dementia

Skip the Soda, Pass on the Frozen Pizza and Other Foods You Should Avoid to Decrease Dementia Risk

A new study finds an association between ultra-processed foods and cognitive decline

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Frozen dinners, ice cream, sugary drinks and other ultra-processed foods have been linked to obesity and heart disease, but a new study warns of a different worry: dementia.

Part of the Brazilian Longitudinal Study of Adult Health found that a higher percentage of ultra-processed foods in a diet was associated with cognitive decline in an ethically diverse group of adults. 

That’s significant because the treatment for dementia is limited, making interventions that can prevent or delay its onset even more important. They include such lifestyle changes as increasing physical activity, quitting smoking and eating well.

"Intact cognitive function is key to successful aging," the authors wrote in JAMA Neurology this week. "Therefore, despite the small effect size of the association between (ultra-processed foods) consumption and cognitive decline, our findings are meaningful to cognitive health."

Previous studies have linked a healthy diet of whole grains, vegetables, fruits, nuts and fish to an increased brain volume and a decreased risk of cognitive decline, the report says. Another study published in September also linked ultra-processed foods with a risk of dementia.

This study, "Association Between Consumption of Ultraprocessed Foods and Cognitive Decline," looked at the diets of 10,775 public servants aged 35 to 74 in six Brazilian cities. During a follow-up after what was a median of eight years, those who ate the most ultra-processed food, more than 19.9% of their daily calories, had a 28% faster cognitive decline and a 25% faster decline in executive function compared to those who ate the least. The researchers found no association with memory scores.

The results were analyzed from December 2021 to May 2022.

Cognitive impairment was evaluated by word recall, word recognition, fluency tests and other measures. It is defined as difficulty remembering, learning new things, concentrating or making everyday decisions, according to the Centers of Disease Control and Prevention. Executive functions are those processes that allow us to plan, focus, remember instructions and juggle tasks.

"Dietary choices are a powerful way in helping maintain a healthy brain function," said one of the authors, Natalia Gomes Goncalves, a member of the faculty of medicine at the University of Sao Paulo.

"Middle age is an important period of life to adopt preventive measures through lifestyle changes, since the choices we make at this age will influence our older years," she said.

But she added, “This does not mean that older adults will not see results if they adopt a healthier lifestyle.”

“Research has shown over and over again that we benefit from healthier choices at any age,” she said.

The number of cases of dementia is on the rise and is expected to increase from 57 million in 2019 to 153 million in 2050.

About 5.8 million people in the United States have Alzheimer’s disease and related dementias, according to the CDC. It estimates that by 2060, there will be 14 million people with Alzheimer's. Dementia is the main reason for disability in high-income countries and among the top 10 in low- and middle-income countries.

The sale of ultra-processed foods such as snacks, breakfast cereals, ice cream, sugary beverages, processed meats and ready-to-eat frozen meals has increased over the last 40 years, according to the study. They amount to 58% of the calories in a typical American diet, 57% for British people, 48% for Canadians, and 30% for Brazilians.

The ultra-processed foods include additives not used at home such as flavors, colors, sweeteners and emulsifiers that disguised undesirable qualities or imitated desirable ones.

The authors note that neuro-imaging studies show that a heavily Western diet is related to a reduction in the left hippocampus of the brain and in the gray matter volume in cognitively healthy people. Another possible biological mechanism for the cognitive decline was systemic inflammation caused by eating ultra-processed foods, they wrote.

Future studies are needed to look at how ultra-processed foods may lead to cognitive decline.

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