Heavy elderly 'don't risk memory drop'
September 25, 2007
Older adults who are overweight do not seem to be at any extra risk of
memory decline, a new study suggests.
In fact, researchers found, it was underweight men and women who were more
likely to see their memory suffer over time. They speculate that this is
because poor nutrition and weight loss may be early manifestations of
Alzheimer's disease in some older people.
The findings, reported in the journal Neurology, stand in contrast to
research that has linked obesity in middle-age to a greater risk of dementia
later in life.
It's thought that obesity in mid-life may raise dementia risk indirectly, by
leading to health problems that impair blood flow to the brain, like high
blood pressure and diabetes.
Experts also theorise that excess fat cells have some direct effect on brain
function.
However, in old age, being overweight or obese may not be a liability when
it comes to mental function, according to the authors of the new study.
"We do not know yet why being overweight or obese does not increase the risk
for cognitive decline in old age," lead study author Dr Maureen T Sturman,
of Rush University Medical Center in Chicago, said in a statement.
"However being underweight may be a correlate of the initial stages of
Alzheimer's disease," she added.
The findings are based on 3,885 adults age 65 and older who took standard
tests of memory and other mental functions at the start of the study, then
twice more over the next six years.
Sturman's team found no relationship between obesity and the risk of memory
changes or other signs of mental decline over time. In contrast, study
participants who were underweight at the outset were at heightened risk of
decline.
"While past studies have found obesity in middle age increases a person's
risk for dementia or Alzheimer's disease, our findings show obesity in old
age has no effect on a person's memory," Sturman said.
Studies should continue to look at the effect of weight on older adults'
mental functioning so that firmer lifestyle advice can be given, Sturman and
her colleagues conclude. Older people may do better to focus on healthy
eating, physical activity and mental "exercise" - like reading and doing
crossword puzzles - than on shedding excess weight, they suggest.