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 [
1,
2] and it plays a role in immune function [
3,
4], protein synthesis [
4], wound healing [
5], DNA synthesis [
2,
4], and cell division [
4]. Zinc also supports normal growth and development during pregnancy, childhood, and adolescence [6–8] and is required for proper sense of taste and smell [
9]. A daily intake of zinc is required to maintain a steady state because the body has no specialized zinc storage system [
10].
Recommended Intakes
Intake recommendations for zinc and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies (formerly National Academy of Sciences) [
2]. DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and gender [
2], include the following:
- Recommended Dietary Allowance (RDA): average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals.
- Adequate Intake (AI): established when evidence is insufficient to develop an RDA and is set at a level assumed to ensure nutritional adequacy.
- Tolerable Upper Intake Level (UL): maximum daily intake unlikely to cause adverse health effects [2].
The current RDAs for zinc are listed in Table 1 [
2]. For infants aged 0 to 6 months, the FNB established an AI for zinc that is equivalent to the mean intake of zinc in healthy, breastfed infants.
Table 1: Recommended Dietary Allowances (RDAs) for Zinc [2]AgeMaleFemalePregnancyLactationBirth to 6 months2 mg*2 mg* 7 months to 3 years3 mg3 mg 4 to 8 years5 mg5 mg 9 to 13 years8 mg8 mg 14 to 18 years11 mg9 mg13 mg14 mg19+ years11 mg8 mg11 mg12 mg
