Trans fat has never been known for its health benefits. It has been associated with cardiovascular diseases caused by high cholesterol levels. But a recent study shows that trans fats don't just affect the heart; it ruins the mind as well.

According to the study, young and middle-aged men who ate foods with large amounts of trans fats showed a significantly reduced ability to recall words during a memory test.

Beatrice A. Golomb, MD, PhD, lead author and professor of medicine at the University of California-San Diego, and colleagues looked at adults who had not been diagnosed with heart disease. This included men aged ≥20 years and post menopausal women.

The participants filled out a dietary questionnaire, where the researchers estimated the amount of trans fat consumed. Memory was evaluated through a series of 104 cards, where participants had to recall whether each word was new or duplicated from an earlier card. 

The study results showed that among men aged below 45 years old, higher trans fat consumption was linked to a worse performance on the word memory test. Participants consuming the highest amount of trans fats had  more than 10 per cent reduction in words remembered as against adults who consumed the least trans fats. 

"The higher the trans fat consumption, the worse the performance," says Golomb.

"For people at the higher end of consumption, that would translate to 11 to 12 fewer words correctly recalled," she says. "The average number of words correctly recalled was 86, so this represents a pretty big detriment to function," she adds.

Golomb said that the oxidizing effects of trans fats may cause brain cells important to memory to die off. Oxidative stress has been associated with diseases such as heart disease and cancer.

"At the same time, the energy-sapping effects of the trans fats may make brain cells more sluggish and less responsive," she explains. "When cells don't get enough energy, they're essentially taken off line."

However, Golomb noted that her study only shows an association between trans fats and memory, not a direct cause-and-effect relationship.

Dr. Golomb stated that analyses in younger women are needed to see if these effects impact this demographic. 

Golomb said her team decided to investigate trans fats' potential effect on memory following another study they did that found that chocolate improved memory.

Trans fats can be found in margarine, fast foods, baked goods, snack foods, frozen pizza, coffee creamers, and some refrigerated doughs. The Food and Drug Administration (FDA) is working to decrease the amount of artificial trans fats in the food supply.

Dr. Martha Daviglus, a professor at the University of Illinois College of Medicine and executive director of the Institute for Minority Health Research, says the research shows that "we have to be careful with what we eat because it has consequences."

According to HealthDay, Daviglus believes that the potential memory effects of trans fats could be reversed by eating healthy and cutting the bad fats from your diet.

"We are living more and more years, so of course we want to maintain our memory and thinking," she says. "We have to do something to reverse the potential damage."

The findings of the study were presented Tuesday at the American Heart Association's annual meeting in Chicago.