Increasing Muscle Strength and Function in Older Adults with Cocoa Powder

Cocoa is able to extend the average lifespan of the worm C. elegans and improve its age-related decline in neuromuscular function. The two population studies that have looked into chocolate consumption and mortality failed to find a significant protective association in people, but what about the muscle function?

Older men and women suffering from peripheral artery disease were randomized to three tablespoons of cocoa powder a day or placebo for six months before having their walking performance assessed by measuring their six-minute walk distance. Twelve meters is considered a meaningful change by that metric, and 34 meters a large meaningful change. The cocoa group beat out the placebo by about 43 meters.

Was it just from an improvement in circulation? Studies show cocoa can acutely improve artery function. For example, in one famous study, a single 1.5 oz dose of dark chocolate (about a typical small chocolate bar’s worth) improved maximal treadmill walking distance of peripheral artery disease patients by 11 percent within hours after consumption. Milk chocolate didn’t work, suggesting it’s the phytonutrients in the cocoa solids (over 85 percent in the dark chocolate vs. 35 percent or less in the milk chocolate).

This was ascribed to the vasodilating, artery-opening capacity of dark chocolate. However, it may be more than just improved blood flow. In the 6-month study, researchers took biopsies from the calf muscles of study subjects and found improved mitochondrial activity in the muscles of the cocoa powder group compared to placebo. This is consistent with a study in which muscle biopsies from the quads of people before and after three months of dark chocolate and cocoa revealed improved mitochondrial structure. Apparent increases in mitochondrial function, revealed in further muscle biopsies, after a half a dark chocolate bar a day for three months were assumed to be the mechanism by which sedentary subjects around 50 years old improved their aerobic fitness (VO₂max) compared to placebo.

Of course, chocolate is calorie-packed with fat and added sugar, though dark chocolate may be less fattening. Researchers gave people three ounces of dark chocolate, milk chocolate, or white chocolate, and then 90 minutes later assessed their appetite by seeing how much oatmeal they eat. After the dark chocolate, they ate about 100 calories less than after the milk or white chocolate. The researchers emphasize that even as few as 30 extra calories a day on a consistent basis could translate into weight gain over time, but apparently fail to see the folly of eating 500 calories of dark chocolate in order to cut 100 calories later on. The good news is that the benefits appear to stem from the cocoa itself, which is de-fatted and sugar-free.

Unfortunately, the tastiest cocoa doesn’t work as well. Researchers randomized older adults to natural cocoa, highly-Dutched (alkalinized) cocoa, or placebo, and the Dutched cocoa didn’t help any better than placebo. Some of the bitter compounds that are removed in the Dutching process are the flavonoid phytonutrients thought responsible for the beneficial effects. But, older men and women given a tablespoon of natural, unprocessed cocoa a day for twelve weeks experienced a significant improvement in a muscle mass index, grip strength, and all four physical function tests (6-minute walking distance, 2-minute step test, sit-up test, and Up and Go test). And refreshingly, the study was not funded by Hershey, as were most of the others.

In general, less processed is best. The consumption of ultra-processed foods, most significantly sweetened dairy yogurt, was found to be associated with incident frailty in a study of more than a thousand older adults followed for years. Ultra-processed foods are industrial formulations where you typically see those long lists of ingredients, which, besides salt, sugar and fat, are typically not something you’d find in any cookbook, like various flavors, colors, sweeteners, emulsifiers, and other additives used to imitate real foods or to disguise undesirable qualities of the final product. Shockingly, in the U.S. and around the world in higher-income countries, ultra-processed foods consistently account for more than half of our dietary caloric intake. More than 50 percent of our diets are junk. Not surprisingly, ultra-processed foods are also associated with higher obesity rates, as well as a greater risk of dying earlier from all causes of death combined.