Ultra-processed foods – like cookies, chips, frozen meals and fast food – may contribute to cognitive decline | Health & Fitness

Another way that diet and ultra-processed foods may influence brain health is through the gut-brain axis, which is the communication that occurs between the brain and the gut microbiome, or the community of microorganisms that live in the digestive tract.

Not only does the gut microbiome help with digestion, but it also influences the immune system, while producing hormones and neurotransmitters that are critical for brain function.

Studies have shown that the ketogenic and Mediterranean diets change the composition of microorganisms in the gut in ways that benefit the person. Ultra-processed food consumption is also associated with alterations in the type and abundance of gut microorganisms that have more harmful effects.

Disentangling the specific effects of individual foods on the human body is difficult, in part because maintaining strict control over people’s diets to study them over long periods of time is problematic. Moreover, randomized controlled trials, the most reliable type of study for establishing causality, are expensive to carry out.

So far, most nutritional studies, including these two, have only shown correlations between ultra-processed food consumption and health. But they cannot rule out other lifestyle factors such as exercise, education, socioeconomic status, social connections, stress and many more variables that may influence cognitive function.

This is where lab-based studies using animals are incredibly useful. Rats show cognitive decline in old age that parallels humans. It’s easy to control rodent diets and activity levels in a laboratory. And rats go from middle to old age within months, which shortens study times.

Lab-based studies in animals will make it possible to determine if ultra-processed foods are playing a key role in the development of cognitive impairments and dementia in people. As the world’s population ages and the number of older adults with dementia increases, this knowledge cannot come soon enough.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. If you found it interesting, you could subscribe to our weekly newsletter.

Sara N. Burke does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.