Diet fads come and go, but in the end, there’s really only one rule for losing weight: Burn more energy than you consume. In April, scientists from California reported on a chemical that might help people burn fat. It’s called dihydrocapsiate, it comes from a pepper, and in a recent study it was shown to boost the body’s energy burn.

Its name, dihydrocapsiate (di-HI-droh-CAP-see-ate), isn’t easy to say. And Peter Piper never picked it. But it might be easy to find: It is a chemical cousin of capsaicin (kap-SAY-sin), the chemical that makes chili peppers so hot. But unlike its fiery family members, dihydrocapsiate won’t send you running for a glass of water if you eat it. In fact, you won’t even know it’s in your body.

Painful foods — like the ones that contain capsaicin — stimulate pain receptors in the mouth. Once stimulated by a fiery food, these pain receptors signal nerves, which send a message to the brain. Dihydrocapsiate, however, is too big to fit into the receptors and tickle those nerve endings, which means it enters and passes through the body without causing pain.

The main compound that gives peppers (pictured are red savina habaneros of New Mexico) their sting has a close cousin that may burn body fat without irritating the mouth or stomach.

NSF; Chile Pepper Institute

David Heber, a scientist at the University of California, Los Angeles reported on the dihydrocapsiate research in April during a meeting of scientists who study nutrition. He and his colleagues tested the chemical on 33 obese men and women. For four weeks, these volunteers consumed only 800 calories per day, and all of those calories came from a nutritious liquid, instead of from solid foods. These liquids did not contain any fat.

At every meal, the participants were also given pills. People in one group received pills that didn’t do anything. Drugs that don’t do anything are called placebos, and they help experimenters figure out whether the drug being tested really works. Other participants were given a small dose of dihydrocapsiate. Finally, other participants were given a high dose of dihydrocapsiate.

All of the pills looked the same, so neither the participants nor the doctors knew who had consumed placebos and who had consumed the pepper chemical.

After the end of the dihydrocapsiate-enhanced (or placebo-“enhanced”) diet, the scientists determined how much fat the participants were burning.

The scientists observed that not everyone burned the same amount of fat. People who were given high doses of dihydrocapsiate were burning more body fat than people who had been given placebos, UCLA’s Heber says. So much more, he says, that the people taking high doses of dihydrocapsiate may have been losing one more pound per month than the people taking placebos. But that’s a guess: The scientists didn’t measure that number, so they don’t know for sure.

Heber and his team think that the pepper chemical works by attaching itself to another type of receptor, this one in a person’s gut. This receptor helps send a message to the brain, which then starts a process that causes a body to burn, burn, burn calories. This process is the same that, when triggered by capsaicin, causes some people to sweat while they eat hot foods. The scientists say that capsaicin could have the same effect as the dihydrocapsiate, but capsaicin causes intense pain to a person’s mouth and gut.

Dihydrocapsiate could help people lose weight, delivering the positive effects of hot peppers without the fiery side effects. In theory, the chemical could be consumed safely and help a 100-pound person burn an extra 160 calories per day.

Of course, it would be very easy to undo these sizzling effects with one slice of cake or a sugary soft drink. A chemical like dihydrocapsiate may help a person burn more than he consumes — but it can’t change a person’s eating habits.

“As I always say,” Heber told Science News, “a supplement doesn’t make up for diet.”

This story and other Science News for Kids features describing research in medicine and biology are supported with funding from The Lasker Foundation. The foundation and its programs are dedicated to the support of biomedical research toward conquering disease, improving human health and extending life.

