Effects of dark chocolate consumption on the prothrombotic response to acute psychosocial stress in healthy men

Abstract

Flavanoid-rich dark chocolate consumption benefits cardiovascular health, but underlying mechanisms are elusive. We investigated the acute effect of dark chocolate on the reactivity of prothrombotic measures to psychosocial stress. Healthy men aged 20-50 years (mean ± SD: 35.7 ± 8.8) were assigned to a single serving of either 50 g of flavonoid-rich dark chocolate (n=31) or 50 g of optically identical flavonoid-free placebo chocolate (n=34). Two hours after chocolate consumption, both groups underwent an acute standardised psychosocial stress task combining public speaking and mental arithmetic. We determined plasma levels of four stress-responsive prothrombotic measures (i. e., fibrinogen, clotting factor VIII activity, von Willebrand Factor antigen, fibrin D-dimer) prior to chocolate consumption, immediately before and after stress, and at 10 minutes and 20 minutes after stress cessation. We also measured the flavonoid epicatechin, and the catecholamines epinephrine and norepinephrine in plasma. The dark chocolate group showed a significantly attenuated stress reactivity of the hypercoagulability marker D-dimer (F=3.87, p=0.017) relative to the placebo chocolate group. Moreover, the blunted D-dimer stress reactivity related to higher plasma levels of the flavonoid epicatechin assessed before stress (F=3.32, p = 0.031) but not to stress-induced changes in catecholamines (p's=0.35). There were no significant group differences in the other coagulation measures (p's≥0.87). Adjustments for covariates did not alter these findings. In conclusion, our findings indicate that a single consumption of flavonoid-rich dark chocolate blunted the acute prothrombotic response to psychosocial stress, thereby perhaps mitigating the risk of acute coronary syndromes triggered by emotional stress.

Acute mental stress and hemostasis: When physiology becomes vascular harm

“…[2] for data from randomized placebo-controlled drug trials). Likewise, dietary flavanoids from black tea (catechin) consumed over six weeks and from a single intake of 50g of dark chocolate with 72% cocoa content (epicatechin) significantly attenuated acute stress-induced platelet activation and D-dimer formation, respectively, compared with placebo [33,34]. …”

Mechanisms Modified by (−)-Epicatechin and Taxifolin Relevant for the Treatment of Hypertension and Viral Infection: Knowledge from Preclinical Studies

“…Similarly, 1 mg/kg EC failed to alter plasma noradrenaline and adrenaline levels 2 h postingestion in mice [149]. These results were obtained in normotensive mice, but EC may be able to lower the plasma catecholamines level when it is elevated, as, for example, in hypertension, because a stress-induced increase in catecholamines was prevented after ingestion of dark chocolate in a clinical trial [150].…”

Circulating neurotrophins and hemostatic risk factors of atherothrombotic cardiovascular disease at baseline and during sympathetic challenge: the SABPA study

“…Explanations similar to those for the fibrinogen results could explain the lack of a stress-induced increase in D-dimer levels, including a minor plasma volume shift 45 with a one-minute stress task, and the characteristics of the stress task. D-dimer increase has particularly been shown in studies applying speech stressors 46,48 , but not for instance when combing the Stroop with mental arithmetic 49 . The varying sensitivity of the different D-dimer assays used in previous stress studies may be another explanation for heterogeneous study results.…”

“…www.nature.com/scientificreports/ mechanism that may underlie an increase in the plasma fibrinogen concentration during acute mental stress 45 . Another explanation could be that speech stress, conferring social evaluative threat 46 , or the combination of the Stroop with another stress like mental arithmetic 31 have greater potency in provoking significant fibrinogen responses than the Stroop alone 47 . A circadian decrease during the morning hours might also explain reduced fibrinogen concentration, although this effect should be minimal within an 11-min period between baseline and stress sampling of fibrinogen measures.…”