The Health Benefits of Eating Fish

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The fish with the highest levels of omega-3s are those that naturally live in cold waters, such as salmon, trout and herring.
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Though many species of fish should be avoided, you’ll find several healthy choices at your local supermarket.

When I was growing up, Friday was the busiest night at the local diner. Folks lined up early for “fish night,” a Catholic tradition that caught on even in our little burg of meat-and-potato-loving Germans. On other nights of the week, my mother frequently served up fish sticks and French fries. Fish made it onto everyone’s table at least once a week.

These days, there are even more compelling reasons to add fish and shellfish to your diet. Recent nutrition research has confirmed the benefits of eating oily fish, which are loaded with omega-3 fatty acids. Omega-3s are proven to boost brainpower and reduce the risk of heart disease and stroke. Studies have shown that eating fish may also improve eye health, reduce the risk of colon cancer and have therapeutic effects for people suffering from depression and arthritis.

Given all these health benefits, one would think Americans would be eating more fish than ever, but just the opposite is true. A recent survey conducted by the University of Maryland’s Center for Food, Nutrition and Agriculture Policy revealed that only 36 percent of Americans eat fish once a week or more, while nearly a third of us (29 percent) eat fish once a month or less.

The dietary guidelines released by the U.S. Department of Agriculture last year suggest that people eat two servings of fish or shellfish each week, a recommendation also endorsed by the American Heart Association. But consumers are also hearing numerous warnings against eating fish. Many supermarkets now post warnings about the dangers of eating fish high in mercury — a potent neurotoxin. (See the
Sustainable Seafood Shopping Guide for a list of fish high in mercury.) And from the news, we hear about the problems of overharvesting wild fish species and the water pollution caused by some commercial fish farms. So it’s no wonder that many of us are eating less fish.

But don’t toss out the tartar sauce just yet — by observing a few guidelines, you can enjoy the health benefits of eating fish, minimize the health risks and avoid choosing overharvested species. Here’s what you need to know to navigate the fish market swimmingly.

Cast Your Line

Fish is a great source of protein, and it has the kind of fat that’s good for your heart. Fish is low in unhealthy saturated fat, especially when compared to red meat, and it’s full of heart-healthy omega-3 fatty acids. There are several types of omega-3s, and all play varying roles in combating heart disease by preventing clots and encouraging healthy blood circulation.

Our bodies can’t make omega-3s, so we need to get them from our diet. In aquatic ecosystems, omega-3s originate in the phytoplankton that fish eat. The fish with the highest levels of omega-3s are those that naturally live in cold waters, such as salmon, trout and herring. (Other good sources of these fatty acids include some leafy vegetables, eggs, nuts and oils.)

Unfortunately, industrial activities have introduced toxic substances into our waters. One such toxin is mercury, which can damage the nervous system, particularly the developing nervous systems of young children. In the 1990s, people took notice when the Food and Drug Administration (FDA) began warning consumers about the danger of eating fish contaminated with methyl mercury — a form of mercury that is absorbed easily into our bodies when we eat contaminated fish. Much of the mercury in our oceans comes from our fossil fuel-burning power plants. That mercury is consumed by fish, and the level of mercury increases as it moves up the food chain, concentrating in large, carnivorous fish such as sharks and swordfish. The FDA updated its warnings on mercury consumption in 2002 and again in 2004, and many concerned consumers opted to skip fish night. (See “Expert Advice on Choosing Fish” later in this article.)

However, the FDA never intended to discourage the entire population from eating any kind of fish. The warnings specifically directed pregnant women and young children to avoid fish high in mercury.  In fact, many fish species are good sources of nutrition for pregnant women, because omega-3s play an essential role in developing cognitive function.

