Ultra-processed foods linked to poorer attention and higher dementia risk scores

By Dr. Liji Thomas, MDReviewed by Lauren HardakerApr 28 2026

A large Australian study suggests that even modest increases in ultra-processed food intake may affect attention and pathways linked to dementia risk, independent of overall diet quality.

Study: Ultra-processed food intake, cognitive function, and dementia risk: A cross-sectional study of middle-aged and older Australian adults. Image credit: DedMityay/Shutterstock.com

Ultra-processed food (UPF) consumption is associated with poorer attention and higher scores on a modifiable dementia-risk index in dementia-free Australian adults aged 40–70 years, according to a cross-sectional study published in the journal Alzheimer’s & Dementia: Diagnosis, Assessment, & Disease Monitoring.

Rising ultra-processed food intake raises brain health concerns

UPFs are here defined as “industrial formulations composed of refined ingredients and cosmetic additives with minimal whole food content”. Their intake now accounts for over half of the total dietary energy intake in many high-income countries, and about 42 % in Australia. Low- and middle-income countries are following the same trend.

Existing literature suggests that higher UPF consumption is associated with poorer cognitive performance and a higher risk of dementia. However, these are not definitive conclusions due to the heterogeneity of the studies and the co-occurrence of lower diet quality with higher UPF consumption.

Dietary quality interacts with UPF in dementia risk

Some commonly used indices of diet quality (e.g., Dietary Approaches to Stop Hypertension (DASH) or Alternative Healthy Eating Index (AHEI)) include UPFs like processed meat, making it difficult to assess the impact of UPF intake by itself on health.

The 2024 Lancet Commission on dementia management concluded that there was too little evidence to support a causal association between reducing UPF intake and preventing dementia. The current study sought to explain the role of UPF in dementia risk apart from overall diet quality.

UPF consumption trends

The cross-sectional study analysed dietary habits and cognitive function in 2,192 adults aged 40 to 70 years, a life stage when dementia risk factors accumulate, and early signs of neurodegeneration may begin to emerge.

Participants were predominantly female, with a mean age of around 57 years. Ultra-processed foods accounted for 21 % of the total daily weight of food and beverages consumed and 41 % of total energy intake, with the energy contribution increasing alongside higher UPF consumption.

The most commonly consumed UPFs included dairy-based drinks and desserts, sweetened beverages, packaged salty snacks and potato products, processed meat, and ready meals, each contributing between 2.4 % and 2.9 % of total intake.

Higher UPF intake was observed among men and younger individuals. It was also associated with lower educational attainment, obesity, and poorer adherence to a Mediterranean diet, which is generally considered low in ultra-processed foods.

UPFs and cognitive function

The analysis showed that a 10 % increase in UPF consumption (equivalent to one more standard 150 g packet of potato chips per day) was associated with a modest but consistent decrease of 0.05 points in attention scores. However, scores on a modified dementia-risk index increased by 0.24 points. This effect size was small, and significant differences in attention were primarily observed in the highest consumption group, despite an overall linear trend.

Attention scores showed a steady decrease as UPF intake increased. The attention scores in the highest consumption quintile were significantly lower than those in the lowest.

While the CAIDE score for dementia risk reflected a slightly higher risk with increasing UPF intake, this association was no longer statistically significant after adjustment for Mediterranean diet adherence. The authors then used the modified CAIDE score (reflecting only modifiable cardiometabolic risk factors). This showed a stronger association independent of diet quality, indicating higher scores on this modifiable risk index with increased UPF intake. The authors point out that the modified CAIDE score is not yet a validated tool for predicting dementia risk.

These associations persisted unchanged after adjusting for adherence to the Mediterranean diet and for body mass index (BMI). This suggests that the link between diet and cognitive function may extend beyond overall diet quality and displacement of whole foods to mechanisms related to food processing. The associations remained intact when UPF as a percentage of total energy was considered.

These findings suggest that higher UPF consumption is associated with poorer attention and increased modifiable dementia risk scores, but do not establish a causal relationship with cognitive decline or dementia. Thus, UPF intake may be associated with modifiable pathways relevant to cognitive health, although causal relationships cannot be inferred from this study design.

Plausible mechanisms

UPF intake has previously been associated with poor cardiometabolic outcomes, which collectively explain 12 % of dementia risk. UPF consumption may also account for the inverse association with attention, which is highly sensitive to multiple stressors that reduce cerebrovascular health.

UPFs may also affect the gut microbiota, thereby triggering gut-brain axis dysregulation, causing neuroinflammation. Further research is necessary to clarify these associations.

Strengths and limitations

The study recruited mostly high-risk participants, many of whom had a family history of dementia, with the assessment being performed in mid-life, a key intervention point. However, self-reported food intake data introduces recall and measurement bias. The population comprised mostly women and more educated and well-off people, limiting the generalizability of the findings.

Overall, the findings suggest an association between UPF consumption and modifiable dementia risk as well as cognitive impairment, especially affecting attention while sparing memory. This could mean that food processing affects cognitive performance independent of overall diet quality.

Future longitudinal intervention studies should examine causal relationships with UPFs, including biomarkers, microbiome changes, and neuroimaging, to provide an integrated model of the pathways linking diet to dementia. While the findings do not establish causation, they contribute to growing evidence linking UPF intake with cognitive health outcomes.

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