Q: I have a hyperactive son who tries our patience sorely at times. A well-meaning friend gave me a book that emphasizes vitamin therapy to treat these children. I know it doesn't work, but she is hurt that I won't even try. Perhaps a word from you will help her understand. What is your opinion?

A: You are correct, and evidence from a well-controlled experiment illustrates the point. Last year a team of pediatricians at the University of Calgary in Alberta, Canada, reported the results of a two-stage study. Children with Attention Deficit Disorder (ADD) -- hyperactivity -- were treated with vitamins according to a popularly suggested regimen.

In part one of the study, six female and 35 male children around 9 years of age were removed from all stimulant drugs and other treatments at least a week before vitamin trials began. They were then given an extensive set of tests, and after about two weeks a vitamin regimen was instituted. It included large doses of ascorbic acid, niacinamide, pyridoxine and calcium pantothenate. Every two weeks, doses were increased. By the end of 12 weeks the children were getting three times the initial dose.

Of the 38 children who completed the study, 12 seemed to show a positive response as measured by a hyperacitiviy index. After a six-week break to wash out the effects of the accumulated vitamins in the body, seven of the 12 children who had been classified as "positive responders" were enrolled in a second study of four six-week treatments. During these trials they were given either the vitamins at the minumum dose at which a positive response had been observed during the open trial, or a placebo.

Using a more complete rating scale, the children's behavior was rated by both parents and the classroom teacher. A trained observer made additional ratings. During this period, neither the children nor the observers knew when they were getting the vitamins and when they were getting placebos.

This time, differences in behavior ratings by parents and teachers were not statistically significant. But the classroom observer found a marked deterioration in behavior in the children when taking the vitamins.

In short, this carefully controlled study demonstrates that vitamin therapy is ineffective in treating ADD. Moreover, the fact that side effects and symptoms of toxicity were observed in just six weeks of high doses of vitamins indicates that it is not in the best interest of the general health of these children.

Q: What is aerobic exercise?

A: Aerobic exercise is the type of physical activity in which the body uses large amounts of oxygen. That is, the heart, lungs and blood vessels are working hard. It is this type of strenuous physical work that conditions these organs and contributes to cardiovascular fitness.

In addition to popular aerobic dance and exercise classes, the vigorous rhythmic movement of running, cycling, swimming and walking at a brisk pace are all examples of aerobic type of exercise.

Q: I have a friend who is always ready to try the latest quick weight-loss remedy. Her latest find is something called DHEA. Can you tell me what this is?

A: DHEA is a steroid hormone. It has been sold both by mail and in some health-food stores, not only for weight reduction but also for enhanced sexual performance and even to prolong life.

According to the Food and Drug Administration, DHEA may be manufactured from human urine as well as from other sources. They point out that there have been no studies of the possible harmful effects of taking it by mouth on a long-term basis. In fact, the FDA has told manufacturers and distributors of DHEA to stop marketing it because the agency does not have proof of safety and effectiveness.

Incidentally, CCK (sholeycystokinin), a normal digestive hormone, has also been promoted recently as controlling appetite and causing dramatic weight loss. While injections of CCK do appear to curb hunger in laboratory animals, this observation does not automatically transfer to humans who take it in pill form. In fact, CCK will not survive the digestive processes and therefore would not be absorbed intact. Again, no data on safety or effectiveness have been provided to the FDA, and the agency has directed that it be removed from the market.

If you do find either of these two products available for sale, you should notify your local branch of the FDA.