Daily consumption of B- vitamins and folic acid may considerably slow the onset of memory loss in older people and even prevent Alzheimer's disease.
A study of 266 people aged 70 and older showed that large doses of B6, B12 and folic acid reduced the overall senile shrinkage of brains by 30 percent.
Participants were suffering mild cognitive impairment (MCI), a condition which is an intermediate stage between the expected cognitive decline of normal aging and the more pronounced decline of dementia. It involves problems with memory, language, thinking and judgment and increases the risk of developing dementia and Alzheimer's disease.
According to the results published in the International Journal of Geriatric Psychiatry, and PLoS One, brain scans of those who took the prescribed supplements showed that the vitamin pills reduced brain atrophy by 30 percent on average.
Taking the vitamins was even more effective on patients with high levels of an amino acid called homocysteine and reduced brain atrophy among them by 50 percent.
"High homocysteine is a known risk factor for cognitive decline in the elderly and Alzheimer's disease and also for other kinds of dementia like vascular dementia," said lead researcher Celeste de Jager. "It can be damaging to the endothelial lining of the blood cells. It also binds to receptors in the brain that are on the neurons and it seems to contribute the atrophy that's associated with Alzheimer's."
Taking B vitamins and folic acid is known to control the levels of homocysteine, which increases in old age, added the scientist who works with Oxford University.
The new findings "definitively" showed that the vitamins were a good way of preventing mental decline, the study concluded.
"A lot of the time brain changes start in your 40s and 50s before you get clinical symptoms," de Jager told the British Science Festival. "I would think that in middle age people should start thinking about their vitamin levels."
Researchers, however, warned people not to take vitamins without consulting their doctors because supplements can cause some harmful impact on other conditions such as cancer.
Asked if she would take the vitamins as a precaution, Dr de Jager said: "I would ask the doctor to check my B12 and my folic acid levels for starters. "I take supplements when I'm feeling a bit low, I don't take one every day but I would certainly have multi-vitamins and B vitamins in my cupboard."