March 19, 2004 -- To protect developing babies from high levels of potentially brain-damaging mercury, the government issued guidelines today to warn women who are pregnant, nursing, or even considering having children to eat no more than two servings of fish each week.
The FDA and the Environmental Protection Agency jointly issued the new guidelines, but they are still emphasizing the benefits of eating fish. They say that fish and shellfish can be important parts of a healthy and balanced diet. They are good sources of high-quality protein and other essential nutrients, such as heart-healthy omega-3 fatty acids.
However, as a matter of prudence, they are recommending that women who are pregnant or nursing, planning to become pregnant, or feeding a young child limit the amount of fish they eat and eat fish with low mercury levels.
Where Does Mercury Come From?
Mercury occurs naturally in the environment and can also be released into the air through industrial pollution. Mercury falls from the air and can accumulate in streams and oceans, where it is turned into methylmercury. It is this type of mercury that can be harmful, especially to the developing brain of an unborn baby or young child. Fish absorb the methylmercury as they feed in these waters. It builds up more in some types of fish and shellfish than others, depending on what the fish eat.
If you regularly eat types of fish that are high in methylmercury, it can accumulate in your bloodstream over time. Methylmercury is removed from the body naturally, but it may take over a year for the levels to drop significantly, according to the FDA. Thus, it may be present in a woman even before she becomes pregnant.
By following their recommendations and guidelines, government officials say that women will receive the benefits of eating fish and shellfish and be confident that they have reduced their exposure to the harmful effects of mercury.
- Do not eat shark, swordfish, king mackerel, or tilefish because they contain high levels of mercury.
- Eat up to 12 ounces (two average meals) a week of a variety of fish and shellfish that are lower in mercury. Five of the most commonly eaten fish and shellfish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
- Another commonly eaten fish, albacore ("white") tuna, has more mercury than canned light tuna. So when choosing your two meals of fish and shellfish, you may eat up to six ounces (one average meal) of albacore tuna per week, they say.
- Because tuna steak generally contains higher levels of mercury than canned light tuna, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of tuna steak per week.
- Fish sticks and "fast-food" sandwiches are commonly made from fish that are low in mercury.
Officials also say you should check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to six ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.
Follow these same recommendations when feeding fish and shellfish to your young child, but serve smaller portions.
"This revised advisory is a culmination of months of hard work by both agencies," said FDA Deputy Commissioner Lester M. Crawford, DVM, PhD. "By following this advice, we're confident that women and young children can safely include fish as an important part of a healthy diet."