A Western-style diet may be associated with a faster decline in attention among older adults who carry a particular variant of the APOE gene, according to a small study by Australian researchers. The findings were published in the journal Nutrients.
The researchers followed 185 people with an average age of about 71 for 7.5 years. Participants underwent regular cognitive tests, while their diets were assessed using a standardized questionnaire.
The scientists identified two main dietary patterns: a Western-style diet, which included more foods typical of a modern high-calorie diet, and a healthier dietary pattern.
The researchers paid particular attention to the APOE gene. Its ε4 variant is considered one of the known genetic risk factors for Alzheimer’s disease, although carrying the variant does not mean that a person will necessarily develop the condition.
Overall, the researchers found no significant association between diet and cognitive decline. However, among APOE ε4 carriers, greater adherence to a Western-style diet was associated with a faster decline in attention scores over the follow-up period.
The authors emphasized that the finding is preliminary. When participants who may have already had cognitive impairment at the beginning of the study were excluded from the analysis, the association became weaker and was no longer statistically significant.
No significant association was found between a Western-style diet and other cognitive functions, including memory. A healthier dietary pattern also showed no statistically significant association with changes in cognitive performance.
The researchers noted several limitations of the study. It included a relatively small number of participants, dietary intake was assessed only at the beginning of the study and was based on self-reported information, and some participants dropped out during the follow-up period. In addition, reverse causation cannot be ruled out—for example, existing changes in cognitive function may have influenced participants’ dietary habits.
The researchers therefore consider the observed association preliminary and say that larger, long-term studies and clinical trials are needed before conclusions can be drawn about the effects of specific dietary patterns on cognitive health.
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