Very simple advice: eat vegetables, exercise and, of course, take vitamins. Or do not take. Decades of research have not given substantial evidence that vitamins and supplements brought some tangible benefits. Moreover, recent studies tend to the opposite view, as revealed, that some vitamins can be harmful. Certain types of vitamins are correlated with an increased likelihood of developing certain types of cancer, while others - with an increase in the risk of stone formation in the kidneys.