In November I mentioned a study which found that supplemental B vitamins which lowered homocysteine levels in the body might be useful to help elderly individuals with mild cognitive [mental function] impairment. A recent study (1) has found that Vitamin B12 may help protect against Alzheimer’s disease. The results of the research suggests that elderly individuals with more of the active part of the vitamin B12 in their blood have a lower risk of developing the disease. However, the findings don’t necessarily mean that taking B vitamin supplements will stave off mental decline.
To recap on homocysteine:
Homocysteine is produced when the amino acid (the building blocks of protein) methionine is broken down in the body. Normal levels of homocysteine are important to help build and maintain body tissues, however elevated concentrations in the blood can be harmful and have been associated with an increased risk of heart disease and other disorders. At normal levels homocystein can be converted in the body into a harmless substance called cystanthionine. The conversion of homocysteine into this harmless substance depends upon various B vitamins (B6, B12 and folic acid). Having good levels of these B vitamins appears to be a very good way of preventing high homocysteine levels and low levels of B vitamins have been associated with raised homocysteine levels.
The study (1)was set up in order to examine the relationship between blood serum levels of homocysteine and holotranscobalamin (holoTC), the active part of vitamin B12, and risk of incident Alzheimer disease in a sample of community-dwelling elderly. The research involved over 250 individuals aged between 65 and 79 years old who were free of dementia. The participants were followed-up for seven years and any cases of Alzheimer’s disease were recorded. The study scientists then looked to see if there was any association between the serum homocysteine levels, Vitamin B12 levels and Alzheimer’s disease. The study found that for each micromolar (1 µmol/L) increase in the concentration of homocysteine, the risk of Alzheimer’s disease increased by 16%, whereas each picomolar (1 pmol/L) increase in concentration of the active form of vitamin B12 reduced risk by 2%. The results stayed the same after taking into account other factors, such as age, gender, education, smoking status, blood pressure, stroke and body mass index. The addition of folate did not appear to raise or lower the risk of Alzheimer’s disease. From the results the authors conclude “This study suggests that both tHcy [homocysteine] and holoTC [vitamin B12] may be involved in the development of AD [Alzheimer’s disease]. The tHcy–AD link may be partly explained by serum holoTC. The role of holoTC in AD should be further investigated” (1)
In a press release Babak Hooshmand, one of the study scientists, said (2) ”Our findings show the need for further research on the role of vitamin B12 as a marker for identifying people who are at increased risk of Alzheimer’s disease,” “Low levels of vitamin B12 are surprisingly common in the elderly. However, the few studies that have investigated the usefulness of vitamin B12 supplements to reduce the risk of memory loss have had mixed results.”
The findings of this trial are very interesting but further large-scale research is needed in order to test whether vitamin B12 supplements can be recommended as a suitable treatment for the prevention of cognitive decline and dementia. Dr Hooshmand said in the press release “More research is needed to confirm these findings before vitamin B12 should be used solely as a supplement to help protect memory,”
Vitamin B12 is found mainly in meat, fish and poultry. Eggs and cheese also contain B12 as does brewer’s yeast. Many vegetarians and vegans have very low intakes of this vital nutrient and may wish to consider a multi-B vitamin supplement. Folic acid is found in beans, green vegetables and wholegrains. Vitamin B6 is found in foods like potatoes, bananas, beans and chickpeas, avocados, fish and poultry. Supplements should never be seen as an alternative to a healthy diet. If you wish to investigate the option of taking B vitamins it is best to discuss this with your medical doctor first.
(1) B. Hooshmand B et al. 2010. Homocysteine and holotranscobalamin and the risk of Alzheimer disease. A longitudinal study. NEUROLOGY 2010;75:1408-1414
(2) Press Release. American Academy of Neurology (2010, October 19). Vitamin B12 may reduce risk of Alzheimer’s disease. ScienceDaily. Retrieved December 6, 2010, from http://www.sciencedaily.com /releases/2010/10/101018162922.htm
Written By Ani Kowal
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