TOPLINE:

Adherence to a high-quality plant-based diet that includes whole grains, fruits, vegetables, and legumes was associated with a lower risk for Alzheimer’s disease and related dementias (ADRDs), while consuming a plant diet high in sugar, refined grains, and potatoes was linked to higher risk, a new study showed.

METHODOLOGY:

• The multiethnic cohort study included nearly 93,000 participants (mean age, 59 years; 55% women) from Hawaii and California who were enrolled between 1993 and 1996 to evaluate baseline diet. African American, Japanese American, Latino, Native Hawaiian, and White individuals were included.
• An additional longitudinal dietary change analysis included more than 45,000 of the participants who completed quantitative food frequency questionnaires about usual diet at baseline and at a 10-year follow-up visit.
• Three plant-based diet patterns were calculated: the overall plant-based diet index, which prioritized plant food over animal products but did not assess quality; the healthful plant-based diet index, which included whole grains, fruits and vegetables, and legumes; and the unhealthful plant-based diet index, which included sugars, refined grains, and potatoes. Vegetarian and vegan diets were not included in the analysis. Comparisons were made across the lowest, middle, and highest quintiles of consumption in the diets.
• ADRDs were identified from Medicare Fee-for-Service claims data using diagnostic codes and occurred in nearly 21,500 participants, as observed during a follow-up of 11 years.

TAKEAWAY:

• The highest vs lowest quintiles of baseline overall and healthful plant-based diets were associated with 12% (hazard ratio [HR], 0.88) and 7% (HR, 0.93) lower risks for ADRDs, respectively, whereas the unhealthful plant-based diet was linked to a 6% higher risk (HR, 1.06; P for trend < .006 for all).
• There was a higher risk for ADRDs in those who had a moderate decrease in overall plant-based diet scores (HR, 1.09), a large decrease in healthful plant-based diet scores (HR, 1.17), and a large increase in unhealthful plant-based diet scores (HR, 1.25) at 10 years. There was an 11% lower risk for ADRDs with a large decrease in unhealthful diet scores (HR, 0.89).
• Among component food groups, increased consumption of added sugars was associated with a 12% higher risk for ADRDs, as was a large decrease in the consumption of eggs (P for trend < .001).
• Similar associations were observed across different age groups, racial and ethnic groups, and subgroups based on APOE epsilon 4 carrier status.

IN PRACTICE:

“We found that adopting a plant-based diet, even starting at an older age, and refraining from low-quality plant-based diets were associated with a lower risk of Alzheimer’s and other dementias,” the lead investigator said in a news release.

“Our findings highlight that it is important not only to follow a plant-based diet, but also to ensure that the diet is of high quality,” she added.

SOURCE:

The study, led by Song-Yi Park, PhD, University of Hawaii Cancer Center, University of Hawaii at Mānoa, Honolulu, was published online on April 8 in Neurology.

LIMITATIONS:

The diagnoses of ADRDs may not have been correctly captured as they were identified using Medicare claims data. Dietary intake determined using the food frequency questionnaire was prone to measurement error, including random recall error.

DISCLOSURES:

The study was funded by the National Cancer Institute and the National Institute on Aging at the National Institutes of Health. The investigators reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.