Nutrition research
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Consumption of a high-fat diet (HFD) is correlated with increased oxidative stress and chronic inflammation in many organs. Regulatory T cells (Tregs) are essential negative regulators of inflammation. We hypothesized that resveratrol (trans-3,5,4'-trihydroxystilbene) could protect against HFD-induced oxidative stress and inflammation. ⋯ Then the experimental group was subdivided into DIO and diet-resistant groups according to their body weights, which were further supplemented with 0.03% resveratrol and 0.06% resveratrol, respectively, for an additional 13 weeks. Resveratrol prevented the accumulation of chronic oxidative stress and suppression of Tregs production in HFD mice, modulated changes of cytokines in the plasma and spleen, and decreased expressions of inflammatory mediators compared with those of the DIO group. Our results indicate that resveratrol, as a feasible effective supplement for HFD, can relieve oxidative stress, inhibit inflammatory genes expression, and increase Tregs number via aryl hydrocarbon receptor activation inhibited by HFD, especially in DIO mice.
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Dietary ratios of n-3/n-6 polyunsaturated fatty acids (PUFAs) have been implicated in controlling markers of metabolic disorders, including obesity, insulin resistance (IR), inflammation, and lipid profiles, which are also presumed to be partly related to type 2 diabetes mellitus (T2DM). However, molecular mechanisms of the different PUFAs related to metabolic disorders have not been systematically addressed. The present study aimed to investigate the impact of dietary n-3/n-6 PUFA ratios on obesity and IR and, further, to determine the underlying mechanisms. ⋯ Interestingly, these changes were accompanied with decreased expression levels of circulating pro-inflammatory cytokines, including tumor necrosis factor α, interleukin-6, and C-reactive protein. Moreover, the TLR4 protein and mRNA levels were markedly down-regulated by PUFA¹:¹ compared with SFA; however, PUFA¹:⁴ diet-fed rats failed to exhibit these changes. Cumulatively, our data highlight a role for a PUFA¹:¹ diet in the prevention of obesity and related metabolic disorders by suppressing the activation of TLR4, a critical modulator of pro-inflammatory cytokines.
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In our study, we hypothesized that higher caffeine intake would be associated with lower sleep duration among 13-year-old adolescents. In addition, we aimed to identify food sources of caffeine intake in this sample. Eligible participants were adolescents who were born in 1990 and attended school in Porto, Portugal, in 2003/2004. ⋯ Overall, boys had higher intakes of caffeine from soft drinks, and private school attendees, those who had parents with more education, who reported less television viewing time and had lower body mass index presented higher intakes of caffeine from chocolate. Considering sleeping more than 9.5 hours as a reference class, for each increase of 10 mg/d in caffeine intake, we found that the odds ratio of sleeping 8.5 hours or less was 1.12 (95% confidence interval, 1.06-1.19). Our results support the hypothesis that caffeine intake was inversely associated with sleep duration in adolescents.
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It is hypothesized that healthy dietary and physical activity choices will be inversely associated with coronary heart disease (CHD) risk factors. Results from a cross-sectional study of 294 first-year University of Rhode Island students were used for the analyses. The presence of CHD risk factors was defined by the National Cholesterol Education Program Adult Treatment Panel III guidelines. ⋯ Sugar intake (OR, 1.015; 95% CI, 1.004-1.026), saccharin intake (OR, 1.047; 95% CI, 1.015-1.080), and body mass index (BMI; OR, 1.139; 95% CI, 1.037-1.252) were associated with an increased risk of low high-density lipoprotein cholesterol; dietary fiber intake (OR, 0.934; 95% CI, 0.873-1.000) was associated with a decreased risk of low high-density lipoprotein cholesterol. Participants with a higher BMI were 9.4% more likely to have elevated fasting glucose (OR, 1.094; 95% CI, 1.004-1.192) and 193.6% more likely to have a larger waist circumference (OR, 2.936; 95% CI, 1.543-5.586). Dietary factors and BMI are better indicators of CHD risk than physical activity is in this population.
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Randomized Controlled Trial
Regional, but not total, body composition changes in overweight and obese adults consuming a higher protein, energy-restricted diet are sex specific.
Secondary analyses of data from 2 studies were used to assess the effects of protein intake and sex on diet-induced changes in body composition. The primary hypothesis was that the changes of body composition via energy restriction (ie, lean body mass [LBM], fat mass [FM], and bone) would be sex and diet specific. For 12 weeks, 43 male (study 1) and 45 female (study 2) overweight and obese adults consumed an energy-deficit diet (750 kcal/d less than energy needs) containing either 0.8 (normal protein [NP], 21 men and 23 women) or 1.4 g protein∙kg(-1)∙d(-1) (high protein [HP], 22 men and 22 women). ⋯ Protein intake did not influence these sex-specific responses or have any independent effects on changes in FM. In addition, protein intake did not influence bone mineral density responses over time; bone mineral density was reduced in women, but not in men. These findings indicate that higher protein intake during weight loss promotes the retention of LBM in both the trunk and legs despite the sex-specific changes in these body regions.