Foliumzuur en
het ontstaan van dementie*
Uit een studie onder 518 personen van 65 jaar en ouder blijkt dat lage bloedwaarden
foliumzuur de kans op het ontstaan van
dementie en de ziekte van Alzheimer wel met 350% kan vergroten. Aan het begin van de studie werden bloedwaarden foliumzuur,
vitamine B12 en homocysteïne gemeten. 20% had hoge waarden homocysteïne en lage waarden vitamine B12 en 3,5% had een duidelijk foliumzuurtekort. Hoge waarden foliumzuur waren gerelateerd met hoge waarden vitamine B12 en lage waarden homocysteïne. Na 2 jaar bleken 45 personen dementie te hebben, waarvan 34 de ziekte van Alzheimer en 11 personen een andere vorm van dementie. Zij die in de twee jaar een duidelijke daling van de waarden foliumzuur hadden en een stijging van homocysteïne hadden een veel hogere kans op het krijgen van een vorm van dementie. Zij met de laagste bloedwaarden foliumzuur aan het begin van de studie hadden wel 350% meer kans op het ontstaan van dementie.
Folate Deficiency Is Associated With A Three-Fold Increased Risk Of Dementia
Among elderly people, lower levels of folate can be associated with a three-fold increase in risk for dementia, claims a study published in the Journal of Neurology, Neurosurgery, and Psychiatry, part of the British Medical Journal Specialist Journals.
Folate, vitamin B12, and the protein homocysteine are involved in reactions that are needed to produce several chemicals, including some neurotransmitters, lipids, and nucleotides. Previously, studies have shown a link between deficiencies in these chemicals and the prevalence of dementia, however, the results have been controversial because of the physical changes dementia often creates. High levels of homocysteine have also been associated with cardiovascular
disease.
In this study, the researchers followed 518 people over 2 years (2001-2003), tracking the development of dementia within the population. All participants were more than 65 years old and lived in one rural or one urban area in the south of the country. To do this, at the beginning and the end of the two year period, validated tests were run to test for any dementing illness. Additionally, blood tests were taken to assess folate, vitamin B12
Similarly, blood tests were taken to assess levels of folate, vitamin B12, and homocysteine levels, and the changes with time were observed. At the beginning of the period, almost one in five participants showed high levels of homocysteine, almost the same had low levels of vitamin B12, and 3.5% were deficient in folate. Higher levels of folate were associated with higher vitamin B12 levels and lower
homocysteine.
At the end of the study, 45 of the participants had developed dementia. Of these, 34 had been diagnosed with Alzheimer's disease, seven with vascular dementia, and four with "other" types of dementia. Dementia showed more prevalence in older patients, in the relatively uneducated, the inactive, and those with deposits of the protein
ApoE.
Dementia onset was more likely in those who were older, relatively poorly educated, inactive, and had deposits of ApoE, a protein associated with the breakdown of lipids. It was also much more likely in those whose folate levels fell further over the two years while homocysteine levels increased. Individuals with folate deficiency at the start of the study were at risk for dementia almost 3.5 times more than others.
This suggests, according to the authors, that changes in micronutrients such as folate could be linked with the other typical signs that lead up to dementia, such as weight loss and low blood pressure. Weight loss could indicate a dietary change in quality or quantity of food intake, but it is unlikely to itself change the levels of micronutrients in the blood.
Changes in folate, vitamin B12 and homocysteine associated with incident dementia
J-M Kim, R Stewart, S-W Kim, I-S Shin, S-J Yang, H-Y Shin, J-S Yoon
Journal of Neurology, Neurosurgery, and Psychiatry 2008
doi 10.1136/jnnp.2007.131482 (Maart
2008)
Reacties:
