Coffee and endothelial function: a battle between caffeine and antioxidants?

Abstract

Although coffee is largely consumed by adults in Western countries, controversy exists about its impact on the cardiovascular system. We recently demonstrated that caffeinated and decaffeinated espresso coffee have different acute effects on endothelial function in healthy subjects, measured using flow-mediated dilation (FMD) of the brachial artery. In this study, we measured the anti-oxidant capacity of two coffee substances in terms of free stable radical 2,2-diphenyl-1-picryl-hydrazyl 50% inhibition (I 50 DPPH). The caffeinated coffee had a slightly higher anti-oxidant capacity than decaffeinated espresso coffee (I 50 DPPH: 1.13±0.02 vs 1.30±0.03 ml; Po0.001). We suggest that the unfavourable effects observed after caffeinated coffee ingestion are due to caffeine and that the antioxidant activity is responsible for the increased FMD observed after decaffeinated coffee ingestion. Further clinical and epidemiological studies are needed to understand the chronic effects of coffee consumption on health.

Coffee polyphenol consumption improves postprandial hyperglycemia associated with impaired vascular endothelial function in healthy male adults

“…According to studies by Buscemi et al [26] and Shechter et al [27], the effect of caffeine (200 and 130 mg, respectively) on FMD is controversial. Accumulated evidence indicates caffeine intake (200 mg or more) increases blood glucose in humans [28,29].…”

Coffee consumption and risk of the metabolic syndrome: A meta-analysis

“…Previous studies suggested that its healthy effects in chronic diseases might depend on the antioxidant compounds contained in coffee, including vitamin E, niacin, potassium and magnesium [18]. The beneficial effects of coffee polyphenols in preventing chronic diseases could be due to their ability to improve endothelial function [40] and to suppress vascular endothelial cell expression of proinflammatory cytokines [41], with the consequent upregulation of adhesion molecules and monocyte adhesion [42]. It might also be due to the anti-inflammatory effects of coffee diterpenes [43,44], although these compounds are thought to be removed by coffee paper filters.…”

“…As between-study heterogeneity is commonly seen in metaanalyses [41], exploring the potential source(s) of heterogeneity is necessary.…”

Effects of red orange juice intake on endothelial function and inflammatory markers in adult subjects with increased cardiovascular risk

“…The total antocyanin content was measured by using the spectrophotometric method as reported by Rapisarda et al (18); cyanidin 3-glucoside (Extrasynthese) was used as a standard to construct a calibration curve. The radical scavenging activity of blood orange juice was measured by using a spectrophotometric method and the free stable radical 2,2-diphenyl-1-picryl-hydrazyl according to the method proposed by Brand-Williams et al (19) with minor modifications as described elsewhere (20). The total content of the polyphenolic compound was measured by using the spectrophotometric method described by Asami et al (21); gallic acid (Fluka) was used as a standard to construct a calibration curve.…”