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Could B vitamins be a way to save your brain from Alzheimer’s?


Research on finding better ways to better diagnose, treat and ultimately prevent Alzheimer’s disease is being investigated around the globe on massive scale. Some researchers are concentrating on ways to prevent amyloid build up; others are looking at ways to increase brain functionality.

Neuroscience has provided us with a far greater understanding of how our brain can adapt and rewire itself throughout our lives. The role of diet has been shown to be vital in helping our brain cells to function and be maintained at their best. Many different studies have examined different micronutrients, the vitamins and minerals we eat, to see what impact they may have in helping us to keep our brains healthy.

This week I received a copy of a report published in the UK on the findings of a research study looking at the effect of B vitamins on brain shrinkage. This was a small trial in Oxford, looking to see whether administering large doses of B vitamins would lower homocysteine levels in the blood and lead to less brain atrophy in elderly subjects who already had mild cognitive impairment.

Our shrinking brain.

Our brains start to shrink from the time we are in our early twenties. Not by much, around 0.2% per year. But once we reach the age of 60, the rate of shrinkage starts to increase to 0.5% per year.
In mild cognitive impairment (MCI), a person is having problems with memory loss, language difficulty and other problems beyond those normally expected simply through ageing.

Around 16% of people over the age of 70 years develop MCI and half of these people subsequently go on to develop Alzheimer’s disease. MCI is seen as a precursor for Alzheimer’s.
In MCI the rate of brain shrinkage increases to 1% and by the time Alzheimer’s is diagnosed is around 2.5% per year.

Homocysteine and the B Vitamins

Homocysteine is an amino acid normally found in the body. Our B vitamins help to keep it in the normal range. In excess it has been shown to be a risk factor for heart disease, brain atrophy, cognitive impairment and dementia.

In a previous blog post I looked at a study on women, which had shown that using measurements of blood homocysteine levels could determine a woman’s risk factor for dementia.
It is known that homocysteine levels can be lowered in the body by administering doses of the B vitamins.
The Oxford study looked to see whether using large doses of the B vitamins would lower homocysteine levels and thereby reduce the rate of brain shrinkage in subjects with mild cognitive impairment.

Big doses of Vitamin B

In the trial, very large doses of B vitamins were used: x300 the RDI for vitamin B12, x15 for Vitamin B6 and x4 that for folic acid.
The co-author Helga Refsum from the University of Oslo indicated that in this study the vitamins were being used as a drug rather than simply vitamin supplementation. It is unknown if these megadoses have any long-term effects and there have been studies linking high dose folate to an increased risk of cancer.

168 people over the age of 70 years who had been diagnosed with mild cognitive impairment were divided into two groups. One group received the mega dose vitamins and the other group received a placebo.
MRI scans were used to measure brain volume at the beginning of the study and then annually over a two year period.

The results showed that in the group taking the vitamins, the average reduction in the rate of brain atrophy was 30%. Moreover those who had had the highest level of homocysteine at the beginning of the study, showed the greatest reduction in shrinkage rate by up to 53%. Those who had received the vitamins also performed better overall on mental testing.

The inference was that this may be a way to help reduce the number of people with mild cognitive impairment from progressing to full blown Alzheimer’s.
The “how” of lowering homocysteine to produce this brain saving effect is not yet known. Being such a small study the results while encouraging will now be followed up with a much larger study to verify the findings.

Where to from here?

The B vitamins are known to be important in helping us to maintain a normal nervous system.
We can obtain our B vitamins from diet. Some of our foods are already fortified with B vitamins especially folic acid. The role of folate in helping to prevent neural tube defects (spina bifida) in babies is well documented.
Good sources of B12 are found in fish, milk ,eggs and chicken.
Vitamin B6 is found in beans , meat, poultry, potato, banana and tuna.
Folate (folic acid) is found in green leafy vegetables and fortified breads and cereals.

So we can enjoy a wide range of foods to provide us with a good intake of the B vitamins. We can already measure homocysteine levels by a simple blood test and it is easy enough to take vitamin B in supplement form. It just remains too early yet to recommend taking big doses to preserve our brains.
What is particularly encouraging from this study is that it may provide a simple and inexpensive treatment to reduce the number of people already with MCI from progressing to full blown Alzheimer’s disease.

Ref: Smith AD, Smith SM, de Jager CA, Whitbread P, Johnston C, et al. (2010) Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment: A Randomized Controlled Trial.

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