Both vitamins C and E, taken alone, may prevent a type of oxidative damage tied to cardiovascular disease. However, taking the two vitamins together doesn't seem to give an added benefit, according to researchers from Johns Hopkins University in Baltimore, Maryland.
In a study of 184 non-smoking adults, investigators found that taking either vitamin C or E reduced the oxidation of blood fats called lipids. Oxidation is a normal chemical reaction in the body, but the process can also damage cells. Lipid oxidation is believed to play a key role in the development of the artery-clogging disease atherosclerosis, which can lead to heart attack oe stroke. A number of studies have suggested that antioxidant vitamins like C and E may help ward off oxidative damage, and that these two vitamins may enhance each others' protective powers.
Over 2 months, study participants followed one of four daily regimens: 500 milligrams (mg) of vitamin C alone; 400 international units (IU) of vitamin E alone; both vitamins together; or placebo (inactive) pills. They were instructed to take no other vitamins during the study.
The researchers found that both vitamins C and E lowered urine levels of a particular substance that is a byproduct of lipid oxidation--a substance that has been found to be elevated in cigarette smokers and people with diabetes and high cholesterol. However, the vitamin combo was no more effective than either C or E alone.
Past studies on the effects of antioxidant vitamins against cardiovascular disease have come up with conflicting results, particularly when it comes to treating people who already have heart disease. Antioxidants may be most effective in the earliest stages of atherosclerosis, when lipid oxidation is key.
The daily vitamin C dose used in this study is attainable through diet, while the vitamin E dose is virtually impossible to come by through food alone. Food sources of vitamin E include wheat germ, nuts and vegetable oils. Citrus fruits, strawberries, tomatoes and broccoli are among the top sources of vitamin C.
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