Dark chocolate acutely improves walking autonomy in patients with peripheral artery disease

Background-nox-2,the catalytic subunit of nadph oxidase,has a key role in the formation of reactive oxidant species and is implicated in impairing flow-mediated dilation (fmd). dark chocolate exerts artery dilatation via down-regulating nox2-mediated oxidative stress. the aim of this study was to investigate whether dark chocolate improves walking autonomy in peripheral artery disease (pad) patients via an oxidative stress-mediated mechanism. methods and results-fmd,serum levels of isoprostanes,nitrite/nitrate (nox) and snox2-dp,a marker of blood nox2 activity,maximal walking distance (mwd) and maximal walking time (mwt) were studied in 20 pad patients (14 males and 6 females,mean age: 69±9 years) randomly allocated to 40 g of dark chocolate (>85% cocoa) or 40 g of milk chocolate (≤35% cocoa) in a single blind,cross-over design. the above variables were assessed at baseline and 2 hours after chocolate ingestion. dark chocolate intake significantly increased mwd (+11%; p<0.001),mwt (+15%; p<0.001),serum nox (+57%; p<0.001) and decreased serum isoprostanes (-23%; p=0.01) and snox2-dp (-37%; p<0.001); no changes of the above variables were observed after milk chocolate intake. serum epicatechin and its methylated metabolite significantly increased only after dark chocolate ingestion. multiple linear regression analysis showed that δ of mwd was independently associated with δ of mwt (p<0.001) and δ of nox (p=0.018). in vitro study demonstrated that huvec incubated with a mixture of polyphenols significantly increased nitric oxide (p<0.001) and decreased e-selectin (p<0.001) and vcam1 (p<0.001). conclusion-in pad patients dark but not milk chocolate acutely improves walking autonomy with a mechanism possibly related to an oxidative stress-mediated mechanism involving nox2 regulation. © 2014 the authors.