Alzheimer’s disease (AD) affects millions of people in the world with symptoms of deteriorating memory and loss of bodily functions. Currently there is no cure for this disease and researches focus on preventing the onset and slowing the progression of the disease.
A clinical study published in JAMA found that patients with mild to moderate Alzheimer’s disease benefited from high dose of Vitamin E supplementation with delayed disease progression over a study period of 5 years.
613 patients participated in the Trial of Vitamin E and Memantine in Alzheimer’s disease (TEAM-AD). The participants were randomized to receive either 200O IU/d α-tocopherol, 20 mg/d of memantine (NMDA antagonist), the combination, or placebo. The participants were assessed every 6 months for functional abilities to perform daily living activities such as dressing or bathing, cognitive function and dementia severity, memory, language and praxis functions in AD using a range of questionnaires and instruments. The time on which caregivers spend assisting AD patients in daily activities were also surveyed. Drug compliance was monitored by measuring the serum levels of α-tocopherol and memantine.
The patients receiving Vitamin E have a delay of 19% per year or approximately 6.2 months in the clinical progression compared to the control, followed by a reduction of 2 hour/d of caregiver time. Despite the high dose of α-tocopherol used in this study, the annual mortality rate in the group receiving α-tocopherol (7.3%) was not increased compared to those in the placebo group (9.4%).
Vitamin E has neuroprotective benefits which are largely attributed to its antioxidant properties. Palm tocotrienols alleviate oxidative stress by free radical scavenging as well as interacting with antioxidant enzymes such as superoxide dismutase and glutathione peroxidase. Oxidative stress plays a major role in the development and progression of AD. A series of clinical studies by Mangialasche et al. have shown that high plasma levels of vitamin E tocotrienol are associated with reduced Alzheimer Disease risk. The plasma levels of vitamin E tocotrienols could be used as a biomarker for diagnosis of cognitive impairment when combined with MRI measures.
The study highlights Vitamin E’s potential in benefiting AD patients. Tocotrienol, being a more potent antioxidant, may confer neuroprotection similar to α-tocopherol.