Zinc:

Zinc is an essential mineral that is involved in over 20 different enzymatic reactions in the body, ranging from the synthesis of proteins and collagen, to the production of cellular energy. This vital metal helps to support the immune system by regulating the thymus glands' production of T cells. Adequate amounts of this nutrient metal are also vital for the body to manufacture the antioxidant enzyme Sodium Oxide Dismutase, a large molecule that serves as our main line of defense against free radical damage. Zinc also helps in protect the liver from damage, and promotes the rapid healing of wounds. Because it's involved in the production of prostaglandin, special hormonelike substances that regulate the reproductive organs, zinc also plays an important role in maintaining healthy prostate function.

After about age 40, the thymus gland begins to shrink and blood serum levels of zinc begin to slide, falling by about 3 percent every 10 years thereafter. This decline is mirrored in the thymus glands declining output of thymulin, the hormone responsible for stimulating the production of immune-system T cells, the killer cells responsible for keeping tumors in check and protecting us from infections. By age 65 the thymus gland shrinks so much that it can only release about10 percent of the thymulin it did in our youth, greatly impairing our ability to fight disease.

While in vitro studies have long shown that zinc inhibits the common cold rhino-viruses, the experimental data has been mixed when the zinc studies have used throat lozenges. Scientists have now identified a flaw in the studies that used hard-candy zinc lozenges containing citric acid. It seems the low pH produced by the acidic formulation inhibited zinc delivery.