New research suggests that a daily dose of vitamin E may help to slow functional decline for patients with mild to moderate Alzheimer's disease and may help reduce the amount of care these patients need. This is according to a study published in JAMA.
Vitamin E is defined as a group of eight fat-soluble compounds. These compounds include a mix of tocopherols and tocotrienols.
The vitamin is naturally found in many foods, including eggs, fortified cereals, fruit, green leafy vegetables, meat, nuts, poultry and vegetable oils. It can also be taken as a supplement.
According to the research team, led by Dr. Maurice W. Dysken of the Minneapolis VA Health Care System, previous studies have looked at the use of alpha tocopherol - a form of vitamin E that also acts as an antioxidant - in patients with severe Alzheimer's disease.
These studies have shown that the vitamin was effective in slowing progression of moderately severe Alzheimer's disease.
However, the investigators note that the use of vitamin E had not been studied in patients with a mild to moderate form of the disease.
With this in mind, the researchers analyzed 613 patients with mild to moderate Alzheimer's disease, all of whom were taking an acetylcholinesterase inhibitor to increase the level and duration of action of the neurotransmitter acetylcholine.
Of these patients, 155 received 20 mg a day of memantine - a class of drugs used to treat Alzheimer's - while 152 patients received 2,000 international units a day (IU/day) of vitamin E, 154 received a combination of both and 152 had a placebo.
The investigators monitored patients' changes in functional decline using the Alzheimer's Disease Cooperative Study/Activities of Daily Living (ADCS-ADL) Inventory score, and patients were followed-up for an average of 2.3 years.
Functional decline refers to patients' lack of ability to carry out everyday tasks without assistance.
Vitamin E 'reduces functional decline by 6 months'
Results of the study revealed that patients who received the vitamin E had a 19% reduction in functional decline, compared with patients who received the placebo. The researchers say this is the equivalent to a "clinically meaningful delay in progression" of 6.2 months.
Furthermore, the investigators found that patients who received vitamin E needed 2 hours less assistance from a caregiver each day.
They note that memantine and a combination of both memantine and vitamin E demonstrated no clinical benefit for the patients.
The researchers point out that functional decline as a result of Alzheimer's disease is increasingly recognized as having a significant impact on a patient quality of life, as well as putting a strain on social and economic costs.
But they say their findings suggest that vitamin E could combat these factors:
"Because vitamin E is inexpensive, it is likely these benefits are cost-effective as alpha tocopherol improves functional outcomes and decreases caregiver burden."
Large doses of vitamin E 'may be harmful'
However, Doug Brown, director of research and development of the Alzheimer's Society in the UK, says that patients should be aware that the dosage of vitamin E taken in this study is significantly higher than the adult upper recommended daily allowance of 1,500 IU/day and may be harmful for some.
"While this study into the link between vitamin E intake and reduction in functional decline is of interest, it is by no means conclusive. More research is needed to see if vitamin E really does have benefits for people with dementia, and whether it would be safe to be taking such a high dose on a daily basis," he adds.
But the researchers say their findings oppose previous studies suggesting that high doses of vitamin E may increase the risk of all-cause mortality.
"We found no significant increase in mortality with vitamin E. The annual mortality rate was 7.3% in the alpha tocopherol group vs. 9.4% for the placebo group," they add.