Corn and sesame oils increase serum gamma-tocopherol concentrations in healthy Swedish women

We studied the effects of dietary intervention with three vegetable oils (Linola, corn or sesame oil, all good sources of gamma-tocopherol) on absolute and relative concentrations of alpha- and gamma-tocopherol in human serum. The oils contained only small amounts of linolenic acid but varying amounts of oleic and linoleic acids, and they had different concentrations of alpha-tocopherol. Forty healthy female students (mean age 26 y) were randomly assigned to one of three groups and consumed a diet that contained one of the three oils for 4 wk. Refined oils were distributed as ingredients in specially prepared buns, in margarine or as dressing. Serum tocopherols, serum lipoproteins and plasma malondialdehyde concentrations were measured. The gamma-tocopherol concentrations normalized to serum lipids increased significantly in the corn and sesame oil groups (P < 0.01), and the alpha-/gamma-tocopherol ratios decreased significantly from baseline concentrations in all groups (P < 0.05). The alpha-tocopherol concentrations did not change during the diet period in any of the three groups. Serum cholesterol, serum apolipoprotein B and plasma malondialdehyde concentrations decreased significantly only in the Linola oil group (P < 0.05). These data show that a moderately modified natural diet that contains both alpha- and gamma-tocopherol increases the serum gamma-tocopherol concentration in healthy women without affecting the serum alpha-tocopherol concentration.