery (EDV) and flow-mediated vasodilation (FMD). Fat distribution was evaluated by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI). EDV, but not FMD, was significantly related to total fat mass, liver fat, subcutaneous (SAT) and visceral (VAT) adipose tissue in a negative fashion in women, but not in men. Using Imiomics, an inverse relationship was seen between EDV and a local tissue volume of SAT in both the upper part of the body, as well as the gluteo-femoral part and the medial parts of the legs in women. Also the size of the liver, heart and VAT was inversely related to EDV. In men, less pronounced relationships were seen. FMD was also significantly related to local tissue volume of upper-body SAT and liver fat in women, but less so in men.

CONCLUSION

EDV, and to a lesser degree also FMD, were related to liver fat, SAT and VAT in women, but less so in men. Imiomics both confirmed findings from traditional methods and resulted in new, more detailed results.

Salt consumption by Australian adults: a systematic review and meta-analysis

OBJECTIVE

Salt reduction is a public health priority because it is a leading contributor to the global burden of disease. As in Australia there is uncertainty about the current level of salt intake, we sought to estimate current levels.

STUDY DESIGN

Random effects meta-analysis of data from 31 published studies and one unpublished dataset that reported salt or sodium consumption by Australian adults on the basis of 24-hour urine collections or dietary questionnaires.

DATA SOURCES

MEDLINE (via Ovid) and EMBASE (to August 2016).

DATA SYNTHESIS

Thirty-one published studies and one unpublished dataset (1989-2015; 16 836 individuals) were identified. The mean weighted salt consumption estimated from 24-hour urine collections was 8.70 g/day (95% CI, 8.39-9.02 g/day); after adjusting for non-urinary salt excretion, the best estimate of salt intake in Australia is 9.6 g/day. The mean weighted intake was 10.1 g/day (95% CI, 9.68-10.5 g/day) for men and 7.34 g/day (95% CI, 6.98-7.70 g/day) for women. Mean weighted consumption was 6.49 g/day (95% CI, 5.94-7.03 g/day) when measured with diet diaries, 6.76 g/day (95% CI, 5.48-8.05 g/day) when assessed with food frequency questionnaires, and 6.73 g/day (95% CI, 6.34-7.11) when assessed by dietary recall. Salt intake had not decreased between 1989 and 2015 (R² = -0.02; P = 0.36).

CONCLUSION

Salt intake in Australian adults exceeds the WHO-recommended maximum of 5 g/day and does not appear to be declining. Measuring salt intake with methods based on self-reporting can substantially underestimate consumption. The data highlight the need for ongoing action to reduce salt consumption in Australia and robust monitoring of population salt intake.

Dietary Composition and Cardiovascular Risk: A Mediator or a Bystander?

The role of nutrition in the pathogenesis of cardiovascular disease has long been debated. The established notion of the deleterious effects of fat is recently under question, with numerous studies demonstrating the benefits of low-carbohydrate, high-fat diets in terms of obesity, diabetes, dyslipidemia, and metabolic derangement. Monounsaturated and polyunsaturated fatty acids, especially n-3 PUFAs (polyunsaturated fatty acids), are the types of fat that favor metabolic markers and are key components of the Mediterranean Diet, which is considered an ideal dietary pattern with great cardioprotective effects. Except for macronutrients, however, micronutrients like polyphenols, carotenoids, and vitamins act on molecular pathways that affect oxidative stress, endothelial function, and lipid and glucose homeostasis. In relation to these metabolic markers, the human gut microbiome is constantly revealed, with its composition being altered by even small dietary changes and different microbial populations being associated with adverse cardiovascular outcomes, thus becoming the target for potential new treatment interventions. This review aims to present the most recent data concerning different dietary patterns at both the macro- and micronutrient level and their association with atherosclerosis, obesity, and other risk factors for cardiovascular disease.

Compensation in response to energy deficits induced by exercise or diet

Obesity is an extremely resilient condition. Weight loss is most challenging, and weight recidivism is rampant. There is accumulating evidence highlighting that energy deficits meant to produce increased mobilization of energy stores trigger a number of somewhat persistent adaptations that together increase the drive to eat and decrease energy output. These adaptations ostensibly enable a context where the likelihood of energy compensation is heightened. In fact, energy compensation is present for both diet and exercise induced energy deficits although at different magnitudes. For the most part, the energy compensation in response to exercise induced energy deficits seems to be larger. Interestingly, energy compensation appears to be greater for longer interventions, an effect independent of whether the energy deficit is induced through diet or exercise. The latter suggests that the increased drive to eat and the reduced energy expenditure that accompany weight loss might be successfully fought off initially. However, with time there seems to be increasing erosion of the behaviours that initially opposed adaptations to weight loss and increased energy compensation progressively sets in. Under such conditions, it would seem prudent to propose weight loss targets that align with a level of behaviour modifications that can be sustained indefinitely.

