Q. I've seen eggs that say they contain omega-3 fatty acids. How is this possible and are they good for me?

A. You're not the only one puzzled over omega-3 fatty acids turning up in eggs.

After all, you typically associate omega-3s with fish, not poultry eggs. How do omega-3s end up in eggs? It all starts with the chicken and not the egg, after all.

It's been observed that when chickens are allowed access to pasture, eating a diverse diet of plants and insects, they produce eggs with double the omega-3 content compared with conventional eggs that contain only about 40 milligrams (mg) of omega-3 fatty acid. So scientists developed a special diet of ground flaxseed and/or marine algae to feed hens, to produce eggs even higher in omega-3 fatty acids. With the increasing interest in the health potential of omega-3s, enriched eggs have become popular. These eggs look, taste, and cook up the same way conventional eggs do--but are they really a healthier food choice?

Back to omega-3 basics.

The long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in coldwater fatty fish and fish oil have been widely studied and linked with important health benefits, such as decreased risk of heart disease. Preliminary research has even associated EPA and DHA with protection against cognitive decline and improvements in depression, bipolar disorder and schizophrenia. The American Heart Association (AHA) suggests that people with heart disease should get 1,000 mg of EPA+DHA per day. Although the short-chain omega-3 fatty acid, alpha-linolenic acid (ALA) found in plant sources like walnuts and flaxseed also has been linked with heart-health benefits, the bulk of positive scientific findings belong to the long-chain omega-3s, making EPA and DHA the omega-3 superstars.

Omega-3 eggs in focus.

All omega-3 enriched eggs are not created equal. Depending on the hen's diet, enriched eggs can vary in content from 100 to 350 mg of omega-3 fatty acids per egg. More important, the omega-3 facts on the egg carton can be confusing. For instance, an egg carton may claim that eggs have 250 mg of omega-3 fatty acids each, but not specify if it's DHA/EPA or ALA. This is why the health advocacy group, Center for Science in the Public Interest (CSPI) urged the Food and Drug Administration to tighten up on the omega-3 egg labeling practices. CSPI reported that producers were making eggs, which are naturally high in cholesterol, appear "heart-healthy" by not differentiating between the two types of omega-3s, DHA/EPA and ALA, on product labels. In addition, some omega-3 eggs boast of lower saturated fat levels, but the decreased amounts are actually trivial (omega-3 eggs contain about 1.2 g saturated fat per egg compared with 1.6 g saturated fat in conventional eggs.) It's also important to consider how little omega-3 fatty acid some eggs contribute to the diet. The omega-3 enriched eggs with the highest levels of DHA+EPA (150 mg per egg) still only provide about 10 percent of the amount found in three ounces of salmon. Despite the recent debate over whether eggs are really as unhealthy for your heart as experts once thought, it's hard to ignore the fact that each large egg contains about 212 mg of dietary cholesterol. The AHA suggests that people approach eggs with caution, keeping in mind that healthy people should limit their dietary cholesterol intake to 300 mg/day. If you eat one egg, you've almost tapped your cholesterol intake for the day. A few studies have demonstrated that eating omega-3 enriched eggs may improve serum lipid levels compared with conventional eggs, but the jury is still out on whether the fatty acid profile of omega-3 eggs offers any overall advantages in heart health.

Before you give up on omega-3 eggs altogether, let's consider the good news.

Even though EPA and DHA are the omega-3 kings, health experts stress that it's a healthy habit to increase all kinds of omega-3 fatty acids in your diet, including ALA. Stocking your refrigerator with enriched eggs is an easy way to inch up your omega-3 intake, especially for vegetarians or people who don't like fish. Even though eggs contain generous amounts of cholesterol, they are a nutrient-rich food, full of protein, choline, folate, iron and zinc in a tidy 75-calorie package.

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