Could a handful of nuts a day prevent cognitive decline?

By Dr. Chinta SidharthanReviewed by Susha Cheriyedath, M.Sc.Feb 2 2025

Regular nut consumption is linked to better cognitive function in older adults, with higher intake associated with a 68% lower risk of cognitive impairment in a study of Southern Italians.

Study: Nut Consumption Is Associated with Cognitive Status in Southern Italian Adults. Image Credit: Eakrat / Shutterstock

A new study published in the journal Nutrients suggests that older adults who regularly consume nuts may have better cognitive health. The research team found that those with higher nut intake had a 68% lower likelihood of cognitive impairment (adjusted odds ratio: 0.32, 95% CI: 0.13–0.77), emphasizing the role of diet in brain function and aging.

Dementia and diet

With the aging world population, cognitive decline has become a growing public health concern. Dementia and related conditions affect millions worldwide, with risk factors ranging from genetics to lifestyle choices. While some preventive strategies remain elusive, growing research has highlighted the potential of diet in maintaining brain health.

Nutrient-rich foods, particularly those in the Mediterranean diet, are associated with better cognitive function. Nuts, a staple of this diet, are packed with healthy fats, antioxidants, and polyphenols—compounds known for their neuroprotective effects. Some studies suggest that nut consumption can reduce oxidative stress and inflammation, both of which are linked to cognitive impairment.

However, past research has focused largely on specific nuts, such as walnuts, with mixed results. Given the rising prevalence of cognitive disorders and the need for effective dietary interventions, this study explores whether regular nut consumption is linked to better cognitive status in older adults, regardless of the specific type consumed.

About the study

In this cross-sectional study, the researchers analyzed data from 883 adults aged 50 and older, drawn from the Mediterranean Healthy Eating, Aging, and Lifestyles (MEAL) study in southern Italy. They assessed the participants' nut consumption using a 110-item questionnaire that detailed their intake of various nuts, including almonds, walnuts, hazelnuts, peanuts, and chestnuts.

Additionally, the participants' cognitive function was measured using a validated mental status questionnaire, a standard screening tool for detecting cognitive impairment. To determine whether nut consumption correlated with cognitive status, the researchers divided the participants into low and high-nut consumers. The median nut intake was 11.7 grams per day, with low consumers averaging 4.3 grams daily and high consumers having an average nut intake of 39.7 grams.

Statistical analyses accounted for factors such as age, sex, education, physical activity, body mass index (BMI), and smoking status to minimize potential confounding variables. Additionally, the researchers adjusted for adherence to the Mediterranean diet, though nuts were not included in the Mediterranean diet scoring, ensuring that the observed cognitive benefits were independent of overall diet quality.

Using multivariate logistic regression models, the study examined whether total nut intake and intake of specific nut types were linked to cognitive status. The analysis aimed to isolate nuts' independent effect on brain health and provide a clearer picture of their potential role in cognitive function.

Major findings

The study found that higher nut consumption was significantly associated with a lower prevalence of cognitive impairment in older adults. Specifically, individuals who consumed more than 11.7 grams of nuts daily had 68% lower odds of cognitive impairment (OR = 0.32, 95% CI: 0.13–0.77) compared to those who ate fewer nuts. Furthermore, this association remained strong even after adjusting for factors such as age, lifestyle habits, and adherence to the Mediterranean diet.

Interestingly, while total nut consumption showed a clear link to cognitive status, no individual nut type demonstrated a significant independent association with cognitive function. This suggested that the benefits may stem from the combined effects of multiple nutrients in nuts rather than any single variety.

Nutritionally, high-nut consumers had greater intakes of healthy fats, including mono- and polyunsaturated fatty acids, as well as higher levels of vitamins A, C, E, and D, along with minerals such as iron, potassium, magnesium, and zinc. These nutrients have been linked to reduced inflammation and oxidative stress, both of which contribute to cognitive decline. Furthermore, nuts are rich in polyphenols and fiber, which may support brain health by promoting gut microbiota balance and improving vascular function.

While the study highlighted a strong association between diet and cognitive function, it is important to note its observational nature, which implies that causality cannot be definitively established. In other words, while nut consumption is linked to better cognitive function, it is not yet proven that nuts directly prevent cognitive decline. Additional longitudinal and interventional studies are needed to confirm whether consistent nut intake directly prevents cognitive impairment. Nonetheless, these findings reinforced the growing evidence that a diet rich in nutrient-dense foods, including nuts, might be a valuable strategy for preserving cognitive health in aging populations.

Conclusions

To conclude, the study added to the growing body of evidence linking diet to brain health and suggested that regular nut consumption may play a role in maintaining cognitive function in older adults. While more research is needed to determine causation, incorporating nuts into a balanced diet appears to be a potentially beneficial strategy for supporting long-term brain health.