A study published in the Journal of the American Heart Association by Loffrendo et al. attributed the effect to dark chocolate’s high polyphenol content.
Peripheral arterial disease is when plaque builds up in arteries carrying blood to the head, organs and limbs. It commonly occurs in the legs, causing pain and hampering walking ability. Over 20% of adults over 70 are affected by the disease.
Walking improvement
Under the study, 20 peripheral artery disease patients with a mean age of 69 were assigned either a 40 g of milk chocolate (35% cocoa) or dark chocolate (85% cocoa).
The patients’ max walking distance and walking time was assessed by a tread mill test before and after eating the chocolate. Researchers also measured flow‐mediated dilation and blood activity.
Milk chocolate ineffective
“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 (nitrogen oxide) regulation.”
“The different effect of dark and milk chocolate on walking autonomy supports the hypothesis that polyphenol content may be responsible for this effect, because dark chocolate is richer in polyphenol compared to milk chocolate.”
Polyphenol levels
The researchers found a total of 799 mg/L of polyphenols in dark chocolate compared to 296 mg/L in milks chocolate. Epicatchein levels were found to be around three times greater in dark chocolate.
The researchers found that the concentration of polyphenols in dark chocolate was relatively similar to that found the patients’ blood after dark chocolate ingestion.
Source:
J Am Heart Assoc. 2014; 3: e001072
‘Dark Chocolate Acutely Improves Walking Autonomy in Patients With Peripheral Artery Disease’
Authors: Loffrendo et al.