Vitamin E: supplement versus diet in neurodegenerative diseases.

Contradicting outcomes have been observed in numerous studies investigating the benefits of vitamin E supplements in the context of neurodegenerative diseases. By reviewing epidemiological studies and clinical trials, it is found that dietary intake of vitamin E exhibits beneficial effects on neurodegeneration, whereas α-tocopherol supplements failed in most interventional trials. Potential reasons for why α-tocopherol supplements exhibit disappointing effects, especially compared with dietary intake, are put forward and implications for future studies are discussed.