Koffie en de ziekte van Alzheimer*
Uit een kleine Amerikaanse studie blijkt dat het drinken van koffie de ziekte van Alzheimer kan voorkomen en vertragen. De deelnemers aan de studie waren 124 mensen in de leeftijd van 65-88 jaar, allen met een milde vorm van cognitieve achteruitgang. Deze aandoening is vaak een voorbode van de ziekte van Alzheimer. De mensen met aan het begin van de studie de laagste bloedwaarden aan cafeďne bleken binnen 2 tot 4 jaar duidelijk meer kans te hebben op het krijgen van de ziekte van Alzheimer dan de mensen met de hoogste bloedwaarden aan cafeďne. Zij met een bloedwaarden cafeďne van 1.200 ng/ml of hoger bleken niet de ziekte van Alzheimer te krijgen. Deze bloedwaarden worden doorgaans bereikt door het drinken van 2-3 koppen koffie per dag.
High Blood Caffeine Levels in MCI Linked to Lack of Progression to Dementia
Abstract.
Although both human epidemiologic and animal model studies have suggested that caffeine/coffee protects against
Alzheimer’s disease, direct human evidence for this premise has been lacking. In the present case-control study, two separate
cohorts consisting of 124 total individuals (65–88 years old) were cognitively assessed and a blood sample taken for caffeine/
biomarker analysis. Subjects were then monitored for cognitive status over the ensuing 2–4 year period to determine the
extent to which initial plasma caffeine/biomarkers levels would be predictive of changes in cognitive status. Plasma caffeine
levels at study onset were substantially lower (−51%) in mild cognitive impairment (MCI) subjects who later progressed to
dementia (MCI→DEM) compared to levels in stable MCI subjects (MCI→MCI). Moreover, none of the MCI→DEM subjects
had initial blood caffeine levels that were above a critical level of 1200 ng/ml, while half of stable MCI→MCI subjects had blood
caffeine levels higher than that critical level. Thus, plasma caffeine levels greater than 1200 ng/ml (≈6M) in MCI subjects were
associated with no conversion to dementia during the ensuing 2–4 year follow-up period. Among the 11 cytokines measured in
plasma, three of them (GCSF, IL-10, and IL-6) were decreased in MCI→DEM subjects, but not in stable MCI→MCI subjects
with high plasma caffeine levels. Coffee would appear to be the major or perhaps only source of caffeine for such stable MCI
patients. This case-control study provides the first direct evidence that caffeine/coffee intake is associated with a reduced risk
of dementia or delayed onset, particularly for those who already have MCI.
De
volledige studie.
(Juni 2012)
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