Fish/Fish Oil: Mercury in Fish and Fish Oil

Fish: What Pregnant Women and Parents Should Know

Source: U.S. Food and Drug Administration

If you’re pregnant, you’ve no doubt been given a list of foods to avoid—undercooked meat, soft cheeses made from unpasteurized milk, and alcohol, to name a few. The good news is that there is a food you should have more of while pregnant and while breastfeeding: fish and shellfish. The latest science shows that eating fish low in mercury during pregnancy and in early childhood can help with growth and neurodevelopment. It can also be good for your health.

That’s why in June 2014 the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA)  issued draft revised advice encouraging pregnant women, those who might become pregnant, breastfeeding mothers and young children to eat more fish—and to eat a variety of fish lower in mercury.

It’s an important recommendation. An FDA analysis of data from U.S. pregnant women surveyed about seafood consumption showed that they ate far less fish than the 2010 Dietary Guidelines for Americans recommend. (The guidelines are the federal government’s most recent science-based advice for how to choose a healthy eating pattern.) In fact, 21 percent of the pregnant women surveyed said they ate no fish in the previous month. Of the women who ate fish in the previous month, 50 percent reported eating fewer than two ounces a week, and 75 percent reported eating fewer than four ounces per week.

“We’re updating our advice because the latest science strongly indicates that eating 8 to 12 ounces per week of a variety of fish lower in mercury during pregnancy benefits fetal growth and development,” says FDA’s Acting Chief Scientist Stephen Ostroff, M.D., noting that FDA reviewed research from the last decade.

Dr. Ostroff adds that 8 to 12 ounces is an excellent range to maximize the developmental benefits that fish can provide. “The science behind that recommendation was not available when we last issued fish consumption advice in 2004.”

The 2004 advice recommends eating up to 12 ounces of fish lower in mercury per week but doesn’t recommend a minimum amount to eat. The new draft advice does, recommending that women who might become pregnant along with pregnant and breastfeeding women eat at least eight ounces and up to 12 ounces weekly, which is two to three servings. This draft advice also extends to young children, although the amounts you serve them should be proportionally smaller.

Which Fish Should You Eat?

Fish and shellfish (collectively called “fish” for this advice) have high-quality protein, vitamins and minerals, and omega-3 fatty acids. Fish also are mostly low in saturated fat, and some have vitamin D. Eating fish during pregnancy, while breastfeeding, and in early childhood can be especially important for a child’s growth and development. Plus there is evidence that consuming fish can reduce your own risk of cardiac death.

The entire package of nutrients that fish provide may be needed to fully benefit fetal and child development. For this reason, consumers who avoid eating fish and instead take omega-3 supplements may be missing out on the full beneficial effect. Plus they miss out on other nutrients in fish that support overall health.

Eating a variety of fish helps ensure that most fish you eat will be lower in mercury. Most fish found in grocery stores are, in fact, lower in mercury, including many popular species such as shrimp, pollock, salmon, canned light tuna, tilapia, catfish and cod.

What About Mercury in Fish?

Fish do take in methylmercury (a form of mercury), and nearly all fish have traces of it. At high levels, methylmercury can be harmful, and developing fetuses can be especially sensitive to it. Young children may be sensitive as well. Some women may even limit or avoid fish because of this concern. That, however, is not what FDA and EPA recommend.

Eating a variety of fish, as FDA and EPA are recommending, will help ensure that most fish you eat will be lower in mercury. However, FDA and EPA are also recommending that women who might become pregnant, or who are pregnant or breastfeeding—along with young children—should try to avoid the four types of commercial fish with the highest levels of methylmercury: Tilefish from the Gulf of Mexico, shark, swordfish and king mackerel. This advice shouldn’t affect your eating patterns because these fish are not popular on the market.

Also remember that most fish found in grocery stores are lower in mercury, and it is these fish that have health benefits for you and your children.

