http://www.newscientist.com/news/news.jsp?id=ns99994101
Dark chocolate boosts antioxidant levels
18:45 27 August 03
NewScientist.com news service
Eating chocolate can boost the level of heart-protecting antioxidants
in the blood, but consuming milk at the same time cancels the
potential health benefits, according to a new study.
The researchers speculate that milk may also have the same effect on
other antioxidant-rich foods, including fruit and green vegetables.
Researchers in Scotland and Italy looked at the body's absorption of
an antioxidant found in cocoa, called epicatechin, and a type of
flavonoid.
Dark chocolate contains about twice the amount of flavonoids as milk
chocolate, so 12 healthy volunteers were given either 100 grams of
plain chocolate or 200 grams of milk chocolate. Some were also given
200 ml of milk to drink in the double-blind experiment. The levels of
antioxidant in their blood plasma were tested after one, two and four
hours.
"Those volunteers who had dark chocolate had a 20 per cent increase in
antioxidants in their plasma," says Alan Crozier, one of the team at
the University of Glasgow. "But those who had milk chocolate, or milk
with their dark chocolate, showed no increase in epicatechin plasma
levels."
Four hours after eating the chocolate, all the volunteers' blood
antioxidant levels had returned to normal. To gain the maximum
potential benefits from chocolate, Crozier suggests it may be
advisable to refrain from milk products during that period.
"Presumably the epicatechins are binding to the milk proteins," he
told New Scientist. "Dairy products may inhibit the body's absorption
of flavonoids from other foods as well."
Antioxidants are involved in lowering the levels of free-radicals in
the blood. Prolonged and high-level exposure to free radical has been
linked to cardiovascular disease and some cancers.
Journal reference: Nature (vol 424, p 1013)
Gaia Vince