Omega 3 fatty acids have been shown to improve the health of human brains, as the presence of this type of oil seems to contribute to improved cognitive function. Some parents supplement their children’s diets for exactly this reason, as this study from the Public Library of Science shows, which included 362 healthy children. In older adults, the Omega 3s from fatty fish are shown to reduce the risk of dementia and Alzheimer’s, but there has been growing concern regarding the contamination of the fish supply with mercury.
It appears that the fear of mercury poisoning from eating fatty fish is unfounded. Mercury can be toxic to the brain, and especially in the aging brain, so it’s encouraging to see that the benefits from fish in the diet are seen regardless of the possibility of this toxic metal.
Relationship of brain health to fish consumption
Researchers unraveled the relationships between the brain’s health, fish consumption, and the presence of mercury in this study from Rush University published in the Journal of the American Medical Association. In this study, researchers looked at the brains of 286 autopsied patients, out of 554 total deceased study participants. Seafood intake was measured by a questionnaire given yearly to the study subjects. The pathologies they compared against were Alzheimer’s disease, micro- and macroinfarcts, and Lewy bodies.
At the conclusion of the study, it was found that those with moderate seafood consumption, at least once a week, had the least incidents of brain impairment. These individuals also were found to have the highest levels of mercury in the brain. It’s interesting to note that the increased mercury did not contribute to additional neuropathology. Since the participants were in housing situations that were subsidized or in retirement communities, it’s likely that the fish consumed were of the more common varieties, which tend to have low to moderate levels of mercury.
The effect of moderate seafood consumption
Dense plaque buildup and tangled neurons are the hallmarks of Alzheimer’s disease. What the researchers found in those with at least moderate seafood consumption was a decrease in the number and density of plaques, and fewer neuron tangles. The potential limit of this study is that the benefits were only seen in those with higher genetic risk factors for Alzheimer’s.
DHA is essential to the structure and function of the brain. As we age, the amount of DHA in the brain decreases. Those with a variant of the APOE gene, called APOE-4, are at greater risk for Alzheimer’s, as this variant have been observed to lose a greater amount of DHA to aging, contributing to the decline of cognitive function. The Framingham Heart Study gives an in-depth analysis of this correlation.
The Rush University study also looked at fish oil supplements, but since there was such a low frequency of use, no significant conclusion can be drawn from this study on supplementation.
Your clients may still have concerns over mercury consumption, so further research is warranted on ways to bind and remove mercury from the body, including ingestion of cilantro, parsley, chlorella, certain clays, and chelating agents. Since there are inadequate studies to support these methods, while they may help, choosing more wild fish and seafood instead of farmed can help reduce the intake of mercury, while still seeing the benefits to brain health.