Mercury Testing Recommended Before Pregnancy

By By Michael Greger M.D.

Recent testing of mercury concentrations in three national brands of canned tuna found that "55 percent of all tuna examined was above the U.S. Environmental Protection Agency's safety level for human consumption." And the problem appears to be getting worse.

Previous studies in 1993 and 2004 showed concerning levels of mercury contamination in canned tuna, but not as high as it is now. VIDEO: Which brand of tuna has the most mercury?

Given the average level of mercury pollution found in canned tuna, researchers suggest that your average nine year old would exceed the EPA limit, even if they only ate one can of tuna every 6 weeks!

They conclude: "These results indicate that stricter regulation of the canned tuna industry is necessary to ensure the safety of sensitive populations such as pregnant women, infants, and children."

Some question whether the federal safety limits are sufficient. A recent review from researchers at Harvard and elsewhere on the adverse effects of mercury in fish proposed that the exposure limits set in the United States should be cut in half.

Already, current regulations in the US allow up to 10 times as much mercury as the EPA limit allows, therefore our fish can have 20 times more mercury than may be considered safe.

Because the EPA safety limit on mercury in fish may not sufficiently protect pregnant women in the US, a recommendation has been put forth that fish-eating women may want to get tested for mercury before considering getting pregnant.

It's a simple test. Since mercury basically contaminates our whole body, a hair sample is all that is needed. VIDEO: Testing for Mercury Before Consider Pregnancy

Studies on children of the neurobehavioral toxicity of mercury suggest that no level of mercury exposure can truly be considered safe, but pressure from the fish industry may be preventing safety limits from dropping further.

In my video Nerves of Mercury I profile a famous study published in the Journal of Pediatrics showing brain damage in adolescents at below the mercury limits placed on fish in this country.

As one former EPA toxicologist told the Wall Street Journal, "They really consider the fish industry to be their clients, rather than the U.S. public."

Mercury is not just a problem for children. Mercury and other toxic pollutants in fish is thought to be why the consumption of dark fish (such as salmon, swordfish, bluefish, mackerel, and sardines) may increase one's risk of atrial fibrillation, an irregularity of heart beat rhythm associated with stroke, dementia, heart failure and a shortened lifespan.

VIDEO: Red Fish, White Fish; Dark Fish, Atrial Fibrillation VIDEO: Fish Fog, fish consumption and neurobehavioral abnormalities VIDEO: Xenoestrogens & Sperm Counts and Fish Intake Biomarker: Industrial pollutants in fish

There are also natural toxins that can bioaccumulate up the aquatic food chain. VIDEO: Amnesic Seafood Poisoning addresses a rare toxin called domoic acid It can turn up in tuna and other seafood and can cause the loss of short-term memory.

Drugs can build up in fish. VIDEO: A Fine Kettle of Fluoxetine is a sequel to Prozac Residues in Fish about pharmaceuticals and personal care products in fish fillets.

For more on canned tuna: Carcinogenic Putrescine, The Effect of Canned Tuna on Future Wages, Amalgam Fillings vs. Canned Tuna, and Mercury in Vaccinations vs. Tuna

Michael Greger, M.D., an author and internationally recognized speaker on healthy eating has produced hundreds of nutrition videos available at Follow Dr. Greger on Twitter

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