Consuming a diet rich in vitamin B-12 may one day help protect you from the ravages of Alzheimer's disease. People who have the condition often have markedly low levels of B-12 for reasons that aren't entirely understood. Vitamin B-12 serves an important role in maintaining healthy nerve cells. Deficiencies produce cognitive impairment and a host of other neurological disorders, according to Linus Pauling Institute. Scientists know that low B-12 play a role in the development of Alzheimer's, but like other common chronic illnesses, Alzheimer's is likely the result of many factors, rather than a single cause such as vitamin B-12 deficiency.
B-12 Details
Vitamin B-12 is structurally unique among the others in the B-complex. It's the largest of the bunch and most complex. It contains the metal cobalt. Your body needs vitamin B-12 for several reasons. It works in protein metabolism by getting rid of odd-numbered amino acids and helps create methionine, which is involved in the development of DNA. And when methionine doesn't work properly, a substance called homocysteine builds up and increase your risk of cardiovascular disease, Linus Pauling Institute states. Vitamin B-12 is also essential to maintain the central nervous system. The same mechanisms that cause a buildup of homocysteine make some neurons dysfunctional and can even cause nerve death.
Alzheimer's Disease
Alzheimer's disease is named after a doctor who had a female patient die with the yet unknown mental illness in 1906. Dr. Alois Alzheimer examined her brain and documented the abnormal clumps and bundles of fiber that are now well-known hallmarks of the disease. Alzheimer's is a progressive neurological disorder that diminishes the brain, memory, emotions and learning. It is the sixth leading cause of death in the United States, and it is the most common cause of dementia. Although a few genetic conditions and health conditions spark the onset of Alzheimer's, the full reasons the disease develops remains unclear.
Vitamin B-12 and Alzheimer's
By following 271 elderly Finnish people for more than seven years, a group of Scandinavian public health researchers linked vitamin B-12 to Alzheimer's through elevated homocysteine levels. None of the participants had any signs of dementia at the start of the study, but over time, 17 developed the disease. Published in the October 19, 2010 "Neurology," researchers said for each increase of homocysteine --- measured units called micromolars --- the risk of getting Alzheimer's shot up by 16 percent. However, with small increases in B-12 --- measured in units called picomolars --- the risk of Alzheimer's dropped by 2 percent.
Why B-12 Gets Low
Vitamin B-12 deficiency is common with aging. The Linus Pauling Institute says the deficiency affects 10 to 15 percent of all people older than 60. Diet can play a role. B-12 is only found in animal foods like meat and dairy, which people may consume less of as they age. But low blood levels of B-12 have more to do with how you digest and absorb B-12. The vitamin binds to protein, and stomach acid is needed to release it. Aging naturally reduces stomach acids, as do antacids, certain other medications and lack of intrinsic factor --- a secreted substance that specifically aids in B-12 absorption.
References
- Linus Pauling Institute; Vitamin B12; Jane Higdon; March 2003
- "Nutrition Bytes"; Nutrition and Alzheimer's Disease: The Role of Folate and Vitamin B; Zachary Edmonds; 1990
- Alzheimer's Association; 2011 Alzheimer's Disease Facts and Figures
- National Institute on Aging; Alzheimer's Disease Fact Sheet; November 2008
- "Neurology"; Homocysteine and Holotranscobalamin and the Risk of Alzheimer Disease"; Babak Hooshmand et al.; October 19, 2010
- "Pathways Towards and Away from Alzheimer's Disease"; Mark P. Mattson; August 2004
