In older individuals, especially those who are suffering from cognitive (brain function) decline, there is often an increased rate of brain wastage/shrinking (atrophy). Previous studies have found that homocysteine is a risk factor for brain atrophy, cognitive impairment and dementia. It is also known that blood plasma concentrations of homocysteine can be lowered by dietary administration of B vitamins.
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 evidence, however is still controversial (please read my prevous posts on homocycteine).
A recent, two year, study (1) was carried out in order to determine whether supplementation with B vitamins that lower levels of plasma total homocysteine can slow the rate of brain atrophy in subjects with mild cognitive impairment. High doses of folic acid (0.8mg/d), vitamins B6 (20mg/d) and B12 (0.5mg/d) were used in the study and participants, who were all over 70 years old, had brain MRI scans both at the start and end of the study in order to track brain shrinkage. The dose of B vitamins in the supplement pills was high, they contained around 300 times the recommended daily intake of B12, four times daily advised folate levels and 15 times the recommended amount of B6.
The results of the study showed that individuals (1) receiving the B vitamins had a significantly reduced rate of brain atrophy per year when compared to those individuals taking the placebo. Brain atrophy was related to the homocysteine levels at the start of the study: the rate of atrophy in participants with homocysteine levels greater than >13 µmol/L was 53% lower in the group receiving the B vitamins. A greater rate of brain shrinkage was associated with a lower final cognitive test scores. The authors conclude that “The accelerated rate of brain atrophy in elderly with mild cognitive impairment can be slowed by treatment with homocysteine-lowering B vitamins. Sixteen percent of those over 70 y old have mild cognitive impairment and half of these develop Alzheimer’s disease. Since accelerated brain atrophy is a characteristic of subjects with mild cognitive impairment who convert to Alzheimer’s disease, trials are needed to see if the same treatment will delay the development of Alzheimer’s disease”.
For more on Alzheimer’s disease please read my previous posts on the topic. Individuals with mild cognitive impairment tend to experience problems with memory, language, or other mental functions, but not to a degree that interferes with daily life. Around half of people with mild cognitive impairment go on to develop dementia , mainly Alzheimer’s disease, within five years of diagnosis (2). Alzheimer’s is a mind-wasting disease for which there are few treatments and no cure, and which affects 26 million people around the world.
In a press release (2) one of the study authors, Professor David Smith of the Department of Pharmacology at Oxford University, said “It is our hope that this simple and safe treatment will delay the development of Alzheimer’s disease in many people who suffer from mild memory problems” “Today there are about 1.5 million elderly in UK, 5 million in USA and 14 million in Europe with such memory problems”. “These are immensely promising results but we do need to do more trials to conclude whether these particular B vitamins can slow or prevent development of Alzheimer’s. So I wouldn’t yet recommend that anyone getting a bit older and beginning to be worried about memory lapses should rush out and buy vitamin B supplements without seeing a doctor”
Rebecca Wood, Chief Executive of the Alzheimer’s Research Trust said (2): “These are very important results, with B vitamins now showing a prospect of protecting some people from Alzheimer’s in old age. The strong findings must inspire an expanded trial to follow people expected to develop Alzheimer’s, and we hope for further success. We desperately need to support research into dementia, to help avoid the massive increases of people living with the condition as the population ages. Research is the only answer to what remains the greatest medical challenge of our time”
The findings of this trial are indeed very encouraging, further large-scale research is needed in order to test whether B vitamins can be recommended as a suitable treatment for the prevention of cognitive decline and dementia.
Vitamin B6 is found in foods like potatoes, bananas, beans and chickpeas, avocados, fish and poultry. 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. Supplements should never be seen as an alternative to a healthy diet and as Professor Smith said in the press release, if you wish to investigate the option of taking B vitamins it is best to discuss this with your medical doctor first.
(1)Smith AD et al. 2010. Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment: A Randomized Controlled Trial. PLoS ONE, 2010; 5 (9): e12244 DOI: 10.1371/journal.pone.0012244
(2)Press Release. University of Oxford (2010, September 12). B vitamins slow brain atrophy in people with memory problems. ScienceDaily. Retrieved September 13, 2010, from http://www.sciencedaily.com /releases/2010/09/100912213050.htm
Written by Ani Kowal
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