DIETARY DOCOSAHEXAENOIC ACID AS A SOURCE OF EICOSAPENTAENOIC ACID IN VEGETARIANS AND OMNIVORES

The utilization of dietary docosahexaenoic acid (DHA; 22:6n-3) as a so urce of eicosapentaenoic acid (EPA; 20,5n-3) via retroconversion was i nvestigated in both vegetarians and omnivores. For this purpose, an EP A-free preparation of DHA was given as a daily supplement (1.62 g DHA) over a period of 6 wk. The dietary supplement provided for a marked i ncrease in DHA levels in both serum phospholipid (from 2.1 to 7.1 mol% in vegetarians and 2.2 to 7.6 mol% in omnivores) and platelet phospho lipid (from 1.1 to 3.4 mol% in vegetarians and 1.4 to 3.9 mol% in omni vores). EPA levels rose to a significant but much lesser extent, while 20:4n-6, 22:5n-6, and 22:5n-3 all decreased. Based on the serum phosp holipid data, the retroconversion of DHA to EPA in vivo was estimated to be 9.4% overall with no significant difference between omnivores an d vegetarians.