Zinc is an essential trace element for all forms of life. The significance of zinc in human nutrition and public health was recognized relatively recently. Clinical zinc deficiency in humans was first described in 1961, when the consumption of diets with low zinc bioavailability due to high phytic acid content was associated with "adolescent nutritional dwarfism" in the Middle East. Since then, zinc insufficiency has been recognized by a number of experts as an important public health issue, especially in developing countries.

Zinc has a variety of functions in the body. Nearly every enzyme reaction in the brain involves zinc. It is a component of at least 25 enzymes involved in digestion and metabolism, including carbohydrate digestion and phosphorous metabolism.
    Zinc is essential for general growth and proper development of the reproductive organs and prostate gland function.
    Zinc is also a component of insulin and many vital enzymes. It also will fight and prevent against the formation of free radicals. Zinc also increases the absorption of vitamin A.

Men should have 12 milligrams every day,women 10 milligrams every day and pregnant women should have 13 milligrams.

Intake:

Recommended Dietary Allowance (RDA) for Zinc
Babies 0-6 months	2 mg/day
Babies 7-12 months	3 mg/day
Children 1 to 3 years	3 mg/day
Children 4 to 8 years	5 mg/day
Children 9 to 13 years	8 mg/day
Teenagers boys 14 to 18	11 mg/day
Teenagers girls 14 to 18	9 mg/day
Adult men	12 mg/day
Adult women	10 mg/day
Pregnant women	13 mg/day
Breastfeeding	14 mg/day

Numerous aspects of cellular metabolism are zinc-dependent. Zinc plays important roles in growth and development, the immune response, neurological function, and reproduction. On the cellular level, the function of zinc can be divided into three roles:

    Catalytic role
    Nearly 100 different enzymes depend on zinc for their ability to catalyze vital chemical reactions. Zinc-dependent enzymes can be found in all known classes of enzymes.

    Structural role
    Zinc plays an important role in the structure of proteins and cell membranes. A finger-like structure, known as a zinc finger motif, stabilizes the structure of a number of proteins. The structure and function of cell membranes are also affected by zinc. Loss of zinc from biological membranes increases their susceptibility to oxidative damage and impairs their function.

    Regulatory role
    Zinc finger proteins have been found to regulate gene expression by acting as transcription factors. Zinc also plays a role in cell signaling and has been found to influence hormone release and nerve impulse transmission.

Shellfish, beef, and other red meats are rich sources of zinc. Nuts and legumes are relatively good plant sources.