Extra vitamin D and calcium may offer some protection against fractures in elderly people but have little or no impact on cancer risk, according to a fresh look at the medical evidence.

Some research has suggested that vitamin D, with or without calcium, might help stave off cancer, but recent trials have slashed those hopes.

"It turns out that as a group, all of the micronutrient supplements have been disappointing," says Dr Michael Pollak, who heads the division of cancer prevention at McGill University in Montreal, Canada, and was not involved in the new work.

"Even one of the best candidates, which is vitamin D, is certainly no slam dunk," he says.

The new report was out on Monday in the Annals of Internal Medicine.