Alzheimer's, Dementia & Mental Health
Older Adults with Diabetes Experience Memory
Declines Immediately after Unhealthy Meal
Can be offset by taking antioxidant vitamins with
meal, but healthy diet rich in fruits and vegetables is best defense
June
26, 2008 – Older adults with type 2 diabetes who eat unhealthy, high-fat
meals may experience memory declines immediately afterward, according to
new research. But, the study found this can be offset by taking
antioxidant vitamins with the meal.
There is already growing evidence linking diabetes
to cognitive complications in humans. Adults with type 2 diabetes are
especially vulnerable to acute meal-induced memory deficits after eating
unhealthy foods.
This latest study, led by Baycrest, an academic
health sciences center associated with the University of Toronto,
suggests that taking high doses of antioxidant vitamins C and E with the
meal may help minimize those memory slumps.
It is published in the July issue of Nutrition
Research.
"Our bottom line is that consuming unhealthy meals
for those with diabetes can temporarily further worsen already
underlying memory problems associated with the disease,"said lead author
Michael Herman Chui, who conducted the research as a University of
Toronto pathobiology undergraduate in the Kunin-Lunenfeld Applied
Research Unit (KLARU) at Baycrest.
"We've shown that antioxidant vitamins can minimize
oxidative stress from the meal and reduce those immediate memory
deficits."
Type 2 diabetes is associated with chronic
oxidative stress, a major contributor to cognitive decline and Alzheimer
disease. Consuming unhealthy foods can induce this type of stress which
is triggered by acute elevations of free radicals – unstable molecules
that can damage tissue, including brain tissue. These destructive
molecule reactions typically occur over a one-to-three hour period after
food ingestion.
Dr. Carol Greenwood, senior author of the study and
a nationally recognized expert in how diet impacts brain function,
cautioned that relying on antioxidant vitamins at meal time is not a
quick fix.
"While our study looked at the pill form of
antioxidants, we would ultimately want individuals to consume healthier
foods high in antioxidants, like fruits and vegetables," said Dr.
Greenwood, a KLARU senior scientist at Baycrest.
Maintaining a healthy lifestyle that includes
regular exercise, a low fat diet rich in antioxidants, and staying
mentally active and socially engaged in a variety of activities, is the
best medicine for optimizing cognitive health during the lifespan, she
said.
The study
In the study, 16 adults (aged 50 years and older)
with type 2 diabetes participated in an unblinded trial where they
attended three weekly sessions that involved consuming a different test
meal.
One meal consisted of high fat products – a danish
pastry, cheddar cheese and yogurt with added whipped cream; the second
meal consisted of only water consumption; and the third test meal was
the high-fat meal plus high doses of vitamins C (1000 mg) and E (800 IU)
tablets.
Fifteen minutes after starting meal ingestion,
participants completed a series of neuropsychological tests lasting 90
minutes that measured their recall abilities for words they had heard
and paragraph information they had read. These cognitive skills are
associated with the brain's memory centre – the hippocampus.
Researchers found that vitamin supplementation
consistently improved recall scores relative to the meal alone.
Participants who ate the high fat meal without vitamin supplements
showed significantly more forgetfulness of words and paragraph
information in immediate and time delay recall tests, relative to those
who had the water meal or the meal with antioxidant vitamins.
Those on water meal and meal with vitamins showed
similar levels in cognitive performance.
Dr. Greenwood and medical student M.H. Chui
emphasize that their findings require further replication in larger
studies with more participants. Future studies will need to look at
whether antioxidant vitamins are directly targeting oxidative stress
reactions or triggering an independent memory-enhancing ability which is
simply masking the detrimental effects.
The study was funded by a grant from the Natural
Sciences and Engineering Research Council of Canada.
Baycrest is an academic health sciences centre,
internationally-renowned for its care of aging adults and its excellence
in aging brain research, clinical treatments and promising cognitive
rehabilitation strategies. Baycrest is fully affiliated with the
University of Toronto.