The temporal effect of a wild blueberry (Vaccinium angustifolium)-enriched diet on vasomotor tone in the Sprague-Dawley rat.

BACKGROUND AND AIMS: We have previously reported that wild blueberry (Vaccinium angustifolium)-enriched diets (WB) attenuate aortic adrenergic response through endothelial-mediated pathways. The duration of dietary intervention necessary to induce the positive changes on vasomotor tone has not been studied to date. Thus, our objective was to investigate the temporal effect of WB consumption on vascular function and reactivity in Sprague-Dawley (SD) rat aorta after 4 and 7 weeks of dietary treatment. METHODS AND RESULTS: Forty male SD rats were randomly assigned to a control (AIN-93) (C) or a WB diet for 4 or 7 weeks. Vascular ring studies were conducted in 3-mm isolated rat aortic rings to investigate vasoconstriction induced by six doses of the α(1)-adrenergic agonist, L-phenylephrine (Phe, 10(-8)-3×10(-6) M) alone or in the presence of the NOS inhibitor, L-N(G)-monomethyl-arginine (L-NMMA, 10(-4)M). The maximum force of contraction (F(max)) and vessel sensitivity (pD(2)) were determined. Analysis of variance revealed no significant differences on F(max) after 4 weeks of the WB diet but only a significant increase in pD(2) in the absence of L-NMMA. Seven week WB consumption significantly attenuated contraction in response to L-Phe and resulted in lower pD(2). Inhibition of NOS induced a significant increase in the constrictor response in both diet groups at both time periods, with the WB group fed for 7 weeks having the greater response. CONCLUSION: Thus wild blueberries incorporated into the diet at 8% w/w positively affect vascular smooth muscle contractility and sensitivity but these effects are evident only after 7 weeks of WB consumption.

The Q223R polymorphism of the leptin receptor gene is significantly associated with obesity and predicts a small percentage of body weight and body composition variability.

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.

Disordered eating attitudes: an emerging health problem among Mediterranean adolescents.

Aim of the present study was to investigate eating attitudes in a group of Mediterranean high school students. One hundred and twenty high school students participated in this survey. The Eating Attitudes Test (EAT-26) was used for evaluating symptoms and attitudes associated with disordered eating. Body composition and dietary intake were also assessed. Using the cut-off point of 20 in the total EAT, 13 females (20.3%) and 4 males (7.3%) exhibited disordered eating behavior. Overweight students had significantly higher scores in the dieting scale than those in the normal BMI range. Percent fat mass was positively related to the total EAT (r=0.326, p<0.001) and the dieting scale (r=0.489, p<0.001). Waist/hip ratio was negatively related to total EAT and its scales. In conclusion, a significant percentage of students in this urban Mediterranean adolescent population found to have abnormal eating attitudes. This finding may be partly explained by the effect of cultural transition.