Natural Trans Fats Less Unhealthy Than Manmade Variety

Naturally Occurring Trans Fats Found in Dairy May Not Increase Heart Risks, Study Finds

Medically Reviewed by Laura J. Martin, MD on January 20, 2012
From the WebMD Archives

Jan. 20, 2012 -- All trans fats are not created equal.

Some are manmade, and have been added to all sorts of foods to increase their shelf life, but others can be found naturally in beef, pork, lamb, butter, and milk. Artery-clogging, manmade trans fats do increase the risk for heart disease, and efforts have been made to get them out of our food supply.

Natural trans fats, however, are another story.

At least in moderation, these trans fats do not seem to be as harmful as their manmade counterparts, a new study shows.

The findings appear in the American Journal of Clinical Nutrition.

Women in the study did not see any effect in their total blood cholesterol levels, low-density lipoprotein or “bad” cholesterol, dangerous blood fats called triglycerides, and other blood indicators of heart risk when they ate diets high in these naturally occurring trans fats. The trans fats in their diet came from enriched butter.

Some women did see a small decrease in their high-density lipoprotein or “good” cholesterol levels when they ate a diet rich in naturally occurring trans fats. This was more pronounced in women who were overweight, the study showed.

Don’t throw the baby out with the bathwater, urges David J. Baer, PhD. He is a supervisory research physiologist at the U.S. Department of Agriculture in Beltsville, Md. Baer wrote an editorial accompanying the new study.

Trans Fat Doesn’t Always Mean Bad Fat

“Milk is a good or excellent source of nine essential nutrients, and yes it does have some naturally occurring trans fats, but these don’t seem to be as harmful as manmade trans fats,” Baer says.

Trans fat is not necessarily a dirty word. “If you see trans fat in dairy products, it is not new or just added,” he says. “It has been around since we have been milking cows and there doesn’t seem to be, at typical levels of intake, a negative impact on risk factors.”

“Before we make broad, sweeping recommendations, let’s figure out what is going on,” Baer says. The new research should help clarify the issue.

Not everything in nutrition is so black and white, Connie Diekman, MEd, RD, says in an email. She is the director of university nutrition at Washington University in St. Louis.

The study “shows that our understanding of how food components affect health is much more complicated than making 'avoid' [and] 'eat more of' statements,” she says. “How diet impacts healthy women, overweight women, men, older people, and all the other variations is not conclusive at this point so recommendations must be global, food-based, and usable.”

Show Sources


Lacroix, É. American Journal of Clinical Nutrition, 2012.

Baer, D.J. American Journal of Clinical Nutrition,2012.

Connie Diekman, MEd, RD, director, university nutrition, Washington University, St. Louis.

David J. Baer, PhD, supervisory research physiologist, U.S. Department of Agriculture, Beltsville, Md.

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