Impact of weight reduction on insulin resistance, adhesive molecules and adipokines dysregulation among obese type 2 diabetic patients

BACKGROUND

Type 2 diabetes mellitus is usually related to vascular problems and is associated with impairment in endothelial function characterized by impaired endothelial-dependent vasodilation and increased platelet adhesion. There is limitation in clinical studies that have addressed the beneficial effects of weight reduction in modulating biomarkers of endothelial dysfunction and adipokines dysregulation for obesity associated with type 2 diabetes mellitus.

OBJECTIVE

This study was designed to detect the effects of weight loss on insulin resistance, adhesive molecules and adipokines dysregulation in obese type 2 diabetic patients.

METHODS

Eighty obese patients with type 2 diabetes mellitus, their age ranged from 35-55 years and their body mass index ranged from 31-37 kg/m² were equally assigned into 2 groups: the weight reduction group received aerobic exercises in addition to diet regimen, where the control group received medical treatment only for 12 weeks.

RESULTS

There was a 24.04%, 19.33%, 22.78% ,12.28%, 9.35%, 22.53% & 10.12 % reduction in mean values of Homeostasis Model Assessment-Insulin Resistance Index (HOMA-IR), Leptin, Adiponectin, Resistin, intercellular cell adhesion molecule -1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin & body mass index (BMI) respectively in addition to 26.20% & 24.58% increase in the mean values of adiponectin & the quantitative insulin-sensitivity check index (QUICKI) respectively in group (A) at the end of the study. The mean values of leptin, resistin, insulin, HOMA-IR, ICAM-1, VCAM-1, E-selectin & BMI were significantly decreased in addition to significant increase in the mean values of adiponectin & QUICKI in group (A) those that received aerobic exercise training in addition to diet regimen. While the results of group (B) those that received no treatment intervention were not significant. In addition, there were significant differences between mean levels of the investigated parameters in group (A) and group (B) after treatment (P<0.05).

CONCLUSION

Within the limit of this study, 10% reduction in body mass index modulates insulin resistance, adhesive molecules and adipokines dysregulation among obese type 2 diabetic patients.

Effect of carbohydrate restriction-induced weight loss on aortic pulse wave velocity in overweight men and women

Increased aortic stiffness, measured by carotid-to-femoral pulse wave velocity (PWV), is an independent predictor of cardiovascular disease, and past data have shown that low-fat and low-energy diets, fed for 8–24 weeks, lower PWV. The purpose of this study was to determine whether a reduction in PWV would be achieved by dietary carbohydrate (CHO) restriction, shown to bring about weight loss over a shorter timeframe. Men (n = 10, age: 41.8 ± 10.2 years, BMI: 34.2 ± 3.0 kg/m2 (mean ± SD)) and women (n = 10, age: 38.6 ± 6.1 years, BMI: 33.5 ± 3.8 kg/m2) with characteristics of insulin resistance and the metabolic syndrome consumed a structured, CHO-restricted diet for 4 weeks (energy deficit, 645 kcal/day). For the whole group, subjects lost 5.4% ± 0.5% (P < 0.001) of body weight and experienced significant reductions in blood pressure (6%–8%), plasma insulin (34%), and triglycerides (34%). PWV was reduced by 6% ± 2% (7.1 ± 0.2 m/s to 6.7 ± 0.2 m/s, P = 0.008) and surprisingly, in women, it fell significantly (from 7.2 ± 0.3 m/s to 6.3 ± 0.3 m/s, P = 0.028), while no changes were observed in men (7.2 ± 0.3 vs. 7.0 ± 0.3 m/s, P = 0.144). This is the first study to demonstrate that weight loss can improve PWV in as little as 4 weeks and that dietary CHO restriction may be an effective treatment for reducing aortic stiffness in women. Future studies are needed to establish the mechanisms by which dietary CHO restriction may confer more cardiovascular benefits to women than to men.

