Why do I need zinc?
Zinc may come last in any alphabetical listing of nutrients, but it's one mineral that your body absolutely can't do without. It plays a key role in your immune system and wound healing. It's also important for fertility and growth. Severe cases of zinc deficiency can cause hair loss, impotence, and skin lesions, among other things. Fortunately, most people get plenty of zinc in their everyday lives. There has been some hope that taking extra zinc in a spray or a lozenge could reduce the severity and length of a cold, but it's no sure thing. (The National Institutes of Health calls the evidence for zinc as a cold remedy "inconclusive.")
How much should I be getting?
The current recommended daily allowance for zinc is 8 milligrams a day for women and 11 mg for men. Pregnant women need 11 mg and breastfeeding women need 12 mg a day. These are pretty easy goals to reach, especially if you're a meat eater. People who drink large amounts of alcohol are often low in zinc levels, though, partly because alcohol flushes some of the zinc out of their system.
Which foods contain the most zinc?
Shellfish, particularly oysters, are a rich source, but not many people eat shellfish often enough to really load up on zinc. The most common source is red meat: One serving -- about the size of a deck of cards -- provides about 6 mg of zinc. Beans and nuts are other good sources. An ounce of almonds, for example, will have almost 2 mg. A glass of milk has about 1 mg.
Do I need a supplement?
If you eat red meat about three times a week, you're probably not suffering any shortage of zinc. However, if you're a vegetarian, avoid red meat or if you're pregnant or nursing, a multivitamin containing zinc may not be a bad idea. Zinc will be included in any decent multivitamin, including prenatal vitamins.
Can I get too much zinc?
Like any other metal, zinc can be toxic if you consume too much. Adults shouldn't get more than 40 mg a day, teenagers shouldn't get more than 23 mg, and grade schoolers shouldn't more than 12 mg. You aren't likely to get into any trouble unless you're taking a zinc supplement. An overload of zinc can cause nausea, vomiting, a loss of appetite, abdominal cramps, and headaches.
Mayo Clinic. Zinc supplement. 2010. http://www.mayoclinic.com/health/drug-information/DR602313
National Institutes of Health. Office of Dietary Supplements. Zinc. 2009. http://ods.od.nih.gov/factsheets/zinc/
Linus Pauling Institute at Oregon State University. 2008. http://lpi.oregonstate.edu/infocenter/minerals/zinc/