Divers often ask about the possible benefits and adverse effects of supplements, used for either general wellness or protection from certain diving injuries. Dietary supplements are clearly helpful to people with a chronic deficit of specific nutrients such as vitamin C (scurvy) or vitamin D (rickets), but effects of supplements in healthy people who eat a balanced diet are less obvious.
We prepared a short list of food supplements that may benefit you as a diver.
Antioxidants include vitamins such as vitamin A and vitamin C as well as minerals such as selenium, plant products such as flavonoids and animal products such as melatonin and omega-3 fatty acids. Antioxidants are used in attempts to control oxidative stress and prevent related diseases. The big three are vitamin E, vitamin C and glutathione. Numerous other small molecules — including polyphenols, carotenoids, bilirubin and uric acid — function as antioxidants. These are contained in foods and drinks including meat, citrus, chocolate, tea and wine.
Vitamin C enhances wound healing. Animal studies have shown that vitamin C can prevent vasoconstriction of coronary arteries caused by hyperoxia. In human studies, vitamin C blocked hyperoxic vasoconstriction and maintained forearm bloodflow. Researchers studied possible protective effects of vitamin C and vitamin E in healthy divers. Divers who received a single dose of 2,000 mg of vitamin C and 400 IU of vitamin E two hours prior to diving had normal endothelial function, and those who received a placebo exhibited endothelial dysfunction. In another study, divers who received 1,000 mg of vitamin C and 400 IU of vitamin E daily for four weeks showed attenuated postdive decrease in FMD. In the same studies, vitamins prevented changes in other measurements of cardiovascular function that seem to occur regularly in diving.
Cocoa contains polyphenols, flavonoid compounds with antioxidant effects, blood-thinning properties and possibly other beneficial effects. The mechanisms involved in these effects include reduction of oxidative stress and increased production of endothelial NO, which supports normal endothelium-dependent vasodilation. This reportedly both lowers blood pressure and reduces risk of heart disease. The majority of studies claiming benefits of chocolate are small-scale studies sponsored or even conducted by chocolate manufacturers.
Benefits of chocolate have been tested in both breath-hold and scuba divers. The scuba dive study was conducted in 91°F water at 108 feet (33 msw) for 20 minutes with no decompression stop. Twenty-one divers ate 30g of dark chocolate (85 percent cocoa) 90 minutes before the dive, while 21 divers in the control group did not have chocolate. The breath-hold study had 10 divers in the chocolate group and 10 in the control group. Both studies found that dark chocolate reduced endothelial dysfunction. Further studies conducted by the same authors found that eating chocolate had no effect on the amount of postdive venous gas bubbles.
In vitro studies of resveratrol, a compound found in wine, showed antioxidant and other effects that may provide protection against aging, various diseases and death. Further animal studies appeared to confirm the beneficial effects.
Among the benefits were effects on skeletal and cardiac muscle functions similar to the effects of endurance exercise training. It was also claimed that resveratrol improves perfusion of the brain and provides neuroprotection, both of which may be helpful in reducing the risk of decompression sickness (DCS).
Because resveratrol is suspected to prevent endothelial cell dysfunction and platelet aggregation, some scientists assumed it may help prevent DCS. Recent resveratrol studies claimed several additional health benefits that could be appealing to divers, but the amount of resveratrol used in these studies would require drinking 50 to 3,000 liters of wine per day. In studies of whole wine, benefits could not be determined in light of the confounding effects of alcohol consumption.
Credits: This article is lifted from alertdiver.com where it was originally posted.