Chocolate is rich in flavonoids, and evidence from observational studies suggests that dietary flavonoids may reduce the risk of death from coronary heart disease, cancer and stroke. Apparently, it was the Aztec Emperor Montezuma II who first noted the effect of chocolate on various symptoms, including fatigue: “A cup of this precious drink [cocoa] permits man to walk for a whole day without food.” So, might high-dose chocolate improve the symptoms of ME/CFS?

In a study published in Nutrition Journal, researchers from Hull York Medical School gave high cocoa liquor/ polyphenol-rich (HCL/PR) chocolate or a sham preparation consisting of cocoa liquor-free/low polyphenol chocolate to ten people with ME/CFS, to test their effects on severe fatigue and disability. Individual 15-g foil wrapped bars (provided by Nestlé, which also did the analysis) were prepared, and participants were asked to consume one bar three times a day.

Using a crossover design, patients received either HCL/PR or sham for eight weeks, followed by a two-week washout period, and then eight weeks of whichever preparation they had not eaten previously. There was a significant improvement in fatigue after eight weeks of taking HCL/ PR chocolate (the fatigue score decreased from 33 to 21.5), while the fatigue score worsened again after taking sham chocolate (from 28.5 to 34.5). The score on the London Handicap scale also improved significantly after taking HCL/PR chocolate (increasing from 0.49 to 0.64), and deteriorated after sham chocolate (decreasing from 0.44 to 0.36). A similar pattern was observed for anxiety and depression, and the average weight of the participants remained unchanged throughout the trial.

The researchers say that the improvement they observed was likely to be due to the high polyphenol content within the active chocolate, and they were surprised at the significance of the results given the small number of trial participants. It would be interesting indeed if the results of this proof-of-concept study could be followed up in a larger independent clinical trial.

Reference: High cocoa polyphenol rich chocolate may reduce the burden of the symptoms in chronic fatigue syndrome. Sathyapalan T et al. Nutr J 2010 Nov 22; 9: 55.