More than 30 percent of multivitamins tested recently by ConsumerLab.com contained significantly more or less of an ingredient than claimed - or were contaminated with lead, the company reports.
Several multivitamin products tested, including three for children, exceeded tolerable upper limits established by the Institute of Medicine for ingredients such as vitamin A, folic acid, niacin and zinc.
Too much vitamin A may cause nausea and blurred vision, and prolonged excessive intake may lead to bone softening and liver problems.
Upper tolerable limits for niacin and zinc were also exceeded by some of the supplements for young children tested.
Excess niacin may cause skin tingling and flushing and high levels of zinc may cause immune deficiency and anemia.
Two out of three men's multivitamins tested did not contain the vitamin or mineral amounts stated on the label.
One men's multivitamin contained too much folic acid (which may increase the risk of prostate cancer) while another was contaminated with lead.
Among the four women's multivitamins tested, one provided only 66 percent of its claimed vitamin A.
Two out of five multivitamins for the general population were short on ingredients. One provided only 50 percent of its claimed folic acid and the other was missing 30 percent of calcium stated on the label.
This report is posted on www.ConsumerLab.com.
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