INCORPORATION OF N-3 FATTY-ACIDS INTO PLASMA-LIPID FRACTIONS, AND ERYTHROCYTE-MEMBRANES AND PLATELETS DURING DIETARY SUPPLEMENTATION WITH FISH, FISH-OIL, AND DOCOSAHEXAENOIC ACID-RICH OIL AMONG HEALTHY-YOUNG MEN

The effects of n-3 fatty acid supplementation in the form of fresh fis h, fish oil, and docosahexaenoic acid (DHA) oil on the fatty acid comp osition of plasma lipid fractions, and platelets and erythrocyte membr anes of young healthy male students were examined. Altogether 59 subje cts (aged 19-32 yr, body mass index 16.8-31.3 kg/m(2)) were randomized into the following diet groups: (i) control group; (ii) fish diet gro up eat ing fish meals five times per week [0.38 +/- 0.04 g eicosapenta enoic acid (EPA) and 0.67 +/- 0.09 g DHA per day]; (iii) DHA oil group taking algae-derived DHA oil capsules (1.68 g/d DHA in triglyceride f orm); and (iv) fish oil group (1.33 g EPA and 0.95 g DHA/d as free fat ty acids) for 14 wk. The fatty acid composition of plasma lipids, plat elets, and erythrocyte membranes was analyzed by gas chromatography. T he subjects kept 4-d food records four times during the study to estim ate the intake of nutrients. In the fish diet, in DHA oil, and in fish oil groups, the amounts of n-3 fatty acids increased and those of n-6 fatty acids decreased significantly in plasma lipid fractions and in platelets and erythrocyte membranes. A positive relationship was shown between the total n-3 polyunsaturated fatty acids (PUFA) and EPA and DHA intake and the increase in total n-3 PUFA and EPA and DHA in all l ipid fractions analyzed. DHA was preferentially incorporated into phos pholipid (PL) and triglyceride (TG) and there was very little uptake i n cholesterol ester (CE), while EPA was preferentially incorporated in to PL and CE. The proportion of EPA in plasma lipids and platelets and erythrocyte membranes increased also by DHA supplementation, and the proportion of linoleic acid increased in platelets and erythrocyte mem branes in the DHA oil group as well. These results suggest retroconver sion of DHA to EPA and that DHA also interferes with linoleic acid met abolism.