When hens consume a diet low in omega-6 fatty acids and high in antioxidants, eating their eggs causes less artery-clogging cholesterol oxidation in your blood, compared to when the hens eat a high-omega-6 diet, the study finds.
Turns out, people who ate two of the high-antioxidant eggs a day had the same LDL oxidation as those who ate two to four unhealthy eggs once a week.
“Antioxidants in the eggs reduce the oxidation of cholesterol in the blood,” says Niva Shapira, Ph.D., and professor of nutrition at Tel Aviv University. On the other hand, omega-6s increase inflammation, which can trigger oxidation.
Likewise, a 2008 experiment by Shapira showed that eating eggs high in omega-3s caused 30 percent less cholesterol oxidation than eating eggs higher in omega-6s. (Though omega-6s aren’t necessarily bad, Americans tend to eat too many omega-6s and not enough omega-3s.)
So, how do you decode the labels on the carton to pick the healthiest egg? Here’s your guide:
Choose eggs high in omega-3s. “An omega-3 label isn’t just a scam,” says Kathy Nichols, R.D. and practicing dietician in California. “It guarantees that the hens have been fed a diet high in omega-3s, which increase the levels of the healthy fatty acids in the eggs.” These eggs can have 400 mg of EPA and DHA omega-3s, Nichols says. Regular eggs have about 40 mg.
Brown vs. white? Same thing. “Some stores get away with selling 40 cents more per dozen for brown eggs, because you are supposed to think they are more natural or healthier—even though you throw out the shells anyway,” writes Marion Nestle, Ph.D., and professor of nutrition at New York University in What to Eat. “Take your pick. It makes no difference.”
Organic isn’t a high-nutrition guarantee. “With organic eggs, the chickens are fed organic feed, which reduces herbicide and pesticide loads on the planet,” says Nestle. But in terms of your individual health, this might not matter directly—these toxins don’t affect the eggs themselves as far as we know.
In terms of nutrition, it depends entirely on what the hens are fed. Hens on an organic farm could still be eating a high-omega-6 diet. An Oregon State University study even found that organic eggs actually had the same levels of omega-3 fatty acids as regular eggs.
Cage-free is about values, not nutrition. “If you don’t like the idea of hens in cages, then you’d be willing to pay more for the eggs,” Nestle explains. Cage-free is simply defined as uncaged; conditions can still be quite crowded and the chickens aren’t necessarily outdoors.