At least for postmenopausal women, multivitamin use “does not confer meaningful benefit or harm” when it comes to cancer and heart diseases, a new report published in the Archives of Internal Medicine has said.

The team of researchers, led by Marian L Neuhouser of the Fred Hutchinson Cancer Research Centre in Seattle, asks, “Why do millions of Americans use a daily multivitamin for chronic disease prevention when the supporting scientific data are weak?” One reason, they say, “may be the varied health messages received by the public.”

Statements from medical organisations that multivitamins do not prevent disease are mixed with messages to take a multivitamin if dietary intake is less than optimal -- leaving the public confused, Neuhouser and her colleagues note.

Until clinical trials prove otherwise, the researchers write, multivitamins should not be seen as a way to prevent chronic disease.