Effect of flax and hemp seed oils on erythrocyte concentrations of eicosapentaenoic and docosahexaenoic acids in vegetarians

Abstract

Flax and hemp seed oils are rich sources of alpha-linolenic acid (ALA; 18:3n-3), which can be converted to eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in humans. We investigated the effects of these oils on erythrocyte concentrations of EPA, DHA, other fatty acids, and plasma lipids in healthy vegetarians. Twenty-two subjects consumed either one tablespoon of flax (7.1 g ALA) or hemp seed oil (2.2 g ALA) daily for twenty-eight days. Diet records were collected at baseline and during supplementation. Blood samples were collected at baseline and post-supplementation. No significant increases in plasma EPA, DHA or dihomo-gamma-linolenic acid (DGLA; 18:3n-6) were observed in either group. Significant increases in plasma high-density lipoprotein cholesterol (HDL) concentrations were observed in both groups. Flax and hemp seed oils were not effective at increasing erythrocyte EPA, DHA or DGLA concentrations but were effective at increasing HDL concentrations.