Serum concentrations of retinol, alpha-tocopherol and the carotenoids are influenced by diet, race and obesity in a sample of healthy adolescents

An important part of understanding the functions of vitamin A, vitamin E an d the carotenoids in nutritional status assessment, health promotion and di sease prevention is knowledge of factors that influence their distribution in human tissues. Our objective was to examine serum concentrations of thes e nutrients and compounds in a sample of 285 healthy participants, 12-17 y old, from three U.S. cities. Pearson correlations between diet measured wit h a food frequency questionnaire and serum nutrient concentrations among th ese adolescents (adjusted for total serum cholesterol, age, sex, race and b ody mass index) were as follows: retinol, 0.23; alpha -tocopherol, 0.16; al pha -carotene, 0.31; beta -carotene, 0.15; beta -cryptoxanthin, 0.38; lycop ene, 0.08; and lutein + zeaxanthin, 0.25. Multivariate linear regression mo deled associations of demographic, dietary and physiologic variables with s erum concentrations of these nutrients. African-American participants had s ignificantly lower concentrations of serum retinol (P < 0.001), <alpha>-toc opherol (P < 0.01) and <alpha>-carotene (P < 0.02), but higher concentratio ns of lutein + zeaxanthin (P = 0.001) compared with Caucasians. Obese parti cipants had serum nutrient concentrations that were 2-10% (P < 0.05) lower than normal weight participants. Dietary intake was a significant predictor of all serum analytes (P < 0.01) except lycopene. These models explained 2 0% of the variability in serum retinol, 28% of the variability in serum <al pha>-tocopherol, and 14-24% of the variability in serum carotenoids.