Fishy Danger

Methylmercury has serious effects on health

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Nutritionists suggest fish as a healthier choice of protein, but certain fish are high in methylmercury. Methylmercury can be dangerous at high levels - especially for pregnant women.

Many Americans eat a variety of seafood. According to a 2007 New York City Department of Health and Mental Hygiene study, a quarter of all New Yorkers and one in every two Asian New Yorkers ate so much fish they surpassed the recommended amount for pregnant women. A new study wants to see the health effects this could cause.

"Pregnant fish lovers should inform their OB/GYN."

Jaymie Meliker, Ph.D., an assistant professor from the Department of Preventive Medicine at Stony Brook University School of Medicine, and lead author is currently recruiting participants for the Long Island Study of Seafood Consumption.

Meliker and team hope to find out the mercury cycles in the environment and the pros and cons of fish consumption.

In general, seafood is good for you, Meliker starts, but some fish have high levels of methylmercury and it’s important for the public to know the risks and benefits from eating these certain types of fish. Hopefully this study will be able to update current seafood recommendations as well as have a better method of communication to inform the public, she says.

Diane Shiao, P.T., M.S.P.T., D.P.T., says, “Fish is a great source of omega 3 fatty acids, calcium, and many minerals. However, pregnant women are warned against consuming too much seafood because of their susceptibility to the methylmercury poisoning.”

Shiao continues, “The consequences can be harmful if the infant's developing nervous system is permanently damaged which can lead to motor, visual, and brain damage. On occasion, the mothers may not have symptoms but the infants are born with severe disabilities.”

“Adult can be affected as well - symptoms of methylmercury poisoning present as nervous system impairments also which can range from limb paraesthesia to visual-spatial dysfunction. “

The study will examine a variety of different fish and measure certain nutrients in fish like omega-3 and omega-6 fatty acids and mercury and selenium. The current United States Department of Agriculture’s guideline for pregnant women is eight to twelve ounces per week.

Nuts, soy, beans and eggs provide similar benefits, Shiao suggests. But, if you can’t say no to fish, then at least try to avoid eating fish that are known to have high levels of mercury.

Fish that are high in mercury:

  • Swordfish
  • Marlin
  • King mackerel
  • Certain tuna: bluefin, yellow fin, big eye

The research is funded by The Gelfond Fund for Mercury Research and Outreach.

Reviewed by: 
Review Date: 
October 6, 2011
Last Updated:
October 18, 2011