Impact of Nutrition on Cardiovascular Function

The metabolic sources of energy for myocardial contractility include mainly free fatty acids (FFA) for 95%, and in lesser amounts for 5% from glucose and minimal contributions from other substrates such lactate, ketones, and amino acids. However, myocardial efficiency is influenced by metabolic condition, overload, and ischemia. During cardiac stress, cardiomyocytes increase glucose oxidation and reduce FFA oxidation. In patients with ischemic coronary disease and heart failure, the low oxygen availability limits myocardial reliance on FFA and glucose utilization must increase. Although glucose uptake is fundamental to cardiomyocyte function, an excessive intracellular glucose level is detrimental. Insulin plays a fundamental role in maintaining myocardial efficiency and in reducing glycemia and inflammation; this is particularly evident in obese and type-2 diabetic patients. An excess of F availability increase fat deposition within cardiomyocytes and reduces glucose oxidation. In patients with high body mass index, a restricted diet or starvation have positive effects on cardiac metabolism and function while, in patients with low body mass index, restrictive diets, or starvation have a deleterious effect. Thus, weight loss in obese patients has positive impacts on ventricular mass and function, whereas, in underweight heart failure patients, such weight reduction adds to the risk of heart damage, predisposing to cachexia. Nutrition plays an essential role in the evolution of cardiovascular disease and should be taken into account. An energy-restricted diet improves myocardial efficiency but can represent a potential risk of heart damage, particularly in patients affected by cardiovascular disease. Micronutrient integration has a marginal effect on cardiovascular efficiency.

Does obesity attenuate the beneficial cardiovascular effects of cardiorespiratory fitness?

BACKGROUND AND AIMS

Higher cardiorespiratory fitness is associated with lower pulse wave velocity and arterial stiffness in normal weight individuals, and this has not been examined in obese individuals. It is unclear whether an altered body composition acts as a modifier of the association between cardiorespiratory fitness and arterial stiffness. We examined the association between peak oxygen uptake and brachial-ankle pulse wave velocity and analysed whether body composition attenuates this association in obese middle-aged individuals.

METHODS

Bio-impedance analysis-derived body composition assessment in 212 healthy and sedentary either overweight or obese individuals was followed by measurement of brachial-ankle pulse wave velocity and spiroergometric peak oxygen uptake. Multivariate analysis was performed to analyse the association between peak oxygen uptake and brachial-ankle pulse wave velocity and to assess the moderating effect of several body composition-related interaction terms (BMI, total body mass, body fat mass, waist circumference, waist-to-height ratio) on this association.

RESULTS

Peak oxygen uptake was inversely associated with brachial-ankle pulse wave velocity (β = -0.059, 95% CI = -0.099; -0.018, p = 0.005). Testing for the impact of different body composition-related interaction terms on this association showed no significance, 95% CI lateralized towards positivity.

CONCLUSIONS

This study shows an inverse association between cardiorespiratory fitness and arterial stiffness in middle-aged obese individuals. We also found a tendency towards an attenuating impact of an obese body composition on this association. Physical fitness seems to be a stronger modulator of cardiovascular risk than body composition but the success of training efforts may be compromised by obesity.

An Integrated Understanding of the Rapid Metabolic Benefits of a Carbohydrate-Restricted Diet on Hepatic Steatosis in Humans

A carbohydrate-restricted diet is a widely recommended intervention for non-alcoholic fatty liver disease (NAFLD), but a systematic perspective on the multiple benefits of this diet is lacking. Here, we performed a short-term intervention with an isocaloric low-carbohydrate diet with increased protein content in obese subjects with NAFLD and characterized the resulting alterations in metabolism and the gut microbiota using a multi-omics approach. We observed rapid and dramatic reductions of liver fat and other cardiometabolic risk factors paralleled by (1) marked decreases in hepatic de novo lipogenesis; (2) large increases in serum β-hydroxybutyrate concentrations, reflecting increased mitochondrial β-oxidation; and (3) rapid increases in folate-producing Streptococcus and serum folate concentrations. Liver transcriptomic analysis on biopsy samples from a second cohort revealed downregulation of the fatty acid synthesis pathway and upregulation of folate-mediated one-carbon metabolism and fatty acid oxidation pathways. Our results highlight the potential of exploring diet-microbiota interactions for treating NAFLD.

Dietary Protein and Energy Balance in Relation to Obesity and Co-morbidities

Dietary protein is effective for body-weight management, in that it promotes satiety, energy expenditure, and changes body-composition in favor of fat-free body mass. With respect to body-weight management, the effects of diets varying in protein differ according to energy balance. During energy restriction, sustaining protein intake at the level of requirement appears to be sufficient to aid body weight loss and fat loss. An additional increase of protein intake does not induce a larger loss of body weight, but can be effective to maintain a larger amount of fat-free mass. Protein induced satiety is likely a combined expression with direct and indirect effects of elevated plasma amino acid and anorexigenic hormone concentrations, increased diet-induced thermogenesis, and ketogenic state, all feed-back on the central nervous system. The decline in energy expenditure and sleeping metabolic rate as a result of body weight loss is less on a high-protein than on a medium-protein diet. In addition, higher rates of energy expenditure have been observed as acute responses to energy-balanced high-protein diets. In energy balance, high protein diets may be beneficial to prevent the development of a positive energy balance, whereas low-protein diets may facilitate this. High protein-low carbohydrate diets may be favorable for the control of intrahepatic triglyceride IHTG in healthy humans, likely as a result of combined effects involving changes in protein and carbohydrate intake. Body weight loss and subsequent weight maintenance usually shows favorable effects in relation to insulin sensitivity, although some risks may be present. Promotion of insulin sensitivity beyond its effect on body-weight loss and subsequent body-weight maintenance seems unlikely. In conclusion, higher-protein diets may reduce overweight and obesity, yet whether high-protein diets, beyond their effect on body-weight management, contribute to prevention of increases in non-alcoholic fatty liver disease NAFLD, type 2 diabetes and cardiovascular diseases is inconclusive.

