A large amount of research has been done over the years regarding the impact of vitamin E supplements on those with Alzheimer's. In 1997, a group looked at the effects of vitamin E supplements on those with Alzheimer's and found that patients taking the supplements exhibited a slower rate of cognitive decline than those who were not. The following year, another study found that people with Alzheimer's and vascular dementia had lower concentrations of vitamin E in their blood than their healthy counterparts, and reported lowered antioxidant concentrations in general in people with dementia. The authors hypothesized that these lowered concentrations were the result of antioxidants being used up by the body in its attempt to mitigate oxidative stress.
Other studies have investigated the ability of vitamin E to protect against dementia and cognitive decline in general. One such study involved more than 3,000 subjects and found that those who reported taking vitamin E and C supplements were at a significantly lower risk of developing vascular dementia, and a similar effect was observed regarding mixed dementia. The supplements were also noted to improve cognition in general. Similar research has suggested that vitamin E and C supplementation also help reduce the risk of developing Alzheimer's. However, it is worth noting that there have also been studies that report no significant benefits to taking vitamin E for Alzheimer's.