chocolate-the-new-health-food-or-is-it.pdf

here is a word for you: “chocoholic,”

when you need chocolate. Nothing

else will do. Just thinking about hot

fudge drizzling over ice cream raises

your spirits. You crave a truffle, a Kit-Kat, a

mug of velvety hot cocoa. Few, if any, other

foods evoke such passion.

So what is unique about chocolate? Recent

scientific findings are providing new evidence

that chocolate may be healthier than is usually

assumed.

So many good

chemicals …

One of the reasons chocolate is unique is

the temperature at which it melts: between

94 °F and 97 °F. A morsel of chocolate slides

across your tongue and liquefies into a perfect

puddle of taste sensation. The human body, at

98.6 °F is just above the chocolate’s melting

temperature. “Melts in your mouth”? Defi-

nitely true.

Chocolate contains more than 300

chemicals. Caffeine, a stimulant, is the most

well known, but it is present only in small

amounts. Another stimulant is theobromine,

found in amounts slightly higher than caffeine.

The two molecules are identical except for one

methyl group (CH

), but it is not yet clear how

they act together in chocolate.

Another chemical known to make us

happy when we eat chocolate is anan-

damide, so named because it means

“bliss” in Sanskrit. Not only is it pres-

ent in chocolate, but it is also produced

by the brain and blocks out pain and

depression.

But when anandamide is produced

by the brain, it is broken down

quickly, so its effects don’t last.

Emmanuelle diTomaso, an assistant

biologist at Massachusetts

General Hospital,

Boston, Mass., and Daniele

Piomelli, professor of phar-

macology at the

University of

California-Irvine,

have shown that

chemicals in

chocolate may inhibit

this natural breakdown

of anandamide. This

means that when

you eat choco-

late, anandamide

molecules from

chocolate stay in

the body longer.

MIKE CIESIELSKI

ALL STRUCURES: CESAR CAMINERO

ChemMatters, APRIL 2009 13

Caffeine

Caffeine molecule

Theobromine

Theobromine molecule

Anandamide

Anandamide molecule

Phenylethylamine

Phenylethylamine molecule

MIKE CIESIELSKI

Then, there is phenylethylamine (PEA), a

natural brain chemical which stimulates the

parts of the brain that keep you alert and mim-

ics the brain chemistry of a person in love.

Is chocolate

healthy?

Recent studies have explored chemicals in

chocolate called polyphenols, which belong

to a larger group of chemicals called antioxi-

dants. These chemicals protect cells against

damage from free radicals—atoms, mol-

ecules, or ions with unpaired electrons.

Inside cells, free radicals damage DNA

and have been associated with Alzheimer’s

disease, heart disease, and cancer. Antioxi-

dants prevent this damage from happening by

blocking the action of free radicals and may

therefore reduce the risk of being affected by

these diseases.

Antioxidants work by slowing or preventing

a chemical reaction called oxidation, which

can produce free radicals. Antioxidants termi-

nate this reaction by preventing free radicals

from being formed. Examples of antioxidants

include thiols, which are organic compounds

that contain a functional group composed of

a sulfur atom and a hydrogen atom (-SH) and

polyphenols, which are organic compounds

that contain OH groups attached to six-mem-

bered benzene rings.

The health benefits of some polyphenols—

such as quercetin, which is found in citrus

fruit, buckwheat, and onions—are well estab-

lished, while other polyphenols’ health effects

are still being investigated. The largest and

best studied group of polyphenols are the

flavonoids, a group of several thousand com-

pounds present in various fruits, vegetables,

and chocolate.

Joe Vinson, professor

of chemistry at the Uni-

versity of Scranton, Pa.,

and his research students

have found that polyphe-

nols in chocolate have

beneficial effects against heart disease. The

scientists showed that cocoa polyphenols

acted as antioxidants in the body, compared

with coconut butter and sugar alone. Also,

the scientists discovered that in hamsters,

cocoa powder at a dose equivalent to two

dark chocolate bars per day significantly

inhibited atherosclerosis, a type of heart

disease in which fat clogs up arteries, and

raised the levels of good cholesterol.

