Antioxidant flavonoids and other chemicals in dark chocolate probably protect against cardiovascular disease such as heart attacks and stroke. But the "dose" is unclear and may be much smaller than you imagine.
Theobroma
cacao, the cocoa tree, has been cultivated in Central and South America for
over 3000 years. Cocoa is derived from
the tree’s seed, also known as the cocoa bean.
"Theobroma cacao" means "food of the gods."
Chocolate is
a product of the processed cocoa bean.
Sweet chocolate is chocolate combined with sugar. Milk chocolate is sweet chocolate combined
with milk powder or condensed milk. Dark
chocolate typically has no added dairy products, has at least 65% cocoa
content, and has much more of the potentially healthy chemicals from the cocoa
bean as compared with milk chocolate.
White chocolate is cocoa butter (aka cacao fat), milk solids, and sugar
without the cocoa solids or mass; in many countries it is not considered
chocolate.
It’s been a
little over 10 years since we first read in a medical journal about cocoa and
chocolate as potential sources of antioxidants for health. What have we learned since then?
Phytochemicals are chemicals produced by plants, and there are
hundreds of thousands of them. Polyphenols are a subset of phytochemicals. Flavonoids, with strong antioxidant properties, are a subset of polyphenols. And a subset of flavonoids, called flavonols, have particularly potent biological effects in humans. Prominent flavonols in dark chocolate are flavan-3-ol, catechin, and epicatechin. Also metabolically active are proanthocyanidins, which are polymeric condensation products of flavan-3-ol.Note that
some chocolate manufacturers process the cocoa beans to remove some of the
polyphenols, which reduces bitterness or pungency.
Other rich
sources of flavonols are wine, tea, and various fruits and berries.
How could dark chocolate, especially its flavonoids, be healthful?
• Flavonoids are antioxidants that protect
from injury caused by free radicals
• Enhanced nitric oxide production, leading
to relaxation of arteries (vasodilation), leading to reduced blood pressure: up
to 6 mmHg systolic and 3 mmHg diastolic
• Elevation of HDL cholesterol, with no
effect on total and LDL cholesterol
• Inhibition of platelet aggregation and
activation, leading to fewer blood clots that cause heart attacks and strokes
• Decreased inflammation
• Reduction of C-reactive protein, a marker
of inflammation
• Decreased neutrophil (white blood cell)
activation. White blood cells play a
role in inflammation
• Decreased LDL cholesterol oxidation,
leading to fewer atherosclerotic complications
• Improved function of the cells that line
blood vessels (endothelium)
• Possible enhanced insulin sensitivity
• May act as anti-carcinogens and
neuro-protective agents
• May act as an antidepressant
Note also
that low-fat natural non-alkalized cocoa powder is also a rich source of
antioxidant flavonoids.
Bottom
line? Dark chocolate, especially because
of flavonoids, may well be protective against cardiovascular disease such as
heart attacks and strokes.
[Did you
notice I’m waffling . . . may be protective.]
What’s in
dark chocolate other than flavonoids?
A 40 gram
serving of a fine dark chocolate bar has:
• Calories: 200
• Calories from fat: 150
• Fiber: 4.5 grams (dark chocolate is a good
source of fiber on a “per calorie” basis)
• Sugar:
11 grams
• Saturated
fats: 10 grams
But aren’t saturated fats bad for me?
The fats in
dark chocolate are 1/3 oleic (healthy monounsaturated, as in olive oil), 1/3
stearic (saturated, but no effect on cholesterol levels, unlike some other
saturated fats), and 1/3 palmitic (saturated, and could increase cholesterol
levels and heart risk). So it’s sort of
a wash.
What’s the healthy “dose” of dark chocolate?
No one is
sure. It’s certainly no more than 100
grams (3.5 ounces) a day, and the optimal dose may be as low as 20 grams every
three days. If you eat too much, it will
make you fat. 100 grams is 500 calories;
that’s way too much for daily consumption.
It would displace other needed nutrients. Even if you start eating 20 grams - 100
calories - every three days, you will gain weight unless you give up some other
food or exercise a little more.
Parker, why are you waffling?
Because no
one has ever done a study to see if adding dark chocolate actually reduces
death rates or sickness from specific diseases in humans. I think it probably does, but who knows for
sure? Nobody. What we need is a randomized, controlled
trial of dark chocolate as a supplement in 10,000 middle-aged adults followed
over the course of 10 years. I’d sign up
for that in a heartbeat. Just don’t give
me the placebo.
