How Do B Vitamins Beat Back Alzheimer's?

Studies show that B vitamins, such as folic acid and vitamin B-12, lower the risk of dementia. How does it work? How clear is the evidence?

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Studies show that the B vitamins, like folic acid and vitamin B-12, prevent dementia. Dr. Peter Garrard, of the Cardiovascular and Cell Sciences Research Institute at St George's, University of London, said that taking B vitamins lowers blood levels of a molecule (homocysteine), which in high concentrations acts as a potent risk factor for dementia. In a recent commentary, Dr. Gerrard highlighted the 'first-rate scientific evidence that the use of B vitamins confers both biological and neuropsychological benefits' on individuals aged over 70 who had noticed a recent decline in their cognitive abilities.

He emphasised the urgent need for a definitive trial to establish whether this simple and safe treatment can slow cognitive deterioration in a similar group of people, as such individuals are known to have a heightened risk of developing full-blown Alzheimer's disease.

Skeptics

Not everyone is convinced. Last year, researchers performed an analysis and suggested that taking B vitamins won't prevent Alzheimer's. That research has been widely quoted in the press.

Recently, clinicians and scientists have fired back at the negative suggestions against B vitamins. Doctors have labelled the statement 'inaccurate and misleading', voicing concerns that the unjustified claim could bias research funding and health policy decisions, as well as having a negative impact on patient welfare.
In separate letters to the American Journal of Clinical Nutrition, Dr. Garrard and Professor David Smith, of the University of Oxford, pointed out a number of flaws in that analysis, including:

1. Reliance on data from trials of vascular disease prevention rather than dementia;
2. The use of the Mini Mental State Examination (MMSE), which is designed to detect dementia but is unsuitable for assessing small changes in cognitively normal people; and
3. The absence of any cognitive decline in untreated patients, rendering the whole study irrelevant to the question of clinical benefits in cognitive impairment or dementia.

The new commentaries strongly encourage the funding of clinical trials to establish the cognitive benefits of B vitamins. The letters are published in the February 2015 edition of the American Journal of Clinical Nutrition.

Source:

• University of St George's London

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Journal Reference:

1. P. Garrard, R. Jacoby. B-vitamin trials meta-analysis: less than meets the eye. American Journal of Clinical Nutrition, 2015; 101 (2): 414 DOI: 10.3945/ajcn.114.097808