Healthy adult men should have 11 milligrams of zinc daily, while women need 8 milligrams per day. (See Reference 1) A varied diet supplies most Americans with enough, but the elderly, vegans, strict vegetarians and people who have kidney disease or a digestive disorder like ulcerative colitis or celiac disease may benefit from a zinc supplement. (See Reference 1) Non-prescription zinc supplements are chelated, meaning they contain the mineral bound to another compound. (See Reference 2) Common chelated zinc supplements include zinc picolinate and zinc citrate. (See Reference 3) Talk to your doctor about possible side effects before taking any form of chelated zinc.
Common Side Effects
The most commonly reported side effects of moderate chelated zinc supplementation include an upset stomach, vomiting and nausea. You may also notice your mouth developing a metallic aftertaste. (See Reference 3) High doses may cause dizziness, excessive sweating, unexplained tiredness, headache, fever, chest pain, fainting, chills, vomiting, sores in your mouth or throat, shortness of breath, yellow skin or eyes and an increased risk of infections due to a suppressed immune system. (See Reference 3 and 4) Taking a large amount of chelated zinc may also lower your HDL, or "good," cholesterol level while increasing your LDL, or "bad," cholesterol. (See Reference 3 and 5)
Increased Risk of Anemia
Taking chelated zinc inhibits your body's ability to absorb copper and may cause a copper deficiency. (See Reference 3) Inadequate copper can cause you to develop anemia since copper is required for the production of red blood cells. (See Reference 2) If you choose to take zinc supplements, you should also take a copper supplement, spacing the minerals approximately two hours apart. (See Reference 4) Have your doctor help you establish a safe dosage for each mineral.
Chelated zinc supplements may interfere with your body's ability to absorb tetracycline and quinolone antibiotics such as ciprofloxacin, demeclocycline and norfloxacin. (See Reference 3) Take these antibiotics two hours before or after your zinc, advises the Linus Pauling Institute. (See Reference 1) Avoid taking zinc if you are on amiloride, a diuretic that raises your blood's concentration of zinc. In addition, do not use chelated zinc if you have been prescribed an ACE inhibitor for your blood pressure, penicillamine, deferoxamine or the chemotherapy drug cisplatin. (See Reference 3)
Dangers of Large Doses
The tolerable upper intake level, or UL, of zinc is 40 milligrams per day. This means that if you take more than 40 milligrams of chelated zinc each day, you have a greater risk of developing potentially harmful side effects. (See Reference 1) A study published in the "Journal of Urology" in 2007 found that subjects taking 80 milligrams of zinc daily for over six years were significantly more likely to require hospitalization for urinary problems, including kidney failure, urinary tract infections and benign prostatic hyperplasia. (See Reference 6)
- Linus Pauling Institute: Zinc
- Ask the Dietitian: Zinc
- University of Maryland Medical Center: Zinc
- Drugs.com: Zinc Chelated
- National Institutes of Health: Zinc
- The Journal of Urology: High Dose Zinc Increases Hospital Admissions Due to Genitourinary Complications
- National Institutes of Health, Office of Dietary Supplements: Zinc Consumer Fact Sheet