Zinc is a mineral that is essential for growth and development at all stages of life. Zinc supports a healthy immune system, participates in wound healing and helps form the structure of proteins and cell membranes.
Good food sources of zinc include beef, shellfish (crab and oysters) and dark meat, such as that found in chicken and turkey. Whole grains tend to be richer in zinc than refined grains because processing removes portions of the grain that contain the majority of the mineral.
Because zinc is involved in so many core processes of the body, the sign and symptoms of deficiency are inconsistent and varied. Zinc deficiency can occur when dietary intake is low, when it is poorly absorbed, when there are increased losses of zinc (which can happen to people with prolonged diarrhea) and during times when the body needs increased amounts of zinc, such as high growth periods. Signs of zinc deficiency include growth retardation, hair loss, diarrhea, delayed sexual maturation and impotence, impaired wound healing, diminished appetite, and eye and skin lesions.
There have been no reports of adverse effects as a result of eating too much naturally occurring zinc from foods. Long-term intakes of supplemental zinc in excess of the body’s needs have been shown to suppress the immune system, decrease HDL (“good”) cholesterol and reduce copper status in the body.
The following table lists the recommended intake for healthy people based on current scientific information.