An assessment of appropriate vitamin E content in fish oil capsules as estimated by lipid peroxide and vitamin E levels in human blood

To assess the appropriate content of vitamin E (VE) in fish oil capsules, w e determined lipid peroxide and VE levels in human blood after hyperlipidem ic female volunteers had beed given purified eicosapentaenoic acid (EPA) et hyl ester (90% purity) in capsules along with a controlled basal diet. A tw o consecutive 7-day menu cycle was used, and the capsules were taken with t he second 7-day menu. The basal diet was based on the recommended dietary a llowances for female Japanese with light physical activities. The faa energ y density of the diet was 25%, and the cholesterol intake was less than 300 mg per day. Each volunteer ingested nine capsules (2.43 g of EPA ethyl est er in total) daily in three divided doses, and a daily total of 5.4 mg of a ll-rac-alpha-tocopherol (4 mg RRR-alpha-tocopherol equivalent) from the cap sules. Blood was collected before and after 1 and 2 weeks of the basal diet periods. Triacylglycerol and total cholesterol concentrations in plasma we re determined, and plasma lipid peroxide levels as estimated by thiobarbitu ric acid reactive substances (TBARS) and water-soluble fluorescent substanc es (WSF) were also measured. In addition, alpha-tocopherol levels in plasma , red blood cells (REC), and platelets were analyzed. The plasma total chol esterol concentration decreased significantly after supplementation with th e capsules, but that of triacylglycerol did not change significantly. The T EARS values expressed as plasma concentration and in terms of plasma lipid levels did not change significantly in each case. An amelioration of plasma lipid levels effectively lowered the plasma concentration of WSF. The plas ma alpha-tocopherol concentration did not change significantly with the tre atment with the capsules, although the concentration decreased significantl y on the controlled basal diet with lower energy but without the supplement ation. Neither the alpha-tocopherol content in RBC nor that in platelets ch anged significantly during the test period. In conclusion, the VE content i n the EPA capsules appears to be sufficient to provide adequate antioxidant protection during the short period of the experiment. An assessment of app ropriate VE content in fish oil capsules is discussed by comparing the curr ent data with those reported elsewhere.