Although children’s nervous systems are the most vulnerable, the rest of us face the same issue: The evidence suggests that omega-3s improve brain function, but high mercury levels can damage it. Almost all of us can expect to suffer some mental decline as we age, but in a study of about 4,000 senior citizens conducted at the Rush University Medical Center in Chicago, researchers found that people over the age of 50 who ate fish once a week slowed their rate of mental decline by 10 percent. The rate was 13 percent slower for those in the study who ate twice as much fish every week.

Another study published in the Journal of the American Medical Association last spring found that, although the elderly can experience cognitive damage from exposure to methyl mercury, low levels are not particularly dangerous. Researchers tested 474 people who ate about 12 ounces of fish per week and found that the amount of mercury they consumed didn’t significantly affect clarity of thinking, memory or coordination.

Furthermore, a Harvard study about the health benefits of eating fish recently published in the American Journal of Preventive Medicine weighed the benefits of eliminating fish from our diets against eating low-mercury species high in omega-3s. The study concluded that eliminating all fish from our diets would have a negative impact on health, because of the evidence that omega-3s reduce the risk of heart disease and stroke, and improve cognitive function.

While the FDA, as well as the previously mentioned studies, emphasize the need for caution about eating fish that contain high levels of mercury, eating other species of fish can offer substantial health benefits.

Reeling in the Right One

Fish and shellfish deserve a spot on our dinner plates, but the sobering fact is that if everyone made them a regular part of their diet, the planet’s wild stocks would be rapidly depleted. To meet the entire world’s demand, the fish of the future will have to be farm-raised.

Aquaculture is not without its own controversy. Some commercial fish farms are a source of water pollution, are constructed in sensitive marine environments, or raise non-native fish species that wreak havoc when they escape into the surrounding body of water. There are also some concerns about the amounts of antibiotics used to keep these fish healthy in such close quarters.

But many aquaculturists operate responsibly, and you can eat the fish from these farms without sacrificing your health or that of the planet. When buying farmed fish, choose domestically farmed whenever possible. Fish farms in the United States typically are better regulated than farms in many other countries, and the fish are likely to contain fewer antibiotic residues. Species such as striped bass, tilapia, sturgeon, catfish and trout are all safe choices when buying farmed fish. (See the Sustainable Seafood Shopping Guide for more suggestions. You can also try raising fish yourself. See Backyard Fish Farming, April/May 2006.)

When choosing a wild species, it’s a good idea to check where the fish was caught. Some bodies of water are more polluted than others, and you can learn a lot about the pollutants that might be present in a species of fish by knowing where it was caught or raised. Information about which species are overharvested also is widely available, as is information on what species are caught with destructive harvesting methods, such as dredging the ocean floor.

While there’s a lot to keep in mind when selecting fish, you can find healthy, sustainably harvested fish in a variety of price ranges. There’s sure to be a type of fish that will inspire you to schedule a fish night for your family.

Expert Advice on Choosing Fish

Here are the latest (2004) recommendations from the Environmental Protection Agency and Food and Drug Administration about eating fish and shellfish:

Pregnant women, women who may become pregnant, nursing mothers and children are advised to eat fish and shellfish that are lower in mercury and to avoid some types of fish. Follow these recommendations if you fall into one of those categories:

  • Do not eat shark, swordfish, king mackerel or tilefish.
  • Eat up to 12 ounces (two average-size meals) a week of a variety of fish and shellfish that have low levels of mercury. Commonly eaten low-mercury fish include shrimp, canned light tuna, salmon, pollock and catfish. Albacore tuna is higher in mercury and should make up no more than one meal per week.
  • Check local advisories about the safety of fish caught in local waters. If no advice is available, eat up to 6 ounces (one average-size meal) per week of fish from local waters, but don’t consume any other fish during that week. 

Children should follow the same recommendations, but in smaller portions.


Environmental Defense Fund

Monterey Bay Aquarium’s Seafood Watch

Center for Food, Nutrition, and Agriculture Policy

Environmental Working Group

Read more: You can learn how to raise your own fish for food in Backyard Fish Farming.

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