Zinc
Zinc: What is it?
Zinc is an essential mineral that is found in almost every cell. It stimulates the activity of approximately 100 enzymes, which are substances that promote biochemical reactions in your body (1,2). Zinc supports a healthy immune system (3,4), is needed for wound healing (5), helps maintain your sense of taste and smell (6), and is needed for DNA synthesis (2). Zinc also supports normal growth and development during pregnancy, childhood, and adolescence (7, 8).
What foods provide zinc?
Zinc is found in a wide variety of foods (2). Oysters contain more zinc per serving than any other food, but red meat and poultry provide the majority of zinc in the American diet. Other good food sources include beans, nuts, certain seafood, whole grains, fortified breakfast cereals, and dairy products (2,9). Zinc absorption is greater from a diet high in animal protein than a diet rich in plant proteins (2). Phytates, which are found in whole grain breads, cereals, legumes and other products, can decrease zinc absorption (2, 10, 11).(Refer to Table 1: Selected Food Sources of Zinc lists a variety of dietary sources of zinc.)
What is the Recommended Dietary Allowance for zinc?
The latest recommendations for zinc intake are given in the new Dietary Reference Intakes developed by the Institute of Medicine. Dietary Reference Intakes (DRIs) is the umbrella term for a group of reference values used for planning and assessing nutrient intake for healthy people. The Recommended Dietary Allowance (RDA), one of the DRIs, is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals (2). For infants 0 to 6 months, the DRI is in the form of an Adequate Intake (AI), which is the mean intake of zinc in healthy, breastfed infants. The AI for zinc for infants from 0 through 6 months is 2.0 milligrams (mg) per day. The 2001 RDAs for zinc (2) for infants 7 through 12 months, children and adults in mg per day are:
Table 1: Recommended Dietary Allowances for Zinc for
Infants over 7 months, Children, and Adults
|
Age
|
Infants and Children
|
Males
|
Females
|
Pregnancy
|
Lactation
|
|
7 months to 3 years
|
3 mg
|
|
|
|
|
|
4 to 8 years
|
5 mg
|
|
|
|
|
|
9 to 13 years
|
8 mg
|
|
|
|
|
|
14 to 18 years
|
|
11 mg
|
9 mg
|
13 mg
|
14 mg
|
|
19+
|
|
11 mg
|
8 mg
|
11 mg
|
12 mg
|
|
Results of two national surveys, the National Health and Nutrition Examination Survey (NHANES III 1988-91) (12) and the Continuing Survey of Food Intakes of Individuals (1994 CSFII) (13) indicated that most infants, children, and adults consume recommended amounts of zinc.
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