Mercury levels not linked to mental impairment in adults

06/05/05 The U.S. Tuna Foundation (USTF) has said that by showing that older Americans are not at risk from the trace amounts of mercury in fish, a new study from the Johns Hopkins Bloomberg School of Public Health should reassure the public -- men as well as women -- that eating fish, such as canned tuna, is safe and should be encouraged because of the many health benefits associated with seafood consumption.

Published in the April 20 issue of the Journal of the American Medical Association (JAMA), the new study finds no evidence of a link between mercury levels and older adults' performance on mental tests. Specifically, researchers from Johns Hopkins tested the blood mercury levels of 474 Baltimore residents aged 50-70 and also gave the study participants 12 tests covering memory, manual dexterity, intelligence, verbal skills, and other traits. After conducting their analysis, the researchers concluded that there is no risk of neurological problems or cognitive decline if seniors eat fish.

Of added significance, the new Johns Hopkins study shows that the amount of mercury in the blood of American seniors is well within the government's "recommended" range for even the more conservative subpopulation, pregnant women and women of childbearing age. Using the Environmental Protection Agency's (EPA) guideline of 5.8 micrograms per liter or less of mercury in the blood, the researchers found that the older Americans studied had an average blood level of mercury of 2.1 micrograms per liter. Since older Americans typically consume about the same amount of fish as younger adults, this study validates findings by the Centers for Disease Control and Prevention (CDC) that no one in the U.S. has anywhere near the amount of mercury in their system from eating seafood known to cause a health problem.

Complementing these findings, the Johns Hopkins study underscored the cardio-protective benefits of seafood consumption, which is why seniors are often encouraged to eat more fish. According to an extensive body of research, the omega-3 fatty acids in fish have been shown to reduce the risk of both sudden death and death from coronary heart disease in adults. Based on these findings, the 2005 Dietary Guidelines for Americans recommend that consumers eat two eight-ounce servings a week of foods, such as fish, that are rich in the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).