Zinc belongs to the category of minerals known as trace elements because it is needed by the human body in very small, or trace, amounts. Several critical biological functions require zinc, including the immune response and maintenance of the immune system. While zinc has a long history as an immune-boosting health supplement, the available evidence suggests that taking extra zinc might not always be beneficial in treating or preventing diseases such as influenza. As with any health supplement, consult your doctor before taking zinc supplements.
Immune Function
Zinc is required for a healthy immune system. The rapidly dividing cells that make up the immune system require zinc for many critical cellular functions, explains the May 2003 issue of the "Journal of Nutrition." People with zinc deficiencies are more likely to develop many types of infections, including pneumonia and influenza, reports the Office of Dietary Supplements of the National Institutes of Health.
Influenza
Although zinc is required for a healthy immune response, taking extra zinc might not necessarily boost the immune system if you are not deficient in zinc. Studies on the effect of zinc supplements on influenza have found mixed results, reports the University of Maryland Medical Center. Of the available studies, many are poorly designed and those that are well-designed often show no benefit from taking zinc supplements. Additional research is needed to clearly define the role of zinc in preventing and treating influenza.
Common Cold
Zinc might be more effective in treating other diseases, such as the common cold. A large-scale review of research into zinc lozenges and the common cold found that using zinc lozenges within 24 hours of the first symptoms might reduce the severity and length of the cold, reports the February 2011 issue of the "Cochrane Database of Systemic Reviews." Taking zinc lozenges for five straight months also appears to reduce the risk of catching a cold; however, because of the risk of side effects and other complicating factors, a firm recommendation cannot be made for the use of zinc supplements to prevent or treat colds.
Risks
Zinc supplements can cause a wide variety of mild side effects, including nausea, vomiting and an odd metallic taste in the mouth, explains the University of Maryland Medical Center. Overdosing on zinc can cause more severe symptoms, including headache, drowsiness, dizziness, loss of muscle control, hallucinations and anemia. Furthermore, taking too much zinc actually can weaken the immune system, making infections of influenza more likely.
References
- Office of Dietary Supplements of the National Institutes of Health: Zinc
- University of Maryland Medical Center: Influenza; Steven D. Ehrlich; September 2009
- Linus Pauling Institute at Oregon State University: Zinc; Jane Higdon et al.; February 2008
- "Journal of Nutrition"; Zinc-Altered Immune Function; K.H. Ibs and L. Rink; May 2003
- "Cochrane Database of Systemic Reviews"; Zinc for the Common Cold; M. Singh and R.R. Das; February 2011
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