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Cooperative Extension Fact Sheet FS017

Eating Fish is Healthy: Keeping Environmental and Health Concerns in Perspective

  • Karen Ensle, EdD, RDN, FAND, CFCS, Family and Community Health Sciences Educator, Union County

Being Savvy About Seafood

Seafood can be a safe and nutritious food and should be part of a healthy diet. To gain the disease prevention benefits of seafood, consumers need to make informed choices on the amount, types, and preparation of fish. Recent statistics from the Food and Drug Administration (FDA) indicate that less than 1% of all food-borne illnesses are related to seafood. Certain at-risk groups such as pregnant women, small children, and women of child-bearing age need to be more careful on the amount, type, and preparation of the fish they choose to eat. Read further to learn more about choosing, preparing, and storing seafood.

Benefits of Eating Fish

The U.S. Environmental Protection Agency (EPA), the U.S. Food and Drug Administration, the Academy of Nutrition and Dietetics, and the American Heart Association recommend eating 2 to 3 fish meals per week. Fish is a low-fat source of protein that may help to lower blood cholesterol. In addition, fish may lower the risk of heart disease-related deaths and obesity. Fatty, cold water fish like tuna, salmon, sardines, mackerel, and lake trout provide essential nutrients known as omega-3 fatty acids, which are essential nutrients for normal growth and development. They are needed for brain, blood vessel, and heart development of infants and newborns. In adults, omega-3 fatty acids help to make the blood less likely to form clots that can lead to heart attack or stroke. In addition, recent research has shown that omega-3 fatty acids may help to improve inflammatory and autoimmune diseases and ease the pain of arthritis by reducing inflammation.

Should Eating Fish Be Avoided Because of Methyl Mercury?

No, eliminating an entire type of food or food group from the diet is generally not recommended from a nutritional standpoint. There are key ways to decrease the risk of methyl mercury without denying consumption, good taste, and the health benefits of eating fish. Nearly all fish contain some methyl mercury. The levels vary greatly based upon the species, size, and age of the fish. Large predatory, saltwater fish such as shark and swordfish contain the most. Fresh water fish, such as pike and walleye, sometimes have high methyl mercury levels if they swim in polluted waters. In general, the larger and older a fish is, the more likely it will contain methyl mercury because this compound accumulates in the fish over time. According to the FDA, methyl mercury levels for most fish range from less than 0.01 parts per million (ppm) to 0.5 ppm. In a few species, methyl mercury levels can reach 1 ppm which is the limit allowed by the FDA for fish intended for human consumption. This level is found most often in large fish, including shark and swordfish. The FDA is conservative in protecting the health of Americans and has set its consumption advice 10 times lower than the lowest level associated with mercury poisoning. This conservative level allows for greater protection of everyone at all ages. Both the FDA and the EPA recommend consuming many different types of fish including shellfish, canned fish, smaller ocean fish, and farm-raised fish.

How Does Methyl Mercury Enter Our Food Supply?

Methyl mercury finds its way into the food chain when naturally occurring mercury from either water or air is deposited into rivers and lakes. Industrial pollution dumped into waterways is another way mercury enters the food supply. Once in the water, bacteria transform the air-borne mercury into methyl mercury. Fish such as shark and swordfish absorb the methyl mercury from the water and also ingest it when they consume algae and other smaller fish.

Who Regulates Methyl Mercury in the Air and Water?

In the U.S. the responsibility for regulating mercury is shared by the EPA and the FDA. The FDA regulates commercially sold fish and seafood and provides consumption advice for consumers, while the EPA regulates the amount of industrial and other forms of mercury released into the environment. The EPA also works with state governments to develop freshwater fish advisories that reveal where the levels of methyl mercury and other toxins are too great to make fish safe to eat. Check the local advisories before going fishing!

Fish Recommendations for Pregnant Women, Young Women & Children

Pregnant women and women who may become pregnant, nursing mothers, and young children should avoid eating large quantities of predatory fish, including shark, swordfish, tilefish, tuna, and king mackerel. For pregnant and nursing women, a safe intake of these fish (according to the EPA) is about 8–12 ounces of cooked fish for adults and children over age 10 and smaller amounts for younger children per week. This advice includes a chart on how often to eat more than 60 types of fish and shellfish weekly. The FDA and EPA both recommend consuming many different types of fish. Fish are part of a healthy eating pattern and provide protein; healthy omega-3 fats called DHA and EPA; more vitamin B-12 and vitamin D than any other type of food; iron, which is important for infants, young children, and women who are pregnant; and other minerals like selenium, zinc, and iodine.

Fish Recommendations for the General Population

The general public can eat “safe” fish from nonpolluted water 2 to 3 times weekly. Try seafood purchased in the food store like salmon, haddock, sole, shrimp, or fish sticks. Varieties may be fresh, frozen, or canned. Adults can eat up to 12 ounces of safe fish per week. A serving of safe cooked fish for adults is about 4 ounces and for children is 1 ounce at age 2 and increases with age to 4 ounces by age 11.

Choosing Fresh Seafood

Figure 1.

Fresh Seafood

Only buy fresh seafood and from reputable sources. The freshest, safest seafood is sold at markets that look and smell clean and are free of insects. Be wary, for example, of vendors selling fish out of the backs of trucks.

Fresh fish should be refrigerated or placed on a bed of ice, preferably in a refrigerated case. The fish should be placed belly down so the melting ice drains away from the fish. For the freshest fish, look for fish that:

Look for shellfish, such as oysters, clams, and mussels, that are tightly closed or that close up when the shell is tapped. Avoid those with cracked or broken shells. Discard shellfish that were purchased alive if they died during storage.

After purchasing fresh seafood, store it in the coldest part of your refrigerator for up to two days after purchase. Place seafood on a loosely covered plate to let air circulate freely around it. If freezing the fish, wrap and then place in a plastic freezer bag to keep it fresh. Keep live shellfish in containers covered with water or damp cloths, not airtight lids. Recreational fishers who plan to eat their catch should follow state and local government advisories about fishing in safe waters.

Choosing Frozen Fish

Here are some guidelines to ensure the quality of frozen fish:

Preparing Seafood

Follow these steps when thawing and preparing seafood to avoid cross-contamination between raw and cooked foods:

Cooking fish is a must for those at-risk. The young and old, along with persons with liver disease, diabetes, stomach problems, cancer, or immune disorders including HIV infection and lupus should not eat raw seafood. The FDA recommends cooking most seafood to an internal temperature of 145 degrees Fahrenheit (63 degrees Celsius) for 15 seconds. Check the internal temperature of cooked fish using an instant-read thermometer.

In summary, the three important messages when eating fish are: (1) to eat a variety of fish rather than concentrating on one species; (2) recreational fishers should follow state and local advisories about where it is safe to catch fish; (3) handle fish safely before preparing and eating it because it could be harmful instead of healthful.


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November 2020