A news study showing that conversion of the plant-based omega-3 ALA to the long-chain EPA and DHA may be increased in vegans and vegetarians who do not eat fish, could lead to fresh thinking about the value of different sources of omega-3s.
The study, the European Prospective Investigation into Cancer and Nutrition, of 14,422 people suggests that the body increases the conversion rate of ALA to EPA and DHA when direct sources of EPA and DHA are lower
The most striking result of this study was that despite having significantly lower intakes of EPA and DHA (associated with fish consumption), blood levels of EPA and DHA in vegans and vegetarians were approximately the same as regular fish eaters indicating that their bodies respond by increasing the conversion rate of ALA to the longer chain Omega 3s EPA and DHA. As the body would only be able to do this if it has enough ALA to begin with this could have implications for public health recommendations and highlight the importance of adequate ALA intake.
ALA is an Essential Fatty Acid that cannot be made by the body and the best source of ALA is from seeds and seed oils. It is also obtained from the green leaves of broad leafed plants and from green vegetables.
The recent study, led by Ailsa Welch from the University of East Anglia (and published in American Journal of Clinical Nutrition), analyzed intakes of omega-3 polyunsaturated fatty acids (PUFAs), in 14,422 men and women aged between 39 and 78, and correlated these with blood levels of ALA, EPA, and DHA in four groups: fish-eaters; non-fish-eating meat-eaters; vegetarians; and vegans.. Blood levels of fatty acids were measured in 4,902 people.
Results showed that omega-3 intakes were between 57 and 80 percent lower in the non-fish-eaters, compared with fish-eaters. However, the differences in plasma levels of DHA and EPA between the groups were much smaller. Indeed, the average EPA level in fish eaters was 64.7 micromoles per liter, compared with 57.1, 55.1, and 50 micromoles per liter for non-fish-eating meat-eaters, vegetarians, or vegans. Furthermore, the average DHA level in fish eaters was 271 micromoles per liter, compared with 241.3, 223.5, and 286.4 micromoles per liter for non-fish-eating meat-eaters, vegetarians, or vegans.
The researchers concluded: “One explanation for this observation may be due to increased conversion, and our data suggest that the precursor-product ration from plant-derived ALA to circulating long chain n-3 PUFAs was significantly greater in non-fish eaters than in those who ate fish,”
