Groenten
voor een goed geheugen.*
Elke dag groenten eten, kan de
achteruitgang van het geheugen vertragen. Vooral groene bladgroenten blijken een
heilzame werking te hebben. Met drie porties groenten per dag is men mentaal
even alert als iemand die vijf jaar jonger is. Veel fruit eten zou geen effect
te hebben. Dat blijkt uit een Amerikaanse studie van de Rush-universiteit uit
Chicago.
Heet heeft o.m. te maken met het gehalte aan vitamine E, dat in groenten hoger
ligt dan in fruit. Van vitamine E is bekend dat het positief inwerkt op het
brein. Vooral groenten als sla, spinazie en boerenkool zijn rijk aan deze
vitamine en in iets mindere mate ook courgettes, aubergines en broccoli.
Groenten en sla worden vaak gegeten met een olieachtige saus of dressing die de
absorptie van vitamine E door het lichaam bevordert.
Het onderzoeksteam, onder leiding van Marta Clare Morris, onderzocht de effecten
van voeding op de mentale gezondheid bij 3.700 gepensioneerde mannen en vrouwen.
Zij ondergingen allemaal een aantal tests die twee keer herhaald werden, telkens
met een tussenpoos van drie jaar. Bij de proefpersonen die minstens drie porties
groenten per dag op hun dieet hadden staan, bleek het geheugen 40 procent minder
achteruitgegaan dan bij zij die weinig of geen groenten aten. Hoe ouder de
proefpersonen waren, hoe groter het effect. Het Amerikaanse onderzoeksteam heeft
eerder al aangetoond dat groenten ook beschermen tegen Alzheimer.
Vegetables,
Not Fruit, Help Fight Memory Problems In Old Age
Eating
vegetables, not fruit, helps slow down the rate of cognitive change in older
adults, according to a study published in the October 24, 2006, issue of Neurology,
the scientific journal of the American Academy of Neurology.
In determining whether there was an association between vegetables, fruit and
cognitive decline, researchers from Rush University Medical Center studied 3,718
residents in Chicago, Illinois, who were age 65 and older. Participants
completed a food frequency questionnaire and received at least two cognitive
tests over a six-year period.
“Compared to people who consumed less than one serving of vegetables a day,
people who ate at least 2.8 servings of vegetables a day saw their rate of
cognitive change slow by roughly 40 percent, said study author Martha Clare
Morris, ScD, associate professor at Rush University Medical Center in Chicago,
Illinois. “This decrease is equivalent to about 5 years of younger age.”
Of the different types of vegetables consumed by participants, green leafy
vegetables had the strongest association to slowing the rate of cognitive
decline. The study also found the older the person, the greater the slowdown in
the rate of cognitive decline if that person consumed more than two servings of
vegetables a day. Surprisingly, the study found fruit consumption was not
associated with cognitive change.
“This was unanticipated and raises several questions,” said Morris. “It
may be due to vegetables containing high amounts of vitamin E, which helps
lowers the risk of cognitive decline. Vegetables, but not fruits, are also
typically consumed with added fats such as salad dressings, and fats increase
the absorption of vitamin E. Further study is required to understand why fruit
is not associated with cognitive change.”
Morris says the study's findings can be used to simplify public health messages
by saying people should eat more or less of foods in a specific food group, not
necessarily more or less of individual foods.
The study was supported by grants from the National Institute on Aging.
Rush University Medical Center is an academic medical center that encompasses
the more than 650 staffed-bed hospital (including Rush Children's Hospital), the
Johnston R. Bowman Health Center and Rush University. Rush University, with more
than 1,270 students, is home to one of the first medical schools in the Midwest,
and one of the nation's top-ranked nursing colleges. Rush University also offers
graduate programs in allied health and the basic sciences. Rush is noted for
bringing together clinical care and research to address major health problems,
including arthritis and orthopedic disorders, cancer, heart disease, mental
illness, neurological disorders and diseases associated with aging.
(Nov.
2006)