Going Deeper:

Raloff, Jane. 2010. “Chili pepper holds hot prospects for painfree dieting,” Science News, April 27. Available at http://www.sciencenews.org/view/generic/id/58689/title/Science_%2B_the_Public__Chili_pepper_holds_hot_prospects_for_painfree_dieting

Picked a pepper? Find out how hot it is using the Scoville scale: http://www.chilliworld.com/FactFile/Scoville_Scale.asp

Sohn, Emily. 2006. “Hot pepper, hot spider,” Science News for Kids, November 15. http://sciencenewsforkids.org/articles/20061115/Note2.asp

Sohn, Emily. 2009. “Greener diet,” Science News for Kids, February 25. http://sciencenewsforkids.org/articles/20090225/Note2.asp

The salt that you sprinkle onto food is easy to measure. Unfortunately, it may be just a fraction of the total salt in your daily diet.

When you look at your food, some ingredients are easy to see. For example, there is obviously milk in your cereal, cheese on your pizza and peanut butter on your toast.

But your meals are also filled with ingredients you can’t see. And you might be surprised to learn just how much those hidden items affect your health.

Salt is a perfect example of an ingredient that you might not notice, even when you eat a lot of it.

Sometimes, salt is obvious. You can see it on pretzels. You can taste it on french fries. And you can sprinkle it on green beans, straight from the shaker.

But it’s the salt we can’t see that concerns scientists most. For decades, doctors have warned patients that too much salt can be bad for their hearts. Still, most Americans continue to eat way too much salt, even when they try to avoid the salt shaker.

That’s because more than 75 percent of the salt we eat is hidden in restaurant meals, fast food and processed foods, such as spaghetti sauce from a jar, canned soup and frozen pizza. Often, you can’t even taste that the salt is there.

Heart trouble has long been considered a grown-up problem, and parents haven’t worried too much about the salt their kids eat. But new research suggests that salt is starting to affect kids — in their hearts, kidneys and waistlines.

Loading up on salt-filled potato chips, hot dogs and canned tuna today could also set young people up for even more health problems down the road.

“Most national heads of policy-making bodies in the United States and Canada and Great Britain are reaching the same conclusion,” says Lawrence Appel, professor of medicine at the Johns Hopkins University School of Medicine in Baltimore. “Reduce your salt intake.”

Straight to the heart

Salt is made up of two elements, or basic components: sodium and chlorine. When put in food or liquid, salt, also called sodium chloride, or NaCl, breaks into its two elements.

The chlorine part of salt isn’t that important. It’s the sodium that can stir up trouble.

We need a small amount of sodium to keep our muscles working and our nerves sending messages throughout the body. But the amount of sodium we actually need is really tiny: about 500 milligrams, or less than a quarter teaspoon of salt. A little bit goes a long way.

Dietary guidelines in the United States and elsewhere recommend that healthy adults consume no more than 2,300 milligrams of sodium a day. That’s about a teaspoonful of salt.

Kids ages 9 to 13 should eat no more than 1,500 to 2,200 mg of sodium a day. Younger kids should get even less.

Some foods just cry out for extra salt, like these fries. That can make them a bad meal choice.

Burke/Triolo

But the average American eats about twice the recommended daily amount. This worries doctors because too much sodium can cause the body to produce more blood. To pump the extra blood, the heart has to work extra hard. This leads to a rise in blood pressure — a measurement of how stressed out the heart is. High blood pressure, also known as hypertension, often leads to heart disease. Heart disease is the leading cause of death in the United States and can lead to ailments like heart attacks.

“Ninety percent of adult Americans develop hypertension in their lifetimes,” Appel says. It’s a big problem.

You are what you eat

Salt isn’t the only cause of hypertension. Eating lots of junk food, weighing too much and exercising too little also contribute to high blood pressure. But a large number of studies suggest that salt is a major player.

Some of the most powerful strikes against salt come from a pair of studies that took place in the 1990s. The goal of the research was to figure out if what we eat affects blood pressure, and if so, how much.

As part of the studies, hundreds of adults ate exactly what researchers told them to. Called DASH, these studies lasted for months at a time.

Although most salad offerings, with the exception of olives and other pickled foods, tend to be low in salt, salad dressings can have plenty. Check out the sodium content on the label before splashing plenty on your veggies.

