Alzheimer's disease is a form of dementia that occurs when cells that produce brain chemicals, known as neurotransmitters, die. Alzheimer's is a progressive disorder characterized by memory loss, personality changes, depression and cognitive problems. There is no cure for Alzheimer's, but a number of medicines, for example, donepezil and galantamine, help to slow its progression. Several vitamins, including vitamin B-12 may play a role in the treatment of Alzheimer's, although strong evidence that it improves symptoms is lacking. Consult your doctor before taking vitamin B-12 to treat Alzheimer's.
Properties and Potential Benefits
Vitamin B-12 is a water-soluble vitamin. It plays several important roles in the body, including blood cell formation and DNA synthesis. The Office of Dietary Supplements states that it also supports neurological function, adding that low vitamin B-12 levels are positively associated with Alzheimer's disease and other forms of dementia. It helps lower levels of an amino acid, known as homocysteine, which is associated with dementia, although this does not necessarily mean that it improves cognitive function.
Sources and Administration
A host of foods contain vitamin B-12 including liver, breakfast cereals, fish, yogurt, milk and eggs. It is also available as a dietary supplement. The University of Maryland Medical Center suggests taking 100 to 1,000 micrograms daily to support Alzheimer's treatment, although it adds that vitamin B-12 injections give the best results. Check with your doctor that this dose is appropriate for you.
Efficacy
Evidence to support the role of vitamin B-12 in the prevention or treatment of Alzheimer's is mixed. An analysis of data from eight clinical trials, published in the October 2008 "Cochrane Database of Systematic Reviews" concludes that there is no consistent evidence that vitamin B-12 has a beneficial effect on cognitive function in elderly patients with dementia. However, early research findings published in the May 1992 issue of "Clinical Therapeutics" show that maintaining consistent vitamin B-12 levels improves cognitive function in Alzheimer's-type dementia. More up-to-date research in support of vitamin B-12 is lacking.
Safety Considerations
The Office of Dietary Supplements states that vitamin B-12 has a low potential for toxicity. However, it may interact with other medicines, including an antibiotic known as chloramphenicol, medicines for peptic ulcers like famotidine and ranitidine, the diabetes drug, metformin, and proton pump inhibitors. If you have any doubts about whether taking a vitamin B-12 supplement is suitable for you, talk to your doctor or pharmacist.
References
- University of Maryland Medical Center; Alzheimer's Disease; Sept. 21, 2008
- Office of Dietary Supplements: Vitamin B-12
- "Cochrane Database of Systematic Reviews"; Folic Acid With or Without Vitamin B12 for the Prevention and Treatment of Healthy Elderly and Demented People; R. Malouf et al.; October 2008
- "Clinical Therapeutics"; Treatment of Alzheimer-Type Dementia With Intravenous Mecobalamin; T. Ikeda, et al.; May 1992
