A Western-style dietary pattern may be associated with faster decline in attention among older adults carrying the APOE ε4 allele, a genetic variant linked to increased susceptibility to late-onset Alzheimer’s disease (AD), according to a study published in Nutrients. The findings suggest that genetic background may influence the relationship between diet and cognitive ageing, although the association was exploratory and did not remain significant after participants with possible baseline cognitive impairment were excluded.
Researchers analysed longitudinal data from 185 older adults participating in the Western Australia Memory Study (WAMS). Participants were recruited in Perth between 2006 and 2009 and had a mean age of 70.6 years. Approximately 31% were men, while 30.8% carried at least one APOE ε4 allele. Dietary intake was assessed using the Cancer Council of Victoria Food Frequency Questionnaire. Using principal component analysis, researchers identified two major dietary patterns. The Western dietary pattern represented comparatively less healthful food choices, while the Prudent dietary pattern reflected healthier eating habits.
Participants underwent neuropsychological assessments at baseline and during up to five additional visits at approximately 18-month intervals. Six cognitive domains were evaluated, including attention, along with the Preclinical Alzheimer’s Cognitive Composite (PACC), a measure designed to detect subtle cognitive changes that may precede clinically apparent AD.
Initial analyses found no significant associations between either dietary pattern and cognitive performance at baseline after correction for multiple comparisons. Similarly, neither the Western nor Prudent dietary pattern was significantly associated with cognitive decline when the entire study population was analysed.
However, an association emerged when participants were stratified according to APOE ε4 status. Among APOE ε4 carriers, greater adherence to the Western dietary pattern was associated with faster decline in attention during follow-up. The association remained statistically significant following false discovery rate adjustment, with a β coefficient of −0.0028, standard error of 0.00095 and adjusted p = 0.016.
The researchers cautioned that the clinical relevance of this finding remains uncertain and that statistical significance does not demonstrate that a Western-style diet causes cognitive deterioration. To assess whether pre-existing cognitive impairment could have influenced the results, an additional analysis excluded participants with a Montreal Cognitive Assessment (MoCA) score below 23. Following this exclusion, the association between Western dietary intake and attention decline among APOE ε4 carriers was no longer statistically significant (β = −0.0017; SE = 0.00092; adjusted p = 0.233). The authors therefore considered the initial association exploratory.
No significant associations were identified between the Western dietary pattern and other cognitive domains among APOE ε4 carriers or among participants without the APOE ε4 allele. The study also found no significant relationship between adherence to the Prudent dietary pattern and cognitive decline. However, the researchers emphasised that this does not establish that healthier dietary habits have no cognitive benefits. The relatively small sample and substantial participant attrition may have limited the ability to detect modest associations.
The findings raise the possibility that the relationship between diet and cognitive ageing may differ according to genetic susceptibility. APOE ε4 is the strongest common genetic risk factor for late-onset AD and has been associated with several biological processes involved in AD development. However, the findings should not be interpreted as evidence that a Western diet causes AD or that APOE ε4 carriers will necessarily develop cognitive impairment because of their dietary habits. The observed association disappeared after participants with lower baseline cognitive scores were excluded.
The study suggests a possible interaction between dietary patterns and APOE ε4 status in cognitive ageing, particularly in relation to attention. However, the evidence remains preliminary. Larger longitudinal studies incorporating repeated dietary assessments, longer follow-up and improved participant retention, together with randomised dietary intervention trials, are needed to determine whether dietary modification can influence cognitive trajectories in individuals with increased genetic susceptibility to AD.
References
- Blagojevic Castro C, Gardener SL, Jahan F, Chen J, Brown BM, Loo RL, Taddei K, Rainey-Smith SR, Weinborn M, Reis ACRD, Garg ML, Martins RN, Sohrabi HR. Dietary patterns and cognitive decline in older adults: findings from the Western Australia Memory Study. Nutrients. 2026;18(16).