Burke/Triolo

The results showed a sizeable drop in blood pressure in people who ate extra fruits and vegetables, lots of whole grains, low-fat dairy products and only small amounts of red meat, sweet treats and fatty foods like fast food and donuts. Eating well, the researchers concluded, is good for your heart.

But blood pressure levels dropped even more when participants who followed the diet described above also lessened their salt intake. In the first DASH study, participants ate a relatively high level of salt — 3,300 mg a day. In the second DASH study, participants’ salt intake dropped to as low as 1,500 mg a day. The low-salt, healthy eating program became known as the DASH diet, and doctors now recommend it to both adults and kids.

“The DASH diet reduces blood pressure in the whole population,” says Eva Obarzanek, a registered dietician and research nutritionist with the National Heart, Lung, and Blood Institute in Bethesda, Md. Better yet, she says, the diet works “as much as any [blood-pressure] drug would.”

What’s more, studies from around the world show that hypertension and heart disease rates are lowest in places where people eat the least amount of salt. (In fact, the Yanomami Indians of South America eat very little sodium and have lower blood pressure readings than American 10-year-olds.)

And in a 2007 study, scientists turned up the first direct link between salt and heart disease. They found that cutting down on salt now can lower a person’s risk of heart disease 10 to 15 years in the future.

“The bottom line is that high sodium levels are definitely bad for you,” Obarzanek says. “It affects everybody. And it’s important even if you don’t have high blood pressure [now], because you’re likely to get it as you get older.”

Start thinking about salt now

Like most kids, you probably don’t spend much time worrying about heart disease. After all, hypertension tends to become more common as people reach middle age and older.

But doctors say it’s never too early to start thinking about your heart — or about salt.

Blood pressure has been going up over the past decade in children and teenagers in the United States and many European countries. And a kid with high blood pressure is more likely to become a grown-up with hypertension.

“It’s better to not have a lifelong exposure to high blood pressure,” Obarzanek says.

Cutting down on salt might help stop the cycle. In one recent study, researchers from the United Kingdom analyzed 10 trials involving nearly 1,000 kids. The trial results showed that lowering sodium intake by 40 to 50 percent led to a significant decrease in blood pressure, even in infants.

Reducing salt might also help combat childhood obesity, a growing public health problem. British researchers recently found that kids who eat less salt also drink fewer sugary soft drinks. Drinking less soda makes kids less likely to gain weight, become obese and develop high blood pressure.

And salt can affect more than just your heart and weight. A study published in October found that a growing number of kids in the U.S are suffering from an ailment called kidney stones. This painful condition used to mostly affect people in their 40s and older. Now, kids as young as 5 are getting it.

The kidneys are responsible for filtering salt out of the bloodstream. So researchers think that kids eating too much salt and not drinking enough water are partly to blame for the trend.

How to lick salt

If you’re like most people, cutting down on salt can be tough, says Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia.

His research shows that when given larger and larger amounts of sodium, people want more and more of it. Even babies drink more formula when it’s saltier. That preference starts as early as 4 months old.

Getting used to eating less salt, on the other hand, can take months. And low-sodium food might taste gross at first when you’re used to highly salted versions.

The good news is that you can retrain your taste buds to prefer less salty food. And now is a good time to do it: Research shows that what you eat as a kid strongly influences what you’ll like as an adult. So, the more salt (or sugar, or even spices, such as hot chili powder) you eat now, the more likely you are to crave those ingredients later. And later, your heart might be weaker and less able to handle a heavy salt load.

“It’s an easy change to make at virtually no cost,” says Darwin Labarthe, director of the Division for Heart Disease and Stroke Prevention at the Centers for Disease Control and Prevention in Atlanta. “And it has an immense health impact.”

The best way to reduce the amount of sodium you consume, researchers say, is to make changes gradually. Start by sprinkling half as much salt on your dinner as you normally do. Switch to fresh foods instead of canned and bottled versions. And go easy on the condiments. Things like ketchup, soy sauce and salad dressing can carry far more sodium than you might expect.

