Short term supplementation of low-dose gamma-linolenic acid (GLA), alpha-linolenic acid (ALA), or GLA plus ALA does not augment LCP omega 3 status ofDutch vegans to an appreciable extent

Vegans do not consume meat and fish and have therefore low intakes of long chain polyunsaturated fatty acids (LCP). They may consequently have little negative feedback inhibition from dietary LCP on conversion of alpha -linol enic acid (ALA) to the LCP omega3 eicosapentaenoic (EPA) and docosahexaenoi c (DHA) acids. We investigated whether supplementation of nine apparently h ealthy vegans with 2.01 g ALA (4 ml linseed oil),1.17 g gamma-linolenic aci d (GLA) (6 ml borage oil) or their combination increases the LCP omega3 con tents of erythrocytes (RBC) and platelets (PLT), and of plasma phospholipid s (PL), cholesterol esters (CE) and triglycerides (TG). The supplements cha nged the dietary LA/ALA ratio (in g/g) from about 13.7 (baseline) to 6.8 (l inseed oil), 14.3 (borage oil) and 6.4 (linseed + borage oil), respectively . ALA or GLA given as single supplements did not increase LCP omega3 status , but their combination augmented LCP omega3 (in CE) and EPA (in fasting TG ) to a statistically significant, but nevertheless negligible, extent. We c onclude that negative feedback inhibition by dietary LCP, if any, does not play an important role in the inability to augment notably DHA status by di etary ALA. The reach of a DHA plateau already at low dietary ALA intakes su ggests that dietary DHA causes a non-functional DHA surplus, or is, alterna tively, important for maintaining DHA status at a functionally relevant lev el. (C) 2000 Harcourt Publishers Ltd.