Foliumzuur houdt geest jong.*
De hersenen van vijftigplussers werken sneller als ze elke dag een pil
met de vitamine foliumzuur slikken. Dat schrijft dr. Jane Durga deze week in The
Lancet.
Het artikel is gebaseerd op haar Wageningse promotieonderzoek uit 2004.
Durga
deed een drie jaar durend experiment met achthonderd Nederlandse ouderen. De
helft van hen slikte dagelijks een pil met achthonderd microgram foliumzuur, de
andere helft een placebo. Achthonderd microgram is veel. De gemiddelde Nederland
krijgt dagelijks tweehonderd microgram binnen.
Toen
Durga haar proefpersonen onderwierp aan een batterij psychologische tests,
ontdekte ze dat de vitamine de veroudering van sommige elementaire cognitieve
vermogens vertraagde. Eén van die tests hield in dat ouderen woordjes moesten
herinneren die ze zojuist hadden gelezen. Op zulke tests scoorden ouderen die
foliumzuur slikten even goed als mensen die vijf jaar jonger waren. Naarmate
onderzoekers complexer mentale vaardigheden testten, was het effect geringer.
Durga
weet niet of alle ouderen zo positief op foliumzuur zullen reageren. Haar
proefpersonen waren uitgekozen op hun hoge homocysteïnespiegel. Homocysteïne
is een aminozuur dat volgens wetenschappers schadelijk is voor bloedvaten en
hersenen. Foliumzuur verlaagt de homocysteïnespiegel.
Folic
Acid Increases Mental Agility In The Elderly
Taking
supplements of folic acid may significantly improve cognitive function in older
men and women.
This is the conclusion of a Dutch study to be published in the Lancet.
The study was led by Jane Durga from the Wageningen University in The
Netherlands.
Diminshing cognitive functions such as deterioration in memory, reduced ability
to process information quickly, and reduced verbal fluency have been linked to
risk of dementia in old age.
Dr Durga and colleagues followed a group of 818 over-50s for three years. Some
were given 800 micrograms of a synthetic form of folic acid per day, the rest
took a placebo. A synthetic version of the vitamin was used because the
naturally occurring form degrades more easily, for example with storage and
cooking, and that would make any results less reliable.
The scientists found that the group who took the folic acid improved on all
aspects of cognitive functioning compared to the group that took the placebo.
Folic acid is a water soluble B vitamin and is found in yeast extract, green
leafy vegetables, for example spinach, in dried beans and peas, some organ meats
such as liver, fortified cereals, certain fruit and vegetables, and certain
seeds, for example sunflower seeds. It plays an important role in the production
of new cells, especially in the spinal cord an embryo, which is why it is
important that pregnant women have their reference daily intake (RDI).
Adults and children need folic acid to generate red blood cells and DNA, and
insufficient daily intake can result in anemia. The vitamin also helps to digest
protein and make effective use of the resulting amino acids, and also to produce
proteins that the body may be lacking. It also plays a role in regulating
appetite.
Because of the discovery of the link between neural tube defects (NTD, such as
that occurring in infants born with spina bifida), and insufficient folic acid
governments have gradually introduced regulations that require certain foods to
be fortified with folic acid, such as cereals, and in some countries bread and
flour also.
Different countries recommend different RDI amounts, ranging from 400 micrograms
a day in the US to 200 in Japan.
Some research studies have linked folic acid supplement taking with reductions
in various age-related impairments such as hearing loss and Alzheimer's. Others
are not so clear, but there seems to be consensus that it helps improve
cognitive function in elderly people with high concentrations of the amino acid
homocysteine in their blood, which could indicate increased riks of stroke,
heart disease and Alzheimer's.
Concerns have been raised that folic acid interacts with Vitamin B12 and taking
too much of it can cause problems, such as masking a deficiency in B12. This is
particularly relevant to older people (over 50), who should ask their doctor to
check their vitamin B12 levels if they considering taking folic acid supplements.
(Febr. 2007) (Opm.
Meer over foliumzuur in de
voeding.)