There are many symptoms and decreased body functions due to zinc deficiency. It may cause slowed growth or slow sexual development in the pubertal years. Lowered resistance, fatigue, and increased susceptibility to infection may occur with zinc deficiency, which is related to a decreased cellular immune response. Sensitivity and reactions to environmental chemicals may be exaggerated in a state of zinc deficiency as many of the important detoxification enzyme functions may be impaired.
Children with zinc deficiency may show poor appetite and slow development, have learning disabilities or poor attention spans, and in later years have acne and decreased sexual development. Dwarfism and a total lack of sexual function may occur with serious zinc deficiency. Fatigue is common.
Acute deficiency may cause hair loss or thinning, dermatitis, and decreased growth. Both poor appetite and digestion are also experienced by adults with zinc deficiency. Loss of taste sensation may occur, as can brittleness of the nails or white spots on the nails, termed leukonykia. These and most other symptoms can be corrected with supplemental zinc. Sulfur may be helpful as well. Skin rashes, dry skin, and delayed healing of skin wounds or ulcers may result from zinc deficiency, and stretch marks, called striae, are also produced by this condition. Zinc and copper are both needed for cross-linking of collagen, and when they are low, the skin tissue may break down.
Zinc deficiency may cause delayed menstruation in teenage females or, in later years, cause menstrual problems. In addition to zinc, vitamin B6 often also helps correct this. Females on birth control pills usually have elevated copper levels and need additional zinc and B6. When zinc is further reduced by the increased copper, depression is more likely, a common side effect of birth control pill use. Morning sickness in pregnancy may result from low zinc and B6 levels, and supplementing these nutrients may help reduce symptoms.
RDAs for Zinc
|Under 1 year||3–5 mg.|
|1–10 years||10 mg.|
|11 years over||15 mg.|
|Pregnant women||20–25 mg.|
|Lactating women||25–30 mg.|
Male teenagers with low zinc have delayed or absent sexual development. Sterility may result from zinc deficiency; when it is caused by testicular degeneration, it may be irreversible. Subtle zinc deficiencies may be responsible for male growth lag in puberty. Even in sexually developed males, low zinc levels have been correlated with a decrease in testosterone levels and a lower sperm count. Prostate problems are more prevalent with zinc deficiency.
Birth defects have been associated with zinc deficiency during pregnancy in experimental animals. The offspring showed reduced growth patterns and learning disabilities. In humans, children with zinc deficiency have decreased intelligence and erratic behavior. With zinc treatment, the IQ and behavior may both improve if the problem is related to zinc deficiency.
Requirements: The RDA for zinc in adults is 15 mg., with additional amounts needed during pregnancy and lactation. Yet the average diet contains only about 10 mg. of zinc. And when zinc needs are considered, we likely need even more than 15 mg. per day to be sure we are meeting our requirements. Adequate amounts can be met by a good diet, especially with good protein and calorie intake. Vegetarians can eat more whole grains; even with some of the zinc binding to grain phytate, we still get a fair share into our body from these zinc-rich foods. Since absorption is about 30-40 percent, our total zinc body tissue needs are about 4-6 mg. per day.
We probably need 15-30 mg. of available (elemental) zinc daily for maintenance and probably about 30-60 mg. for treatment, though more is sometimes used. Fifteen mg. of zinc is often included in general supplement formulas. Separately, zinc gluconate and sulfate in reasonable amounts are used commonly without any side effects, though zinc gluconate is usually a little better tolerated than zinc sulfate. The amino-acid-chelated zinc is probably the best tolerated and absorbed though it is more expensive. Zinc sulfate tablets or capsules of 220 mg. provide 55 mg. of elemental zinc. A supplement labeled "zinc 25 mg. as gluconate" should provide 25 mg. elemental zinc. In medical treatment or research, zinc sulfate 220 mg. may be used two to three times daily, supplying about 100-150 mg. of available zinc for absorption. This dosage is usually tolerated fairly well.
Although 30-60 mg. of elemental zinc per day is the usual therapeutic level, more may be needed to correct zinc deficiency. Taking zinc alone two hours after meals or first thing in the morning will increase absorption by reducing the competition with other nutrients, such as calcium and copper, or food constituents such as the phytates and fibers in grains. With infections, burns, before or after surgery, in pregnancy, or with aging (often accompanied with lower absorption), 50-75 mg. per day is suggested as a therapeutic dose.
When taking higher amounts of zinc, we must make sure we get adequate amounts of copper-at least 2-3 mg. supplemented, and possibly more with higher zinc intakes-so copper deficiency does not occur. The suggested zinc to copper ratio is about 15:1. About 200 mcg. per day of selenium should also be taken, to prevent depletion by supplemental zinc. Zinc may be taken with magnesium, vitamin C, and B complex vitamins, but it is best to take a regular vitamin-mineral combination with 15-30 mg. of zinc in proper proportion to other minerals, so that deficiencies of zinc or imbalances of the other minerals do not occur.