Vegetarians and Vegans Have Lower Omega-3 Levels

Magdalena S Rosell, Zouë Lloyd-Wright, Paul N Appleby, et al. Long-chain n?3 polyunsaturated fatty acids in plasma in British meat-eating, vegetarian, and vegan men. American Journal of Clinical Nutrition 2005; 82: 327-334

Abstract

Background:
Plasma concentrations of long-chain n?3 polyunsaturated fatty acids are lower in vegetarians and in vegans than in omnivores. No data are available on whether these concentrations differ between long- and short-term vegetarians and vegans.

Objectives:
We compared plasma fatty acid composition in meat-eaters, vegetarians, and vegans and examined whether the proportions of eicosapentaenoic acid (20:5n-3; EPA), docosapentaenoic acid (22:5n-3; DPA), and docosahexaenoic acid (22:6n-3; DHA) were related to the subjects' duration of adherence to their diets or to the proportions of plasma linoleic acid (18:2n-6; LA) and alpha-linolenic acid (18:3n-3; ALA).

Design:
The present cross-sectional study included 196 meat-eating, 231 vegetarian, and 232 vegan men in the United Kingdom. Information on anthropometry, diet, and smoking habits was obtained through a questionnaire. Total fatty acid composition in plasma was measured.

Results:
The proportions of plasma EPA and DHA were lower in the vegetarians and in the vegans than in the meat-eaters, whereas only small differences were seen for DPA. Plasma EPA, DPA, and DHA proportions were not significantly associated with the duration of time since the subjects became vegetarian or vegan, which ranged from <1 y to >20 y. In the vegetarians and the vegans, plasma DHA was inversely correlated with plasma LA.

Conclusions:
The proportions of plasma long-chain n-3 fatty acids were not significantly affected by the duration of adherence to a vegetarian or vegan diet. This finding suggests that when animal foods are wholly excluded from the diet, the endogenous production of EPA and DHA results in low but stable plasma concentrations of these fatty acids.

COMMENT: Our bodies need the long-chain fatty acids for brain development, among other things. They can make EPA and DHA from alpha-linolenic acid, but the amount of ALA in plant foods is small and the amount of EPA and DHA is nil. When vegans rant on about others eating animal foods, and members of animal rights groups commit acts of terrorism, we should bear in mind that, if they are taking their own advice, their brains might not be functioning properly.