Do you like to run, cycle, or work out with vigor?
The results of a small trial suggest that cocoa or extra-dark chocolate can reduce destructive, exercise-induced “oxidative stress”.
Compared with a control group, volunteers who ate a full bar of dark chocolate before cycling had lower levels of a marker for oxidative damage … and maintained steadier blood sugar levels.
As study co-author Glen Davison said, “We believe that the small effects observed here could be physiologically important.”
The results add to substantial prior evidence that cocoa's potent polyphenols bear anti-aging benefits.
You wouldn't want to frequently eat a full bar of chocolate … which would mean eating too much sugar and calories in order to get the cocoa polyphenols that produce these effects.
But these results suggest that smaller amounts of dark chocolate can significantly deter exercise-induced cell damage … with the benefits likely tied to cocoa content.
Of course, you can get as much or more cocoa polyphenol content from smaller amounts of non-Dutched (non-alkalized) cocoa powder – dissolved in water, milk, or low-fat yogurt smoothies – or the cocoa bean kernels called “nibs”.
Cocoa polyphenols act on genes that curb oxidative stress and inflammation
People naturally produce reactive oxygen species – better known as free radicals – to perform a range of essential functions … including the so-called “cell signaling” that triggers or resolves inflammation and other basic physiological functions.
However, overproduction of free radicals from smoking, pollution, sunlight, high-intensity exercise, or natural aging can overwhelm the body's own antioxidant defenses and lead to oxidative stress.
Oxidative stress is linked to increased risk of major degenerative disorders including cancer, Alzheimer's, and cardiovascular disease.
Based on growing evidence, the potential health benefits of polyphenols from cocoa include enhanced cardiovascular health, skin health, and brain health.
The potential benefits of cocoa clearly stem from its extremely high polyphenol content, which features unrivalled levels of tea-type catechins and berry/grape-like procyanidins.
Pilot trial supports health promise of cocoa polyphenols
The authors of the Nestle-funded study included scientists from three universities in the UK, and the Nestle Research Center in Switzerland (Davison G et al. 2011).
The researchers recruited 14 healthy men, who were assigned to consume 100 grams of dark chocolate (Nestlé Noir 70 percent), a cocoa-free sports bar, or nothing.
Two hours later, they cycled on a stationary bike for 2.5 hours … vigorously, at 60 percent of maximal oxygen uptake level.
Compared with the control group, the dark chocolate group showed an increase in their bodies' antioxidant status before the cycling began, and reduced levels of a marker for oxidative stress (F2-isoprostane) – one hour after they'd stopped.
In addition, the dark chocolate group had higher blood insulin levels before and after cycling … and this was associated with steadier blood sugar levels.
However, the chocolate group showed no advantages in terms of blood levels of stress hormones or markers for inflammation – levels of which are normally raised by vigorous exercise.
Significantly, as the researchers wrote in reference to another study they conducted (Allgrove J et al. 2011), “These results with acute dark chocolate consumption are similar to those observed following 2 weeks of daily dark chocolate ingestion.” (Davison G et al. 2011)
In other words, the benefits seen in the small study were immediate.
Allgrove J, Farrell E, Gleeson M, Williamson G, Cooper K. Regular dark chocolate consumption's reduction of oxidative stress and increase of free-fatty-acid mobilization in response to prolonged cycling. Int J Sport Nutr Exerc Metab. 2011 Apr;21(2):113-23.
Davison G, Davison G, Callister R, Williamson G, Cooper KA, Gleeson M. The effect of acute pre-exercise dark chocolate consumption on plasma antioxidant status, oxidative stress and immunoendocrine responses to prolonged exercise. Eur J Nutr. 2011 Apr 5. [Epub ahead of print]