Study Finds Eating Too Much Fish Can Harm Your Health

Omega-3 fatty acids normally found in fish, if taken in excess could have unintended health consequences in certain situations, suggests a new study.

"We are seeing the potential for negative effects at really high levels of omega-3 fatty acid consumption. Because we lack valid biomarkers for exposure and knowledge of who might be at risk if consuming excessive amounts, it isn't possible to determine an upper limit at this time," Norman Hord, associate professor in OSU's College of Public Health and Human Sciences and a coauthor on the paper, said.

Advantages of Eating Fish Foods - Health Benefits
Researchers worldwide have discovered that eating fish regularly is good for health. Regular consumption of fish may reduce the risk of diseases such as asthma, prostate cancer and eyesight.

Omega-3 fatty acids have anti-inflammatory properties, which is one of the reasons they can be beneficial to heart health and inflammatory issues. However, the researchers said excess amounts of omega-3 fatty acids can alter immune function sometimes in ways that may lead to a dysfunctional immune response to a viral or bacterial infection.

"The dysfunctional immune response to excessive omega-3 fatty acid consumption can affect the body's ability to fight microbial pathogens, like bacteria," the researcher said.

Generally, the researchers point out that the amounts of fish oil used in most studies are typically above what one could consume from foods or usual dosage of a dietary supplement.

Fish: The Best and The Worst
Some fish are contaminated with high levels of methyl mercury. Methyl mercury is a neurotoxin, which affects the pregnant or lactating mother’s child’s brain.

However, an increasing amount of products, such as eggs, bread, butters, oils and orange juice, are being "fortified" with omega-3s. Hord said this fortified food, coupled with fish oil supplement use, increases the potential for consuming these high levels.

"Overall, we support the dietary recommendations from the American Heart Association to eat fish, particularly fatty fish like salmon, mackerel, lake trout or sardines, at least two times a week, and for those at risk of coronary artery disease to talk to their doctor about supplements," he said.