For many years, the American Heart Association has recommended that people eat fish rich in omega-3 fatty acids at least twice a week. Doctors have long believed that the unsaturated fats in fish, called omega-3 fatty acids, are the nutrients that reduce the risk of dying of heart disease. However, more recent research suggests that other nutrients in fish or a combination of omega-3 fatty acids and other nutrients in fish may actually be responsible for the health benefits from fish.
Some people are concerned that mercury or other contaminants in fish may outweigh its heart-healthy benefits. However, when it comes to a healthier heart, the benefits of eating fish usually outweigh the possible risks of exposure to contaminants. Find out how to balance these concerns with adding a healthy amount of fish to your diet.
What are omega-3 fatty acids, and why are they good for your heart?
Omega-3 fatty acids may decrease triglycerides, lower blood pressure, reduce blood clotting, decrease stroke and heart failure risk, reduce irregular heartbeats, and in children may improve learning ability. Eating at least one to two servings a week of fish, particularly fish that's rich in omega-3 fatty acids, appears to reduce the risk of heart disease, particularly sudden cardiac death.
Does it matter what kind of fish you eat?
Are there any kinds of fish you should avoid?
Some researchers are concerned about eating fish produced on farms as opposed to wild-caught fish. Researchers think antibiotics, pesticides and other chemicals used in raising farmed fish may cause harmful effects to people who eat the fish.
How much fish should you eat?For adults, at least two servings of omega-3-rich fish a week are recommended. A serving size is 3.5 ounces (99 grams), or about the size of a deck of cards. Women who are pregnant or plan to become pregnant and young children should limit the amount of fish they eat because they're most susceptible to the potential effects of toxins in fish.
Does mercury contamination outweigh the health benefits of eating fish?
Mercury occurs naturally in small amounts in the environment. But industrial pollution can produce mercury that accumulates in lakes, rivers and oceans, which turns up in the food fish eat. When fish eat this food, mercury builds up in the bodies of the fish.
Large fish that are higher in the food chain — such as shark, tilefish, swordfish and king mackerel — tend to have higher levels of mercury than do smaller fish. Larger fish eat the smaller fish, gaining higher concentrations of the toxin. The longer a fish lives, the larger it grows and the more mercury it can collect.
Pay attention to the type of fish you eat, how much you eat and other information such as state advisories. Each state issues advisories regarding the safe amount of locally caught fish that can be consumed.
Should anyone avoid eating fish because of the concerns over mercury or other contaminants?
Still, the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) recommend that these groups limit the amount of fish they eat:
- Women who are pregnant or trying to become pregnant
- Breast-feeding mothers
- Young children
Pregnant women, breast-feeding mothers and children can still get the heart-healthy benefits of fish by eating fish that's typically low in mercury, such as salmon, and limiting the amount they eat to:
- No more than 12 ounces (340 grams) of fish in total a week
- No more than 6 ounces (170 grams) of canned tuna a week
- No amount of any fish that's typically high in mercury (shark, swordfish, king mackerel and tilefish)