"In adult centers the nerve paths are something fixed, ended, immutable. Everything may die, nothing may be regenerated."
-- Santiago Ramon Y Cajal, "Degeneration and Regeneration in the Nervous System," 1928
This long-held tenet, first proposed by Professor Cajal, held that brain neurons were unique because they lacked the ability to regenerate.
In 1998, the journal Nature Medicine published a report indicating that neurogenesis, the growth of new brain cells, does indeed occur in humans. As Sharon Begley remarked in her book, "Train Your Mind, Change Your Brain," "The discovery overturned generations of conventional wisdom in neuroscience. The human brain is not limited to the neurons it is born with, or even the neurons that fill in after the explosion of brain development in early childhood."
What the researchers discovered was that within each of our brains there exists a population of neural stem cells which are continually replenished and can differentiate into brain neurons. Simply stated, we are all experiencing brain stem cell therapy every moment of our lives.
As one might expect, the process of neurogenesis is controlled by our DNA. A specific gene codes for the production of a protein, brain-derived neurotrophic factor (BDNF) which plays a key role in creating new neurons. Studies reveal decreased BDNF in Alzheimer's patients, as well as in a variety of neurological conditions including epilepsy, depression, schizophrenia and obsessive-compulsive disorder.
Fortunately, many of the factors that influence our DNA to produce BDNF factors are under our direct control. The gene that turns on BDNF is activated by a variety of factors including physical exercise, caloric restriction, curcumin and the omega-3 fat, DHA.
This is a powerful message. These factors are all within our grasp and represent choices we can make to turn on the gene for neurogenesis. Thus, we can treat ourselves to stem cell therapy by taking control of our gene expression.
Laboratory rats that exercise have been shown to produce far more BDNF in their brains compared to sedentary animals. And there is a direct relationship between elevation of BDNF levels in these animals and their ability to learn, as one might expect.
With this understanding of the relationship of BDNF to exercise, researchers in a report in theJournal of the American Medical Association, entitled "Effect of Physical Activity in Cognitive Function in Older Adults at Risk for Alzheimer's Disease," found that elderly individuals engaged in regular physical exercise for a 24-week period had an improvement of an astounding 1,800 percent on measures of memory, language ability, attention and other important cognitive functions compared to an age-matched group not involved in the exercise program.
The mechanism by which exercise enhances brain performance is described in these and other studies as sitting squarely with increased production of BDNF. Just by engaging in regular physical exercise, you open the door to the possibility of actively taking control of your mental destiny.
In January, 2009, the Proceedings of the National Academy of Science published a study entitled "Caloric Restriction Improves Memory in Elderly Humans." In this study, German researchers imposed a 30 percent calorie reduction on the diets of elderly individuals and compared their memory function with a similar age group who basically ate whatever they wanted. At the conclusion of the three-month study, those who ate without restriction experienced a small, but clearly defined decline in memory function, while memory function in the group consuming the calorie-reduced diet actually increased, and fairly profoundly. In recognition of the obvious limitations of current pharmaceutical approaches to brain health, the authors concluded, "The present findings may help to develop new prevention and treatment strategies for maintaining cognitive health into old age." What a concept. Preventive medicine for the brain.
Because curcumin, the main active ingredient in the spice turmeric, increases BDNF, it has attracted the interest of neuroscientists around the world. Interestingly, in evaluating villages in India where turmeric is used in abundance in curried recipes, epidemiological studies have found that Alzheimer's disease is only about 25 percent as common as in the U.S. There is little doubt that the positive effects of enhanced BDNF production on brain neurons is at least part of the reason why those consuming curcumin are so resistant to this brain disorder.
Like curcumin, DHA enhances gene expression for the production of BDNF. In a recently completed double-blind interventional trial, 485 healthy older individuals (average age 70 years) with mild memory problems were given a supplement containing DHA from marine algae or placebo for six months. Lead researcher of the study, Dr. Karin Yurko-Mauro, commented, "In our study, healthy people with memory complaints who took algal DHA capsules for six months had almost double the reduction in errors on a test that measures learning and memory performance versus those who took a placebo ... The benefit is roughly equivalent to having the learning and memory skills of someone three years younger."
Harnessing the expression of our DNA is empowering, and the tools to better brain health are available to us all -- right now!
Results of the MIDAS trial: Effects of docosahexaenoic acid on physiological and safety parameters in age-related cognitive decline. Karin Yurko-Mauro, Deanna McCarthy, Eileen Bailey-Hall, Edward B. Nelson, Andrew Blackwell, MIDAS Investigators
Alzheimer's & Dementia: The Journal of the Alzheimer's Association, July 2009 (Vol. 5, Issue 4, Supplement, Page P84).