But when evaluating how some diets may erode brain health as we age, research on the effects of consuming minimally processed versus ultra-processed foods has been scant – that is, until now.

It is not yet clear if the small difference in cognitive decline associated with higher consumption of ultra-processed foods will have a meaningful effect at the level of an individual person.

Many ultra-processed foods are high in additives, preservatives, or coloring agents, while also having other features of an unhealthy diet, such as being low in fiber and nutrients.

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.

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.

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.