May 2013

B vitamin supplements stop Alzheimer's brain shrinkage


Ground-breaking research from Oxford University is published today, in the Proceedings of the National Academy of Sciences[1], showing that inexpensive B vitamins stopped shrinkage in the area of the brain that defines Alzheimer's disease, called the medial temporal lobe. While most people diagnosed with dementia have Alzheimer's the diagnosis of Alzheimer's requires confirmation with a brain scan that shows degeneration of this specific area of the brain. The discovery that the medial temporal lobe virtually stops shrinking in some people with high dose B vitamins is a highly important and convincing breakthrough in understanding what causes, and can prevent Alzheimer's.

The study, led by Professor David Smith from the University of Oxford, gave a combination of vitamin B6 (20mg), B12 (500mcg) and folic acid (800mcg) or placebo pills to people with mild cognitive impairment (MCI), the stage before a diagnosis of dementia or Alzheimer's. "In those with high homocysteine levels, the specific areas of the brain associated with

Alzheimer's disease shrank eight times more slowly in those taking B vitamins than in those on the placebo. This is strongly indicative that the B vitamins may be substantially slowing down, or even potentially arresting, the disease process in those with early stage cognitive decline. This is the first treatment that has been shown to do this." said Professor David Smith.

"This is the first treatment that has been shown to potentially arrest Alzheimer's related brain shrinkage.” Professor David Smith, Oxford University.

(Reproduced with permission of PNAS. Yellow denotes area of significant atrophy in 2 years)


David Smith


In a previous study the Oxford research group had shown that the higher a person's homocysteine level, which is a reliable marker for Alzheimer's risk, the greater was the rate of shrinkage of the whole brain, and that lowering homocysteine with B vitamins markedly slowed any further memory decline in those with raised homocysteine levels[2].

Approximately half of all people over 65 have a level of homocysteine above that associated with accelerated brain shrinkage which means that, according to this research, it may be possible to prevent up to half of all cases of Alzheimer's or at least considerably slow down its development providing those at risk are identified early. The global cost of Alzheimer's dementia is estimated at $604 billion so the likely cost savings are immense.

According to Professor Smith "This makes the need for early screening for the first signs of cognitive decline from the age of 50, for example with the Cognitive Function Test at vitally important, backed up by homocysteine testing and potential B vitamin treatment. Our study shows that those with a homocysteine level above 10mcmol/l, which is about half of all people over age 65, potentially may benefit with reduced brain shrinkage by taking high dose B6, B12 and folic acid, but this should be done under medical supervision. Because the study shows for the first time that modification of the disease process in Alzheimer's is possible, it opens up other approaches to prevention by modifying other risk factors."

The Cognitive Function test is an on-line 15 minute screening test anyone can do to check your memory, offered for free by the charity If a person's results are not good they receive a letter to take to their GP recommending homocysteine testing. GPs can test your homocysteine level, which is a routine screening in Germany and Scandinavia, but rarely performed in the UK. It can also be done privately at most medical laboratories or with a home test kit (see

According to this research anyone with a level above 10mcmol/l can benefit from supplementing a high daily dose of B6 (20mg), B12 (500mcg) and folic acid (800mcg). According to nutritionist Patrick Holford from the Food for the Brain Foundation "These doses, which have now been shown to stop memory loss and brain shrinkage are much higher than you can get from a good diet alone. For example, the basic recommended daily amount (RDA) of B12 is 1mcg while the level that stops accelerated brain shrinkage in those with cognitive impairment is 500mcg. This dose is considered to be safe, but means taking specific homocysteine lowering supplements that are available in health stores, not just any multivitamin or B complex. Some also provide tri-methyl glycine (TMG) and zinc, which also help lower homocysteine. But these high doses are not necessary in those with healthy homocysteine levels, ideally of 7 or less. However, even in those with a homocysteine level below 10 it is a wise precaution to take a multivitamin that provides at least 10mcg of B12, 20mg of B6 and 200mcg of folic acid.”

The reason for the need for such high doses of B12 is not fully understood but is thought to be largely due to declining absorption with age, a factor that is made worse by certain medications including metformin, the most commonly prescribed drug for diabetes and commonly prescribed antacid 'proton-pump inhibitor' drugs such as omeprazole. Coffee, smoking and lack of exercise also raise homocysteine.

Other areas that Professor Smith and Patrick Holford think are worthy of exploring for research into prevention include the high risks associated with diabetes and obesity, and hence high sugar and carbohydrate diets, and the potential benefits of increasing antioxidant and omega 3 supplements and foods, such as vegetables, berries and fish. A trial last month found that supplements of DHA, a type of omega 3 fat found in oily fish, taken over 6 months improved memory in adults[3] while previous research found it improved memory in those with age-related memory decline[4]. There is a highly informative film on Alzheimer's prevention, and a downloadable 'Ten Alzheimer's Prevention Steps' at