I would say that the three newest important risk factors are nutritional status, cardiovascular disease, and high stress.

Redwood: How does stress affect the brain and alter its function over time?

Khalsa: It has been shown, first in animal studies and then with humans, that those with the highest cortisol levels have memory loss. The way it works is that the adrenal glands release a chemical called cortisol, which is toxic to the memory center of the brain known as the hippocampus. It's rather like battery acid in the memory centers of the brain. It initially produces explicit memory loss, where an individual loses the ability to recall previously learned information. It works in three ways. One is that cortisol blocks the uptake of glucose to the brain cells, which are totally dependent of glucose. Another is by blocking the neurotransmitters, the chemicals that cause the message to go from one cell to another. The third thing is that, just like an injury anywhere else, the brain cell will swell up, and after that it will shrink and die. Brain cells can be at varying states of health and illness, depending on what the individual does.

Redwood: What can people do to minimize stress?

Khalsa: The number one thing we can do to help our brains and to limit the effects of stress is to meditate, or to do other kinds of relaxation techniques. Guided imagery, getting a massage. The best thing is a regular morning practice of meditation, because it has been found that cortisol levels are high in the morning.

Redwood: Do you recommend a particular type of meditation, or do you feel that a number of types can be of value?

Khalsa: Many things can be of value. A person can read the Bible and say prayers. Or, there is Transcendental Meditation and sitting Zen meditation. In my experience it depends on the person's own inclination. The methods I've mentioned are the more "yin" techniques, or relaxing techniques. There are also more energizing techniques that I mention in my book, which come from the lineage of kundalini yoga, as taught by Yogi Bhajan. These are much more stimulating to the brain, and I consider them to be the most powerful techniques. They are more rapid-acting. They don't take years to take effect; the effects can often be felt in a couple of sessions. But any technique will work as long as you are carving out space for yourself, rather than jumping into the stress of the day by watching CNN and grabbing a newspaper, having a cup of coffee and jumping into your car, driving on the freeway and getting back into the stress-work cycle. So, contrary to what you hear on TV, the best part of waking up is not "Folgers in your cup." It's meditation.

Redwood: You tell a number of stories in Brain Longevity about patients you were able to help after other doctors had led them to believe they had to resign themselves to a life of significantly diminished mental capacity. I'm wondering if you could briefly recount a story or two.

Khalsa: Let me tell you about three recent cases. One is a man from Southern California, 78, a retired real estate agent, who started to have memory loss and became depressed about it. He went to a doctor at a large medical center. The doctor took out her prescription pad and wrote on it, "Alzheimer's Disease." She gave it to him, offered him no therapy and had his driver's license taken away. Obviously, he became very despondent over this. He somehow heard of me -- I'm not sure whether he read my book or read about me in a magazine. Anyway, he came to Tucson to consult with me. I was not convinced that he had Alzheimer's; I thought he might have severe age-associated memory loss. Whatever it was, he went on a program and started experiencing positive improvement right away. A year later he came to a medical meeting that was open to the public, and was interviewed by the media there. He said, "I may have had Alzheimer's Disease. If I did, I don't have it any more. I'm not perfect, but there is tremendous progress." So it's just not true that nothing can be done. He illustrates that.