Research: Ultra-processed foods speed brain decline

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By Jim Herlihy | Alzheimer’s Association

Eating a large amount of “ultra-processed” food (UPF) can significantly accelerate cognitive decline, according to new research unveiled at the Alzheimer’s Association International Conference (AAIC) in San Diego. 

Breakfast cereals, white bread, potato chips, soda, hamburgers and French fries along with frozen foods such as lasagna, pizza and ice cream were among the UPF cited by researchers at University of São Paulo, Brazil, who looked at 10,775 people over eight years.

The study found that people who consume the highest amount of ultra-processed foods (more than 20 percent of daily caloric intake) have a 28 percent faster decline in global cognitive scores — including memory, verbal fluency and executive function — compared to those with lower consumption.

Ultra-processed foods are defined as those that go through significant industrial processes and contain large quantities of fats, sugar, salt, artificial flavors/colors, stabilizers and/or preservatives.

“There is growing evidence that what we eat can impact our brains as we age,” said Claire Sexton, Alzheimer’s Association senior director of scientific programs and outreach. “Many studies suggest it is best to eat a heart-healthy diet low in processed foods and high in whole, nutritional foods like vegetables and fruits.” 

Study and methodology

Title: “Consumption of ultra-processed foods and cognitive decline in the ELSA-Brasil study: a prospective study.”

Background: Consumption of UPF has progressively increased worldwide in the last 30 years. High intake of UPF is associated with cardiovascular disease and cancer and hypothesized to induce systemic inflammation and oxidative stress. Although UPF may also be a risk factor for cognitive decline through these pathways, little is known about the effects of UPF on cognition. We aimed to investigate the longitudinal association between UPF consumption and cognitive decline in the ELSA-Brasil study during nine years of follow-up.

Method: Participants were evaluated in three study waves (2008-10, 2012-14 and 2017-19). Data on diet measured by food frequency questionnaire was categorized according to degree of food processing using NOVA. Cognitive performance was evaluated using a standardized battery of tests: the immediate recall, late recall, recognition, semantic and phonemic verbal fluency and the trail-making tests. A global composite z-score was derived from these tests. Association of consumption of UPF ( percent of total daily gram intake) with cognitive performance over time was evaluated using linear mixed effects models, adjusted for sociodemographic, lifestyle and clinical variables.

Result: In 8,160 participants (mean 50.6±8.7 y, 56 percent women, and 55 percent white) during a median follow-up of nine years, the mean baseline calorie intake was 2,842±982 kcal, 28 percent (493g) of which came from UPF. During follow-up time, consumption of UPF in the fourth and fifth versus the first quintile were related to a decline in the executive function and memory performance, respectively. No association of UPF consumption and verbal fluency was observed.

Conclusion: During nine years of follow-up, high consumption of UPF was associated with cognitive decline, particularly in the memory and executive function domains.

Presenting author: Natalia Gonçalves, Ph.D., University of São Paulo (natalia.g@fm.usp.br).