Cocoa is especially rich in chemicals called

flavanols, which are flavonoids also found in

tea, wine, and nuts. Ian Mcdonald, professor

of metabolic physiology at The University

of Nottingham, and colleagues have shown

that people who consumed a flavanol-rich

cocoa beverage had increased blood flow in

their brains. This result suggests that cocoa

flavanols could be used to prevent vascular

impairments in the brain resulting from, say,

a stroke.

Norman Hollenberg, professor of medicine

at the Harvard Medical School and

Brigham and Women’s Hospital,

and colleagues have observed that

the consumption of a flavanol-rich

cocoa beverage also increases the

amount of nitric oxide in the blood

vessels, allowing them to dilate and

stay pliable. This result suggests that

cocoa flavanols could also be used

to improve heart health.

Also, Juan Carlos

Espin de Gea, a senior

research scientist at

the Spanish Research

Council in Murcia,

Spain, and colleagues

are working on pro-

cessing the cocoa

beans differently to

include the flavonoids

usually lost in the processing of the

beans. They asked six volunteers to

consume a milk beverage made with

flavonoid-enriched cocoa and later

to drink chocolate milk made from

traditional cocoa. When they drank

the flavonoid-enriched cocoa, these

volunteers had eight times more of

antioxidants epicatechin and procyanidin B2

than when they drank regular chocolate milk.

Another piece of good news: You might

think that chocolate causes acne, decays

teeth, and makes you fat. Not so. No cur-

rent research connects specific foods to skin

problems. Chocolate husks contain chemicals

that prevent tooth decay (although they don’t

offset the added sugar), and too much food

causes weight gain.

But how about all this saturated fat, usually

blamed for the ills of chocolate? Let’s look

at how chocolate is made to understand why

chocolate is not totally healthy.

How chocolate

is made

The cacao beans used to make chocolate

come from a tree called Theobroma cacao

(food of the Gods) that is cultivated in the

tropics. Tiny flies called midges pollinate the

ALL STRUCTURES: CESAR CAMINERO

14 ChemMatters, APRIL 2009

www.acs.org/chemmatters

Examples of polyphenols: phenol (a); pyrocatechol (b); phloroglucinol (c);

hydroquinone (d)

(a) (b) (c) (d)

Examples of flavanols: epicatechin (a) and epigallocatechin (b).

Examples of flavanols: epicatechin (a) and epigallocatechin (b)

(a)

(b)

Production of Chocolate

Phenol (a) and three examples of phenol derivatives: pyrogallol

(b), phloroglucinol (c), and hydroquinone (d). These molecules

are components of large molecules called polyphenols.

Cocoa beans are harvested Cocoa beans are fermented

and dried

Chocolate liquor is pressed,

creating cocoa butter

Beans are ground, leading

to a “chocolate liquor”

Chocolate liquor is pressed

and ground, creating cocoa

powder *

Products:

* baking chocolate and

liquid chocolate

** chocolate-coated

products

*** plain or milk chocolate

trees, and each pod contains 20 to 60 seeds

in a sweet pulp. The pods are removed from

the tree, split with a machete, and the pulp

and beans are removed and fermented under

banana leaves in the sun.

Then, the sugary pulp breaks down, heat-

ing the beans. Many chemical changes take

place, affecting flavor, aroma, and color. The

rich cocoa aromas develop, and the beans

change from purple to chocolate brown. After

fermentation, the beans are dried on

bamboo mats or wooden floors.

These dried beans are

shipped to the manufacturing

plants, where they are cleaned,

sorted, and roasted. This

roasting loosens

the bean shells so

they can be easily

removed. What is left

are dark chips called

nibs, which are crushed

to form a liquid paste called chocolate liquor.

To make dark, semisweet, and bittersweet

chocolates, nibs and sugar (and sometimes

additional cocoa butter) are mixed together

for up to 72 hours to further smooth and

blend all particles, creating creamy chocolate.

