Getting too much calcium from supplements and/or over-the-counter antacids can cause dangerously high blood levels of calcium, as highlighted in a recent report. Get the details in the Concerns and Cautions section of our Calcium Supplements Review.
Also find out how much calcium is enough, and how much is too much, based on age and gender, in the ConsumerTips section of the Review.
Strontium is included in some "bone health" supplements, but be aware that very high doses of strontium may interfere with blood tests for calcium and bone density scans. Get the details in the Concerns and Cautions section of our Calcium and Bone Health Supplements Review, which includes our Top Picks among products.
Also see: Which vitamins and supplements should be stopped before getting blood work and laboratory tests?
Can taking a PPI drug such as Prilosec (omeprazole), Prevacid, or Nexium, reduce the absorption of calcium? The answer is yes, but there are ways to minimize this problem, as discussed in our Calcium Supplements Review.
Which forms of calcium interfere with the absorption of levothyroxine (Synthroid)? Find out in the updated Concerns and Cautions section of our Calcium Supplements Review.
Supplementing with calcium appears to pose a higher risk of death for people with existing narrowing of the aorta. Get the details in the Mortality and Cardiovascular Disease section of our Calcium Supplements Review.
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/.