Zinc supports your immune system by fighting viruses and bacteria. If you take zinc within 24 hours of the onset of a cold, it might shorten the duration. Growing children, infants and pregnant women especially need zinc. Your body is incapable of storing zinc, so you need to ingest a certain amount daily.
According to the Office of Dietary Supplements, you need somewhere between 2 milligrams and 13 milligrams of zinc daily, depending on your age. Infants need the least and breastfeeding teenagers need the most. A man requires 11 milligrams, while women need 8 milligrams. You can eat foods rich in zinc -- including oysters, poultry and red meat -- or opt for a supplement. Most multivitamins contain some level of zinc. Any of the three available forms of zinc -- zinc gluconate, zinc acetate and zinc sulfate -- will work.
Most people get sufficient amounts of zinc in their daily diet, but you might be at risk for deficiency if you are a vegetarian or an alcoholic. If you've had gastric bypass surgery or have digestive disorders, such as Crohn's disease, you might also be deficient. Pregnant or breastfeeding women and older breastfed infants could also have zinc deficiency, and breast milk lacks sufficient zinc levels for babies over 6 months, according to the Office of Dietary Supplements..