Entries in Mercury (4)


Study Links Prenatal Mercury Exposure to ADHD Symptoms

Jupiterimages/Thinkstock(BOSTON) -- A new study highlights the difficulty pregnant women face while eating for two, finding that more mercury exposure leads to a higher incidence of ADHD symptoms, while more fish consumption -- the main source of mercury exposure -- leads to a decreased risk.

"How much fish you eat is not equivalent to how much mercury you are exposed to," said study author Dr. Susan Korrick of Brigham and Women's Hospital.  "I think the public health conclusion that I would come to is that one can benefit from fish consumption, but it's important to try to consume fish that are low in mercury."

Researchers at Brigham and Women's tested more than 400 women for mercury about 10 days after they gave birth between 1993 and 1998, and asked them to fill out a survey about their fish consumption.  They measured the mercury in samples of the mothers' hair.  When the children were eight, researchers tested their cognitive abilities with a parent questionnaire and other tests, searching for symptoms of ADHD.  (It is important to note that these children were not diagnosed with clinical ADHD, but only exhibited some of the symptoms.)

Symptoms of ADHD, or attention deficit hyperactivity disorder, include inattention, hyperactivity and impulsive behavior, according to the National Institutes of Health.

Researchers say cutting fish out of the prenatal diet to avoid mercury exposure entirely is a bad idea, and pregnant women should look for fish that are low in mercury, such as salmon.

"It's elegantly showing the paradoxical paradigm that it's both good for you and bad for you," said Christina Chambers of the Organization of Teratology Information Specialists' Collaborative Research Center in San Diego, who read the study but was not involved in it.  Teratology is the study of abnormalities in physical development.

"They're finding the kids are slightly above average in the number of symptoms," Richard Gallegher, a professor of child and adolescent psychiatry at NYU Langone, said of the children born to mothers with higher mercury levels in their hair samples.  "They [the ADHD symptoms] can certainly impact how well kids are tending to things in school."

Researchers at Brigham and Women's also learned that pregnant women who ate more than two 6-ounce servings of fish a week were less likely to have children with these symptoms.  This is actually more than the Federal Food and Drug Administration recommends, which is only 12 ounces of fish a week.

Because the fish consumption survey was originally designed to look at organic chlorine contaminants, the fish were grouped by how much chlorine they were likely to contain -- not how much mercury they had, Korrick said.  As a result, the study could not name which fish increased ADHD symptoms and which did not.

Fish high in mercury include shark, swordfish and fresh tuna, Korrick said.  Fish with lower mercury levels -- which are also rich in healthy fats -- include salmon, rainbow trout and herring.  A third group, which has different health benefits but still is low in mercury, includes cod, shrimp and haddock.

Copyright 2012 ABC News Radio


Mercury from Fish Doesn't Increase Risk of Cardiovascular Disease

Jupiterimages/Thinkstock(BOSTON) -- According to a new study in the New England Journal of Medicine, eating omega-3 fatty acids is good for the heart and can lower the risk of cardiovascular disease. But fish also contain methylmercury, which has been linked in the past to an increase in the risk of cardiovascular disease. 

To determine if methylmercury levels were associated with cardiovascular disease, the authors measured levels of it in the toe clippings of almost 7,000 people.  The levels of mercury did correlate with reported fish consumption, but the authors found that there were no differences in the rates of heart disease, stroke, or cardiovascular disease in general between people with low or those with high levels of methylmercury. 

Therefore, there are no clinically relevant negative effects of mercury exposure on cardiovascular disease in adults, at least at the levels seen in this study.

Copyright 2011 ABC News Radio


FDA Panel Reviews Safety of Mercury Amalgam Dental Fillings

Photo Courtesy - Getty Images(WASHINGTON) -- A federal advisory panel is trying to decide whether the U.S. Food and Drug Administration relied on adequate science when it determined last year that mercury amalgam can safely be used to fill cavities in healthy people.  At the time, the FDA didn't find evidence that dental mercury hurts developing fetuses, young children and those more sensitive to its potential health effects.

The FDA's scientific review of evidence about dental amalgam fillings, commonly called "silver fillings" because of their silver-gray color, found them safe for adults and children at least six years old.  Dental amalgam is an approximately 50-50 mixture of liquid mercury and powdered metal alloy of silver, tin and copper.  When mixed, it forms a pliable putty-like substance that hardens into place.

The mercury in amalgam fillings, called elemental mercury, releases small amounts of mercury vapor -- a substance that at high levels can be toxic to the brain and kidneys.  Vapor levels are highest right after fillings have been placed in a tooth, and later if they're being removed or replaced.  People trying to stop the use of mercury in dentistry say mercury vapor levels are boosted by chewing, eating, brushing teeth and drinking hot liquids.

"Even in adults and children ages 6 and above who have 15 or more amalgam surfaces, mercury exposure due to dental amalgam fillings has been found to be far below the lowest levels associated with harm," according to an FDA document titled About Dental Amalgam Fillings.

Copyright 2010 ABC News Radio


New Ad 'Demands' Mercury-Free Flu Vaccine

Photo Courtesy- Getty Images(HUNTINGTON BEACH, Calif.) -- If you haven't gotten your flu shot yet, the vaccine safety organization SafeMinds has a message for you.

A new video campaign, running with other previews in movie theaters around nine cities nationwide beginning the day after Thanksgiving, will urge viewers -- especially pregnant mothers and children -- to "demand" your doctor give you a mercury-free flu vaccine this year.

The video features Lyn Redwood, executive director of SafeMinds, who warns that many flu vaccines contain mercury, suggested by the organization to be a potential toxin linked to neurodevelopmental disorders, including autism.

"Don't take the risk. Demand mercury-free flu shots," Redwood says in the video.

The public service announcement is one of the largest campaigns launched by SafeMinds yet.  The group estimates it will be viewed by more than half a million moviegoers.  But the message has many experts bracing for another turn on the vaccine-safety merry-go-round.

"I don't look at it as a PSA but as a PDA -- a public disservice announcement," said Dr. William Schaffner, chairman of preventive medicine at Vanderbilt University Medical Center.

Multi-dose vials of flu vaccines, which contain about ten flu shots in one vial, are the most common type of vaccine manufactured for public use.  Thimerosal, a compound that contains mercury, is used to preserve the vaccine.  However, vials that contain only a single dose of the flu shot, along with the nasal spray vaccine, are manufactured without thimerosal.  Those, according to SafeMinds, are the type of vaccines consumers should demand.

But many manufacturers don't make enough, and many local pharmacies and doctors' offices may not carry single-dose vaccines.  Some experts say they fear that consumers who will have to request and wait for the special order if providers will place them, may choose not to get vaccinated at all.

But according to SafeMinds executive director Redwood, the more people ask for thimerosal-free vaccines, the more likely doctors will keep them in stock.

Copyright 2010 ABC News Radio

ABC News Radio