"I don't really like manufactured vitamins. I like whole foods," said Bowen, 53, who is a nurse. "Of course, I'm like everybody else. I don't always eat right."
And that, in a nutshell, is the debate over multivitamins - doctors argue people are better off getting their vitamins and minerals from food rather than a pill that might be doing them no good; a manufacturer's group says few people are getting all they need from their diets. And while some might view it as a "just in case" insurance policy, some vitamins and supplements can be harmful in higher doses, doctors argue.
The National Nutritional Food Association, which represents vitamin and supplement makers, said other studies - on vitamin E, for instance - have found the opposite to be true.
There is a lot at stake: Multivitamin sales accounted for $3.8 billion in 2004, and sales of mineral supplements were $1.7 billion, according to trade publication Nutrition Business Journal. If all supplements are added together, it tops $20 billion a year, the journal said.
But some of that might be completely unnecessary and in some cases harmful, said Dr. Marvin M. Lipman, the chief medical adviser for Consumers Union, which publishes Consumer Reports, and emeritus clinical professor of medicine at New York Medical College. In its February issue, Consumer Reports offers guidelines for who would benefit from a multivitamin, which Dr. Lipman classed into three groups.
"They're the sick people, the older people and the younger people," he said. "Kids before the age of 2 should probably be on vitamins, and men and women as they age."
People older than 50 might have a harder time absorbing calcium and vitamin B12, so they might want to think about a supplement, Dr. Lipman said.
Vegetarians also will not get enough zinc, iron or B12 from their diets, so a supplement would be in order, said Daniel Fabricant, the vice president of scientific affairs for the Nutritional Foods Association.
There is widespread agreement on the need for pregnant women to get vitamin supplements. But in younger healthy people, there is a difference.
"So if you have a fairly adequate, and it doesn't have to be every day ... source of fruits and vegetables, I think you get most of your vitamins," Dr. Lipman said. Also, "you get fiber, you get phytochemicals and you get combinations of vitamins that won't fight against each other."
Zinc and magnesium together, for instance, can hurt copper absorption, he said.
But there is a problem with the food-only argument, Dr. Fabricant said. According to the Centers for Disease Control and Prevention, only 23 percent ate the recommended five or more servings of fruits and vegetables in 2003.
"So the argument that, oh, you can get it all through the diet is not necessarily true for everyone," Dr. Fabricant said.
The division becomes sharper when it comes to supplements. For instance, many people take extra vitamin C during the winter to fight off colds, but a long-term study found that doing so was ineffective, Dr. Lipman said. And in the case of water-soluble vitamins such as vitamin C, taking extra doses usually doesn't amount to much, said Vadivel Ganapathy, the chairman of the Department of Biochemistry and Molecular Biology at the Medical College of Georgia, who studies how vitamins are transported in the body.
"If you take more, usually the body balances them out by eliminating them in the urine," he said.
In the case of vitamin A, taking too much could be toxic, and excess vitamin D could lead to hypercalcimia or excess calcium absorption, Dr. Ganapathy said.