Evidence that supports the prescription of low-carbohydrate high-fat diets: a narrative review

Low-carbohydrate high-fat (LCHF) diets are a highly contentious current topic in nutrition. This narrative review aims to provide clinicians with a broad overview of the effects of LCHF diets on body weight, glycaemic control and cardiovascular risk factors while addressing some common concerns and misconceptions. Blood total cholesterol and LDL-cholesterol concentrations show a variable, highly individual response to LCHF diets, and should be monitored in patients adhering to this diet. In contrast, available evidence from clinical and preclinical studies indicates that LCHF diets consistently improve all other markers of cardiovascular risk-lowering elevated blood glucose, insulin, triglyceride, ApoB and saturated fat (especially palmitoleic acid) concentrations, reducing small dense LDL particle numbers, glycated haemoglobin (HbA_1c) levels, blood pressure and body weight while increasing low HDL-cholesterol concentrations and reversing non-alcoholic fatty liver disease (NAFLD). This particular combination of favourable modifications to all these risk factors is a benefit unique to LCHF diets. These effects are likely due in part to reduced hunger and decreased ad libitum calorie intake common to low-carbohydrate diets, allied to a reduction in hyperinsulinaemia, and reversal of NAFLD. Although LCHF diets may not be suitable for everyone, available evidence shows this eating plan to be a safe and efficacious dietary option to be considered. LCHF diets may also be particularly beneficial in patients with atherogenic dyslipidaemia, insulin resistance, and the frequently associated NAFLD.

Vitamin D status and circulating biomarkers of endothelial dysfunction and inflammation in non-diabetic obese individuals: a pilot study

INTRODUCTION

Obesity and inadequate vitamin D status are associated with endothelial dysfunction and cardiovascular disease. We evaluated the associations between vitamin D status (i.e. serum levels of 25-hydroxyvitamin D (25(OH)D)), biomarkers of endothelial dysfunction (i.e. serum concentrations of soluble intercellular adhesion molecule 1 (sICAM-1) and soluble E-selectin (sE-selectin)), inflammatory markers (i.e. high-sensitivity C-reactive protein (hsCRP) and fibrinogen) and cardiometabolic risk factors.

MATERIAL AND METHODS

Fifty obese (body mass index (BMI) ≥ 30 kg/m²) non-diabetic adults (mean age: 36.2 ±5.4 years) without pre-existing cardiovascular abnormalities and 25 clinically healthy, normal weight and age-matched individuals were included. Anthropometric parameters, markers of glucose and lipid metabolism, and serum levels of inflammatory and endothelial dysfunction biomarkers were assessed in all subjects.

RESULTS

The mean serum 25(OH)D level was significantly lower in the obese group than in controls (33.5 ±15.2 vs. 60.1 ±23.1 nmol/l; p < 0.001). In the obese group, sE-selectin (36.4 (32.1-47.2) vs. 32.4 (24.6-35.5) ng/ml, p < 0.05) and hsCRP (6.0 ±3.4 vs. 3.5 ±1.0 mg/l, p < 0.05) were significantly higher in individuals with lower than median vitamin D levels (i.e. 31 nmol/l) compared with those with higher vitamin D levels. In multivariable linear regression analysis, hsCRP (β = -0.43; p < 0.001) and sE-selectin (β = -0.30; p = 0.03) were independently and significantly associated with serum 25(OH)D levels in the obese group.

CONCLUSIONS

Vitamin D levels may be related to increased levels of biomarkers of endothelial dysfunction and inflammation in obese non-diabetic individuals.

