No, fish should not automatically be avoided because of their mercury content. And yes, tuna can be a particular problem, depending on the type of tuna that is chosen. This topic of fish and mercury is confusing, not only because it has gotten a lot of media attention, but also because different guidelines for fish consumption have been proposed by different organizations. Here are the most up-to-date recommendations on fish and mercury — particularly recommendations for pregnant women.
Women who may become pregnant, pregnant women, nursing mothers, and young children are placed into a separate category by the EPA and FDA in terms of general fish consumption guidelines. If you are only interested in the guidelines that apply to individuals in this group, you may want to skip ahead to the next section in this article. For women who are not pregnant, considering pregnancy, or nursing; for all men; and for older children, no general recommendations have been established about mercury contamination risk and fish consumption. If you fall into the second category of individuals for whom no guidelines have been issued, you may still want to read over our "Generalized versus Personalized Guidelines" section below to learn more about mercury risk in seafood and how this issue might apply to you as an individual.
In March 2004, the U.S. Environmental Protection Agency (EPA) and U.S. Food and Drug Administration (FDA) issued a joint set of recommendations for fish consumption by pregnant women. This set of recommendations established guidelines not only for pregnant women, but also for women who may become pregnant, nursing mothers, and young children. These most recent 2004 guidelines included 3 basic recommendations:
(1) Do not eat any shark, swordfish, king mackerel, or tilefish whatsoever.
(2) Eat no more than 12 ounces (2 average meals) of total fish per week.
(3) Check local advisories about the safety of fish caught by family and friends in local lakes, rivers, and coastal areas. If no advice is available, eat no more than 6 ounces (one average meal) per week of fish you catch from local waters, and do not consume any other fish whatsoever during that week.
In addition to these 3 basic recommendations, the EPA and FDA pointed out 5 types of commonly eaten fish that are relatively low in mercury. These 5 types were shrimp, canned light tuna, salmon, pollock, and catfish. All 5 types were considered good choices within the recommended limit of 12 ounces per week.
The EPA and FDA also singled out albacore tuna as being especially high in mercury and problematic for consumption. For this reason, they recommended a limit of 6 ounces of total fish per week if albacore tuna was the fish chosen for consumption.
While the EPA and FDA guidelines are a welcomed set of generalized guidelines for the fish-consuming public, they do not attempt to address individual situations or personalized dietary guidelines related to fish consumption and mercury contamination risk. For this reason, we'd like to address some of these more individualized issues in the section below.
When the actual amount of mercury contained in fish is measured, it turns about to be present in very small microgram amounts (often falling into the range of 100-500 micrograms per 6 ounces of fish). This amount of mercury is small enough that it can be successfully metabolized and detoxified by a wide range of individuals who are in good health, have otherwise healthy diets, and who do not have any other life issues that make mercury particularly problematic for their health. On the other hand, a person without a healthy diet and lacking good health might have trouble metabolizing or detoxifying this same small amount of mercury.
Personal guidelines for fish consumption can be very different than generalized public health guidelines, because they take into account individual health issues like the ability to metabolize and detoxify mercury and other toxins. Personalized guidelines also take into account lifestyle, genetics, environmental exposure to all toxins, use of medications, and other factors. While we cannot provide you with truly personalized guidelines in this article, we can tell you more about the principles used to provide these kinds of individualized recommendations.
If your meal plan closely resembles the meal plans we recommend at the World's Healthiest Foods, and you purchase many organically-grown foods, you are more likely to have good nutrient supplies and good detoxifying ability than if your meal plan contains routine fast-food and take-out. The reason is simple. The World's Healthiest Foods are the most nutrient-dense foods available — they provide you with the greatest amount and best variety of nutrients in exchange for the least amount of calories. When your body is faced with several hundred micrograms of mercury to detoxify, it will draw upon many nutrients to help support this process. In order to detoxify even a small amount of mercury, more antioxidant vitamins and minerals are needed; some specific kinds of amino acids are often needed; and specialty nutrients (like glutathoine, lipoic acid, or glucuronic acid) are also commonly required. If your diet is primarily composed of the World's Healthiest Foods, you'll be more likely to have these nutrients readily available to meet your mercury detoxification needs.
However, if your diet is more similar to a fast food and take-out diet than to a World's Healthiest Food meal plan, you are less likely to have good nutrient supplies and detoxifying ability. Under this circumstance, you might want to be even more conservative about your consumption of mercury-containing fish than suggested by the EPA and FDA in their general public health guidelines. For example, if you are pregnant, have a fast food-oriented diet, and do not enjoy a vibrant state of health, you may want to avoid all fish during pregnancy, even fish that are very low in mercury content. This decision is not one to make lightly, however, and may require consultation with your healthcare provider. Particularly when it comes to protein, fish can be difficult to replace in a meal plan. In addition, there are not many common food sources of omega-3 fatty acids, and cold-water fish, especially salmon, are great omega-3 foods. (Omega-3 fats are an essential type of fat required for healthy functioning of all cells, and they play a key role in the health of our brain and nervous system). Both protein and omega-3 fatty acids play a role in pregnancy that is even more important than usual. Luckily, however, there are other foods besides fish that contain significant amounts of omega-3 fatty acids, and these foods could be used as fish replacements. Included in this category would be walnuts, flaxseeds, soybeans, and tofu. In terms of protein, there are also some outstanding fish replacements. In this category of nutrition, you cannot do much better than very lean meats, egg whites, and lower-fat yogurts and cheeses.
You can use our Recipe Assistant to help you find some good fish replacements. Just select omega-3 fatty acids and protein as the nutrients you want to include, and then click on all seven of our fish (cod, halibut, salmon, scallops, shrimp, snapper and tuna) as foods to exclude, and you'll get a list of fantastic tasting recipes that provide omega-3 fatty acids and protein without relying on fish to do so.
For more information on this topic, see:
Kales SN, and Goldman RH. (2002). Mercury exposure: current concepts, controversies, and a clinic's experience. J Occup Environ Med 44(2):143-54.
Patrick L. (2002). Mercury toxicity and antioxidants: Part 1: role of glutathione and alpha-lipoic acid in the treatment of mercury toxicity. Altern Med Rev 7 (6):456-71.
U.S. Food and Drug Administration (FDA) and U.S. Environmental Protection Agency (EPA). (2004). What You Need to Know About Mercury in Fish and Shellfish. 2004 EPA and FDA Advice For Women Who Might Become Pregnant,
Women Who are Pregnant,Nursing Mothers, and Young Children. Document Number EPA-823-R-04-005, U.S. Environmental Protection Agency, Washington, D.C.
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