Can ultra-processed foods affect cognitive performance?

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While canned vegetables are labeled as processed, prepackaged foods such as snacks and pizzas are considered ultra-processed. wragg/Getty Images
  • Researchers have studied the effects of ultra-processed foods such as pizza, white bread and chocolate on the cognitive performance of older adults.
  • They found that ultra-processed foods are linked to reduced language and executive function in older people without chronic disease.
  • They noted that reducing the consumption of ultra-processed foods can prevent cognitive decline and reduce the risk of dementia.

Ultra-processed foods (UPF) are increasingly replace traditional diets based on minimally processed and unprocessed foods around the world.

In the United States, UPFs include 57% energy intake in the adult population and 67% in children and adolescents.

Processed foods typically consist of two or three ingredients and include:

  • canned vegetables
  • salted nuts
  • cheese
  • plain yogurt

UPFs contain no whole foods, undergo multiple industrial processes, and contain ingredients including flavors, colors, and cosmetic additives. Examples include:

  • packaged snacks
  • Chocolate
  • prepared meals such as pizza and pasta
  • breakfast cereals

The increase in UPF consumption is related to reduced the nutritional quality of diets and chronic diseases, including obesity, metabolic conditionsand cardiovascular disease (CVD).

Knowing more about the impact of UPFs on overall health could help formulate dietary recommendations to improve public health.

Recently, researchers have studied the effects of UPFs on cognitive performance in the elderly.

They found that UPF consumption was linked to poorer performance in cognitive tests of language and executive functions in people without chronic disease. They noted that decreasing UPF intake may help improve impaired cognition in older adults.

The study was published in the European Journal of Nutrition.

For the study, researchers looked at data from 2,713 people aged 60 and over in the United States. National Health and Nutrition Examination Survey (NHANES) 2011-2014.

The researchers subjected the participants to various cognitive tests and assessed their food intake via two 24-hour food recalls.

Ultimately, the researchers found no significant link between overall cognitive test scores and UPF intake.

However, UPF consumption was linked to poorer performance in animal fluency tests, which assess language and executive function, only in those without preexisting chronic health conditions, including cardiovascular disease. and diabetes.

Animal fluidity tests consist to name as many animals as possible in a short period of time, usually taking about a minute.

To explain their findings, the researchers noted that over the past few years, many studies linked diets generally high in UPF to cognitive dysfunction.

They wrote that the underlying mechanisms could to understand systematic metabolic changes that lead to low-grade inflammation, impaired blood-brain barrier and neuroinflammation.

They further noted that consuming high levels of UPF can disrupt the microbiota and the gut-brain axis, as consuming them instead of whole foods can lead to lack essential nutrients and bioactive compounds with anti-inflammatory and antioxidant properties.

When asked what might explain the effects of FPU consumption on cognitive performance, Professor Kaarin Ansteyscientia professor of psychology at the University of South Wales and senior principal investigator at Neuroscience Research Australia (NeuRA), who was not involved in the study, said Medical News Today that UPFs, in theory, can worsen cognitive performance through several mechanisms.

“[U]healthy fats and sugars, which include [ultra-processed] foods, have been independently shown to impact brain health. [C]eat these foods [also] replaces potential consumption of healthier foods that are more nutrient dense and associated with better cognitive health.
— Professor Kaarin Anstey

Professor Antsey added that ‘UPF can increase obesity and type 2 diabetes, and both of these conditions increase the risk of cognitive decline. Moreover, the contribution of the many food additives present in these foods to cognitive decline is not yet known.

The researchers concluded that reducing UPF intake may be a way to alleviate age-related cognitive decline and reduce the risk of dementia.

Asked about the limitations of the study, one of the study authors Dr. Barbara Cardosolecturer in dietary nutrition and nutrition at Monash University, said DTM this causality cannot be inferred from the study, as its participants were assessed only once.

As cognitive impairment tends to develop over several years, a longer-term study would therefore be needed to draw stronger conclusions.

She further noted that 24-hour dietary recalls might not accurately represent usual dietary intake.

“Additionally, since we understand that people with chronic conditions are recommended to change their dietary habits, it is possible that reverse causation could dilute the associations studied,” she said.

“The battery of cognitive tests was small, and it is possible that associations were found with other tests. […] Finally, although the study samples different racial groups, there was a higher proportion of non-Hispanic whites in the sample and lower proportions of other racial groups than reflected in the general US population,” also pointed out Dr. Anstey.

Despite the limitations, Dr. Cardoso noted that this was the first study to investigate the link between FPUs and cognitive decline and could pave the way for future research.

When asked what people should eat more of to prevent cognitive decline, Dr Cardoso said current research suggests a Mediterranean-style diet may have cognitive benefits.

“Research indicates that diets that follow a Mediterranean style diet, recognized by the high proportion of foods with anti-inflammatory and antioxidant properties, are associated with a reduced risk of age-related cognitive decline and dementia. Foods eaten as part of these diets include fish, nuts, olive oil and vegetables.
— Dr. Barbara Cardoso

Dr Anstey agreed with Dr Cardoso and pointed out that a specific version of the Mediterranean diet known as the ‘MIND diet’ has been linked to a reduced risk of Alzheimer’s disease and dementia.

“The MIND diet emphasizes daily consumption of green leafy vegetables, nuts, and berries a few times a week,” she noted.

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