Combined effects of resistance training and carbohydrate-restrictive or conventional diets on weight loss, blood variables and endothelium function

ABSTRACT Objective: To compare the effects of either a carbohydrate-restrictive diets or a conventional hypoenergetic diet combined with resistance training. Methods: Twenty-one overweight and obese adults participated in an eight-week program consisting of progressive resistance training combined with carbohydrate-restrictive diets (initially set at <30 g carbohydrate; n=12) or conventional hypoenergetic diet (30% energetic restriction; carbohydrate/protein/lipid: 51/18/31% of total energy consumption; n=9). It was hypothesized that the carbohydrate-restrictive diets would induce greater weight loss but that both diets would elicit similar effects on selected health markers. Body mass, and body composition, blood variables and flow-mediated brachial artery dilation (flow-mediated brachial artery dilation; by ultrasound) were used to assess changes due to the interventions. Results: Significant within-group reductions in body mass (-5.4±3.5%; p=0.001 versus -3.7±3.0%; p=0.015) and body fat (body fat; -10.2±7.0%; p=0.005 versus -9.6±8.8%; p=0.017) were identified for carbohydrate-restrictive diets and conventional hypoenergetic diet, respectively, but there were no significant differences between groups as the result of the interventions. Fat free mass, blood variables and flow-mediated brachial artery dilation did not significantly change, except for the total cholesterol/high-density lipoprotein ratio, which was reduced 10.4±16.9% in carbohydrate-restrictive diets (p=0.037) and 0.5±11.3% in conventional hypoenergetic diet (p=0.398). Conclusion: Carbohydrate-restrictive diets associated with resistance training was as effective as conventional hypoenergetic diet in decreasing body mass and body fat, as well as maintaining fat free mass, blood variables and flow-mediated brachial artery dilation, however it was more effective at lowering the total cholesterol/low density lipoprotein ratio.

First-Stage Development and Validation of a Web-Based Automated Dietary Modeling Tool: Using Constraint Optimization Techniques to Streamline Food Group and Macronutrient Focused Dietary Prescriptions for Clinical Trials

BACKGROUND

Standardizing the background diet of participants during a dietary randomized controlled trial is vital to trial outcomes. For this process, dietary modeling based on food groups and their target servings is employed via a dietary prescription before an intervention, often using a manual process. Partial automation has employed the use of linear programming. Validity of the modeling approach is critical to allow trial outcomes to be translated to practice.

OBJECTIVE

This paper describes the first-stage development of a tool to automatically perform dietary modeling using food group and macronutrient requirements as a test case. The Dietary Modeling Tool (DMT) was then compared with existing approaches to dietary modeling (manual and partially automated), which were previously available to dietitians working within a dietary intervention trial.

METHODS

Constraint optimization techniques were implemented to determine whether nonlinear constraints are best suited to the development of the automated dietary modeling tool using food composition and food consumption data. Dietary models were produced and compared with a manual Microsoft Excel calculator, a partially automated Excel Solver approach, and the automated DMT that was developed.

RESULTS

The web-based DMT was produced using nonlinear constraint optimization, incorporating estimated energy requirement calculations, nutrition guidance systems, and the flexibility to amend food group targets for individuals. Percentage differences between modeling tools revealed similar results for the macronutrients. Polyunsaturated fatty acids and monounsaturated fatty acids showed greater variation between tools (practically equating to a 2-teaspoon difference), although it was not considered clinically significant when the whole diet, as opposed to targeted nutrients or energy requirements, were being addressed.

CONCLUSIONS

Automated modeling tools can streamline the modeling process for dietary intervention trials ensuring consistency of the background diets, although appropriate constraints must be used in their development to achieve desired results. The DMT was found to be a valid automated tool producing similar results to tools with less automation. The results of this study suggest interchangeability of the modeling approaches used, although implementation should reflect the requirements of the dietary intervention trial in which it is used.

The Effects of Low-Carbohydrate Diets on Psychosocial Outcomes in Obesity/Overweight: A Systematic Review of Randomized, Controlled Studies

Background: Little is known about the relative psychosocial effects of carbohydrate reduction in comparison to other weight-loss diets in subjects receiving treatment for obesity/overweight. We, therefore, set out to conduct a systematic review of the psychosocial outcomes of such patients, treated by means of either a low-carbohydrate diet or an isocaloric diet of other macronutrient composition. Methods: Literature searches, study selection, method development, and quality appraisal were performed independently by two authors, and data were synthesized using a narrative approach, in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Results: Eight randomized controlled studies met the inclusion criteria, and their subsequent analysis revealed that improvements in psychological and social outcomes do occur during short- and long-term weight loss programmes, but that low-carbohydrate diets have no greater effect on psychosocial outcomes when compared to diets of different macronutrient composition at either short- or long-term follow-up (one-year). However, the lack of studies with longer duration follow-up, and the absence of data in the adolescent population limit the generalizability of our findings. Conclusion: The short- and long-term improvements in psychosocial outcomes seen in patients undergoing weight-loss treatment appear to be independent of the macronutrient composition of their diet.

Weight loss improves biomarkers endothelial function and systemic inflammation in obese postmenopausal Saudi women

BACKGROUND

Although postmenopausal associated disorders are important public health problems worldwide, to date limited studies evaluated the endothelial function and systemic inflammation response to weight loss in obese postmenopausal women.

