Diet Isn't Everything
Medscape: There are a lot of data on other lifestyle factors with benefits in dementia -- physical activity and mental and social stimulation in particular. How much weight do you give these nondietary factors?
Dr. Perlmutter: We were all over exercise in Grain Brain. One of the notions that I think is very, very empowering and compelling is the idea of neurogenesis -- that humans retain the ability to grow new neurons in the hippocampus throughout our entire lifetime. We can enhance our ability for this activity through the process of epigenetics.
A study published in Proceedings of the National Academy of Sciences in 2011 showed that we can actively modify the gene for the production of brain-derived neurotrophic factor (BDNF) with simple exercise. The investigators looked at 120 elderly nondemented individuals over a 1-year period who either stretched or did aerobics. They measured 3 variables: serum BDNF levels, memory function, and morphometric analysis of hippocampal size on MRI before and after the intervention period. After 1 year, the group that did the aerobic exercise had an increase in hippocampus size by about 1%, improvement of memory function, and higher levels of serum BDNF.
What is so incredible about that is there is no pharmaceutical that can do that. Believe me, you would have probably the world's most valuable pharmaceutical if you could develop a drug that would do that. Plain old physical exercise, nonproprietary. No one owns it. That's why you don't hear about this on the evening news. It's not advertised in our medical journals. Just aerobic exercise improved memory, grew the hippocampus, and raised BDNF levels -- which beyond neurogenesis also stimulates neuroplasticity, which is fundamental for learning. How incredible that you can modify the growth of your brain today by engaging in aerobic exercise! All you need to go out and buy is a pair of sneakers.
The Obama administration just dedicated $33 million to help pharmaceutical companies develop an Alzheimer disease prevention pill, and yet this article has already been published showing preservation of hippocampal size and function -- in fact, regeneration of hippocampal size and function.