Worried about vitamin safety? Experts offer advice

_ Pregnant women, who may need extra iron.

_ Breastfed infants and possibly other infants concerning vitamin D.

Vitamin D is a nutrient many of us may need to supplement. Last fall, the Institute of Medicine, a panel of scientists who advise the government, raised the recommended amount but also warned against overdoing it. People ages 1 to 70 should get 600 international units a day, older folks 800 units.

If you do need a supplement, beware: Quality varies. Consumerlab.com, a company that tests supplements and publishes ratings for subscribers, has found a high rate of problems in the 3,000 products it has tested since 1999.

“One out of 4 either doesn’t contain what it claims or has some other problems such as contamination or the pills won’t break apart properly,” said company president Dr. Tod Cooperman.

For example, one gummy bear calcium product had 250 percent of the amount of vitamin D claimed on the label. Another liquid product made with rose hips had just over half the amount of vitamin C listed.

“You don’t have to pay a lot. Price is not necessarily linked to quality,” he said. “The quality doesn’t really relate to where you’re buying it. I know many people are surprised by that or don’t want to believe it, but that is the case. We find good and bad products in every venue.”

Mark Blumenthal, executive director of the American Botanical Council, suggests looking for “seals of approval” or certifications of quality from groups that spot-test supplements such as the USP, or United States Pharmacopeia; NSF International and NPA, the Natural Products Association.

Experts offered this advice:

_ Keep it simple. The more ingredients there are in a supplement combo, the more chance that one of them will not be the right amount, Cooperman said.

_ Consider a supplement combo tailored to your gender and age, the Office of Dietary Supplements suggests. Multivitamins often contain little iron, and ones for seniors give more calcium and vitamin D than products aimed at younger adults.

_ Take vitamin D with dinner. A study found significantly more absorption of that nutrient when it was consumed at the largest meal, which tends to have more fat, than at breakfast, Cooperman said.

_ Watch out for vitamin K _ it promotes clotting and can interfere with common heart medicines and blood thinners such as warfarin, sold as Coumadin and other brands.

_ Current and former smokers are advised to avoid multivitamins with lots of beta-carotene or vitamin A; two studies have tied them to increased risk of lung cancer.

_ For cancer patients, “vitamins C and E might reduce the effectiveness of certain types of chemotherapy,” Engel said.

Story Continues →

Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.