Investigating whether vitamin B12 and folic acid supplementation slows cognitive decline

Abstract

Given the increase in average lifespans in countries around the world, diseases that afflict the elderly are a major focus for scientists. Uppermost among these is dementia, a broad term which includes many types of cognitive decline from mild impairment to severe conditions such as Alzheimer's disease. We lose brain volume and function as we age, and it is this atrophy of different parts of the brain that leads to loss of cognitive function. Although atrophy takes many different forms and thus results in a range of conditions, there are commonalities between each that might be targets for treatment. One area of research is the possibility of using large doses of B vitamins to lower levels of the amino acid homocysteine, which has been linked to many conditions including cardiovascular disease and dementia. This is the focus of Professor Timothy Kwok's ongoing research at the Chinese University of Hong Kong. Kwok is also a practising consultant geriatrician at the Prince of Wales Hospital in Hong Kong and has been inspired to pursue this field of inquiry by the need for simple and inexpensive treatments which could be made available to large numbers of elderly patients. He says: 'A trial at the University of Oxford showed that lowering homocysteine levels led to a significant reduction in the rate of brain atrophy. However, many questions remain unanswered and our current two-year trial will hopefully give further insights into the benefits or otherwise of vitamin B supplementation. If a causative link can be found between vitamin B supplementation and a slower rate of cognitive decline, this would be an inexpensive and safe way of treating people at the early stage of disease. In addition, these vitamins could potentially be given as a preventative treatment in older people who are not yet showing signs of cognitive impairment. As Kwok says: 'Dementia is a major cause of dependency in old age and has a big impact on the people affected, their families and scarce medical resources. If supplementation could prevent dementia in people with early symptoms, this simple intervention could make a huge difference to the quality of life of elderly people and reduce the burden of dementia on national health services.'