You might also want to start reading nutrition labels. You may be surprised to find out that a serving of tomato sauce has more than 500 mg of sodium. And that there are 1,150 mg of sodium in a McDonald’s double cheeseburger, and more than 2,000 mg in many frozen meals.

“Kids today need to give salt the shake,” says David Grotto, a dietician and author in Chicago, “For overall health’s sake.”

Growing evidence, however, suggests that these medicines don’t really work. What’s worse, they can have unpleasant—even dangerous—side effects, especially for young children. That’s why some doctors are now recommending an ancient remedy for their coughing patients: honey.

Honey might be good for more than just sweetening foods and beverages.

U.S. Department of Agriculture (USDA), Photo by Scott Bauer

It’s the kind of advice you might expect from your grandmother. But a new study suggests that the sticky sweet stuff might have real healing power.

“Honey has been used for centuries in folk remedies by cultures all over the world,” says Ian Paul, a pediatrician at Pennsylvania State University Children’s Hospital in Hershey, Pa. “We thought it would be reasonable to test it.”

Stubborn coughs

Paul was motivated to test honey because treating coughs in children has recently become a sticky subject.

Coughing is the body’s way of clearing irritated airways to help you breathe. But too much coughing can irritate your lungs and throat even more. Hacking away can also make it tough to get the sleep your body needs to heal. Hoping to ease the suffering of their children, parents often give them cough medicine.

Parents are often desperate to ease the suffering of their sick kids.

CDC, Public Health Image Library

These drugs have been around for decades, and their manufacturers claim they help kids feel better. But there have never been any good studies showing that they work, Paul says.

In 1997, the American Academy of Pediatrics even warned that codeine and dextromethorphan (DM)—two of the four most common ingredients in cough medicines—did nothing for young children. Codeine and DM are supposed to work by blocking messages from the brain that tell the body to cough.

A drug that doesn’t work is bad enough. But cough and cold medicines can also cause severe side effects, including drowsiness or hyperactivity, hallucinations, headaches, vomiting, rapid heart rate, and worse. Hundreds of kids end up in the hospital each year—and some even die—after receiving too much cough medicine by mistake.

Drug test

Frustrated by the lack of good studies, Paul decided to do one himself. A few years ago, he and colleagues designed a study that involved 100 kids who were sick with coughs and other cold symptoms. All were between the ages of 2 and 18.

The researchers divided the kids into three groups. Before bed, one group of kids took syrup that contained DM. A second group received syrup containing another common cough medicine called diphenhydramine (DPH). A third group took nonmedicated syrup.

In medical experiments, these fake medicines are called placebos. By comparing patients who have taken a real drug with those who’ve taken a placebo, doctors can understand the drug’s effectiveness.

Neither the researchers nor the kids and their parents knew which group was getting which syrup.

Medicated syrup might not be the best solution for a cough.

iStockphoto.com

Parents answered five questions about their children’s symptoms, both the night before the kids took the syrup and the night after. Results showed that kids who swallowed nonmedicated syrup improved just as much as did kids who got the drugs. Paul and colleagues published those results in 2004.

Last October, the U.S. Food and Drug Administration reviewed all the data, including Paul’s, and concluded that parents should not give cough medicines to children under 6. Around the same time, drug companies stopped selling these medicines for use in young children.

Sweet solution

Paul knew that parents would be dismayed by the news. He felt the same way.

“It’s hard as a doctor to tell people that medicine is no better than placebo when I don’t have an alternative to give them,” he says.

In his search for a different solution, Paul came across ancient anecdotes about honey’s healing powers. Doctors in ancient Egypt, for example, used it to treat wounds, coughs, and joint pain thousands of years ago.

Paul also discovered that the World Health Organization recommended honey as a throat soother, even though there was no scientific evidence of its effectiveness. Honey couldn’t hurt, Paul figured. Why not find out if it could help?

