We've all heard those reports on "super fruit" or the next magical food to prevent this disease or to cure that disease during slow news days. While these stories are lovely fluff pieces, they often lack substantial support. Fortunately, a group of neuroscientists took it upon themselves to perform a legitimate study and to pull information from reliable research in order to identify certain foods that may be helpful in fighting the curse of aging, as well as pinpoint the beneficial effects of these dietary components.
The studies revolved around prevention and possible therapeutic techniques for neurodegenerative diseases and the aging of the brain in general. The first substance of focus was polyphenol, found most often in berry fruits. During experimentation on rat subjects, there proved to be a significant improvement in motor abilities in the group receiving a diet rich in polyphenol while the abilities of the control group either
deteriorated or maintained. In the experimental group, there was also an improvement in various aspects of memory, including LTP, fear conditioning, and both hippocampal-dependent and striatum-dependent memory. It is believed that the reasons for these enhancements are not only the antioxidant activity of the fruit, but also the positive effects on neuronal communication, a neuron's ability to buffer against calcium, and lessening of stress signals. Polyunsaturated fatty acids found mainly in walnuts have been found to improve age related motor and cognitive declines, too.
The article makes it clear that two important factors of the negative effects of aging are oxidative stressors and inflammatory issues. While not much is known about the specific mechanisms that these compounds work on, it is inferred that one of the reasons that they are so beneficial is because of their ability to reduce oxidative stress. Oxidative stress could cause disruptions in the balance of cellular calcium and could cause issues in neuronal signaling. Furthermore, high levels of oxidative stress can ultimately cause gene expression to be changed which could have drastic effects on the dynamics of individual cells, as well as the function and interaction of large groups of neurons. Docosahaenoic acid, or DHA, contained in walnuts and fish oil also plays a large role in the positive activities of these foods. DHA has been linked to anti-inflammatory properties that work to prevent Alzheimer's Disease. It seems that DHA is able to reduce Aβ oligomer production which in turn reduces toxicity levels within cells.
The disadvantages of the use of these foods are heavily outweighed by the advantages. The principal disadvantage stated in the article is the fact that relying on these foods to prevent neurodegenerative diseases could be hard to stick to because of the lack of variety. That is obviously dwarfed by the advantages brought up in the study, a few of the obvious being "safety, broad spectrum utility, low cost, and suitability for prevention." Giving up variety in order to delay ailments such as Alzheimer's Disease and Parkinson's Disease is a minor drawback.
Joseph, James, et. al. Nutrition, Brain Aging, and Neurodegeneration. The Journal of Neuroscience. 29(41): 12795-12801. < http://www.jneurosci.org/content/29/41/12795.full?sid=8a55155f-f531-41b3-90f4-e52fceaf9313 >