Serum alpha-tocopherol status in the United States population: findings from the Third National Health and Nutrition Examination Survey.

Despite the role vitamin E may have in protecting against various chronic conditions, little is known about vitamin E status in the US population. Using data from the Third National Health and Nutrition Examination Survey (1988-1994), the authors examined the distribution and correlates of serum alpha-tocopherol among 16,295 US adults aged 18 or more years. The mean concentration of alpha-tocopherol was 26.8 micromol/liter (geometric mean, 25.0 micromol/liter). The 25th, 50th, and 75th percentiles were 19.6, 24.1, and 30.4 micromol/liter, respectively. The mean alpha-tocopherol/cholesterol ratio was 5.1 (geometric mean, 4.9); the 25th, 50th, and 75th percentiles were 4.1, 4.7, and 5.5 (10(-3)), respectively. About 27% of the US population had a low alpha-tocopherol concentration (<20 micromol/liter). After age standardization, 29% of the men, 28% of the women, 26% of the Whites (men, 27%, and women, 26%), 41% of the African Americans (men, 42%, and women, 40%), 28% of the Mexican Americans (men, 29%, and women, 27%), and 32% of the other participants (men, 36%, and women, 29%) had this low concentration. For all participants, age, educational attainment, serum cholesterol, and several serum vitamins and carotenoids were directly related to and high density lipoprotein cholesterol was inversely related to serum alpha-tocopherol concentration in multiple linear regression analysis. Men had a higher concentration than did women, and African Americans had the lowest concentration of any racial or ethnic group. These results show that important proportions of US adults have a low serum alpha-tocopherol concentration, which may increase their risk for chronic diseases in which low dietary intake or blood concentration of alpha-tocopherol have been implicated.