linked free radicals with cell death, ageing, cancer, heart disease, Alzheimer's Disease and other conditions that you haven't pencilled into your appointment book yet. Antioxidants such as betacarotene and vitamins C and E are said to offset the effect

. You can also check your urine colour. It should be clear or light yellow (unless you have recently taken some B vitamins, which can turn the urine bright yellow).When running long and slow – three or four hours or more – monitor your fluid consumption

're easily swayed. However, eating standard, simple, unprocessed natural foods will give you the same end results. "Every time one of those vitamin or supplement studies produces a negative result, I am reassured that focusing on quality calories is the best