Do the benefits of docosahexaenoic acid (DHA) outweigh the risk of mercury exposure?
The FDA recommendations regarding mercury are controversial. Some feel the EPA reference dose for mercury should be lowered because of the high cord-blood mercury concentration.14 However, the selenium in the fish may protect against high mercury levels.10 In addition, the positive effects of omega-3 fatty acids were not considered when these agencies were making their mercury recommendations. The long-chain polyunsaturated fatty acids, especially DHA, are important in the development of the nervous system, and the fetus accumulates DHA rapidly in the third trimester of pregnancy.15-17 Fatty fish are the most concentrated sources of DHA.17-19 Some believe that the risk of eating less fish (and thus, less omega-3 fatty acids) outweighs the increased risk of mercury exposure.20 Specific questions arise for tuna. Different species accumulate different levels of mercury, but, in general, smaller fish accumulate less. For that reason, advise caution with tuna steaks and sushi tuna. As for c
