Dark chocolate consumption buffers intracellular pro-inflammatory reactivity to acute psychosocial stress in healthy men

Abstract

Flavanoid-rich dark chocolate consumption has beneficial effects on cardiovascular health, but underlying mechanisms are elusive. We investigated the effect of acute dark chocolate consumption on inflammatory measures before and after stress. Healthy men aged 20–50 years were randomly assigned to a single intake of either 50 g of flavonoid-rich dark chocolate (n = 31) or 50 g of optical identical flavonoid-free placebo chocolate (n = 34). Two hours after chocolate intake, both groups underwent the Trier Social Stress-Test. We measured DNA binding activity of the pro-inflammatory transcription factor NF-kappaB (NF-kappaB-BA) in peripheral blood mononuclear cells, and plasma and whole blood mRNA levels of the pro-inflammatory cytokines IL-1beta and IL-6, and the anti-inflammatory cytokine IL-10 prior to chocolate intake, before and several times after stress cessation. We also repeatedly measured the flavonoid epicatechin. Compared to the placebo chocolate group, the dark chocolate group revealed a marginal increase in IL-10 mRNA prior to stress (p = .065), and a significantly blunted stress reactivity of NF-kappaB-BA, IL-1beta mRNA, and IL-6 mRNA ( p ′ s . 037 ) with higher epicatechin levels relating to lower pro-inflammatory stress reactivity ( p ′ s . 034 ). None of the other measures showed a significant chocolate effect ( p ′ s > . 18 ). Our findings indicate that acute flavonoid-rich dark chocolate exerts anti-inflammatory effects both by increasing mRNA expression of the anti-inflammatory cytokine IL-10 and by attenuating the intracellular pro-inflammatory stress response. This mechanism may add to beneficial effects of dark chocolate on cardiovascular health.