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November 22, 2014
by Dr. C. Wayne Winkle,Phd

Dementia, Alzheimer’s, and Vitamin B-12 - Is There A Connection?

November 22, 2014 09:25 by Dr. C. Wayne Winkle,Phd


The short answer to that question is a conditional Yes. There appears to be a connection between dementia, Alzheimer’s Disease, and Vitamin B-12, but not one that suggests a cure for dementia of the Alzheimer’s or another type.

With dementia and Alzheimer’s Disease on the rise (Alzheimer’s and Dementia Weekly, 2013), this connection assumes greater significance. The fact that there is no known cure and no treatment that stops the progression of dementia (Alzheimer’s Association, n.d.) adds to the importance of research that may lead to treatments either to stop dementia or slow the deterioration it brings. 

The impact of dementias in the United States increases as the incidence of dementias of all types increases. In 2012, the financial burden for unpaid care by family and other caregivers totaled $219 billion (Alzheimer’s and Dementia Weekly). This doesn’t include the stress burden placed on caregivers. In addition, another $9.1 billion was accumulated in additional healthcare costs for caregivers.

One form of dementia, Alzheimer’s Disease, increased 68% in the decade from 2000 to 2010. One in three seniors in the U.S. die from one form or another of dementia.

Promising Recent Research

Recent research published by the American Academy of Neurology (2010) suggests vitamin B12 to be of use in reducing risk of memory loss associated with Alzheimer’s disease. This Swedish study looked at the role of B12 in determining those who could be at risk for the development of Alzheimer’s. The effect of vitamin B12 on homocysteine was a focus of the study.

In general, the study found risk of developing Alzheimer’s disease increased by 16% for every micromolar increase in homocysteine level in blood samples. And the risk decreased by 2% with each picomolar increase in the active form of vitamin B12. Results were robust even after controlling for factors like age, gender, education, smoking status, blood pressure, and body mass index.

The main conclusion of this study was that more research is needed into the effects of vitamin B12 on protection of memory function in the dementias.

Another study (Rush University Medical Center, 2011) addressed vitamin B12 serum levels in loss of brain volume and cognitive skills. The study was part of the Chicago Health and Aging Project involving 10,000 biracial subjects over the age of 65.

In general, this study suggested B12 deficiency to be associated with difficulty on tests of cognitive ability and with less total brain volume. Researchers concluded more research is needed to determine whether increased B12 would prevent cognitive and brain volume loss. But it appears that lower levels of vitamin B12 may be a possible risk factor for these kinds of losses.

A third study, conducted in 2010 (Douaud, et al., 2010), suggested the addition of doses of three B vitamins (folic acid, B6, and B12) appeared to slow shrinkage of the brain by 50% compared to placebo. Brain shrinkage and memory loss are two of the most common signs of Alzheimer’s disease.

A recent (Gutierrez, 2013), more advanced re-analysis of the results of the study mentioned above showed the possible effects of the addition of B vitamins to be greater than originally proposed. In the original study, brain shrinkage among the 271 elderly subjects was reduced by 50% compared to placebo. In the re-analysis, the shrinkage was actually 90%! And, this more robust re-analysis showed the reduction in shrinkage occurred in the very areas of the brain most affected by Alzheimer’s.

It appears the addition of B vitamins enhanced the conversion of homocysteine into acetylcholine. In Alzheimer’s patients, the levels of homocysteine are increased and levels of acetylcholine are decreased. This latter chemical is a memory-regulating substance.

Thus, it appears that levels of homocysteine may be a biomarker for the development of Alzheimer’s disease. Should high levels be indicated, the addition of B vitamins could at least slow the loss of memory and brain atrophy seen in Alzheimer’s and some other dementias.

Signs and Symptoms of Dementia

Common signs and symptoms of dementia, regardless of type, include (Mayo Clinic, 2014):

  • Loss of memory
  • Communication problems
  • Executive function problems, such as planning and organizing
  • Coordination and motor difficulty
  • Disorientation
  • Personality and behavior changes
  • Thinking and reasoning problems
  • Possibly agitation, paranoia, and hallucinations

The diagnosis of dementia requires at least two of these signs and symptoms. Usually, memory loss heads the list. Any of the signs and symptoms that lead to the diagnosis of dementia must be significant enough to interfere with daily functioning. Dementias may be reversible or irreversible. A good example of a progressive, irreversible dementia is Alzheimer’s disease.

Prevalence and Incidence of Dementia

In general, about two million people in the United States have a severe form of dementia (Swierzewski, 2011). Possibly another five million have mild to moderate dementia. The prevalence of dementia appears to double every five years for those over the age of 65.

The incidence of Alzheimer’s disease, one form of dementia, is estimated to be 5.3 million in the U.S. (American Speech-Language-Hearing Association, 2014). Alzheimer’s is the 6th leading cause of death in the United States. Due to an aging population, the prevalence of this for of dementia is projected to double by 2050.

Mild Cognitive Impairment and Dementia

Mild Cognitive Impairment (MCI) is a commonly-occurring condition among elderly Americans (Etgen, et al., 2011). It manifests as loss of memory, attention, and cognitive abilities over what is expected for age and education level. MCI is usually noticeable, but not significantly limiting in the areas of daily living.

MCI is associated with a greater risk of developing dementia, including Alzheimer’s (Alzheimer’s Association, n.d.). Two primary types of MCI are suggested: Amnestic MCI and nonamnestic MCI. The amnestic type of MCI has been suggested as the one most likely to transition into Alzheimer’s disease (Golomb, et al., 2004).

The rate of advancement from MCI to dementia is estimated to be 10-20% per year (Etgen, et al., 2011).

