infants: (0–6 months): 3 mg
infants: (7–12 months): 3 mg
children (1–3 y): 3 mg
children (4–8 y): 5 mg
children (9–13 y): 8 mg
adolescents (14–18): males, 11 mg, females, 9 mg
adults: males, 11 mg, females, 8 mg
pregnancy: 13 mg
lactation: 14 mg
Zinc in nutritional supplements is available as zinc
gluconate, zinc oxide, zinc aspartate, zinc picolinate,
zinc citrate, zinc monomethionine and zinc histidine.
They are distributed as stand-alone or combination
products as tablets, capsules or liquids.
Precautions
Zinc deficiency most often occurs when zinc intake
is inadequate or poorly absorbed and it can have seri-
ous health consequences. Moderate to severe zinc defi-
ciency is rare in the United States. However, it is highly
prevalent in developing countries. The symptoms of
severe deficiency include the slowing or cessation of
growth and development, delayed sexual maturation,
skin rashes, chronic and severe diarrhea, immune system
deficiencies, poor wound healing, decreased appetite,
impaired taste sensation, night blindness, swelling
and clouding of the corneas, and behavioral disor-
ders. These symptoms were first accurately described
when a genetic disorder called acrodermatitis enter-
opathica was linked to zinc deficiency. Although
mild dietary zinc deficiency is unlikely to cause such
severe symptoms, it is known to contribute to several
health problems, especially in young children. Zinc
deficiency leads to impaired physical and neuropsy-
chological development, and to an increased risk of
life–threatening infections in young children. Indi-
viduals at risk of zincdeficiency include:
infants and children
pregnant and breastfeeding women, especially
teenagers
patients receiving intravenous feeding
malnourished individuals, including those with ano-
rexia nervosa
people with severe or persistent diarrhea
people with malabsorption syndromes, including cel-
iac disease and short bowel syndrome
people with inflammatory bowel disease, including
Crohn’s disease and ulcerative colitis
people with alcoholic liver disease
people with sickle cell anemia
elderly people
strict vegetarians whose major food staples are grains
and legumes because the high levels of phytic acid in
these foods lower the absorption of zinc
Fortified foods include many types of breakfast
cereals that make it easier to consume the RDA for
zinc. However, they also make it easier to consume too
much zinc, especially if zinc supplements are also
taken. Anyone considering zinc supplementation
should accordingly first consider whether their needs
could be met by dietary zinc sources and from fortified
foods. Intakes between 150 and 450 mg of zinc per day
lead to copper deficiency, impaired ironfunction,
reduced immune function, and reduced levels of
high-density lipoproteins, the ‘‘good cholesterol’’. A
few isolated cases of acute zinc toxicity have been
reported for food or beverages contaminated with
zinc present in galvanized containers. Single doses of
225–450 mg of zinc are known to induce vomiting.
Milder gastrointestinal distress has been reported at
doses of 50–150 mg/day of supplemental zinc.InteractionsThe simultaneous administration of zinc supple-
ments and certain antibiotics, such as tetracyclines and
quinolones, may decrease absorption of the antibiotic
with potential reduction of their action. To prevent
this interaction, it is recommended to take the zinc
supplements and antibiotics at least two hours apart.
Metal chelating agents like penicillamine, used to treat
copper overload in Wilson’s disease, and diethylene-
triamine pentaacetate (DTPA), used to treat iron
overload, can lead to severe zinc deficiency. Anticon-
vulsant drugs, such assodiumvalproate, may also
cause zinc deficiency. The prolonged use ofdiuretics
may increase urinary zinc excretion, resulting in
increased zinc losses. A medication used to treat tuber-
culosis, ethambutol, has been shown to increase zinc
loss in rats.
Interactions of zinc taken with other supplements
are as follows:
Calcium: May lower zinc absorption in postmeno-
pausal women.
Iron: May reduce the absorption of both iron and
zinc.
Phosphate salts: May lower the absorption of zinc.
L-cysteine: May increase the absorption of zinc.
L-histidine: May also enhance the absorption of zinc.Zinc