A new study by lead author Shelly Gray and published in the latest issue of the Journal for the American Geriatric Society, found no effect from taking Vitamin C or E, either alone or in combination, on the risk of dementia or Alzheimer’s disease after 5.5 years. Vitamins C and E were chosen because they both have significant antioxidant activity, and so this study was partly to test the hypothesis that oxidative stress causes or contributes to dementia.
The science behind the role of oxidative stress in aging and neurodegenerative disorders and the modulation of oxidative stress by nutritional antioxidants is complex and has not yielded many confident therapeutic recommendations. And yet, by contrast, antioxidants are sold to the public with dramatic health claims as if they were well established. It is common for marketing hype to out pace scientific reality, especially when the science is complex and preliminary so that there is as yet no firm scientific consensus.
For background, oxidative stress refers to the production in the cells of the body of certain oxygen-based compounds, collectively called reactive oxygen species (ROS), that are highly reactive. Some of these compounds are simply waste products of cell metabolism. Others serve a useful purpose, such as nitric oxide that is used in neurotransmission. What these ROS compounds have in common is that they react with proteins, DNA, and other cell components and cause damage.