"This is a big industry," she said. "Even small risks, with widespread use, result in large numbers of women [and men] affected."
This echoes the thoughts of the study authors, who write, "The public health consequences may be substantial."
Doctors tend to agree that moderation is key when it comes to vitamins.
After reviewing the study, internist Dr. Ted Palen of Colorado Permanente Medical Group said, "I will counsel patients that moderate multivitamin intake may be beneficial, but megadoses may actually be harmful."
Keith Ayoob, associate professor in the department of pediatrics at Albert Einstein College of Medicine in New York, agrees.
"The best research says to take a complete multivitamin with 100 percent of the [recommended dietary allowance or RDA] and not more," he said.
Some doctors recommend concentrating on improving your diet rather than stressing about which supplements to take.
People "should spend their money on multiple varieties and colors of vegetables and fruits, whole grains, and lean protein," said Dr. John Messmer, associate professor of family and community medicine at Pennsylvania State University's College of Medicine in Hershey, "and stop wasting it on supplements."
Dobsevage agrees. However, she said, "the American diet is so degraded, and so many of us no longer cook whole foods in our own homes for most of our meals, that I often recommend a modest level of vitamin and mineral supplementation -- less than RDAs."