Bigger Brains, Better Genes

"Go pump some neurons! Expand your craniums!"
—Robin Williams, in "Mrs. Doubtfire"

You don't need to read this column to know that exercise is good for you. You probably already know that regular, moderate exercise is one of the best things you can do for your health and well-being. What you may not know is that new research is showing that exercise beneficially affects your genes, helps reverse the aging process at a cellular level, gives you more energy, makes you smarter, and may even help you grow so many new brain cells (a process called neurogenesis) that your brain actually gets bigger.

Really.

So does improving your nutrition. A diet high in sugar and saturated fat diminishes neurogenesis, whereas other foods increase it, including chocolate (in moderate amounts), tea and blackberries, which contain a substance called epicatechin that improves memory. Small amounts of alcohol increase neurogenesis, whereas larger amounts decrease it. Chronic emotional stress decreases neurogenesis, but stress management techniques increase it. Drugs such as nicotine, opiates and cocaine decrease neurogenesis, whereas a study published in the Journal of Clinical Investigation in 1995 showed that cannabinoids (found in marijuana) increase it, at least in rats. (Uh, what were we just talking about?)

Use It or Lose It
Until about nine years ago it was thought that you were born with a certain number of neurons, and they tended to decrease in number as you got older. The best you could hope to do was to slow the rate at which you lost brain cells.

Fortunately, it's not true. Researchers at the Salk Institute for Biological Studies and at Columbia University showed that older adults continue to generate new neurons at virtually any age. Earlier this year these researchers found that in addition to growing new neurons, exercise doubled blood flow to the brain. A study published last year by researchers at the University of Illinois reported that just walking for three hours per week for only three months caused so many new neurons to grow that it actually increased the size of people's brains.