Mild Cognitive Impairment has been studied for 40 years and is currently at the forefront of research to determine possible early diagnosis and treatment of the symptoms of Alzheimer’s disease (Golomb, et al., 2004).

The prevalence of MCI may exceed the cases of Alzheimer’s, mainly due to the length of time for the symptoms to progress. Thus, prevalence is related to age of the individual. From a prevalence of about 1% at age 60 to 42% at age 85, this condition appears to be a significant part of the aging population of America (Golomb, et al., 2004).

Understanding the entire condition of MCI may lead researchers to an extended period of time in which treatment for the symptoms that may deteriorate into dementia would be possible. If this happens, successful treatment of MCI may lessen the impact of what appears to be a dramatic increase of dementias in not only the U.S., but around the world.

To date, there are no recognized or approved treatments for mild cognitive impairment (Alzheimer’s Association, n.d.; Etgen, et al., 2011; Golomb, et al., 2004). Finding some type of treatment possibilities would be a tremendous step in the right direction of slowing or eliminating the progression of MCI into a dementia.

B Vitamins, Homocysteine, and Dementia

Research appears to show a relationship among B vitamins, homocysteine, and dementia. Overall, it appears the B vitamins may reduce the cognitive decline seen with dementia while higher levels of homocysteine may be associated with cognitive decline. The role of the B vitamins may be in their converting homocysteine into acetylcholine which enhances memory.

In any case, higher levels of homocysteine seems to be related to poor cognition and the development of signs and symptoms of dementia (Seshadri, et al., 2002; Clarke, et al., 2007). Also, low levels of vitamin B12 have been associated with fast cognitive decline (Clarke, et al., 2007). Vitamin B12 deficiency has been reported to increase with age and may be at 20% of those age 75 and older (Etgen, et al., 2011). And studies have shown a relationship between low levels of B12 and the development of MCI.

With the information regarding the association of MCI and later development of dementias, including Alzheimer’s, research exploring the effects of B12 on homocysteine and dementia symptoms assumes greater importance.

Vitamin B12 is a water-soluble vitamin found in some foods and available as a nutritional supplement as well. When ingested in foods, it is released from the protein to which it is bound by the action of hydrochloric acid in the stomach. This vitamin is found naturally in animal products, but not in plant foods. Some older adults have difficulty absorbing B12 from food sources and require supplementation (National Institute of Health, 2011).

Other Opinions

Even though the research into the use of B vitamins, especially vitamin B12, to slow or stop cognitive decline and possibly the development of dementias when MCI symptoms are present appears to be significant, there are others who do not appear to agree.

There is general agreement that low levels of vitamin B12 may cause cognitive deficits and even dementia, but the question arises about whether these deficits and dementias are merely deficits in B12 and not indicative of a decline into Alzheimer’s (Osimani, et al., 2005). Symptoms of B12 deficiency are very similar to those of dementia of the Alzheimer’s type.

Vitamin B12 deficiency symptoms (National Institute of Health, 2011) include:

  • Balance problems
  • Weight loss
  • Fatigue
  • Confusion
  • Dementia
  • Depression
  • Poor memory

It is important to have a thorough physical examination to determine the appropriate diagnosis. A deficiency in vitamin B12 is relatively easy to treat, whereas there are no effective treatments for Alzheimer’s. Another reason for an appropriate diagnosis in these cases is the financial and psychological cost involved.

Financially, the cost of treatment of B12 deficiency is very significantly less than that for Alzheimer’s disease. And the psychological impact is much less. Thus, early recognition and treatment of B12 deficiency is very valuable in reducing costs and symptoms that could be mistaken for Alzheimer’s or another of the dementias.  


Whether the addition of vitamin B12 or other of the B vitamins addresses the symptoms of dementia is still to be determined. Further rigorous research is clearly called for. It does appear clear as well that B12 plays an important role in decreasing the symptoms associated with dementia. This is important because of the paucity of currently approved treatments for dementia. If B12 reduces memory loss and deterioration of brain volume, it is a step in the right direction for the eventual effective treatment of the terrible condition known as dementia.



Alzheimer’s Association. (n.d.) Mild cognitive impairment. Retrieved from

American Academy of Neurology. (2010). Vitamin B12 may reduce risk of Alzheimer’s disease. Retrieved from

American Speech-Language-Hearing Association. (2014). Dementia incidence and prevalence. Retrieved from

Clarke, R. et al. (2007). Low vitamin B-12 status and risk of cognitive decline in older adults. Retrieved from

Douaud, G., et al. (2013). Preventing Alzheimer’s disease-related gray matter atrophy by B-vitamin treatment. Retrieved from

Etgen, T., et al. (2011). Mild cognitive impairment and dementia. Retrieved from

Golomb, J., et al. (2004). Mild cognitive impairment: historical development and summary of research. Retrieved from

Gutierrez, D. (2013). B vitamins slow progression of Alzheimer’s: study. Retrieved from

Mayo Clinic. (2014). Dementia. Retrieved from

National Institutes of Health. (2011). Vitamin B12. Retrieved from

Osimani, A., et al. (2005). Neuropsychology of vitamin B12 deficiency in elderly dementia patients and control subjects. Retrieved from

Rush University Medical Center. (2011). Low vitamin B12 levels may lead to brain shrinkage, cognitive problems. Retrieved from

Seshardri, S., et al. (2002). Plasma homocysteine as a risk factor for dementia and Alzheimer’s disease. Retrieved from

Swierzewski, S.J. (2011). Dementia overview, types, incidence & prevalence. Retrieved from

About the Author

C. Wayne Winkle C. Wayne Winkle

I have over 30 years experience as a psychologist. My current 'day job' involves writing job descriptions, policy and procedure manual entries, and other writing activities for a mental health center.

C. Wayne Winkle can be found at
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