What Are the Potential Harms of Vitamin Supplements?
Beta-carotene supplements were associated with an increased risk for lung cancer among smokers, especially heavy smokers, in 2 randomized clinical trials (RCTs); the effects of beta-carotene supplementation among nonsmokers are unknown.
Moderate doses of vitamin A may reduce bone mineral density. High doses of vitamin A may be toxic to the liver and put pregnant women at risk for delivering babies with birth defects.
People who choose to take vitamins should be encouraged to adhere to the dosages recommended in the DRI of the Institute of Medicine, since the potential harms of higher dosages outweigh the potential benefits.
For more information on vitamin supplementation, contact the following organizations:
Institute of Medicine (IOM)
Dietary Reference Intake
http://www.iom.edu/iom/iomhome.nsf/WFiles/webtablevitamins/$file/webtablevitamins.pdf (PDF Help)
Page Last Updated July 5th 2004