Metabolism: clinical and experimental
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Comparative Study
Influence of obesity on vitamin D-binding protein and 25-hydroxy vitamin D levels in African American and white women.
25-Hydroxy vitamin D (25OHD) is lipophilic and highly bound to vitamin D-binding protein (VDBP) in plasma. In the present study, we examined VDBP and 25OHD levels by race and body mass index (BMI) in young adult women to determine whether circulating VDBP plays a role in the low levels of 25OHD with obesity and among African Americans. In agreement with previous studies, mean 25OHD levels were lower in African American women than in whites (P < .01). ⋯ The VDBP levels, by contrast, were similar in African Americans and whites, and were unrelated to BMI in either racial group. Furthermore, VDBP was unrelated to the plasma level of 25OHD. These data confirm an interaction between race and obesity in vitamin D metabolism, and imply that the carrier protein is not an important determinant of circulating 25OHD in women, nor is it affected by race or adiposity.
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The international guidelines issued by the World Health Organization recommend reduction in dietary saturated fat and cholesterol intakes as means to prevent hypercholesterolemia and cardiovascular disease (CVD); however, only limited data are available on the benefits of fruit and vegetable consumption on CVD risk factors in a community-based population. The aim of this study was to examine whether, and to what extent, intake of fruits and vegetables is inversely associated with CVD risk factors in adults. In this population-based cross-sectional study, a representative sample of 840 Tehranian adults (male and female) aged 18 to 74 years was randomly selected in 1998. ⋯ This association was observed across categories of smoking status, physical activity, and tertiles of the Keys score. Exclusion of subjects with prevalent diabetes mellitus or coronary artery disease did not alter these results significantly. Consumption of fruits and vegetables is associated with lower concentrations of total and low-density lipoprotein cholesterol and with the risk of CVD per se in a dose-response manner.
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Hyperglycemic crises of diabetic ketoacidosis and nonketotic hyperglycemia are associated with elevation of counterregulatory hormones and proinflammatory cytokines, markers of lipid peroxidation, and oxidative stress. To investigate if other conditions besides hyperglycemia could evoke such a prompt increase in cytokine levels, lipid peroxidation, and oxidative stress markers, we induced hypoglycemic stress by standard insulin tolerance test and measured proinflammatory cytokines, markers of lipid peroxidation, reactive oxygen species (ROS), and counterregulatory hormones. Insulin tolerance test was performed in 13 healthy male subjects with no history of infection, cardiovascular risk factors, or abnormal glucose. ⋯ Corticotropin predicted area under the curve of IL-6 with borderline significance (P = .06). In the present study, insulin-induced hypoglycemia in nondiabetic male subjects is associated with increased proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6, and IL-8), markers of lipid peroxidation, ROS, and leukocytosis. Elevations of NE, EP, corticotropin, and cortisol in hypoglycaemia are associated with the elevation of the proinflammatory cytokines and leukocytosis.