People who carry the strongest common genetic risk factor for Alzheimer’s disease may experience faster decline in attention if they follow a Western-style diet, according to new research. The study, published in the journal Nutrients, followed 185 older adults without dementia from the Western Australia Memory Study and examined whether dietary habits were linked to changes in cognitive performance over time. Researchers tracked participants for up to 7.5 years and analyzed the results according to whether they carried the APOE ε4 gene variant, a well-established genetic risk factor for Alzheimer's disease.
They found that among APOE ε4 carriers, greater adherence to a Western dietary pattern was associated with a faster decline in attention. No significant links were observed for a healthier "Prudent" dietary pattern or among participants who did not carry the risk gene. The Western dietary pattern is typically characterized by higher intakes of processed foods, refined grains, red and processed meats, fried foods and sugary products.
The Prudent pattern emphasizes foods such as fruits, vegetables, fish and whole grains. However, the researchers cautioned that the findings do not prove that diet caused the cognitive decline. The study was observational, meaning it can identify associations but cannot establish cause and effect.
The association also became weaker after researchers excluded participants who may already have had subtle cognitive impairment at the start of the study. "I would be cautious about using our findings to guide individual decisions about genetic testing at this stage," lead author Dr. Carolina Blagojevic Castro, a postdoctoral research fellow in nutrition and healthy aging, told Newsweek.
"APOE ε4 is an important genetic risk factor for Alzheimer’s disease, but it is not deterministic,” Castro said. "For asymptomatic individuals, I therefore would not recommend APOE testing on the basis of our findings alone," she added. Anyone considering APOE testing should do so with medical and genetic counseling to fully understand what the results can and cannot tell them, Castro said.
The study also cannot determine whether changing dietary habits later in life could help slow cognitive decline. Castro pointed to broader research suggesting that protecting brain health may require a combination of approaches. She highlighted the landmark FINGER trial, which found cognitive benefits from a multidomain intervention involving dietary guidance, physical activity, cognitive training and management of vascular and metabolic risk factors.
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