September 2008
When to take a supplement
Eating iron-rich foods can help make up for a minor deficiency caused by a poor diet, but it can't compensate for a severe
shortage. "You only absorb about 10 percent of the iron that you take in from foods—somewhere between 1.5 and 2 milligrams
daily," says Jerry Spivak, M.D., professor of medicine at Johns Hopkins University School of Medicine and an NAAC board member.
"And that just isn't enough to build back iron levels."
But don't start popping iron supplements without first being diagnosed, warns John Beard, M.D., professor of nutritional sciences at the University of Pennsylvania. The body has limited ways of ridding itself of excess iron, and over time it can build up to dangerous levels in the liver and heart. Extra iron can even be deadly if you've got hemochromatosis, a surprisingly common genetic condition that causes the body to absorb iron too efficiently. And because iron almost always turns stools black (a harmless side effect), it can mask bleeding from the digestive tract, making it hard to diagnose disorders such as colon cancer. If you start taking a supplement, your doctor should redo blood work within a month to make sure that your body is responding properly. Don't take supplements longer than six months without your doctor's OK.
If your doctor recommends supplements, see our advice below. Keep in mind that iron is best absorbed when taken on an empty
stomach-either 30 minutes before or 2 hours after a meal. If it upsets your stomach, you can take it with food. A small portion
of meat and a food rich in vitamin C or a vitamin C supplement is best. Antacids can decrease absorption; so can coffee, eggs, spinach, soy protein, tea, and whole-grain cereals and breads. High doses of some minerals, including calcium, copper,
magnesium, manganese, or zinc, also block iron. So wait at least an hour to take your iron after consuming any of those foods
or mineral supplements.
Your body can't absorb a lot of iron at once, so large amounts should be split into two or three doses throughout the day. Supplements have different amounts of usable iron, so always look for the amount of elemental iron, which should be clearly marked on the label. The usual dose of elemental iron to correct a deficiency is 100 to 200 milligrams daily, but you may need more or less to get your optimal balance. Start with a low dose and build up gradually to make it easier on your stomach.
First try... one of the iron salts: ferrous sulfate, ferrous fumerate, or ferrous gluconate. They're inexpensive and they work. Children's formulations and some adult products that contain carbonyl iron are somewhat
safer in case of accidental overdose. But older folks should avoid carbonyl iron because they often lack the stomach acid
required to absorb it.
If supplements cause nausea or constipation, then try... slow-release versions of iron salts or iron-polysaccharide complex. These cost more that ferrous salts, but some studies suggest they are better tolerated. Other options include chelated iron, ferrous bisglycinate, or ferrous glycinate.
As a last resort, use... prescription supplements. These usually don't work better than over-the-counter supplements, however. Also, they're expensive, and insurance might not cover them.
But don't start popping iron supplements without first being diagnosed, warns John Beard, M.D., professor of nutritional sciences at the University of Pennsylvania. The body has limited ways of ridding itself of excess iron, and over time it can build up to dangerous levels in the liver and heart. Extra iron can even be deadly if you've got hemochromatosis, a surprisingly common genetic condition that causes the body to absorb iron too efficiently. And because iron almost always turns stools black (a harmless side effect), it can mask bleeding from the digestive tract, making it hard to diagnose disorders such as colon cancer. If you start taking a supplement, your doctor should redo blood work within a month to make sure that your body is responding properly. Don't take supplements longer than six months without your doctor's OK.
Your body can't absorb a lot of iron at once, so large amounts should be split into two or three doses throughout the day. Supplements have different amounts of usable iron, so always look for the amount of elemental iron, which should be clearly marked on the label. The usual dose of elemental iron to correct a deficiency is 100 to 200 milligrams daily, but you may need more or less to get your optimal balance. Start with a low dose and build up gradually to make it easier on your stomach.
If supplements cause nausea or constipation, then try... slow-release versions of iron salts or iron-polysaccharide complex. These cost more that ferrous salts, but some studies suggest they are better tolerated. Other options include chelated iron, ferrous bisglycinate, or ferrous glycinate.
As a last resort, use... prescription supplements. These usually don't work better than over-the-counter supplements, however. Also, they're expensive, and insurance might not cover them.
