Just a handful a day: researchers reveal which types of nuts boost brain health.

A recent study by scientists has found that older adults who regularly consume nuts may enjoy better cognitive health. Researchers analyzed data from 883 individuals aged 50 and older participating in the Mediterranean Diet, Aging, and Lifestyle (MEAL) study in southern Italy. They discovered that participants with a higher nut intake had a 68% lower likelihood of cognitive impairment, even after accounting for factors such as age, education, physical activity, body mass index, and smoking, reports News Medical.

The findings, led by Dr. Justyna Godos, an associate professor in the Department of Human Nutrition, were published in the journal Nutrients and highlight the potential role of diet, particularly nut consumption, in preserving brain function as people age. The decline in cognitive abilities is a growing global health issue, affecting millions of individuals suffering from dementia and related disorders.

While genetics play a certain role, lifestyle factors, including diet, have gained attention for their potential to reduce the risk of neurodegenerative diseases. Nutrient-rich foods, especially those associated with the Mediterranean diet, have been linked by researchers to improved brain health.

Nuts, a key component of this diet, are rich in healthy fats, antioxidants, and polyphenols—compounds known for their ability to combat oxidative stress and inflammation that are associated with cognitive decline. While previous studies primarily focused on specific nuts, such as walnuts, this research aimed to determine whether overall nut consumption, regardless of type, contributes to cognitive health.

Participants' nut intake was assessed using a 110-item questionnaire covering almonds, walnuts, hazelnuts, peanuts, and chestnuts. The median nut consumption was 11.7 grams per day, with some individuals averaging 39.7 grams, while others consumed only 4.3 grams. Cognitive functions were evaluated using a standardized mental status questionnaire, and statistical adjustments ensured the results were independent of overall dietary quality.

The study revealed a strong correlation between nut consumption and a reduced risk of cognitive impairment, but no specific type of nut showed a clear advantage. This suggests that the cognitive benefits may stem from a combination of nutrients found in various types of nuts rather than any one specific type.

Nuts are rich in polyphenols and fiber, which may enhance gut microbiota diversity and gut integrity, linked to improved brain function. Additionally, compounds in nuts may help protect the blood-brain barrier, reduce oxidative stress, and counteract the accumulation of beta-amyloid—factors that contribute to the development of neurodegenerative diseases like Alzheimer’s.

Despite the promising associations, the study was largely observational, which does not allow for proof of a direct causal link between nut consumption and cognitive functions, the authors stated. However, their findings suggest that including nuts in the diet may be beneficial for brain health at a certain age.

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