Key Findings
The Omega 3 Index measures EPA plus DHA as a percentage of total fatty acids of red blood cell (RBC) membranes and shows good agreement with tissue n 3 fatty acid status. The goal is 8% but some studies show a mean Omega 3 Index of less than 4% in vegetarians and vegans. The author recommends that efforts be made to encourage high intakes of ALA (and less linoleic acid). Such strategies can take advantage of the health benefits of both n 3 fatty acids and a vegetarian diet.
ABSTRACT
The long chain n 3 (omega 3) fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), although originally synthesized by microorganisms in the oceans, are primarily obtained from the consumption of fish. Vegetarians, by definition, do not eat fish and thus consume virtually no EPA and DHA. Because conversion of the plant derived n 3 fatty acid alpha linolenic acid (ALA) to EPA and DHA is very low, n 3 tissue concentrations in vegetarians are lower than in omnivores. This review asks 2 questions: what is the evidence that increased n 3 concentrations reduce the risk of cardiovascular disease in vegetarians, and, if it does, how can vegetarians increase their blood and tissue concentrations of these animal derived fatty acids? At present, both cardiovascular risk markers and cardiovascular events appear to be significantly reduced in vegetarians compared with those in omnivores. If so, and in the absence of data to show that risk in vegetarians could be even lower with higher n 3 concentrations, then the second question becomes moot. However, the absence of evidence is not evidence of absence; therefore, at our present state of knowledge, increasing n 3 concentrations is not an unreasonable goal for vegetarians. This can be accomplished by a variety of approaches, including increased intakes of ALA, consumption of stearidonic acid enriched soybean oil (if and when it comes to the market), and the use of supplements containing EPA, DHA, or both derived from non animal sources (microalgae, biotech yeast, and, in the future, biotech plant oils). (Authors abstract)
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