Honey may become an unexpected addition to your medicine cabinet.

National Honey Board

He designed his next study much like the first one. At bedtime, 105 sick kids took honey-flavored DM syrup, buckwheat honey syrup, or no treatment. Parents and kids in the no-treatment group knew they weren’t getting anything, but the other two groups weren’t told which treatment they were getting.

This time, surveys showed that kids who swallowed about 2 teaspoons of buckwheat honey before bedtime coughed less and slept better than did youngsters in the other groups. Their parents slept better too.

Honey isn’t safe for children younger than 1 year old, Paul says, but his results have convinced him to recommend it as a cough suppressant for older children.

“When parents want something for their kids to take,” Paul says, honey “seems like the best option.”

Why honey?

Most people think of honey as a tasty substitute for sugar in their tea, or as a topping on a peanut butter-and-banana sandwich. So what gives the sweet stuff its healing powers?

For one thing, its thick, sticky consistency probably helps coat and soothe the throat, says Katherine Beals, a registered dietician at the University of Utah in Salt Lake City. She’s also a nutrition consultant for the National Honey Board, a honey-promoting group that funded Paul’s recent study.

Substances called antioxidants may also be part of the answer, Beals says. Antioxidants—which are also found in foods such as blueberries, spinach, and dark chocolate—protect our cells from damage.

Studies show that antioxidant levels in the body rise after someone swallows honey. All honey contains antioxidants, but certain types contain more than others.

There are more than 300 types of honey, Beals says. Color, flavor, and health benefits depend on which types of flowers honey-producing bees visit.

The types of flowers that honeybees visit determine the type of honey they produce. This bee is pollinating an apple blossom.

USDA, Photo by Jack Dykinga

Most of the honey we buy in U.S. grocery stores is made by bees that visit clover plants. Darker honeys, such as the buckwheat type that Paul used in his experiment, are generally higher in antioxidants than lighter ones, including clover, Beals says.

Honey has another health advantage. At least some types seem to kill infectious microbes. One honey from New Zealand has proved especially good at healing wounds when slathered on the skin.

There is no evidence that eating honey will help prevent colds, Beals says. But if your throat is sore and you can’t stop coughing, it might make you feel better. And a little dose of sweetness might just cheer you up!

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Word Find: Honey Power

Strawberries.

Brian Prechtel, U.S. Department of Agriculture

Plants and animals often use color to attract attention. Deep, rich colors also provide another, important benefit for plants. Scientists have shown that the substances responsible for these colors actually help protect plants from chemical damage.

“When we see plants, we see a lot of different colors,” says Wayne Askew. “In particular, we see a lot of reds and greens and yellows.” Askew is a professor of nutrition at the University of Utah.

The good news for us is that, when we eat colorful fruits and vegetables, the pigments (or colorings) protect us, too.

Built-in sunscreen

The pigments responsible for plant color belong to a class of chemicals known as antioxidants. Plants make antioxidants to protect themselves from the sun’s ultraviolet (UV) light.

Ultraviolet light causes chemicals called free radicals to form within plant cells. If free radicals move through plant cells without being neutralized or eliminated, they can begin to destroy parts of the plant. Antioxidants stop free radicals in their tracks, shielding cells from harm.

Carrots contain antioxidants that help protect cells from chemical damage.

U.S. Department of Agriculture

Typically, an intensely colored plant has more of these protective chemicals than a paler one does.

Free radicals aren’t a problem just for plants. They also affect people and animals. And ultraviolet light isn’t the only source of these damaging chemicals.

If you breathe polluted air, such as smog, automobile exhaust, or discharges from a factory, you take in chemicals that also cause such damage, Askew says. And, the body itself produces free radicals as it processes food.

White suit

All organisms use oxygen to convert food into energy, just as burning wood in a fireplace produces heat. At the same time, oxygen is involved in the production of free radicals that are often very similar to compounds needed by a cell to stay healthy.

