A higher intake of trans fatty acids, commonly used in processed foods to improve the taste, texture and shelf life, has been linked to a decline in memory function.
This work has already shown an association between consumption of trans fats and the worsening mood and aggressive behavior. Thus, trans fats show associations to two of the other main pillars of brain function, mood and behavior.

At the University of California, San Diego, we have been analyzed data on 694 men who completed a dietary survey and a test of word recall. On average, men aged 45 years and younger recall about 86 words.
However, every gram per day of dietary intake of trans fatty acids was associated with an estimated 0.76 less than remember words. This translates to 11 to 12 words in less remember with the highest intake vs no for an average of 86 words.

A great deal of research has been connected between the consumption of trans fats and other health risks, including high rates of cardiovascular disease and obesity.
Often, people who consume diets with higher levels of trans fat tend to eat less healthy diets in general – for example, less fruit and vegetables and whole grains and most commercially prepared baked and fried foods. To fully assess the study, it would be important to see the full range of nutrients and food groups in your diet and some estimate of the quality of the diet, and then see if there are associations with additional memory or if it is only for trans fats.

Currently we recommend the population to consume as little trans fat as possible.

From this study it found that the association of obesity with cognitive decline and that the intake of trans fatty acids can mediate the influence of obesity on cognitive function.

The FDA said the artificial trans fats in processed foods are “generally recognized as safe” for human food, and the elimination of Phos could prevent 20,000 heart attacks and 7,000 deaths from heart disease each year.