The alpha and gamma tocopherol levels in serum are influenced by the dietary fat quality

Alpha tocopherol in serum is thought to be of importance in protecting lipids against oxidation and low serum levels of alpha tocopherol has been suggested to increase the risk for coronary heart disease. However, low levels of gamma, rather than alpha, tocopherol have been found in patients with manifest coronary heart disease and in populations with a high incidence of coronary heart disease.

The aim of this study was to determine the tocopherol concentrations in serum after two diets with identical nutrient content but with different fat quality, enriched in butter and rapeseed oil-based fats, respectively.

Twenty moderately hyperlipidemic, healthy subjects (six females and 14 males) participated in this double-blind cross-over study, where two isoenergetic diets were given in a randomized order during two 3-week periods, interrupted by a wash-out period of 3-4 weeks.

The lipid-corrected serum concentrations of alpha and gamma tocopherol increased during the diet rich in rapeseed oil (by 7 and 23%, respectively) compared with on the baseline diet (P < 0.001), while these concentrations decreased (by 5 and 37%, respectively, P < 0.01) during the diet rich in saturated fat. The ratio between alpha and gamma tocopherol decreased significantly during the rapeseed oil diet (-23%, P < 0.01) and increased (+46%, P < 0.001) during the butter diet.

Alpha and gamma tocopherol levels in serum are influenced by the type of fat used in the diet. The most unexpected finding is that the lipid-adjusted gamma tocopherol concentration significantly decreased by 37% during a diet rich in saturated fat with an increased ratio between alpha and gamma tocopherol, similar to the situation found in CHD patients.