A caveat for people relying on large doses of vitamin E to halt the aging process. A study in today's Journal of the American Medical Association says the popular vitamin might actually lead to an elevated risk of heart failure in people with diabetes or clogged arteries. Researchers at McMaster University looked into whether vitamin E pills offered any protection to nearly 40-thousand healthy women. They found no benefit when it came to protecting against heart attacks and cancer. The lead researcher said it's unclear how vitamin E pills might be linked with heart failure. She theorizes that high doses might disturb the balance of beneficial, naturally occurring antioxidants.