The easy way to ward off dementia?
Older people who drink moderate amounts of alcohol may have a lower risk of dementia, a US study suggests.
Researchers found people who consumed between eight and 14 alcoholic drinks a week had a 37% lower risk of the disease than the general population.
However, people who consumed more than 14 drinks a week were at twice the normal risk of developing dementia.
The Wake Forest University study was presented at the International Conference on Alzheimer's Disease.
The US researchers focused on 3,069 people aged 75 or older.
At the beginning of the six-year study, 2,587 participants had no signs of problems with their brain while 482 had mild cognitive impairment. During the study 523 new dementia cases emerged.
The researchers took account of factors such as smoking, depression and social activity, and found that one or two drinks a day was associated with a 37% lower risk of dementia among those who were cognitively normal at the start of the study.
However, among those who already had mild cognitive impairment alcohol intake was associated with faster cognitive decline.
Among the people in the study, four in ten did not drink alcohol, four in ten consumed up to seven drinks a week, one in ten consumed 8-14 drinks a week, and one in ten consumed more than 14 drinks a week.
Reason not clear
Why a moderate amount of alcohol seems to be good for the brain is not clear.
Lead researcher Dr Kaycee Sink said: "There are several possible ways in which moderate drinking might be associated with reduced risk of dementia.
"One is the same as the way we think moderate alcohol reduces the risk of heart disease, by beneficial effects on HDL cholesterol and blocking platelets.
"Additionally, animal studies have shown that low amounts of alcohol stimulate the release of acetylcholine, a chemical in the brain that is important in memory."
Dr Sink added: "We cannot recommend that older adults who don't drink start drinking alcohol based on this study.
"But it is reasonable to say that if you are already a light to moderate drinker, you may be at a lower risk of developing Alzheimer's disease or other dementias.
"However, if you already have memory or thinking problems, drinking alcohol may accelerate memory decline."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "Although moderate alcohol intake does appear to reduce dementia risk, exceeding one to two drinks per day on a regular basis - becoming a heavy drinker - may double risk of developing dementia.
"On the basis of this study, older people with memory problems should consider not drinking at all.
"The best way to reduce dementia risk is to eat a balanced diet, exercise regularly and remain socially active."
The results conflict with those from a small study published in Neurology in 2007, which suggests people with mild cognitive impairment might slow their mental decline with up to one drink a day.