OBJECTIVE

This study was done to evaluate the endothelial function and systemic inflammation response to weight loss in obese postmenopausal Saudi women.

MATERIAL AND METHODS

Eighty postmenopausal obese Saudi women (mean age 52.64±6.13 year) participated in two groups: Group (A) received aerobic exercise on treadmill and diet whereas, group (B) received no intervention. Markers of inflammation and endothelial function were measured before and after 3 months at the end of the study.

RESULTS

The values of body mass index(BMI), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), inter-cellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1) and plasminogen activator inhibitor-1 activity (PAI-1:Ac) were significantly decreased in group (A), while changes were not significant in group (B). Also, there were significant differences between mean levels of the investigated parameters in group (A) and group (B) after treatment.

CONCLUSION

Weight loss ameliorates inflammatory cytokines and markers of endothelial function in obese postmenopausal Saudi women.

Impact of low-carbohydrate diet on body composition: meta-analysis of randomized controlled studies

The effect of low-carbohydrate diet (LCD) on body composition, especially fat mass, in obese individuals remains to be elucidated. We performed a meta-analysis to provide quantitative summary estimates of the mean change of body weight (kg) and fat mass (kg) in LCD comparing to those in control diet. Literature searches were performed using EMBASE, MEDLINE and Cochrane Library until Dec 2014. Fourteen randomized controlled studies were included in this meta-analysis. Eight studies including very LCD (50 g carbohydrate or 10% calorie from carbohydrate) and seven studies including mild LCD (about 40% calorie from carbohydrate). Meta-analysis carried out on data of 1416 obese individuals, showed that LCD was associated with decrease in body weight (-0.70 kg [95% CI -1.07/-0.33]) or fat mass (-0.77 kg [-1.55/-0.32]). Subgroup meta-analysis of studies in over 12 months suggested that LCD was not associated with decrease in body weight (-0.44 kg [-0.94/0.07]), but LCD was associated with decrease in fat mass (-0.57 kg [-1.05/-0.09]). In addition, very LCD was associated with decrease in fat mass (-0.97 kg [-1.50/-0.44]), but mild LCD was not associated with decrease in fat mass (-0.43 kg [-1.15/0.33]). LCD, especially very LCD, might be effective for decrease in fat mass in obese individuals. © 2016 World Obesity.

Influence of a low-carbohydrate diet on endothelial microvesicles in overweight women

Low-carbohydrate diets (LCD) are increasing in popularity, but their effect on vascular health has been questioned. Endothelial microvesicles (EMV) are membrane-derived vesicles with the potential to act as a sensitive prognostic biomarker of vascular health and endothelial function. The aim of this study was to examine the influence of a LCD on EMV and other endothelial biomarkers of protein origin. Twenty-four overweight women (age, 48.4 ± 0.6 years; height, 1.60 ± 0.07 m; body mass, 76.5 ± 9.1 kg; body mass index, 28.1 ± 2.7 kg·m(-2); waist circumference, 84.1 ± 7.4 cm; mean ± standard deviation) were randomised to either 24 weeks on their normal diet (ND) or a LCD, after which they crossed over to 24 weeks on the alternative diet. Participants were assisted in reducing carbohydrate intake, but not below 40 g·day(-1). Body composition and endothelial biomarkers were assessed at the crossover point and at the end of the study. Daily carbohydrate intake (87 ± 7 versus 179 ± 11 g) and the percentage of energy derived from carbohydrate (29% versus 44%) were lower (p < 0.05) on the LCD compared to the ND, but absolute fat and saturated fat intake were unchanged. Body mass and waist circumference were 3.7 ± 0.8 kg and 3.5 ± 1.0 cm lower (p < 0.05), respectively, after the LCD compared with the ND phases. CD31(+)CD41(-)EMV, soluble (s) thrombomodulin, sE-selectin, sP-selectin, serum amyloid A and C-reactive protein were lower (p < 0.05) after the LCD compared to the ND, but serum lipids and apolipoproteins were not different. EMV along with a range of endothelial and inflammatory biomarkers are reduced by a LCD that involves modest weight loss.

Effect of nutritional status and dietary patterns on human serum C-reactive protein and interleukin-6 concentrations

The inflammatory process plays an important role in the pathogenesis of many chronic diseases, such as cardiovascular diseases, diabetes mellitus type 2, and metabolic syndrome. Serum C-reactive protein (CRP) and interleukin-6 (IL-6) are widely tested inflammatory markers involved in the development of these diseases. Several studies indicate a relation between nutritional status and the concentrations of human high-sensitivity CRP and IL-6. Similarly, the role of diet in reducing inflammation and thereby modulating the risk of non-communicable diseases is supported by numerous studies. This review focuses on the effects of the selected nutrition models in humans on the concentrations of CRP and IL-6. It seems that the Mediterranean diet model is most effective in inhibiting inflammation. The Dietary Approaches to Stop Hypertension model and the plant nutrition model also have proven to be beneficial. The data on low-fat and low-carbohydrate diets are inconclusive. Comprehensive studies are necessary, taking into account the cumulative effect of dietary and other factors on the inflammatory process.

