Taking calcium supplements may double the risk of dying from cancer, a new study suggests.
Analysis of the medical records of 27,000 adults found links between high doses and cancer in later years.
However, no link was found between increased consumption of foods containing calcium and the disease.
Meanwhile certain other nutrients in food - but not supplements - were generally linked to a lower risk of all-cause and cancer death.
Scientists writing in the journal Annals of Internal Medicine said cancer patients could be putting themselves in greater danger by taking calcium supplement doses higher than 1,000 milligrams per day.