Prevalence and interrelationships between cardio-metabolic risk factors in abdominally obese individuals

Phenotypic and metabolic dichotomy in obesity: clinical, biochemical and immunological correlates of metabolically divergent obese phenotypes in healthy South Asian adults

INTRODUCTION

Metabolic heterogeneity among obese individuals is thought to translate into variations in cardiovascular risk. Identifying obese people with an unfavourable metabolic profile may allow preventive strategies to be targeted at high-risk groups. This study aimed to identify clinical, biochemical and immunological differences between insulin-sensitive and insulin-resistant obese subgroups, to understand the population-specific pathophysiological basis of the adverse cardiovascular risk profile in the latter group.

METHODS

Cardiovascular risk indicators, including anthropometric parameters, blood pressure, acanthosis nigricans area, and related biochemical, endocrine and inflammatory markers, were determined in 255 healthy South Asian volunteers aged 18-45 years, with a 2:1 ratio of obese/overweight to normal-weight individuals. Lifetime atherosclerotic cardiovascular disease (ASCVD) risk was also calculated.

RESULTS

Body mass index (BMI) and insulin sensitivity-based tertiles independently showed incremental trends in waist-hip ratio, skinfold thickness, acanthosis nigricans area, blood pressure, serum lipids, hepatic enzymes, adipokines, inflammatory markers and ten-year ASCVD risk. The anthropometric, biochemical and inflammatory parameters of obese insulin-sensitive and obese insulin-resistant groups differed significantly. Extreme group analysis after excluding the middle tertiles of both insulin resistance and BMI also showed significant difference in anthropometric indicators of cardiovascular risk and estimated lifetime ASCVD risk between the two obese subgroups.

CONCLUSION

Obese insulin-sensitive individuals had a favourable metabolic profile compared to the obese insulin-resistant group. The most consistent discriminative factor between these phenotypic classes was anthropometric parameters, which underscores the importance of clinical parameters as cardiovascular risk indicators in obesity.

Dairy foods and dairy protein consumption is inversely related to markers of adiposity in obese men and women

A number of intervention studies have reported that the prevalence of obesity may be in part inversely related to dairy food consumption while others report no association. We sought to examine relationships between energy, protein and calcium consumption from dairy foods (milk, yoghurt, cheese, dairy spreads, ice-cream) and adiposity including body mass index (BMI), waist (WC) and hip circumference (HC), and direct measures of body composition using dual energy X-ray absorptiometry (% body fat and abdominal fat) in an opportunistic sample of 720 overweight/obese Australian men and women. Mean (SD) age, weight and BMI of the population were 51 ± 10 year, 94 ± 18 kg and 32.4 ± 5.7 kg/m², respectively. Reduced fat milk was the most commonly consumed dairy product (235 ± 200 g/day), followed by whole milk (63 ± 128 g/day) and yoghurt (53 ± 66 g/day). Overall dairy food consumption (g/day) was inversely associated with BMI, % body fat and WC (all p < 0.05). Dairy protein and dairy calcium (g/day) were both inversely associated with all adiposity measures (all p < 0.05). Yoghurt consumption (g/day) was inversely associated with % body fat, abdominal fat, WC and HC (all p < 0.05), while reduced fat milk consumption was inversely associated with BMI, WC, HC and % body fat (all p < 0.05). Within a sample of obese adults, consumption of dairy products, dairy protein, and calcium was associated with more favourable body composition.

Cardiac insulin resistance and microRNA modulators

Cardiac insulin resistance is a metabolic and functional disorder that is often associated with obesity and/or the cardiorenal metabolic syndrome (CRS), and this disorder may be accentuated by chronic alcohol consumption. In conditions of over-nutrition, increased insulin (INS) and angiotensin II (Ang II) activate mammalian target for rapamycin (mTOR)/p70 S6 kinase (S6K1) signaling, whereas chronic alcohol consumption inhibits mTOR/S6K1 activation in cardiac tissue. Although excessive activation of mTOR/S6K1 induces cardiac INS resistance via serine phosphorylation of INS receptor substrates (IRS-1/2), it also renders cardioprotection via increased Ang II receptor 2 (AT2R) upregulation and adaptive hypertrophy. In the INS-resistant and hyperinsulinemic Zucker obese (ZO) rat, a rodent model for CRS, activation of mTOR/S6K1signaling in cardiac tissue is regulated by protective feed-back mechanisms involving mTOR↔AT2R signaling loop and profile changes of microRNA that target S6K1. Such regulation may play a role in attenuating progressive heart failure. Conversely, alcohol-mediated inhibition of mTOR/S6K1, down-regulation of INS receptor and growth-inhibitory mir-200 family, and upregulation of mir-212 that promotes fetal gene program may exacerbate CRS-related cardiomyopathy.

Dairy consumption and metabolic syndrome: a systematic review of findings and methodological issues

A growing body of observational research suggests that dairy consumption may have a beneficial effect on the metabolic syndrome (MetS). MetS is a clustering of cardiometabolic risk factors within an individual that carries with it an increased risk of developing cardiovascular disease. A systematic search of electronic databases identified cross-sectional studies (n = 10) and prospective cohort studies (n = 3) that assessed dairy intake in relation to MetS. The quality of the included studies was assessed based on study methodology, measurement and reporting of dietary intake, use of standardized MetS diagnostic criteria and statistical analysis. Dairy intake was inversely associated with incidence or prevalence of MetS in seven out of 13 studies. Three studies found no association between dairy and MetS. Three studies reported mixed relationships between specific dairy foods and MetS. The majority of studies suggested a potential benefit of dairy consumption on the risk of having MetS, but methodological differences, potential biases and other limitations in the studies conducted prevent conclusions to be drawn. Future randomized controlled trials are needed to confirm the effect of dairy consumption on MetS.