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Zinc Shows Promise in Combatting AIDS-Related Diseases

Scientists are racing to find a cure for AIDS. But until one is discovered, researchers say there are many things HIV-infected people can do to improve their chances of survival.

In Miami, a new study is focusing on nutrition. Specifically, researchers are looking at zinc, a mineral which is found in protein-rich food, such as meat, and the role it plays in helping the body combat opportunistic diseases associated with AIDS.

Florida International University medical researcher Mary Anna Baum says nutrition in general, and zinc in particular, has a direct impact on the body's ability to fight disease. "Zinc has been known for decades to be important for the function of the immune system," she says.

An FIU team is launching a long-term study of more than 200 HIV-infected individuals. Dr. Baum says half of the participants will be given zinc supplements, the other half a placebo.

"The amounts we are planning to supplement are relatively small, one-time the recommended daily allowance of zinc, and we believe that this amount is going to be therapeutic, it's going to slow disease progression in HIV-infected individuals," she says.

Previous studies have shown that HIV positive people often suffer a zinc deficiency. There are many possible reasons for this: a poor overall diet, the intestinal distress caused by many anti-viral medications that may prevent zinc absorption and the fact that the HIV virus itself uses zinc and competes with the body for available supplies of the mineral.

Regardless of the cause, zinc levels are thought to be one of several factors that help determine whether HIV positive people develop full-blown AIDS. Long-term survivors of the virus often show higher levels of the mineral than those who succumb to opportunistic diseases associated with AIDS.

FIU researchers hope to assure the greatest-possible contrast in results between the experimental and control groups in the study. To accomplish this, subjects will be recruited from a Miami homeless shelter, Camillus House. It is there they expect to find individuals with the greatest nutritional deficiencies.

Camillus House Director Dale Simpson says he hopes the study will benefit science - and some of the people who rely on the shelter.

"Anybody who gets HIV suffers a very tragic disease," he says. "But for somebody who lives on the street and struggles daily for their existence, this is the most dreadful challenge you could imagine. So, anything that might help [them] is a wonderful advantage."

But just what is the right amount of zinc? Florida International University researcher Adriana Campa says that question has yet to be answered.

"There are studies that show that too much [zinc] might be harmful, and too little also [might be harmful]," she says. "There are a lot of questions as to what is the right amount, and this is one of the questions that this study will address: if giving a nutritional supplement will be enough to give the host person a fair advantage over the virus."

While recommending slightly elevated zinc consumption for HIV infected people, Dr. Campa cautions against taking mega-doses of the mineral. She says extreme levels of zinc are toxic to the body, and can actually depress the immune response.

No one is suggesting that zinc is a "magic bullet" in the fight against AIDS. But until a cure is found, Dr. Campa says HIV positive people can and should pay special attention to their diet.

"After 20 years into the epidemic, we know it is not going away," she says. "Those who are infected are going to have to live with the virus, at least until we find the miracle drug that will eliminate the virus. Nutrition is an important component of that [healthy] lifestyle that they are going to have to maintain."

The FIU study is expected to run for five years, and is funded by the National Institutes of Health.