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

J Am Heart Assoc. 2014 Jul 2;3(4):e001072. doi: 10.1161/JAHA.114.001072.


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.

Clinical trial registration url: http://www.clinicaltrials.gov. Unique identifier: NCT01947712.

Keywords: antioxidant; atherosclerosis; chocolate; oxidant stress; peripheral vascular disease.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antioxidants
  • Cacao*
  • Candy*
  • Catechin / blood
  • Cross-Over Studies
  • Exercise Test
  • Exercise Tolerance*
  • Female
  • Humans
  • Isoprostanes / blood
  • Male
  • Membrane Glycoproteins / blood
  • Middle Aged
  • NADPH Oxidase 2
  • NADPH Oxidases / blood
  • Nitrates / blood
  • Nitrites / blood
  • Oxidative Stress
  • Peripheral Arterial Disease / blood
  • Peripheral Arterial Disease / diet therapy*
  • Peripheral Arterial Disease / physiopathology
  • Single-Blind Method
  • Vasodilation
  • Walking*


  • Antioxidants
  • Isoprostanes
  • Membrane Glycoproteins
  • Nitrates
  • Nitrites
  • Catechin
  • CYBB protein, human
  • NADPH Oxidase 2
  • NADPH Oxidases

Associated data

  • ClinicalTrials.gov/NCT01947712