A helpful guide to fish-oil supplements

Research shows that the omega-3 fatty acids in fish oil have health benefits. That's why a growing number of once-skeptical doctors now recommend fish-oil to patients at risk for heart disease.

Yes. Fish-oil supplements are the next best thing to eating fin food.

• Research shows that people who take fish-oil supplements cut their risk of developing cardiovascular disease.
• For example, a study involving 11,324 recent heart attack survivors found that patients who took one gram of fish oil every day cut their risk of sudden cardiac death (a type of heart attack) by 45 percent.
• Fish oil, whether from seafood or a supplement, stabilizes heart rhythm, lowers levels of artery-clogging blood fats called triglycerides, makes blood less likely to clot, reduces inflammation and may even reduce blood pressure.
• Fish-oil capsules may even have an edge over fish. Although the benefits of eating fish outweigh the risks posed by any toxins in fish, most seafood nonetheless contains at least traces of mercury, PCBs and other contaminants. Some species have dangerously high levels.
• Fish-oil supplements seem to be more pure. Consumerlab.com researchers tested the purity of 43 different brands of fish-oil supplements and failed to find a single contaminated capsule.

Maybe. Your grandmother had the right idea — fish oil truly is good for you — but if you take cod-liver oil, you may be overdosing on vitamin A.

• People of a certain age may recall the days when taking a daily dose of cod-liver oil was as common as popping a multivitamin is today.
• Today it seems cod-liver oil is back. Encouraged by claims touted on the Internet, many people now turn to the fishy-tasting liquid (also available in capsules) to protect their hearts, ward off cancer, strengthen bones, relieve joint pain, promote healthy digestion and improve mood.
• While growing evidence suggests that fish oil has a range of health benefits, it's not clear that there is anything special about cod-liver oil in particular.
• Scientists do know this much, however:  cod-liver oil is a very rich source of certain nutrients, including vitamin A. In fact, just five grams (one teaspoon) contains far more than the recommended daily intake of the vitamin.
• Other fish-oil capsules contain somewhat less vitamin A but are still rich sources of the nutrient.
• Your body is particularly adept at using the form of vitamin A that comes from animal foods — so-called preformed vitamin A — including cod-liver oil.
• Emerging evidence indicates that vitamin A toxicity may occur at lower levels than previously believed. For example, osteoporosis and hip fractures have been linked to an intake of preformed vitamin A that's twice as high as the recommended amount.
• Liver problems and birth defects have been associated with high vitamin A levels, too.
• If you choose to include cod-liver oil supplements in your daily regimen, find a product that has 2,000 IU or less of vitamin A per five grams (one teaspoon).

So, the point is that fish oil supplements are a good addition to your regular diet. The short-term and long-term benefits are too good to ignore, and there is virtually no downside. However, make sure you read the ingredients carefully and make sure you are not getting too much of certain vitamins, especially if you are taking other supplements as well.