The adipocyte-derived hormones leptin [which circulates in a free form and bound to a soluble leptin receptor (sOB-R)], adiponectin, and resistin play a key role in regulating energy homeostasis and metabolism. We assessed the association between body composition, total energy, and macronutrient intake and serum leptin, sOB-R, free leptin index, adiponectin, and resistin concentrations in 61 female and 53 male consecutively enrolled healthy Greek students. In this cross-sectional study, total energy and macronutrient intake were determined using 3-d food records. Body composition was assessed by bioelectrical impedance analysis; fasting blood samples were taken for the measurement of total leptin, sOB-R, adiponectin, and resistin; and the ratio leptin/sOB-R was used as an index of free leptin. Serum sOB-R concentrations were lower in the female subjects compared with the males (27.24 +/- 29.06 vs. 50.14 +/- 39.74 ng/ml, P < 0.001), whereas leptin, adiponectin, and resistin concentrations were significantly higher in females (leptin: 9.93 +/- 6.01 vs. 3.27 +/- 2.54 ng/ml, P < 0.001; adiponectin: 11.40 +/- 6.73 micro g/ml vs. 4.90 +/- 2.79 micro g/ml; P < 0.001; resistin: 16.86 +/- 5.39 ng/ml in females vs. 14.00 +/- 7.16 ng/ml in males, P < 0.02). Simple regression analysis showed that, in both genders, leptin, free leptin index, adiponectin, and resistin correlated positively with body fat mass and negatively with waist to hip ratio. sOB-R correlated negatively with body fat mass and positively with waist to hip ratio. Multiple regression analysis models controlling for gender, body fat, and total energy intake demonstrated that sOB-R is positively associated with energy intake from carbohydrates and negatively with energy intake from dietary fat, whereas free leptin index is negatively associated with energy intake from carbohydrates and positively with energy intake from dietary fat. No statistically significant correlations were observed between serum adiponectin or resistin concentrations and total energy or macronutrient intake. Thus, total energy intake and macronutrient composition of the diet are associated with sOB-R and free leptin index but do not play a role of comparable significance in predicting adiponectin and resistin concentrations in healthy young subjects.

In conclusion, the consumption of the WB drink for 6 weeks significantly reduced the levels of oxidized DNA bases and increased the resistance to oxidatively induced DNA damage. Future studies should address in greater detail the role of WB in endothelial function.

Wild blueberries are a rich source of polyphenols and other compounds that are highly metabolized by the intestinal microbiota and may, at the same time, affect the intestinal environment itself. A repeated-measure, crossover dietary intervention on human volunteers was designed to study the effect of six week consumption of a wild blueberry ( Vaccinium angustifolium ) drink, versus a placebo drink, in modulating the intestinal microbiota. Relative to total eubacteria, Bifidobacterium spp. significantly increased following blueberry treatment (P ≤ 0.05), while Lactobacillus acidophilus increased after both treatments (P ≤ 0.05). No significant differences were observed for Bacteroides spp., Prevotella spp., Enterococcus spp., and Clostridium coccoides . Bifidobacteria, which have been largely proposed to be of benefit for the host, appeared to be selectively favored suggesting an important role for the polyphenols and fiber present in wild blueberries. Results obtained suggest that regular consumption of a wild blueberry drink can positively modulate the composition of the intestinal microbiota.

Genetic variation at the leptin receptor gene locus may play an important role in the pathophysiology of human obesity, a leptin-resistant state. Previous studies exploring potential associations between leptin receptor gene polymorphisms and obesity have reported conflicting results. The aim of this study was to evaluate a genetically homogeneous population for associations between body composition variables and three common leptin receptor gene polymorphisms (K109R, Q223R, and K656N) that have potential functional significance as well as to assess the contributions of these polymorphisms to the variability of obesity. One hundred and eighteen consecutively enrolled subjects (62 women: mean age, 17.5 +/- 1.6 yr; body mass index range, 16.2-30.1; 56 men: mean age, 17.8 +/- 1.8 yr; body mass index range, 15.4-35.9) were genotyped for the three polymorphisms, and their body mass index, sum of 4 skinfolds, fat-free mass, percent fat mass, serum leptin levels, caloric intake, fat intake, and exercise patterns were determined. Allele frequencies were estimated by the gene-counting method, and genotype distributions between 89 normal weight (body mass index, < or =25 kg/m(2)) and 29 overweight-obese (body mass index, >25 kg/m(2)) subjects were compared using chi(2) test (using codominant, dominant, and recessive models). Analysis of covariance was also performed to evaluate associations between the polymorphisms and body composition variables after controlling for potential confounders. For the Q223R polymorphism, there was a higher prevalence of the R223 allele in the homozygous form among overweight-obese subjects vs. normal weight subjects (20.7% vs. 4.5%; P = 0.01). Furthermore, simple and multiple regression analyses revealed that the R223 allele in the homozygous form is a significant predictor of both body mass index (P = 0.015) and percent fat mass (P = 0.02) even after adjusting for age and gender and explains 4.5% of the variance in percent fat mass and 5% of the variance in body mass index. There was no significant difference in allele frequencies or genotype distributions for the K109R or K656N polymorphisms. These findings support the hypothesis that the Q223R polymorphism (but not the K109R or K656N polymorphism) of the leptin receptor gene is associated with obesity and predicts a small percentage of body weight and body composition variability in a genetically homogeneous population.

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