Zinc is an essential trace mineral. Every cell in the body needs this nutrient and hundreds of body processes rely on it, from the immune system and the enzymes that produce DNA to the senses of taste and smell. There's now evidence that supplements may also be useful in providing the extra zinc needed to fight cold and flu symptoms. Zinc is believed to promote a strong immune system by, among other things, revitalising the thymus gland and its production of white blood cells. In addition, zinc has shown promise for speeding the healing of canker sores and sore throat, promoting recovery from skin injuries, reducing tinnitus (ringing in the ears), and controlling acne and eye problems.