Acute caffeine intake ‘improves endothelial function’
MedWire News: Acute caffeine intake improves endothelial function and reduces plasma markers of inflammation in people with and without coronary artery disease (CAD), Israeli researchers report.
Michael Shechter (Tel Aviv University) and team evaluated the impact of caffeine on the cardiovascular system among 40 people with stable documented CAD and 40 healthy controls matched for age and gender.
After an overnight fast and a 2-day abstinence from caffeine, participants took a capsule containing either caffeine 200 mg or placebo. One hour later they were assessed using high-resolution ultrasound for brachial artery flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NFM).
At baseline, FMD was significantly lower in CAD patients versus controls (5.6% vs 8.4%) whereas NFM was not significantly different (13.0% vs 12.9%), write the authors in the American Journal of Cardiology.
After caffeine ingestion, FMD rose significantly in both CAD patients (from 5.6% to 14.6%) and in controls (from 8.4% to 18.6%); the magnitude of increase was significantly greater in CAD patients than in controls.
NFM rose only marginally, by ≤1% in both groups, following caffeine ingestion.
Caffeine ingestion was also associated with a significant reduction in high-sensitivity C-reactive protein in CAD patients (from 2.6 to 1.4 mg/l) and controls (from 3.4 to 1.2 mg/l).
Finally, caffeine induced a rise in adiponectin levels in patients with CAD (from 7.4 to 13.6 mg/dl) but not in controls.
Shechter et al remark: "Acute caffeine ingestion significantly improved endothelial function assessed by brachial artery FMD in subjects with and without CAD and was associated with lower plasma markers of inflammation."
However, they admit that their study does not resolve the controversy regarding the long-term impact of caffeine on vascular reactivity, and add: "Only a large-scale crossover study comparing the effects of coffee (boiled and filtered, caffeinated and decaffeinated) and caffeine on vascular reactivity may solve this issue."
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By Joanna Lyford