I am a chain smoker but i also drink carrot juice everyday and somebody told me it prevents cancer. is it true ?

No: Most "nutritional advice" (even the stuff from retrospective studies) is best ignored. In fact, there's a big study on smokers and the more vitamin a they had in their diet, the more cancer they got. Forget the nonsense about carrot juice, and do yourself and those you love (including your future family) by stopping smoking now, by whatever means.

No: The most effective way to reduce your cancer risk is to stop smoking. No food, herbal rememdy, or medication will help at all. If you are chain smoking at 18 you are at high risk for emphysema as well.

No.: In fact, two studies, the atbc and caret studies surprisingly found that giving extra antioxidant vitamins and b-carotene, increased lung cancer risk in smokers by 16-28%. B-carotene is found in carrots; it is what makes them orange!