Vitamin E 'ineffective against dementia'
20th March 2017 – A new study has cast doubt on whether taking certain antioxidant supplements can prevent the onset of dementia – at least among older men.
The study in the journal JAMA Neurology found that vitamin E and selenium – taken on their own or in combination – did not prevent dementia symptoms in a large group of men aged 60 or older.
Antioxidants have been of interest for years in dementia research because of suggestions that oxidative stress could be a cause of the condition. These findings contradict some previous research which has found they could play a positive role in prevention.
The research, led by the University of Kentucky in Lexington, is based on The Prevention of Alzheimer's Disease by Vitamin E and Selenium (PREADViSE) clinical trial. It initially involved 7,540 older men who used supplements for an average of 5.3 years, of whom 3,786 agreed to continue in the trial for a further 6 years.
The men, from the US, Canada and Puerto Rico, were assigned to 1 of 4 groups: those who were given 400 IU of vitamin E each day, 200 μg of selenium, both supplements at these dosages, or a placebo.
During the trial, 325 of 7,338 men evaluated – or 4.4% – developed dementia.
The researchers report no difference in dementia rates between all 4 groups.
'Not a recommended treatment'
"The supplemental use of vitamin E and selenium did not forestall dementia and [they] are not recommended as preventive agents," they conclude.
However, they say shortcomings of the study include the fact that only men took part and whether supplement dosages were appropriate.
Commenting on the findings by email, Dr Clare Walton, research manager at the Alzheimer's Society says: "Dementia is the biggest health and social care issue facing our society and is set to be the 21st century's fastest growing killer, so there is an urgent need to intensify research efforts to find ways to prevent or delay the onset of the condition.
"Although studies in the lab suggest that antioxidants could protect brain cells from damage in neurodegenerative diseases like Alzheimer's, there is a lack of evidence from studies in people to support this theory.
"This large study found no evidence that vitamin E or Selenium supplements can play a significant role in reducing the risk of dementia. Given the fact that the trial only looked at men and was terminated early, we cannot completely rule them out. But it is looking increasingly unlikely that these antioxidants will play a big role in our armoury against dementia."