Lipids. 1997 Mar; 32(3): 341-5.

Dietary docosahexaenoic acid as a source of eicosapentaenoic acid in vegetarians and omnivores.

Conquer JA, Holub BJ.

Department of Human Biology and Nutritional Sciences, University of Guelph, Ontario, Canada.

The utilization of dietary docosahexaenoic acid (DHA; 22:6n-3) as a source of eicosapentaenoic acid (EPA; 20:5n-3) via retroconversion was investigated in both vegetarians and omnivores. For this purpose, an EPA-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 increase 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 phospholipid (from 1.1 to 3.4 mol% in vegetarians and 1.4 to 3.9 mol% in omnivores). 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 phospholipid data, the retroconversion of DHA to EPA in vivo was estimated to be 9.4% overall with no significant difference between omnivores and vegetarians.