Effect of 12 Weeks High Oleic Peanut Consumption on Cardio-Metabolic Risk Factors and Body Composition

Epidemiological evidence indicates an inverse association between nut consumption and obesity, inflammation, hyperlipidaemia and glucose intolerance. We investigated effects of high oleic peanut consumption vs. a nut free diet on adiposity and cardio-metabolic risk markers. In a randomised cross-over design, 61 healthy subjects (65 ± 7 years, body mass index (BMI) 31 ± 4 kg/m²) alternated either high oleic peanuts (15%-20% of energy) or a nut free diet for 12 weeks. Body composition and mass, waist circumference, C-reactive protein (CRP), lipids, glucose and insulin were assessed at baseline and after each phase. Repeated measures analysis of variance (ANOVA) compared the two diets. Consistent with other nut studies, there were no differences in lipids, CRP, glucose and insulin with peanut consumption. In contrast, some reports have demonstrated benefits, likely due to differences in the study cohort. Energy intake was 10% higher (853 kJ, p < 0.05), following peanut consumption vs. control, attributed to a 30% increase in fat intake (p < 0.001), predominantly monounsaturated (increase 22 g, p < 0.05). Despite greater energy intake during the peanut phase, there were no differences in body composition, and less than predicted increase (0.5 kg) in body weight for this additional energy intake, possibly due to incomplete nutrient absorption and energy utilisation.

Weight Loss, Dietary Intake and Pulse Wave Velocity

We have recently conducted a meta-analysis to determine the effect of weight loss achieved by an energy-restricted diet with or without exercise, anti-obesity drugs or bariatric surgery on pulse wave velocity (PWV) measured at all arterial segments. Twenty studies, including 1,259 participants, showed that modest weight loss (8% of the initial body weight) caused a reduction in PWV measured at all arterial segments. However, due to the poor methodological design of the included studies, the results of this meta-analysis can only be regarded as hypothesis generating and highlight the need for further research in this area. In the future, well-designed randomised controlled trials are required to determine the effect of diet-induced weight loss on PWV and the mechanisms involved. In addition, there is observational evidence that dietary components such as fruit, vegetables, dairy foods, sodium, potassium and fatty acids may be associated with PWV, although evidence from well-designed intervention trials is lacking. In the future, the effect of concurrently improving dietary quality and achieving weight loss should be assessed in randomised controlled trials.

Carbohydrates and endothelial function: is a low-carbohydrate diet or a low-glycemic index diet favourable for vascular health?

Low-carbohydrate diets have become increasingly popular in both media and clinical research settings. Although they may improve some metabolic markers, their effects on arterial function remain unclear. Endothelial dysfunction is the well-established response to cardiovascular risk factors and a pivotal feature that precedes atherosclerotic diseases. It has been demonstrated that a high carbohydrate-induced hyperglycemia and subsequent oxidative stress acutely worsen the efficacy of the endothelial vasodilatory system. Thus, in theory, a carbohydrate restricted diet may preserve the integrity of the arterial system. This review attempts to provide insight on whether low-carbohydrate diets have a favorable or detrimental impact on vascular function, or it is perhaps the quality of carbohydrate that should direct dietary recommendations. Research to date suggests that diets low in carbohydrate amount may negatively impact vascular endothelial function. Conversely, it appears that maintaining recommended carbohydrate intake with utilization of low glycemic index foods generates a more favorable vascular profile. Understanding these relationships will aid in deciphering the diverging role of modulating quantity and quality of carbohydrates on cardiovascular risk.

Palmolein and olive oil consumed within a high protein test meal have similar effects on postprandial endothelial function in overweight and obese men: A randomized controlled trial

OBJECTIVE

This study assessed the postprandial effects of high fat, high protein meals containing either palmolein or olive oil on endothelial function in overweight/obese men.

DESIGN

28 men (32-65 yr; 25-35 kg/m(2)) consumed, in random order 1 wk apart, isocaloric high protein, high fat meals (2791 kJ, 40 g protein (∼3 g l-arginine), 44 g fat, 21 g carbohydrate) prepared with either 40 g palmolein or 40 g olive oil after an overnight fast. The SFA:MUFA:PUFA ratio of the oils were: palmolein, 42:47:12; olive oil, 17:76:7. Brachial artery flow-mediated dilatation (FMD), circulating endothelial function markers, nitrotyrosine (oxidative stress marker), triglycerides, glucose and insulin were assessed pre-meal and hourly for 5 h. Mixed model procedures were used to analyze the data.

