Eating trans fats, those staples of fast-food fryers, may not just be bad for your heart; it may also be bad for your mind. These partially hydrogenated oils have been banned in some places, but they are still around, for example, in many of the snack foods we love.

The more trans fat the men in a recent study ate, the worse they did when their memory was tested. All the men were under 45.

Artificially-produced trans fats are still added to some foods. They can turn liquids into solids at room temperature, which helps keep food from spoiling. They also give food a creamier texture.

But once eaten, trans fats lead to clogged arteries and increase the risk of heart disease. They also seem to raise the risk for depression. Now there's evidence that they worsen memory.

Trans fats still lurk in the food supply, most often in margarine and snack foods such as cakes and cookies.

The study's lead author, Beatrice A. Golomb, a professor of medicine at the University of California, San Diego, says she likes to tell her patients that trans fat increases the shelf life of food, but decreases the shelf life of people.

About 1,000 men were tested on their ability to recall words. Each was shown a series of 104 cards with a word on them and had to tell whether each word was a new one or a repetition of a word he had previously seen. The average score was 86 correct answers.

Men whose diets included trans fats scored worse — almost one additional incorrect answer for every gram of trans fat in their daily diet. Those who ate the most trans fat scored over 10% worse than the average.

The effect remained even after taking into account factors like age, education, ethnicity and depression, all of which are known to affect memory.

The current study was conducted just before FDA rules limiting added trans fat in food to 0.5 grams per serving went into effect. Trans fat consumption has probably gone down since then, though it still lurks in the food supply, most often in margarine and snack foods such as cakes and cookies.

The manufacturer gets to decide what a serving size is, sometimes only a single cookie. So snackers beware, if you eat a lot of cookies, you may still be eating a sizeable dose of trans fat in your diet.

Trans Fat Consumption is Linked to Diminished Memory in Working-aged Adults (#15572) was presented at the American Heart Association's 2014 Scientific Sessions.