Scientists believe that antioxidants strengthen the body resistance and protect the body against the effects of free radicals. Free radicals in organism proceed from respiration by-product and cause damage to cells. Damage of cells stimulates aging and cancerous tumour development and also promotes chronic and cardiovascular diseases formation. Antioxidants help to reduce damage of cells and prevent disease appearance.

Scientists believe that free radicals are the cause of almost all known diseases and these are closely related to the aging process. Scientists believe that the amount of antioxidants in the human body is correspond with how long we live. A good example of free radicals harmful effect is a sliced apple on kitchen table, which becomes brown in contact with oxygen. Brownish colour is the effect of free radicals. Brown colour does not appear if we will spray the apple slices with lemon juice which has antioxidant effect.