Vitamin E fails to slow Alzheimer's onset
has found no benefit to patients taking vitamin E.
The findings appear to contrast with prior research suggesting that it may help slow progression of the disease.
The randomized, double-blind study, carried out at different centres in the US and Canada, compared vitamin E, an Alzheimer's treatment drug donepezil and placebo for delay or prevention of progression to Alzheimer's disease in mild cognitive impairment patients.
For those taking vitamin E -1000 IU per day for the first six weeks and then 2000 IU per day until the study's end - progression to Alzheimer's disease was not significantly slower during the three-year trial.
However the results would seem to confirm findings reported by John Hopkins researchers earlier this year - use of vitamin E and C in combination reduced prevalence of the disease by about 78 per cent and incidence by about 64 per cent but they found no benefit from vitamin E used alone.
The new results were presented at the 9th International Conference on Alzheimer's Disease and Related Disorders in Philadelphia last weekend. The Alzheimer's Association described the trial as "among the most anticipated studies" to be presented at the conference.
During the three-year study, almost 800 participants developed Alzheimer's disease at a rate of 13 per cent per year. Among those who progressed to Alzheimer's disease, patients treated with donepezil averaged 661 days until diagnosed with Alzheimer's disease, while those treated with vitamin E averaged 540 days until Alzheimer's diagnosis and those treated with placebo averaged 484 days to Alzheimer's disease.
In another study presented at the conference, researchers from Harvard Medical School reported that women who ate green leafy or cruciferous vegetables in middle age preserved more of their cognitive abilities as they entered their 70s.
Following more than 13,000 women over 11 years, they found that although increased consumption of fruits and vegetables overall did not affect the decline in cognitive scores, whether due to ageing or any forms of dementia, women with the highest consumption of green leafy vegetables and cruciferous vegetables - both high in folate and antioxidants such as carotenoids and vitamin C - declined less than women who ate little of these vegetables.
"This difference can be approximated as being one to two years younger in terms of cognitive ageing," said study author Jae Hee Kang. "Although this difference may be modest, if confirmed by other studies it may have a large impact in reducing the public health burden of dementia."
There are currently nearly 18 million people with dementia in the world, and the most common cause of this dementia is Alzheimer's disease. By 2025 this figure will rise to 34 million, with 71 per cent of these likely to live in developing countries.
