Five cups of coffee a day could reverse memory problems seen in Alzheimer's disease, according to US scientists.
A reseach team based in Florida has carried out tests on mice, also found that caffeine hampered the production of the protein plaques which are the hallmark of the disease. The latest findings back up previous research which also suggested a protective effect from caffeine.
The British Journal of Alzheimer's disease though advise caution saying the study did not mean that dementia patients should start using caffeine supplements.
The 55 mice used in the University of Florida study had been bred to develop symptoms of Alzheimer's disease.
The research team used behavioural tests to confirm the mice were exhibiting signs of memory impairment when they were aged 18 to 19 months, the equivalent to humans being around 70.
They gave half the mice caffeine in their drinking water, while the rest were given plain water.
The mice were given the equivalent of five 8 oz (227 grams) cups of coffee a day approximately 500 milligrams of caffeine, this equates to two cups of coffee such as lattes or cappuccinos from coffee shops, 14 cups of tea, or 20 soft drinks.
When the mice were tested again after two months, those who were given the caffeine performed much better on tests measuring their memory and thinking skills and performed as well as mice of the same age without dementia, while the mice drinking plain water continued to do poorly on the tests.
Further tests showed the brains of the mice given caffeine showed nearly a 50% reduction in levels of the beta amyloid protein, which forms destructive clumps in the brains of dementia patients.
These and other tests suggested caffeine affects the production of both the enzymes needed to produce beta amyloid as well as suppressing inflammatory changes in the brain that lead to an overabundance of the protein.
Earlier research by the same team had shown younger mice, who had also been bred to develop Alzheimer's but who were given caffeine in their early adulthood, were protected against the onset of memory problems.
The BBC reports head researcher Dr Gary Arendash, feals the results are particularly exciting in that a reversal of pre-existing memory impairment is more difficult to achieve.
They provide evidence that caffeine could be a viable 'treatment' for established Alzheimer's disease and not simply a protective strategy.
The importance of the discovery is caffeine is a safe drug for most people, it easily enters the brain, and it appears to directly affect the disease process."
The team now hope to begin human trials of caffeine to see if the mouse findings are replicated in people.
They do not know if a lower amount of caffeine would be as effective, but said most people could safely consume the 500 milligrams per day, though people with high blood pressure, and pregnant women, should limit their daily caffeine intake.
The Alzheimer's Research Trust, say, that the study on mice with symptoms of Alzheimer's, researchers found that caffeine boosted their memory. Then there ie a need to do more research to find out whether this effect will be seen in people.
But cautions, that it is too early to say whether drinking coffee or taking caffeine supplements will help people with Alzheimer's.
Tagged in Alzheimer's