Diets rich in plant protein, dairy, omega-3 fatty acids, whole foods = lower Alzheimer's risk

 

Alzheimer's disease affects more than 55 million people worldwide, and that number is projected to nearly triple by 2050. It has long been thought of as something that happens in the brain: a slow accumulation of toxic proteins, a gradual loss of neurons, a tragedy that unfolds in the mind. But a new collaborative transdisciplinary study by the University of Technology Sydney and Massachusetts General Hospital/Harvard Medical School is pointing somewhere else entirely: the gut.

In one of the largest multi-modal machine learning studies of its kind using artificial intelligence (AI) trained on data from nearly 10,000 people, a team of UTS researchers analysed more than 120 everyday factors, including diet, medical history, gut bacteria, and lifestyle, to identify which of them are most strongly associated with Alzheimer's risk. The outcome could lead to an AI framework that could be deployed as a low-cost, community-level screening tool.

Diet as a driver, not just a signal

Dietary patterns emerged as one of the strongest predictors of Alzheimer’s risk, highlighting the role of everyday habits in shaping brain health.

“Rather than individual nutrients, the study found that overall eating patterns were more informative,” said Khalilpour “Diets rich in plant protein, dairy, omega-3 fatty acids, and whole foods were consistently associated with lower Alzheimer's risk. Whereas diets dominated by processed food, refined sugars, and saturated fats pointed sharply in the other direction.

“Notably, overall dietary patterns outperformed individual nutrient measurements, meaning it is not a single vitamin or supplement that matters, but the cumulative, daily effect of how a person eats across years and decades.”

Higher dairy consumption emerged as a particularly striking individual signal, with higher dairy consumption associated with lower predicted risk, that may reflect the gut microbiome's response to fermented and dairy-rich foods, as well as calcium's known neuroprotective properties.

“The implication is significant: if diet contributes to neurodegeneration, it can also, potentially, help prevent it.”, said Ali Zomorrodi, Assistant Professor at Massachusetts General Hospital & Harvard Medical School, and a collaborator of this ongoing project.

The appendix finding that changes the picture

“The most unexpected result in the study was perhaps also among the most revealing,” said Associate Professor Kaveh Khalilpour, co-lead of the project and a specialist in complex socio-technical systems at the UTS Visualisation Institute “People who had their appendix removed – one of the most routine surgical procedures in the world – showed substantially elevated Alzheimer's risk, emerging as one of the strongest contributors in the entire analysis.

“We speculate that it functions as a reservoir of beneficial gut bacteria. When it is removed, the microbiome loses a key recovery mechanism, its ability to replenish healthy microbial communities after illness, infection, or antibiotic use,” he said.

 Over decades, that disruption may compound, leaving the gut progressively less able to protect the brain from the inflammatory signals linked to neurodegeneration.

“This finding is particularly compelling, as it indicates that long-term brain health may be shaped by earlier life experiences through their enduring effects on the gut microbiome,” said PhD researcher Tallat Jabeen.

“It reframes how we think about Alzheimer's risk, not as something that arrives with old age, but as something quietly accumulating across a lifetime.”