Other Considerations

FDA and EPA continue to recommend that no more than six ounces of fish per week (of your 8 to 12 ounces weekly) should be white (albacore) tuna. Although canned light tuna is lower in mercury, albacore tuna has more of it. An easy way to follow this advice? Just vary the types of fish that you eat, per the overall recommendations.

And if you or someone you know goes fishing in a lake, stream, or river, follow local fish advisories. If local advice isn’t available, you should eat six ounces or less of these locally caught fish per week, and children should eat no more than one to three ounces per week. Then avoid eating other fish for the rest of the week.

The Bottom Line

“The science shows that eating fish has direct health benefits, so it’s important to get enough fish in your diet,” Ostroff says. “To obtain the health and nutrition benefits of fish, stick to the advice we’re offering, and have 8 to 12 ounces of fish lower in mercury per week as part of a balanced eating plan.”

This advice will be open for public comment, and FDA encourages feedback. See the notice of availability that published in the Federal Register for more information regarding how to submit comments.

Exposure to mercury, seafood associated with risk factor for autoimmune disease

One of the greatest risk factors for autoimmunity among women of childbearing age may be associated with exposure to mercury such as through seafood, a new University of Michigan study says.

The findings, which appear in Environmental Health Perspectives, found that mercury - even at low levels generally considered safe - was associated with autoimmunity. Autoimmune disorders, which cause the body's immune system to attack healthy cells by mistake, affects nearly 50 million Americans and predominately women.

"We don't have a very good sense of why people develop autoimmune disorders," says lead author Emily Somers, Ph.D., Sc.M, an associate professor in the departments of Internal Medicine in the division of Rheumatology, Environmental Health Sciences, and Obstetrics & Gynecology at the U-M Medical and Public Health Schools.

"A large number of cases are not explained by genetics, so we believe studying environmental factors will help us understand why autoimmunity happens and how we may be able to intervene to improve health outcomes. In our study, exposure to mercury stood out as the main risk factor for autoimmunity."

Autoimmune disease - which can include such conditions as inflammatory bowel disease, lupus, Sjögren's syndrome, rheumatoid arthritis and multiple sclerosis - is among the 10 leading causes of death among women.

Researchers analyzed data among women ages 16-49 from the National Health and Nutrition Examination Survey from 1999-2004. Greater exposure to mercury was associated with a higher rate of autoantibodies, a precursor to autoimmune disease. Most autoimmune diseases are characterized by autoantibodies, proteins made by a person's immune system when it fails to distinguish between its own tissues and potentially harmful cells.

Many fish consumption recommendations are aimed at pregnant women, those who may become pregnant, nursing moms and young children. The Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) say pregnant women can safely eat up to 12 ounces (340 grams) of seafood a week. Fish such as swordfish, king mackerel and tilefish contain the highest levels of mercury while shrimp, canned light tuna and salmon have lower levels.

Authors note there are many health benefits to seafood, a lean protein packed with vital nutrients. However, the findings provide further evidence that women of reproductive age should be mindful of the type of fish they're eating."

"The presence of autoantibodies doesn't necessarily mean they will lead to an autoimmune disease," Somers said. "However, we know that autoantibodies are significant predictors of future autoimmune disease, and may predate the symptoms and diagnosis of an autoimmune disease by years.

"For women of childbearing age, who are at particular risk of developing this type of disease, it may be especially important to keep track of seafood consumption."

 

 

Minimal Mercury in Fish Oil Supplements

Studies have found that most of the widely available supplements contain little or no mercury, dioxins or PCBs. 

Most companies use species of fish that are lower on the food chain, like cod and sardines, which accumulate less mercury. Many companies also distill their oils to help remove contaminants.

A report by ConsumerLab.com, which conducts independent tests of supplements, examined 41 common fish oil products and found none contaminated with mercury or PCBs. Another report, by researchers at Harvard Medical School and at Massachusetts General Hospital, studied five popular brands of fish oil and found that the brands had “negligible amounts of mercury.”