Zinc deficiency might occur in people with severe diarrhea, conditions that make it hard for the bowel to absorb food, liver cirrhosis and alcoholism, after major surgery, and during long-term use of tube feeding in the hospital. Taking zinc by mouth or giving zinc intravenously (by IV) helps to restore zinc levels in people who are zinc deficient. However, taking zinc supplements regularly is not recommended.
Recommended Dietary Allowance (RDA) quantities of zinc have been established for boys and men age 14 and older, 11 mg/day; women 19 and older, 8 mg/day; pregnant women 14 to 18, 13 mg/day; pregnant women 19 and older, 11 mg/day; lactating women 14 to 18, 14 mg/day; lactating women 19 and older, 12 mg/day. Tolerable Upper Intake Levels (UL) of zinc for people who are not receiving zinc under medical supervision: adults 19 years and older (including pregnancy and lactation), 40 mg/day. The typical North American male consumes about 13 mg/day of dietary zinc; women consume approximately 9 mg/day. Different salt forms provide different amounts of elemental zinc. Zinc sulfate contains 23% elemental zinc; 220 mg zinc sulfate contains 50 mg zinc. Zinc gluconate contains 14.3% elemental zinc; 10 mg zinc gluconate contains 1.43 mg zinc.
Zinc might decrease how much antibiotic the body absorbs. Taking zinc along with some antibiotics might decrease the effectiveness of some antibiotics. To avoid this interaction take zinc supplements at least 1 hour after antibiotics.<br /> Some of these antibiotics that might interact with zinc include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).
Zinc is LIKELY SAFE for most adults when taken by mouth in amounts not larger than 40 mg daily. Routine zinc supplementation is not recommended without the advice of a healthcare professional. In some people, zinc might cause nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage, and other side effects. Zinc is POSSIBLY SAFE when taking by mouth in doses greater than 40 mg daily. There is some concern that taking doses higher than 40 mg daily might decrease how much copper the body absorbs. Decreased copper absorption may cause anemia. Taking high amounts of zinc is LIKELY UNSAFE. High doses above the recommended amounts might cause fever, coughing, stomach pain, fatigue, and many other problems. Taking more than 100 mg of supplemental zinc daily or taking supplemental zinc for 10 or more years doubles the risk of developing prostate cancer. There is also concern that taking large amounts of a multivitamin plus a separate zinc supplement increases the chance of dying from prostate cancer. Taking 450 mg or more of zinc daily can cause problems with blood iron. Single doses of 10-30 grams of zinc can be fatal.
Zinc sulfate has been assigned to pregnancy category C by the FDA. Safety for use in pregnancy has not been established. The risk of fetal harm if used during pregnancy is remote. A dietary intake of 11 mg of zinc per day (19 to 50 years of age) and 12 mg per day (14 to 18 years of age) is recommended during pregnancy.