Researchers found that men who consumed high levels of trans fats performed poorer on memory tests.
The researchers found that the links were just as strong when they took into account other factors that might influence them.
The study findings were recently presented at the American Heart Association's Scientific Sessions 2014 in Chicago, IL.
Lead author Beatrice A. Golomb, professor of medicine at the University of California-San Diego, notes that health studies have previously shown trans fat consumption is linked to heart disease, aggression and higher body weight. In this latest study, Prof. Golomb says they found:
"Trans fats were most strongly linked to worse memory in young and middle-aged men during their working and career-building years."
She says she tells her patients that "while trans fats increase the shelf life of foods, they reduce the shelf life of people."
For their study, Prof. Golomb and her colleague studied a group of 1,000 healthy people without heart disease, including nearly 700 men aged 20 and over. The remaining participants were postmenopausal women.
The researchers note that their analysis focused primarily on the men as they were the only ones represented at all adult ages.
Working-age men who consumed the most trans fats performed worse in memory tests
From questionnaires the participants had completed about their diet, the researchers estimated their trans fat consumption.
The participants also underwent assessments of memory performance. They were shown a series of 104 cards with words on them. For each card, they had to say whether they had seen the word before or whether this was the first time it had been shown to them.
The results showed that for men under 45 years of age, eating more trans fats was linked to notably worse performance on the word memory tests.
This link was still strong when the researchers took into account potential influencers, such as age, education, depression and ethnicity.
The analysis showed each extra gram of trans fat consumed per day was linked to an estimated 0.76 fewer words recalled.
For those who ate the most trans fats, this translated to 11 - or more than 10% - fewer words remembered, compared with those who ate the least amount of trans fats. The average number of words correctly remembered was 86.
When they repeated their analysis with the full sample - that is, including the postmenopausal women - the researchers found the same results, suggesting it is not just men that are affected.
They suggest that further studies should be done to confirm that these conclusions apply to working-age women; their dataset did not have any information on this group.
Trans fats increase oxidative stress, affecting cell energy
Speculating on the reasons why trans fats may have this effect on memory, Prof. Golomb explains that:
Oxidative stress arises when the balance between the reactive oxygen species (free radicals) and antioxidant defenses is disturbed. It is associated with the development of diseases, such as heart disease and cancer.
"Foods have different effects on oxidative stress and cell energy. 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 pro-oxidant and linked adversely to cell energy - might show the opposite effect, and they did."
Trans fats are the result of a process that converts liquid oils into solid fats. The food industry uses them to extend the shelf life of foods such as margarines, fast foods, various baked goods, frozen pizzas, snacks, coffee creamers and some refrigerated doughs.
Read nutrition labels to check trans fat content of food
The Food and Drug Administration (FDA) are targeting trans fats to reduce amounts in the US food supply.
Meanwhile, Medical News Today recently learned of new research that shows while trans fats consumption in the US has come down, it is still not low enough.
Prof. Golomb advises consumers to read the nutrition labels on foods and check the amount of trans fats they contain.
The American Heart Association website contains a section on understanding food nutrition labels.