Most colds are caused by a rhinovirus virus type, which thrives and multiplies in the upper respiratory system. Zinc may work by preventing the rhinovirus from multiplying as well as stop the rhinovirus from lodging in the mucous membranes of the throat and nose.
Zinc is an essential mineral that is naturally present in some foods, added to others, and available as a dietary supplement. Zinc is also found in many cold lozenges and some over-the-counter drugs sold as cold remedies.
Zinc is involved in numerous aspects of cellular metabolism. It is required for the catalytic activity of approximately 100 enzymes and it plays a role in immune function, protein synthesis, wound healing, DNA synthesis, and cell division. Zinc also supports normal growth and development during pregnancy, childhood, and adolescence and is required for proper sense of taste and smell. A daily intake of zinc is required to maintain a steady state because the body has no specialized zinc storage system.
Zinc is an essential mineral for immune system. Only 15 mgs a day of Zinc supplement will improve wound healing, the functioning of our immune system, eyesight, brain development, sperm and the synthesis of testosterone.
Zinc antiviral properties were first discovered in 1980 when doctors treated a 3-year old girl with a 50 mg zinc gluconate tablet to help boost her immune system. In a controlled trial, 50 volunteers took about 13 mg of zinc in the form of zinc acetate or placebo every 2-3 hours as long as they had cold symptoms. The results were statistically significant. The zinc group had a shorter average duration of colds, 4.5 days versus 8 days. The total zinc taken was about 80 mg a day, which although well above the daily requirement, should not cause any problems over such a short period.
The National Institutes of Health (NIH) recommends the following daily doses of the above micronutrients for adults:
- Zinc: 8 mg for women; 11 mg for men
- Vitamin A: no more than 3,000 micrograms (mcg)
- Vitamin C: 75 milligrams (mg) for women; 90 mg for men
- Vitamin D: 600 international units (IU)
- Vitamin E: 15 mg
- Vitamin B2: 1.1 mg for women; 1.3 mg for men
- Vitamin B6: 1.3 mg
- Vitamin B12: 2.4 mcg
- Folic acid: 400 mcg of dietary folate equivalents
- Iron: 18 mg for women; 8 mg for men
- Selenium: 55 mcg