Vitamin E may have special health benefits Large doses of vitamin E apparently can reduce harmful side effects of bypass surgery in heart patients. A study involving 28 bypass patients found that the 14 patients who took vitamin E for two weeks before their operations had significantly better heart function after the procedure than the 14 patients who took placebos. The vitamins apparently prevent damage to the heart muscle by destroying the toxic chemicals, called free radicals, that form when blood is cut off during the surgery, said Dr. Terrance Yau of the University of Toronto. Experimental Units [ Choose ] Explanatory Variable [ Choose ] Treatments [ Choose ] Response variable Choose