Polyphenolic compounds found in walnuts not only reduce the oxidant and inflammatory load on brain cells but also improve interneuronal signaling, increase neurogenesis, and enhance sequestration of insoluble toxic protein aggregates.
In conclusion, age-related increases in oxidative stress and inflammation, especially when coupled with metabolic and cardiovascular dysfunction, lead to neurodegeneration and cognitive decline. This process of brain aging occurs even in the absence of specific neurodegenerative diseases. Although most chronic neurodegenerative diseases cannot currently be cured, preventive measures earlier in life can protect cognitive function in old age and may prevent or delay the onset of debilitating neurodegenerative diseases. Dietary interventions provide a safe and palatable means of modifying the body's internal environment and, importantly, the neuronal environment within the brain. Walnut polyphenols and tocopherols can reduce oxidative stress and inflammation; furthermore, PUFAs help maintain neuronal membrane integrity and attenuate protein aggregation involved in AD. In rodent studies, the addition of dietary walnuts, equivalent to a single serving of walnuts for humans, was sufficient to improve both motor and cognitive behavior in aged animals. In humans, the inclusion of walnuts in the diet improved cardiovascular health, which is itself a risk factor for neurodegenerative diseases and age-related cognitive decline. Taken together, this evidence suggests that the integration of walnuts into a healthy diet could be an effective means of prolonging health spans, slowing the processes of brain aging, and reducing the risk of chronic neurodegenerative disease.
