Supplementing with iron can cause constipation and even bowel obstruction. Find how to reduce these risks when taking iron in the ConsumerTips section of the Iron Supplements Review. Also see our Top Picks for iron.

A new study showed that women getting more iron had a significantly lower risk of suffering PMS (premenstrual syndrome) -- but not just any type of iron. Get the details, as well as our ratings of iron supplements, in the updated Iron Supplements Review »

Regular use of certain popular medicines was associated with a large increase in the risk of iron deficiency, according to a new study. Get the details in the ConsumerTips section of the Iron Supplements Review. (Also see our Top Picks among iron supplements.)

Having too much iron in the body is associated with an increased risk of a variety of conditions and, according to a recent study, stroke is among these. For details, see the Concerns and Cautions section of the Iron Supplements Review. (Also see our Top Picks for iron when you need to supplement.)

A new study showed that iron supplementation speeds the recovery of hemoglobin levels by several weeks after blood donation and suggests that the current time between donations may be too short. For details, as well as our tests of iron supplements, see the Iron Supplements Review >> 

Iron supplements can be hard on the stomach, but be aware that very high doses may actually cause erosions and ulcers. Certain formulations are less likely to cause this problem. For details, see the Concerns and Cautions section of the Iron Supplements Review. Also see our Top Picks among iron supplements.

Iron supplementation may help to reduce the severity of restless legs syndrome (RLS) symptoms in people who have deficient or low levels of iron, according to guidelines from the American Academy of Neurology. For details, including dosage, see the "What It Does" section of the Iron Supplements Review, which also includes our tests and quality comparisons of products.

There are downsides to taking too much iron, but a recent analysis suggests that getting a basic amount of iron may reduce stroke risk for women. Get the details in the Concerns and Cautions section of our Iron Supplements Review.

A recent study suggests a link between iron deficiency anemia and fibromyalgia, particularly in women. Get the details in the What It Does section of our Iron Supplements Review. Also see our Top Picks among iron supplements.

Vitamin C is often touted to boost iron absorption. But does it really work? Find out what a recent study found in the ConsumerTips section of our Iron Supplements Review. Also, see our Top Picks for iron.

Recommended doses for correcting iron deficiency may be too high, according to recent guidelines. Get the details in the ConsumerTips section of our Iron Supplements Review. Also, see our Top Picks among iron supplements.

A surprising number of foods and beverages, including tea, can interfere with the absorption of iron. When you drink your tea can make a big difference, according to a new study. Get the details in the Iron Supplements Review >>

A study shows that iron can bind to a key flavanol (EGCG) in green tea, causing it to lose its anti-oxidant activity. Should you avoid iron-containing foods when using green tea? Find out in the "What to Consider When Using" section of the Green Tea Supplements and Teas Review >>

Iron should not be taken at the same time as any of several prescription medications, due to potential interactions. A recent study adds to the list of medications of concern. For details, see the Concerns and Cautions section of the Iron Supplements Review.

You may have heard this week about a new study which found a higher risk of death among women who used certain supplements. It's a complicated study, but we've summarized some key findings. Bear in mind that only white women ages 55 to 69 were enrolled in the study and they were followed for 22 years.

Those taking calcium supplements had a 3.8% reduced risk of death. The calcium benefit ended, however, when taking more than 900 mg per day from supplements. It's worth noting that experts suggest many older women who take calcium supplements may not need to -- see the Calcium Supplement Review for more.

The mineral most strongly associated with an increased risk of death was iron, which showed a risk increase of 3.9% -- and the risk increased as the dose increased, particularly over 50 mg per day. However, the study grouped dosages of under 50 mg together, making it hard to determine the risk of low dosages of iron, such as those in many multivitamins. However, there is very little reason why a postmenopausal woman should be taking iron -- see the Iron Supplement Review for more.

Although not as statistically meaningful, other supplements were associated with the following increases in the risk of death during the study: multivitamins (2.4%), vitamin B6 (4.1%), folic acid (5.9%), magnesium (3.6%), zinc (3.0%), and copper (18.0%). An abstract of the study is online.

The bottom line: Don't take a supplement you don't need. If you want to know how much of each vitamin and mineral you need from your total diet and how much is too much, see our chart at www.consumerlab.com/rdas/.

If you’re low in iron, be careful with high doses of curcumin (turmeric extract). See the Concerns and Cautions section of the Curcumin and Turmeric Review. Also see our Top Picks among products.