RESULTS

Meal consumption increased serum triglycerides (time effect, P < 0.001); with no meal differences (meal × time interaction, P = 0.93). Serum insulin peaked 1 h post-consumption and returned to pre-meal concentrations by 5 h with both meals (time effect, P < 0.001; meal × time effect, P = 0.68). FMD, serum intercellular adhesion molecule-1 (ICAM-1) and E-selectin did not change (meal × time effect, P > 0.4). Olive oil transiently increased plasma nitrotyrosine after 1 h compared to palmolein (meal × time interaction, P = 0.002) whereas both meals increased serum vascular cell adhesion molecule-1 (VCAM-1) after 1 h (time effect, P < 0.001; meal × time interaction, P = 0.98). Both nitrotyrosine and VCAM-1 returned to pre-meal concentrations after 2 h.

CONCLUSION

In the context of a high protein meal, palmolein similarly to olive oil did not affect postprandial endothelial function in overweight/obese men.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR) (http://www.anzctr.org.au/default.aspx). Trial ID: ACTRN12613000136707.

Effect of aerobic exercise training on arterial stiffness in obese populations : a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Controversy exists as to whether aerobic exercise training decreases arterial stiffness in obese subjects. The aim of this study was to systematically review and quantify the effect of aerobic exercise training on arterial stiffness in obese populations.

METHODS

MEDLINE, Cochrane, Scopus, and Web of Science were searched up until May 2013 for trials assessing the effect of aerobic training interventions lasting 8 weeks or more on arterial stiffness in obese populations (body mass index ≥30 kg/m(2)). Standardized mean difference (SMD) in arterial stiffness parameters (augmentation index, β-stiffness, distensibility, pulse wave velocity, arterial waveforms) was calculated using a random-effects model. Subgroup and meta-regression analyses were used to study potential moderating factors.

RESULTS

Eight trials, comprising a total of 235 subjects with an age range of 49-70 years, met the inclusion criteria. Arterial stiffness was not significantly reduced by aerobic training (SMD -0.17; 95 % confidence interval (CI) -0.39, 0.06, P = 0.14). Similarly, post-intervention arterial stiffness was similar between the aerobic-trained and control obese groups (SMD 0.02; 95 % CI -0.28, 0.32, P = 0.88). Neither heterogeneity nor publication bias were detected in these analyses. In subgroup analyses, arterial stiffness was significantly reduced in aerobic-trained subgroups having below median values in post- minus pre-intervention systolic blood pressure (SBP) (P < 0.01), exercise intensity rating score (P < 0.01), and methodological quality score (P < 0.01). Equivalent results were obtained in meta-regression analyses.

CONCLUSION

Based on current published trials, arterial stiffness is generally not reduced in middle-aged and older obese populations in response to aerobic training. However, in studies using low-intensity aerobic training and yielding a decrease in SBP, arterial stiffness may decrease. Long-term studies are needed to assess the prognostic value of these findings.

Weight loss improves fasting flow-mediated vasodilation in adults: a meta-analysis of intervention studies

BACKGROUND

Obesity is associated with vascular endothelial dysfunction. Effects of weight loss on endothelial function are however not clear. Therefore, we performed a meta-analysis to quantify effects of weight loss on flow-mediated vasodilation (FMD) of the brachial artery, a measurement of endothelial function.

METHODS

Studies with experimental (RCTs) and quasi-experimental designs published before June 2014 were identified by a systematic search. Changes in FMD were defined as the difference between measurements before and after the study. For RCTs, changes were corrected for those in the no-weight loss control group. Summary estimates of weighted mean differences (WMDs) in FMD and 95% confidence intervals (CIs) were calculated using random-effect meta-analyses. The impact of subject characteristics, type of weight-loss treatment, and dietary composition on changes in FMD was also investigated.

RESULTS

Four RCTs involving 265 subjects were included. Weight loss increased FMD vs. control by 3.29% (95% CI: 0.98-5.59%; P = 0.005; mean weight loss: 8.6 kg). A total of 1517 subjects participated in 33 studies with 49 relevant study arms. It was estimated that each 10 kg decrease in body weight increased fasting FMD by 1.11% (95% CI: 0.47-1.76%; P = 0.001). Effects were more pronounced when participants had coexisting obesity-related morbidities. Also, effects may be larger when subjects received low-fat diets or weight-reduction regimens including exercise therapy or weight-loss medication.

CONCLUSION

Weight loss significantly improves fasting FMD in adults, which is a risk marker for cardiovascular disease. Effects may depend on subject characteristics, type of weight-loss treatment, and dietary composition.