Is there a health difference between eating grass-fed beef and conventional beef?

Grass-fed beef tends to be higher in some nutrients, and studies suggest it may contain fewer bacteria that can cause food poisoning — which could be good for your health.

Grass-fed can mean a lot of things. But the American Grassfed Association, which has a certification program, refers to grass-fed animals “as those that have eaten nothing but grass and forage from weaning to harvest, have not been raised in confinement, and have never been fed antibiotics or growth hormones.”

Conventionally raised cattle are typically fed primarily corn and soy, which causes them to fatten more quickly, said Glenn A. Nader, an emeritus livestock and natural resources farm adviser for the University of California Cooperative Extension.

In 2010, Mr. Nader and his colleagues at California State University, Chico, published a review in Nutrition Journal that found that on a gram-for-gram basis, grass-fed beef contained higher levels of beneficial fats such as omega-3 fatty acids and conjugated linoleic acid, or C.L.A. It also contained more antioxidants and higher levels of beta carotene, a precursor to vitamin A that can give grass-fed beef a yellowish appearance.

“When people go to their retail store and see yellow fat, they think there’s something wrong with it,” Mr. Nader said. “That’s not some bad piece of meat. That’s actually vitamin A you’re looking at.”