Key points from article :
You can't undo the effect of a bad diet by taking supplements.
Nutrients such as vitamins A and K, magnesium and zinc, were found to reduce the risk of death.
But only when nutrients consumed in food, not supplements.
People taking high doses of calcium supplement (>1,000 mg/day) had a 53% higher risk of dying from cancer over 6 years.
But no link between increased consumption of foods containing calcium and the disease.
Britons spent an estimated £442m on supplements in 2018.
Tufts University in Massachusetts analysed the medical records of 27,000 US adults.
The study was published in Annals of Internal Medicine.
