Summary: A new international study identified a direct link between the consumption of ultra-processed foods (UPFs) and a measurable decline in the brain’s ability to focus.
The research followed over 2,100 middle-aged and older adults. The results reveal that even a minor daily increase in UPFs, such as adding a single packet of chips, is enough to significantly lower scores on standardized tests for attention and processing speed, regardless of how “healthy” the rest of the diet is.
Key Facts
- The 10% Threshold: For every 10% increase in daily energy from UPFs, researchers observed a distinct drop in visual attention. A 10% increase is roughly equivalent to adding one standard bag of chips or a soft drink to a daily routine.
- The Mediterranean Myth: Surprisingly, the negative effects of UPFs occurred even in individuals who otherwise followed a “healthy” Mediterranean diet. This suggests the processing of the food itself is as damaging as the lack of nutrients.
- Attention as a Foundation: While the study did not find a direct link to immediate memory loss, it highlighted that attention is the prerequisite for learning and problem-solving. Eroding this foundation increases long-term dementia risk.
- Structural Destruction: Ultra-processing often destroys the natural cellular structure of food and introduces artificial additives and industrial chemicals that may trigger cognitive decline through mechanisms like neuroinflammation.
Source: Monash University
New research from Monash University, the University of São Paulo and Deakin University shows a diet high in heavily processed foods can negatively impact the brain’s ability to focus and increases the risk of developing dementia.
The study published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, a journal of the Alzheimer’s Association, examined the diets and cognitive health of more than 2,100 Australian dementia-free adults middle-aged and older.
The findings demonstrate that a slight daily increase in a person’s intake of ultra-processed foods (UPFs) is linked to a measurable drop in attention span – even if someone otherwise eats healthy.
Lead author Dr Barbara Cardoso, from the Department of Nutrition, Dietetics and Food and the Victorian Heart Institute at Monash University, said the study reinforces a clear connection between industrial food manufacturing and cognitive decline.
“To put our findings in perspective, a 10 per cent increase in UPFs is roughly equivalent to adding a standard packet of chips to your daily diet,” Dr Cardoso said.
“For every 10 per cent increase in ultra-processed food a person consumed, we saw a distinct and measurable drop in a person’s ability to focus.
“In clinical terms, this translated to consistently lower scores on standardised cognitive tests measuring visual attention and processing speed.”
The participants of the study consumed roughly 41 per cent of their daily energy from UPFs, closely mirroring the national Australian average of 42 per cent.
UPFs include everyday products like soft drinks, packaged salty snacks and ready-made meals – essentially anything that’s not fresh whole foods.
Because the negative effects of UPFs take place regardless of a person’s overall diet quality, even for people following a healthy Mediterranean diet, researchers say the degree of food processing plays a critical role in the damage.
“Food ultra-processing often destroys the natural structure of food and introduces potentially harmful substances like artificial additives or processing chemicals,” Dr Cardoso said.
“These additives suggest the link between diet and cognitive function extends beyond just missing out on foods known as healthy, pointing to mechanisms linked to the degree of food processing itself.”
Eating more UPFs was linked to an increase in dementia risk factors, which include health conditions such as high blood pressure or obesity that can actively be managed to protect the brain.
While the study did not find a direct association between UPFs and memory loss, attention span is the foundation for many important brain operations, such as learning and problem-solving.
Funding: The research used data from the Healthy Brain Project, which is funded by the National Health and Medical Research Council (NHMRC), the Alzheimer’s Association, the Dementia Australia Research Foundation, the Bethlehem Griffiths Research Foundation, the Yulgilbar Alzheimer’s Research Program, the National Heart Foundation of Australia and the Charleston Conference for Alzheimer’s Disease. Dr Euridice Martinez Steele was funded by FAPESP (2023/16144-3), Dr Priscila Machado by an NHMRC Emerging Leadership Fellowship (APP2034008) and Professor Yen Ying Lim by an NHMRC Career Development Fellowship (GNT1162645) and an Emerging Leadership Grant (GNT2009550).
Key Questions Answered:
A: According to this study, no. The harmful substances and additives in UPFs seem to impact the brain independently of your healthy choices. The degree of food processing acts as its own risk factor for cognitive decline.
A: Think beyond just fast food. It includes soft drinks, packaged salty snacks, reconstituted meat products, and most ready-made “heat and eat” meals. Essentially, if it contains industrial ingredients you wouldn’t find in a home kitchen (emulsifiers, dyes, flavor enhancers), it’s likely a UPF.
A: The study focuses on risk factors like high blood pressure and obesity associated with UPFs. Because these are manageable conditions, reducing UPF intake and focusing on whole foods can help protect the brain’s “processing speed” and lower the long-term risk of developing dementia.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this diet and neuroscience research news
Author: Barbara Cardoso
Source: Monash University
Contact: Barbara Cardoso – Monash University
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Ultra-processed food intake, cognitive function, and dementia risk: A cross-sectional study of middle-aged and older Australian adults” by Barbara R. Cardoso, Euridice Martinez Steele, Barbara Brayner, Xinyi Yuan, Lisa Bransby, Hannah Cummins, Yen Ying Lim, Priscila Machado. Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring
DOI:10.1002/dad2.70335
Abstract
Ultra-processed food intake, cognitive function, and dementia risk: A cross-sectional study of middle-aged and older Australian adults
INTRODUCTION
Ultra-processed food (UPF) consumption is linked to over 30 adverse health outcomes, including several risk factors for dementia such as cardiovascular disease, type 2 diabetes, and obesity. We aimed to examine the association of UPF consumption with cognitive performance and dementia risk scores, and whether these associations are independent of overall diet quality.
METHODS
This cross-sectional analysis assessed 2,192 Australian dementia-free adults aged 40–70 years. Diet was assessed using a validated food frequency questionnaire and classified according to the Nova system. Cognitive function was measured using the Cogstate Brief Battery, and dementia risk was estimated with the CAIDE tool.
RESULTS
Each 10% increase in UPF intake was associated with lower attention scores (−0.05 points) and higher dementia risk (+0.24 points), independent of Mediterranean diet adherence.
DISCUSSION
Higher UPF consumption is associated with poorer attention and increased modifiable dementia risk, independent of overall diet quality.