The level of a toxic amino acid in the blood, called homocysteine, has been shown to predict the rate of decline in Alzheimer’s disease. This finding, presented today at the International Conference on Alzheimer’s Disease, is especially important because homocysteine levels can be lowered relatively easily by supplementing specific B vitamins.
In Alzheimer’s, the decline in memory and other cognitive skills over time occurs at different rates in different people. For some, the decline is rapid so that in a few years they cannot cope with living on their own, no longer recognise friends or family and require full-time care. In others, the decline is slower and it may be ten years or more before the final stage is reached. Little is known about why these rates of decline differ so much between individuals.
This is an area researchers at the Oxford Project to Investigate Memory and Ageing (OPTIMA) at the University of Oxford, UK, are currently investigating. A team led by Professor David Smith have examined the association between the level of homocysteine measured when a person with Alzheimer’s first visited their clinic and the subsequent rate of decline in cognitive skills. Some 102 people with a clinical diagnosis of Alzheimer’s were evaluated every six months using memory tests (CAMCOG – the cognitive and self-contained part of the Cambridge Examination for Mental Disorders of the Elderly) for a minimum of 18 months up to a maximum of 11 years.
The scientists found that the higher the homocysteine level at the first measurement, the more rapid the subsequent decline. Patients with twice as much homocysteine as other study participants declined twice as rapidly. The relationship was strongest in patients younger than 75 at the start of the study.
“Because homocysteine can be lowered by taking high doses of folic acid and vitamin B12, the next step is to see whether B vitamin treatment will slow the rate of decline in Alzheimer’s, giving people with the disease more time with higher levels of functioning,” Smith told me.
At the Brain Bio Centre, a team of nutritional therapists routinely measure homocysteine in people who visit the clinic with memory decline, and give special supplements where levels are high. They are already seeing memory function stop declining and, in some cases, significantly improve in those with dementia, by giving a cocktail of high-dose nutrients, including B12, folic and B6. The scale of improvement they are seeing is far more significant that drugs such as Aricept.. And it’s a real breakthrough for Alzheimer’s prevention to see the University of Oxford working in this area too.
Professor David Smith and other leading research groups are now conducting trials to test the effects of B vitamin therapy using amounts proven most effective to lower homocysteine. However, sourcing these nutrients from diet alone is unlikely to be enough. The level of B12, for example, you need to lower raised homocysteine in an elederly person is around 1,000mcg a day. That’s one thousand times the RDA (recommended daily allowance set the by the government) – much more than you can achieve from diet alone.
