We Love Fish

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Still, some important issues haven't yet been addressed. While omega-3s do indeed lower the level of triglycerides in the blood, they have a tendency to raise the level of LDL, or "bad cholesterol." No one knows if that's a healthy trade-off or for whom. Pregnant women in particular should be careful about fish-oil supplements. Taking cod liver oil, for example, can lead to an overdose of vitamin A, which can in turn cause birth defects. Some nutritionists speculate that omega-6 fatty acids--found in corn and many other vegetable oils--may limit the health benefits of omega-3 fatty acids. But here again, the evidence is incomplete. "We have a long way to go before we understand the minimal amount of omega-3 needed by the body and whether the ratio of omega-3 to omega-6 is critical," says Alice Lichtenstein, a professor of nutrition at Tufts University School of Medicine.

One thing is clear whether you get your omega-3s from pills, oils or fish: they are not panaceas. You still have to eat a well-balanced diet that's lower in calories and total fat than most Americans currently consume. Otherwise, you're fishing for trouble.