of money each year trying to convince you that you need to supplement your diet to improve performance and stay healthy.The science partThere are 13 main types of vitamins, most of which we obtain from our diet. Most of our vitamin D, however, is produced

to convince you that you need to supplement your diet to improve performance and stay healthy.The science partThere are 13 main types of vitamins, most of which we obtain from our diet. Most of our vitamin D, however, is produced from exposure to the sun

haemoglobin and ferritin levels. Ferritin is an iron-storing protein and this test can give a good indication of your body's iron stores.Iron aweIf you're active, you may be more prone to anaemia. Heavy training can increase your iron needs by 1-2mg per day

're not getting enough omega-3s," says Leslie Bonci, one of the authors of Total Fitness for Women."What do we athletes do instead? We go straight for anti-inflammatories like ibuprofen. What we should be doing is aiming for 1,000g to 2,000mg of omega-3 a day

-dense," says dietician Cara Marrs. Don't expect to shave pounds with low-fat versions; one cup of two per cent milk contains 138 calories - eight fewer than a cup of whole milk.Myth 2: Dairy increases mucus productionThe truth Several studies, including a 2005