So here’s the bad news: Cocoa butter is

essentially all fat. There are three major kinds: a

“bad-for-you” saturated fat called palmitic acid;

oleic acid, a heart-healthy monounsaturated fat;

and stearic acid, part of which later converts

to oleic acid in the liver. Overall, one-third of

chocolate’s fat is known to be unhealthy. All

three kinds of fats produce high amounts of

calories in the body, although they do not cause

an increase in blood cholesterol when

consumed in chocolate.

Here’s the good news: Choco-

late straight from the tree has

more beneficial chemicals than

possibly any other food, including

blueberries, red wine, or green tea.

They are not only antioxidant, but

anti-inflammatory, anti-allergic,

anti-cancerous, and anti-viral.

So why is chocolate often rated

junk? It’s all in the processing.

Processing determines whether

chocolate is a healthy food or a

high-calorie indulgence. Roasting

and fermenting tends to decrease

the amount of antioxidants. Food

stores sell mainly milk chocolate,

with sugar, milk, and extra

cocoa butter added

because they taste

good, but the more

noncocoa items are

added to cocoa, the

more dilute the healthy

chemicals become.

Making

healthier

versions

of chocolate

W. Jeffrey Hurst, principal

scientist at Hershey Co., Hershey,

Penn., and colleagues have com-

pared the amount of antioxidants

in cocoa-containing products.

The products they considered

were natural cocoa, unsweetened

baking chocolate, dark chocolate,

semisweet baking chips, milk

chocolate, and chocolate syrup. They dis-

covered that natural cocoa contains the most

antioxidants, followed by baking chocolates,

dark chocolates, baking chips, and finally

milk chocolate and syrups, when compared

on an equal weight basis. So if you want to

consume a lot of chocolate, you may be better

off choosing natural cocoa or dark chocolate

rather than milk chocolate or chocolate syrup.

Over the past two decades, various candy

makers—including The Hershey Co. and

Mars, Inc.—have been trying to use this sci-

entific knowledge by making chocolate-based

candies that are high in antioxidants and fla-

vanols. The most recent trend is “premium”

chocolate, often made of top-quality beans

with high cacao content, no milk, and fewer

additives.

Scientists may even be able to modify the

genes of the cocoa tree in the future. Last

June, Mars, Inc., partnered with IBM and the

U.S. Department of Agriculture to launch a

five-year project to unravel the genome of the

cocoa bean. The team of scientists from these

three institutions may find ways to make the

cocoa tree more resistant to pests and disease

and provide healthier, more nutritious, and

better-tasting chocolate.

Want the most for your calories? And your

dollars? Check out the nutrition information

on the labels. The fewer additives, the better.

Meanwhile, dark chocolate or chocolate nibs

are a healthy alternative to milk chocolate or

chocolate syrup.

So, is chocolate a healthy food, a

luxury item, or junk? It can be all three,

just not all at the same time. The

choice is yours. Go easy! Go dark!

Go chocolate!

ANTHONY FERNANDEZ

ChemMatters, APRIL 2009 15

SELEcTED REfERENcES

Beckett, S. P. The Science of Chocolate,

2nd ed; The Royal Society of Chemistry:

Cambridge, UK, 2008.

American Chemical Society: The Elements of

Chocolate

http://acselementsofchocolate.typepad.

com/elements_of_chocolate/ [February

2009].

The Exploratorium, Science Museum in San

Francisco: The Sweet Lure of Chocolate

http://www.exploratorium.edu/exploring/

exploring_chocolate/ [February 2009].

Gail Kay Haines is a science writer and book

author from Olympia, Wash. Her most recent

article, “Coffee: Brain Booster to Go?” appeared in

the December 2008 issue.

Cocoa beans are cleaned

and roasted

The beans’ shells are removed

Chocolate liquor is mixed with

sugar and cocoa butter (and

milk for milk chocolate)

The mixture is stirred in a

tank with more cocoa butter

Enrobing process **

Molding process ***

MIKE CIESIELSKI

JUPITERIMAGES