Not all vitamins may be good for you. A new study shows instead of safely protecting the heart from disease, antioxidant vitamins, such as E, C and beta carotene, could raise liver production of the "bad" form of cholesterol.
Some studies have shown that vitamin E prevented the activation of the lipoprotein-breakdown pathway in rat and mouse liver cells. Thus, the liver destroyed fewer of the bad lipoproteins.
Though direct tests on people to explore liver function are difficult, observational studies show a diet rich in polyunsaturated fats increases blood levels of lipid peroxides and decreases levels of VLDL, or very low density lipoprotein, and LDL, or low-density lipoprotein. After its secretion from the liver, VLDL is converted in the bloodstream to LDL, the so-called bad form of cholesterol. The liver is the major source of lipoproteins that block arteries.
However researchers say that until more data becomes available, they can't make any recommendations regarding use vitamins since in some animal studies vitamins have shown to protect the arteries from clogging and the pancreas and other organs from damage caused by diabetes.