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SPRING 2016
Despite a small number of subjects, these findings
prompted discussion among divers about the use of
vitamin C to protect them from possible adverse health
effects of diving. Evidence-based justification is not yet
available. It is not known what transitory endothelial
dysfunction means for long-term health or if vitamin C
can provide divers with any measurable health benefits.
Regular intake of vitamin C is necessary for health
maintenance, but the recommended dose is about 100
mg per day, which can be obtained from one orange or
a serving of green vegetables. The dose for treatment of
scurvy is 400 to 1,000 mg per day for one week, and the
maximum recommended dose is 2,000 mg. There is no
evidence that higher doses of vitamin C improve health.
CHOCOLATE
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.
WINE
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
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