Dark Chocolate: It Doesn’t Just Taste Good, It’s Good For Your Diving

Belgians make great chocolate, so it's fitting that a group of Belgian researchers wanted to see if it had a beneficial effect on divers as a pre-dive snack. It's theorized that chocolate benefits cardiovascular health because the cocoa bean is rich in a plant nutrient called flavonoids, which help protect plants from environmental toxins and repair damage. When humans eat flavonoid-rich foods, we also benefit from this "antioxidant" power because it helps the body's cells resist damage caused by free radicals, which are formed by normal body processes (like breathing) and environmental toxins (like cigarette smoke). If your body doesn't have enough oxidants to balance out the free radicals, it can cause plaque to form on the artery walls.

The Belgian researchers were specifically looking at dark chocolate, and its post-dive effect on the endothelium, the inner lining of blood vessels, which helps regulate blood coagulation. The polyphenols in dark chocolate can improve cardiovascular health by stimulating nitric oxide, which stimulates blood dilation, and thus lowers blood pressure. For divers, nitric oxide hinders bubble formation, which means dark chocolate may help with off-gassing and the prevention of decompression sickness.

The researchers divided 42 male scuba divers into a control group and a chocolate group. Each group went down to 108 feet in a diving pool, warmed to 91 degrees, for 20 minutes; 90 minutes before their dive, the chocolate group ate 30 grams of dark chocolate (86 percent cocoa). The control group had a significant decrease in blood-flow dilation after the dive, while the chocolate group had an increase. Nitric oxide levels stayed the same in the control group, while it increased in the chocolate group.

The researchers concluded that eating dark chocolate before the dive prevented post-dive dysfunction of the endothelium because the antioxidants in chocolate probably scavenge free radicals and, therefore, reduce diving-induced oxidative stress. "A small intake of dark chocolate rich in polyphenols as part of nutrition reduces arterial hypertension and promotes nitric oxide formation," they summarized.

For the best dose, they recommend eating 38 to 125 grams of dark chocolate a day, which you can stuff in your carry-on as you head off to your next dive trip.

"The Effect of Pre-Dive Ingestion of Dark Chocolate on Endothelial Function After a Scuba Dive," by S. Theunissen, C. Balestra, A. Boutros, D. De Bels, F. Guerrero and P. Germonpré, Diving and Hyperbaric Medicine, Volume 45, No. 1, pages 4-9.