Vitamin pills Research has produced mixed results
Taking certain vitamin supplements may adversely affect people's lifespan, researchers have suggested.
Millions worldwide use antioxidant supplements such as vitamins A and E, and beta-carotene.
Looking at dozens of previous studies, Copenhagen University researchers suggested these appeared to raise, not lower, the risk of early death.
A supplements industry expert said the Journal of the American Medical Association study was fatally flawed.
But nutritionists said it reinforced the need to eat a balanced diet, rather than relying on supplements.
While vitamin supplements have been popular for decades, the precise benefits they offer - if any - remain uncertain, despite hundreds of research projects.
BBC NEWS | Health | Vitamins 'could shorten lifespan'
Vitamins 'could shorten lifespan' 
