Brain Cells: Tougher Than We Thought

by James Stroehecker for HealthWorld Online
November 18, 2003

The human brain contains more than 100 billion nerve cells called neurons. Until a few years ago, neuroscientists said thousands of brain cells died every day, year after year, decade after decade, eventually culminating in an enormous, inevitable loss of good mental function.

Fortunately, this bleak view was misguided.

Recent research shows that few neurons are lost and that, in reality, the brain is highly capable of reorganizing and rebuilding itself, even into old age. Although there is some loss, it's far less than once believed and appears to be confined to certain highly select areas. Those areas essential for memory, though, largely are spared.

Better yet, the evidence strongly suggests that certain good habits and simple lifestyle measures can preserve and even boost mental well-being.

The long-held belief that nerve cells cannot regenerate also is inaccurate. In 1998, researchers proved that the adult brain contains cells capable of dividing and becoming healthy new nerve cells. Instead of dying, these cells seem to shrink.

Although the shrinkage appears to contribute to the general slowdown of mental function associated with aging, it does not seem to cause disability. Serious mental impairment seems to occur only when vast clusters of neurons are destroyed by a major disorder, such as a stroke or Alzheimer's disease.

It also appears that a reduction in the production of specialized brain chemicals needed to conduct signals from one nerve cell to another contributes to age-related memory changes. That may be good news. If the neurons still are intact and only the specialized brain chemicals are lacking, we might be able to enhance the speed of mental processing by treating the chemical deficiency.

What these and other recent findings show is that the brain is not hard-wired but remarkably plastic, even when challenged by stress. For example, in the wake of a stroke, the brain often can compensate for damage to speech or motor centers by rerouting nerve signals through new pathways.

There are several ways that we can keep our minds sharp. These activities include mental stimulation, physical exercise and social connections. These things are important:

** Education and mental activity. Repeated rehearsal of information and the developing critical thinking skills promote plasticity, increasing both the number and the strength of synapses (electrochemical connections between neurons).

** Physical activity. The brain requires more oxygen than any other organ. It utilizes about 25 percent of all the oxygen taken in by the lungs, yet it has no oxygen storage capability. Thus, brain cells need a continuous supply of oxygen. Regular, vigorous aerobic exercise enhances circulatory health, which, in turn, promotes adequate oxygen delivery.

** Emotional well-being. Having a strong sense of purpose and meaning is a key characteristic of people who thrive in their later years. Frequent contact with family and friends, community activities and satisfaction with one's accomplishments are important.

** Managing stress. Stress triggers the release of hormones that can block the production of new brain cells and, over prolonged periods, kill nerve cells. Stress hormones also can lead to chronic medical conditions capable of undermining brain health. Regular exercise, yoga, meditation and seeking help from support groups or a professional counselor can help defuse stress.

** Limiting alcohol and caffeine intake. Excessive alcohol consumption quickly can destroy large numbers of brain cells, which can lead to confusion, impaired balance and coordination, sleep disturbances and depression. While a little caffeine temporarily seems to enhance concentration, too much can cause jitters and confusion.

** Not smoking.

** Treating chronic physical and mental problems. Certain health problems can lead to secondary brain function problems. For example, overly aggressive treatment of diabetes can produce low blood sugar, which starves the brain of the glucose it needs to function properly. Similarly, untreated heart disease can reduce the brain's blood supply.

** Limiting television. Watching television is not as stimulating as reading, conversation, playing word games and working puzzles.

** Getting adequate sleep. As we age, we need fewer hours of sleep per night and tend to awaken more frequently throughout the night. It is nonetheless crucial to get enough sleep, generally at least six hours per night.

** Eating right. Although there is no compelling evidence that any foods or nutrients will enhance normal memory or intelligence, a well-balanced, low-fat diet is essential for good circulatory health.

** Natural Progesterone. Dr John R. Lee, MD, among many authoritative resources report that brain activity and recovery is greatly enhanced by adequate levels of natural progesterone. HRT does not have positive proof of any benefits. New studies indicate possible negative impact from HRT use.

Breaking routine also is helpful. Simple tricks such as occasionally brushing your teeth with the non-dominant hand, taking a different route on your errands, and finding your car keys by touch instead of sight can help sharpen mental skills.

Periodically review your medication. Memory problems can be a side effect of many drugs. Furthermore, some drugs that would be fairly harmless when taken alone may cause problems when combined with other drugs.