Distribution of serum concentrations of α-tocopherol and γ-tocopherol in the US population 1–3

Abstract

Although the population distribution of serum concentrations of alpha-tocopherol has been described in the United States, little is known about the distribution of gamma-tocopherol or the ratio of alpha-tocopherol to gamma-tocopherol. Our aim was to describe the distribution of serum concentrations of alpha-tocopherol and gamma-tocopherol in a nationally representative sample of US adults. We reviewed data from 4087 adults aged >/=20 y who participated in the National Health and Nutrition Examination Survey (1999-2000). Concentrations of alpha-tocopherol and gamma-tocopherol were measured by using HPLC with ultraviolet-visible wavelength detection. The arithmetic mean (+/-SEM) of serum concentrations of alpha-tocopherol was 30.09 +/- 0.45 micromol/L, the median was 25.94 micromol/L, and the geometric mean (+/-SEM) was 27.39 +/- 0.38 micromol/L. The arithmetic mean of serum concentrations of gamma-tocopherol was 5.74 +/- 0.22 micromol/L, the median was 5.25 micromol/L, and the geometric mean was 4.79 +/- 0.18 micromol/L. The median ratio of alpha-tocopherol to total cholesterol was 4.93 micromol/mmol, that of gamma-tocopherol to total cholesterol was 1.03 micromol/mmol, and that of alpha-tocopherol to gamma-tocopherol was 4.53 micromol/mmol. Concentrations of alpha-tocopherol increased significantly (P for trend < 0.001) with age and were significantly (P = 0.015) lower in men than in women. African Americans and Mexican Americans had significantly (P < 0.001) lower concentrations of alpha-tocopherol than did whites. The median concentrations of gamma-tocopherol showed a trend with respect to age, did not differ significantly between men and women, and were slightly but nonsignificantly lower in white participants than in African American or Mexican American participants. Sociodemographic variations in serum concentrations of alpha-tocopherol and gamma-tocopherol exist among US adults.