Reduce Mercury in Your Diet: What You Need to Know About Eating Fish

As a source of lean protein and good-for-the-heart omega-3 fatty acids, fish is just about as good as it gets. Many people who follow a high-protein diet find that fish is the answer for upping their protein intake without having to consume huge amounts of food. On the outside, it looks like a great choice - high protein, low calorie and rich with omega-3s.

However, concerns about mercury levels in fish have caused some experts to rethink the role of fish in a well-balanced diet. Nearly all fish and shellfish contain some traces of mercury; mercury is a naturally occurring element in the environment, but also accumulates in our rivers and streams due to industrial pollution. When fish feed in these polluted waters, the absorb mercury, and the amount of mercury they have depends on such facts as what they eat, how long they live and where they are on the food chain.

Mercury is one of the planet's most poisonous naturally occurring substances, and chronic mercury poisoning has been linked with everything from Alzheimer's disease and autism to multiple sclerosis and even death. At lower levels, mercury poisoning is evidenced by weakness, fatigue, faulty memory, tremors, recurring headaches, skin rashes and other symptoms.

We are exposed to mercury in different ways, including silver-mercury amalgam fillings in our teeth, but among the most common is through our diet.

Which fish is safest?

Not all fish are created equal, and which type of fish you eat determines how much mercury you'll be exposed to. The Food and Drug Administration has determined that the risk posed by eating fish and shellfish is not a health concern for most people, although they advise that women who want to become pregnant, along with pregnant women, nursing mothers and young children, should avoid certain fish - namely those with higher mercury levels, such as shark, swordfish, king mackerel, orange roughy and tilefish.

Popular fish such as ocean perch, mahi mahi, haddock and Atlantic cod have a mid-level mercury content, so should be consumed in moderation.

The most commonly eaten fish that are low in mercury include shrimp, canned light tuna, salmon, Pollock and catfish. The FDA advises limiting the intake of fish to 12 ounces per week, which is about two meals for most people. Don't forget to factor in those fish sandwiches from fast food restaurants. Even though they're typically made from fish that are low in mercury, they still need to be included in your weekly meal planning to avoid excess exposure to mercury.

If tuna is your fish of choice, you've still got some tricky waters to navigate when planning your diet. Albacore, or "white" tuna, is a popular alternative to canned light tuna - but it contains more mercury than its counterpart. Experts advise eating no more than six ounces of albacore tuna each week.

Tuna steak also is a different animal than canned light tuna, and it also contains higher levels of mercury. As with albacore, experts suggest that only one of your two meals containing fish should include tuna steak.

So what happens if you go overboard and have too much fish one week? The FDA says that one week of heavy consumption won't significantly change mercury levels in the body, but you should cut back the next week or two.