I was amazed to discover the power of what I’d once considered to be simple fruits and nuts. A few years ago Tufts University researcher, James Joseph, Ph.D. reported that diets containing two percent, six percent, or nine percent walnuts, when given to senior rats, reversed several signs of brain aging, along with age-related movement decline and cognitive deficits.
In earlier research, Joseph and his colleagues showed that old rats maintained for two months on diets containing two percent high antioxidant strawberry or blueberry extracts exhibited reversals of age-related deficits in the way that nerve cells function. In the brain, antioxidant molecules halt the damage caused by molecules known as free radicals. This study builds upon the earlier findings and demonstrates that walnuts can have a similar effect.
Walnuts contain alpha-linolenic acid (ALA), an essential omega-3 fatty acid, and other molecules, known as polyphenols that act as antioxidants. They may actually block the signals produced by free radicals that can later trigger the creation of compounds that increase inflammation.
These findings for the first time determined that shorter chain fatty acids found in plants, such as walnuts, may have beneficial effects on cognition similar to those from long chain fatty acids derived from other sources, such as fish, which have been reported previously.
A six percent diet is equivalent to a person eating 1 ounce of walnuts each day, which is the recommended amount to reduce harmful low-density lipoprotein, or LDL, cholesterol, while a nine percent diet is equivalent to people eating 1.5 ounces of walnuts per day. "Importantly," Joseph says, "this information, coupled with our previous studies, shows that the addition of walnuts, berries, and grape juice to the diet may increase 'health span' in aging and provide a 'longevity dividend' or economic benefit for slowing the aging process by reducing the incidence and delaying the onset of debilitating degenerative disease."
Joseph and his colleagues are currently assessing whether increased nerve cell creation or changes in stress signaling, or both, may be involved in the actions through which the walnut diets could be producing their effects.
Walnuts are involved in more than the mere "quenching" of free radicals and may in fact involve direct effects on blocking the deleterious "stress signals" generated by the oxidative stressors. Dr. Joseph suggests the beneficial effects of walnuts may be due to the enhancement of signals that control very important functions as nerve cell growth and communication.
A great deal of data suggests that the deficits associated with aging, for example, Alzheimer's disease and cardiovascular diseases, occur as a result of an increasing inability of the “aging” organism to protect itself against inflammation and oxidative stress, providing fertile ground for the development of neurodegenerative diseases.
"The good news," Joseph says, "is that it appears that compounds found in fruits and vegetables -- and, as we have shown in our research, walnuts -- may provide the necessary protection to prevent the demise of cognitive and motor function in aging."