Do Processed Foods Affect Adults' Cognitive Performance?

Adults might want to consider slowing down their consumption of processed foods after a new study linked the diet to early cognitive decline.

It’s no secret that ultra-processed foods (UPF) are increasingly replacing healthier diets based on minimally-processed and unprocessed foods globally. In the U.S. alone, these food items comprise about 57% of the energy intake among adults and 67% among children and adolescents.

Containing no whole foods and filled with flavorings, colorings, and cosmetic additives, UPF examples include packaged snacks, breakfast cereals, chocolate, and pizza.

A new study published in the European Journal of Nutrition linked regular consumption of UPF to poor language and executive function in adults without chronic conditions.

Examining data from 2,713 individuals aged 60 years and older from the U.S. National Health and Nutrition Examination Survey, the researchers subjected the participants to several c cognitive tests and assessed their dietary intake.

But while the researchers found no significant link between overall cognitive test scores and UPF intake, its consumption was linked to worse performance in Animal Fluency tests, which assess a person’s language and executive function. This was observed in adults without pre-existing chronic health conditions, like diabetes.

According to the researchers, this may be due to high levels of UPF disrupting the microbiome and gut-brain axis, given that such foods lack essential nutrients and bioactive compounds with anti-inflammatory and antioxidant properties.

Nevertheless, the team acknowledged the limitations of their study. Dr. Barbara Cardoso, a senior lecturer in nutrition dietetics and food at Monash University and one of the study authors, said that since the participants were only assessed on one occasion, causality could not be inferred from the study.

A longer-term study is needed to make stronger conclusions, given that impaired cognition tends to develop over several years.

She also noted that 24-hour dietary recalls might not be enough to represent usual dietary intake.

Still, Dr. Cardoso noted that the study was the first to investigate the link between cognitive decline and UPFs, and she hoped that it could pave the way for future bodies of research.