Vitamin pill that may slow Alzheimer's goes on trial

[Regina]

A vitamin pill that could slow the progression of Alzheimer's disease is to enter human trials after scientists found it protected animals from memory loss associated with the condition.

High doses of vitamin B3 will be given to 70 people who have recently been diagnosed with the disease as part of the trial due to begin in the new year, which is open to volunteers over the age of 50.

If the six-month trial is a success it could have a dramatic impact on the treatment of an estimated 417,000 people in Britain who have been diagnosed with Alzheimer's. There is currently no cure for Alzheimer's or any other type of dementia.

Delaying the onset of the disease by five years would halve the number of deaths from the condition, saving 30,000 lives a year, according to the Alzheimer's Society. Scientists at the University of California, Irvine, gave high doses of a form of vitamin B3 called nicotinamide to mice which had been genetically modified to develop Alzheimer's disease. The researchers, led by Dr Kim Green, tested the animals' memories over the four month study by seeing how well they remembered the location of a submerged platform in a large water tank.

At the end of the trial the mice with Alzheimer's performed as well in the memory test as healthy mice, suggesting the vitamin had protected their brains from memory loss. Healthy mice who were fed the vitamins outperformed mice on a normal diet. "The vitamin completely prevented cognitive decline associated with the disease, bringing them back to the level they'd be at if they didn't have the pathology," said Green. "It actually improved behaviour in non-demented animals too."

"This suggests that not only is it good for Alzheimer's disease, but if normal people take it, some aspects of their memory might improve," said Frank LaFerla, a co-author on the study.

The results, which are published in the Journal of Neuroscience, encouraged the scientists to draw up plans for a human trial that will be run from the university.

"At the moment we're talking about a disease for which there is no sort of treatment and this is likely to be far safer than any of the upcoming drugs. Nicotinamide is just vitamin B3, it's really cheap, it's safe and easy to get hold of," said Green.

Research so far suggests that over-the-counter vitamin supplements will contain too little vitamin B3 to have an effect. Volunteers taking part in the trial will be given 2g of the vitamin a day. Previously scientists have only seen serious side effects in doses of 10g or more, which were found to cause liver damage.

The vitamin is believed to prevent the build-up of "tau" proteins along tracks inside neurons. In the early stages of the disease these protein clumps are thought to make nerve cells work less efficiently, but ultimately they can stop the nerves working completely and kill them off.

Brain scans of Alzheimer's patients reveal they also experience clumps of a second type of protein outside the nerve cells. Many scientists believe these amyloid plaques also drive the progression of the disease. Green said that as nicotinamide only appears to reduce the build-up of the proteins in the brain, more effective treatments may combine drugs that attack both types.

Susanne Sorensen, head of research at the Alzheimer's Society, said: "This research is interesting as it points towards new ways of treating Alzheimer's disease. The best evidence around reducing your risk of dementia is to eat a healthy balanced diet, take regular exercise, don't smoke and check your blood pressure and cholesterol."

Ian Sample