Zinc is a trace element, meaning it is found in the body only in trace amounts equivalent to about 2 g, of which 65% is accumulated in muscles and 20% in bones. It is present in all cells, including the adrenal glands, skin, parts of the brain, pancreas, eye membranes, prostate and sperm.
Zinc is important for growth, the immune system, neurological and reproductive functions. It is required for more than 100 vital enzymatic processes in the body. It is involved in DNA, RNA and protein synthesis, immune processes, wound healing, reproduction and growth. Zinc plays a role in mood changes, learning processes, vision, taste and smell. It is involved in blood clotting, thyroid hormone function and insulin metabolism.
Sources of zinc in food
In general, the body absorbs from 15 to 40 percent of zinc in food. The greatest amount of zinc is found in oysters. Meat, various nuts, legumes and whole grains also contain large amounts of zinc.
The body requires very low levels of zinc, but it is nevertheless very necessary. Mild zinc deficiency is prevalent in modern society. In women, adolescents, children and the elderly, intake of this micronutrient is often below the daily minimum due to poor eating habits.
Pregnant women with colds, the flu, or other infections can have decreased zinc levels, which can pose a risk to the fetus.
Other factors also play a role in decreasing zinc levels in foods, including modern farming practices that deplete zinc reserves in the soil and grain refining.
Because the best sources of zinc are animal products, vegetarians need to pay special attention to consuming enough of this micronutrient from whole grains, legumes, nuts and seeds.
Alcoholics, diabetics, and people with kidney or digestive system problems (Crohn’s disease) are at greater risk of zinc deficiency. People with HIV are often deficient in zinc.
Zinc deficiency can lead to decreased immune function (frequent infections and poorly healing wounds), stunted growth, decreased sense of smell and taste, male fertility, dermatitis, diarrhea, depression, weight loss, irritability and apathy.
Zinc reduces the duration and severity of a runny nose, provided it is given within 24 hours of the onset of symptoms. In addition, if taken as a preventative for at least 5 months, it will reduce the frequency of colds and the amount of antibiotics prescribed to children. However, the longer-term effects of this consumption of zinc by a growing child are unknown.
Some researchers believe that zinc-supplemented lozenges are ineffective because of the sweetener used to mask the metallic taste of zinc, because a number of sweeteners suppress the antiviral effects of zinc. Therefore, zinc is better taken in the form of tablets or syrup.
Zinc gluconate, taken for 3 months, has been shown in studies to be effective against acne. However, an oral antibiotic (minocycline in this study) was significantly more effective in reducing lesions in 63.4% of participants.