Quiz: The Facts About Fish Oil and Omega-3s

Fish like salmon, tuna, and mackerel, as well as fish oil capsules all have heart-healthy omega-3 fatty acids.

But adding fish to your diet has bonuses you won't get from a supplement: calcium and vitamins B2 and D. It's also an excellent source of protein.

So try to eat fish more often. Have it two times a week instead of meat.

If you have heart problems, though, you may need to boost your omega-3s with a supplement or a prescription if you have very high triglycerides. Talk to your doctor.

Omega-3s like DHA and EPA, which are found mainly in fish, can help lower triglycerides, a type of fat in your blood. To lower those levels, you should take 2-4 grams of DHA/EPA a day under the supervision of your doctor.

If you don't have high triglycerides, find a favorite fish to eat.

Fish is still your best bet for omega-3s. While organ meats, like liver, do have some omega-3s, you can't rely on them to give you all you need.

Walnuts provide an omega-3 called ALA, which your body doesn't make. ALA is also found in:

• Some vegetable oils, especially flaxseed oil
• Green vegetables like kale or spinach

Your body can turn ALA into small amounts of EPA and DHA, the omega-3s found in fish. There's more proof that they protect against heart disease.

Vegetarians and vegans can try algae oils as a source of omega-3s.

Krill oil, made from shrimp-like creatures, has about as much DHA as fish oil. And it has even more EPA. Krill oil is at least as good a source of omega-3s as fish oil is for lowering triglycerides and cholesterol.

Eat fish -- preferably oily fish like salmon, herring, lake trout, sardines, or albacore tuna -- twice a week. A serving is 3.5 ounces, or about 3/4 cup of flaked fish.

It's generally safe to eat up to 12 ounces of fish or shellfish a week, if they don’t have much mercury.

Fish that are low in it include:

• Shrimp
• Canned light tuna
• Salmon
• Pollock
• Catfish

Fish can come in contact with things like mercury, PCBs, and other contaminants through the environment, as well as household and industrial waste. Over time, these things can cause health problems, particularly for pregnant women and young children.

Wild Alaskan salmon is rich in omega-3s and has low levels of chemicals.

But swordfish and mackerel are among a group of fish high in contaminants like mercury and PCB. This list also includes:

• Shark
• Marlin
• Tilefish
• Tuna steak
• Bluefin
• Bigeye

DHA in a mom's diet has been linked to a brainpower boost in her babies. But studies haven't always found that same benefit from taking fish oil supplements.

Pregnant women should eat some, but not a lot, of fish that's low in mercury. In most cases, you should try to get the same amount of omega-3s as other healthy adults. Have low-mercury fish twice a week -- just make sure those two servings don't add up to more than 12 ounces.

DHA does help your baby's brain and eyes develop. It also reduces the risk of premature birth. Remember, your body can turn healthy fats in dark leafy greens or flaxseed oil into this important nutrient

Some people who take fish oil capsules are bothered by fish burps or a fishy taste in their mouth. Often, there's a simple answer: Take them with meals.

Also, you can swallow them frozen.

Fish oil supplements seem to help prevent more troubles for people with heart disease. Heart patients should get about 1 gram of EPA and DHA combined, preferably from fish, every day. Supplements may also help, but check with your doctor.

If you take aspirin, warfarin, or other drugs for heart patients, know that fish oil can thin the blood. At high doses, it might thin it too much.

Studies show that omega-3 fatty acids lower high triglycerides, a common problem in people with diabetes. Talk with your doctor about taking fish oil if you have high triglycerides for any reason.

Research hasn't shown consistently that omega-3s help asthma. Research on Alzheimer's and dementia patients has found a link between low levels of DHA and those diseases, but taking more omega-3s hasn't been found to improve either condition. Studies have shown that adding DHA does improve memory and learning in older healthy adults.