Working-age men who eat a diet high in trans fats have worse memories than their counterparts who eat less of the artificial fats, according to a study conducted by researchers from the University of California-San Diego and presented at the American Heart Association’s Scientific Sessions 2014.
The effect was seen even after researchers adjusted for other risk factors such as age, depression, education and ethnicity.
“Trans fats were most strongly linked to worse memory, in young and middle-aged men, during their working and career-building years,” said lead author Beatrice A. Golomb, MD, PhD. “From a health standpoint, trans fat consumption has been linked to higher body weight, more aggression and heart disease.
“As I tell patients, while trans fats increase the shelf life of foods, they reduce the shelf life of people.”
Ten percent memory reduction
Trans fats are vegetable oils that have had extra hydrogen atoms artificially added, in order to make them solid at room temperature. They are used primarily to extend the shelf life of food and are most often found in fast food, margarine, baked good, coffee creamers and certain other packaged foods such as refrigerated doughs, snack foods and frozen pizza.
Any trans fat content higher than 0.5 grams per serving must be listed on food labels, but food manufacturers can hide trans fats by adjusting the serving size. Any “hydrogenated oil” on a product’s ingredient list, however, indicates trans fats.
In the new study, researchers examined roughly 1,000 men between the ages of 20 and 65, as well as postmenopausal women. None of the participants had ever been diagnosed with heart disease. Participants completed a food frequency questionnaire, which allowed the researchers to estimate their trans fat consumption.
All participants also underwent a memory test, involving viewing a series of 104 cards, each one containing a word. The participants were required to say whether the word on each card was new, or whether it had already appeared on a prior card.
Among men under the age of 45, a higher trans fat consumption was associated with worse performance on the memory test, with each additional gram of daily trans fat consumption leading to 0.76 fewer words remembered correctly. Men who ate the most trans fats remembered approximately 11 words fewer than the men who ate the least, a memory reduction of about 10 percent.
People still eating too many trans fats
The researchers believe that trans fats damage memory, in part, by promoting oxidative damage to cells and DNA, including those in the brains.
“Foods have different effects on oxidative stress and cell energy,” Golomb said. “In a previous study, we found chocolate, which is rich in antioxidants and positively impacts cell energy, is linked to better word memory in young to middle-aged adults. In this study, we looked at whether trans fats, which are prooxidant and linked adversely to cell energy, might show the opposite effect. And they did.”
The findings were announced only weeks after the publication of another study in the Journal of the American Heart Association, which found that, while trans fat intake in the United States has declined, it is still too high.
The researchers reviewed the results of six dietary surveys conducted as part of the Minnesota Heart Survey from 1980-2009. They found that trans fat consumption has decreased over the last 30 years by about one-third.
However, men still get about 1.9 percent of their calories from trans fats, and women get about 1.7 percent. This is significantly higher than the 1 percent maximum recommended by the American Heart Association.
“To make your diet more in line with the recommendations, use the nutritional panel on food labels to choose foods with little or no trans fats,” lead author Mary Ann Honors, PhD, said.