Vitamin E delays functional decline in Alzheimers disease
Patients with Alzheimer's disease given high-dose vitamin E combined with a cholinesterase inhibitor show less long-term deterioration in their ability to perform activities of daily living than those who do not receive the vitamin, exciting research published this month in JAMA shows.
The findings add weight to earlier data also suggesting the vitamin has a modifying effect on the progression of this debilitating disease.
According to the US research team, led by Dr. Maurice W. Dysken of the Minneapolis VA Health Care System, these previous studies have looked at the use of alpha tocopherol for patients with severe Alzheimer’s disease (AD).
However, Dr Dysken and colleagues say that theirs is the first study to assess use of vitamin E in patients with AD in its earlier stages.
The researchers recruited over 600 patients with mild to moderate AD, all of whom were taking an acetylcholinesterase inhibitor (AChEI).
Of these patients, 155 received 20 mg a day of memantine - a novel class of Alzheimer's disease medications acting on the glutamatergic system by blocking NMDA receptors - 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.
Changes in the patients' functional decline were assessed using the Alzheimer's Disease Cooperative Study/Activities of Daily Living (ADCS-ADL) Inventory score, and they were followed-up for an average of 2.3 years.
The results showed that patients who received vitamin E had a 19% reduction in functional decline, compared with patients who received the placebo.
This, the researchers say, translates into a "clinically meaningful delay in progression" of 6.2 months. In practical terms, this difference could represent a person's ability to dress or bathe themselves for that much longer.
Furthermore, the research shows that patients who were taking vitamin E needed two hours less assistance from a caregiver each day.
Interestingly, the data also shows that memantine and a combination of both memantine and vitamin E demonstrated no clinical benefit for the patients.
The study authors conclude that their results suggest vitamin E could be effective in combatting the functional decline of AD.
"Because vitamin E is inexpensive, it is likely these benefits are cost-effective as alpha tocopherol improves functional outcomes and decreases caregiver burden," they add.
According to Chris Oliver, Senior Scientific Researcher from the Blackmores Institute who, in conjunction with Professor Stephen Myers from Southern Cross University, has been evaluating the significant body of evidence on vitamin E since 2008, the present study is important “because an affordable, easily accessible nutrient showed clinical benefit in a highly debilitating disease in a way that the comparative pharmaceutical drug could not match.
“These results highlight the importance of assessing complementary medicines in disease management, and gives hope for Alzheimer’s patients and their care givers,” he added.
SAFETY CONCERNS OF VITAMIN E CALLED INTO SCRUTINY
The research on vitamin E to date has been controversial with leading scientists split on the benefits and safety of vitamin E.
However, the current study found NO increase in the risk of all-cause mortality in the patients taking vitamin E. The annual mortality rate was 7.3% in the alpha tocopherol group vs. 9.4% for the placebo group.
This finding is in opposition to previous studies have shown an increased risk for death with vitamin E doses greater than 400 IU/day, and calls into scrutiny the resulting abandonment of high-dose vitamin E therapy for Alzheimer's disease over the past few years.
“In contrast to the conclusion drawn from a 2005 meta-analysis of vitamin E1, which showed that high-dose vitamin E (greater than or equal to 400 IU/d) may increase the risk of all-cause mortality, we found no significant increase in mortality with vitamin E,” the authors write.
On the issue of safety, the Council for Responsible Nutrition argues the present study is significant as it “presents strong data on the safety of vitamin E, at high doses, and dismisses previous questions raised about the safety of this essential nutrient.
EVIDENCE BOLSTERS BENEFITS OF VITAMIN E IN ALZHEIMER’S DISEASE
This is not the first study to show that vitamin E may be beneficial in delaying functional decline in AD.
Clinical data indicates that vitamin E, and drugs that reduce generalised inflammation, may slow the decline of mental and physical abilities in people with Alzheimer's disease (AD) over the long term. There is also clear evidence of oxidative damage in the brains of patients with the disease.
The results of a study presented at the 2009 American Geriatrics Society (AGS) Annual Scientific Meeting by Dr. Alireza Atri from the Memory Disorders Unit Massachusetts General Hospital (MGH), Boston, were consistent for a potential benefit of vitamin E on slowing functional decline and a smaller possible benefit of anti-inflammatory medications on slowing cognitive decline in patients suffering from Alzheimer's disease.
Antioxidant supplements were included in a 2004 review of therapies for the treatment of Alzheimer’s disease in the New England Journal of Medicine.
The review noted studies have shown that vitamin E given with the drug selegiline, can help delay placement in a nursing home, the development of severe dementia, and death, better than a placebo.
Also noted in the review were results showing that a combination of vitamin E with a cholinesterase inhibitor was safe and beneficial.
Overall, the review article indicates that there is strong evidence that vitamin E and vitamin C can play a role in delaying the onset of Alzheimer’s disease.