Percentage of daily energy from ultraprocessed food was associated with cognitive decline in participants younger than 60 years, suggesting the importance of preventive interventions in middle-aged adults.
Findings from the Brazilian Longitudinal Study of Adult Health showed that consumption of ultraprocessed foods (UPF) greater than 19.9% of total daily calories was associated with a faster decline in global cognitive performance and executive function. Additionally, the percentage of daily energy from UPF was associated with cognitive decline in participants with a low healthy diet core, whereas no association was found for those with high healthy diet scores.1
The study investigators concluded that "Limiting UPF consumption, particularly in middle-aged adults, may be an efficient form to prevent cognitive decline. Future studies investigating the mechanism by which UPF may lead to cognitive decline are needed, as well as confirmation of our findings in other longitudinal studies and randomized clinical trials."
A total of 15,105 individuals, aged 35 to 75 years old, were recruited from 6 Brazilian cities and 4330 were excluded, leaving 10,775 participants whose data were analyzed. Led by Claudia K. Suemoto, MD, PhD, MS, associate professor, University of Sao Paolo Medical School, the data were collected in 3 waves, approximately 4 years apart, starting in 2008 to 2010. The second wave took place in 2012 to 2014, and the third was in 2017 to 2019.
To better understand the association between UPF consumption at baseline and cognitive decline, the study excluded those who did not have dietary data, had extreme amounts of energy intake (<600 kcal/day or >6000 kcal/day), had missing data on cognitive tests or covariates, or reported taking medication that could negatively interfere with cognitive performance.
For the dietary assessment, patients were asked to complete the validated Food Frequency Questionnaire (FFQ) with 114 items. Foods were classified according to the extent of industrial processing using the Nova classification system. The study included 3groups: unprocessed or minimally processed foods and processed culinary ingredients (Nova groups 1 and 2), processed foods (Nova group 3) and UPFs (Nova group 4). Consumption of UPF was then expressed as a percentage of total daily energy consumption and grouped into quartiles (0%-19.9%; 20.0%-26.7%; 26.8%-34.1%; 34.2%-72.7%).
Demographically, the mean age of participants were 51.6 years and more than half of the sample was White (53.1%) and had at least a college education (56.6%). The mean body mass index was 26.9, and the mean total calorie intake was 2856 kcal, 27% of which came from UPF. After a median follow-up of 8 years, participants who reported consumption of UPF of more than 19.9% of daily calories had a 28% faster rate of global decline compared with those who reported consumption of UPF up to that amount (ß = –0.004; 95% CI, –0.006 to –0.001; P = .003).
Overall, there was no found association between percentage of daily energy from UPF and memory score, which was assessed using the immediate recall, late recall, and recognition word list tests from the Consortium to Establish a Registry for Alzheimer Disease. Age was a modifier for the association between percentage of daily energy from UPF and cognitive function, as those who were less than 60 years with UPF consumption greater than 19.9% showed faster global cognitive decline than those who consumed less than that amount (ß = –0.006; 95% CI, –0.009 to –0.003; P <.001).
Investigators failed to find an association between UPF consumption and cognitive decline for those aged 60 years or older. Adhesion to a healthy diet was also a modifier of cognitive decline, as individuals with low healthy diet scores who consumed more than the lowest quartile of calories from UPF showed a faster global cognition decline than those who consumed less than 19.9% (ß = –0.005; 95% CI, –0.009 to –0.002; P = .004). Notably, there was no association between the percentage of daily energy from UPF and global cognition for those with high healthy diet scores.