Tomatoes contain a powerful antioxidant.

Scott Bauer, U.S. Department of Agriculture

Free radicals are like a friendly dog that’s just been out in the mud, says James Joseph. He’s a nutrition researcher at Tufts University. If you play with the dog while wearing a white suit, the dog will leave muddy paw prints. Unfortunately, the dirt may permanently stain the suit.

It’s not as if the dog meant to hurt you, Joseph says. After all, it didn’t try to bite you. It merely wanted to bond with you.

Similarly, free radicals can bond with molecules in a cell, changing the molecules into forms that aren’t as useful or good for the cell as the originals were.

For example, free radicals can attack lipids—molecules that form a fence around cells to allow only certain chemicals to travel in and out of cells. They can also damage DNA, the genetic material that serves as the master plan for a cell and governs how it works. Proteins, the molecules in a cell that actually do the work of processing food, also face problems if they run into free radicals.

In general, free radicals can keep a cell from functioning properly.

Sunscreen on the inside

Our bodies have natural defenses for fighting off free radicals. The body makes certain molecules, known as antioxidants or repair enzymes, that stop free radicals before they can harm us. It’s like a video game of opposing chemical reactions in which good-guy repair enzymes battle bad-guy free radicals for control of cell and body.

These newly developed, strongly colored potatoes have more flavor and greater potential health benefits that white potatoes do.

Agricultural Research Service, U.S. Department of Agriculture

While we’re young, our defenses are pretty strong. However, our natural defenses get weaker as we get older. The body’s built-in stoppers can only go so far without extra help.

And we can sometimes see the effects of free-radical, or oxidative, damage directly. Wrinkled skin, for example, is one sign of skin-cell damage. Certain cancers and heart disease are linked to free radicals. Overeating and obesity are linked to oxidative damage.

We can help by sending in reinforcements: antioxidants. For people, this means a lifestyle of consistently eating a variety of fruits and vegetables with intense colors. Joseph compares eating fruits and vegetables to “putting on sunscreen for the inside of your body.”

Recently, the U.S. Department of Agriculture released new guidelines that recommended we eat five to nine servings of fruits and vegetables each day.

Colorful food

The key to fighting free radicals with fruits and vegetables is to mix and match colors. Go for very bright colors and for many different colors.

Blueberries.

PhotoDisc

If you’re looking for greens, spinach, broccoli, and dark green lettuces do the job. Pale iceberg lettuce packs little chemical bang per bite. For reds, strawberries and other berries are best, and tomatoes are tremendous. Carrots, oranges, sweet potatoes, and squash all shine among the yellow/orange foods.

In general, fresh fruits and vegetables are great, but dried or frozen forms of these foods can also be healthy.

Blue or purple foods, in particular, can be very beneficial, Joseph says. Have blueberries, Concord grapes, and eggplant, for example, on your menu as often as you can. These blue foods contain hundreds of healthful chemicals not found anywhere else, he says.

Joseph’s research on how chemicals in blueberries affect brain function in rats even suggests that these chemicals may help our own brains work more efficiently. Wouldn’t it be nice to be both healthier and smarter?

An antioxidant vitamin?

Antioxidants are just chemical compounds. Why can’t we just make a good antioxidant pill?

The deep purple color of eggplants shows that they contain antioxidants.

Bill Tarpenning, U.S. Department of Agriculture

People who have tried to make pills with antioxidants in them have found that the pills don’t seem to work as well as eating the fruits and vegetables themselves.

The different amounts of different antioxidants in the same food appear to work together to fight free radicals more effectively than the ingredients do by themselves, Askew says.

Nature has already worked out the right balance in plants. Scientists have a long way to go before they’ll really understand how much of each antioxidant chemical works best.

So, the next time you’re at a supermarket, you can shop for your own personal chemistry experiment. Pick out interesting fruits and vegetables with lots of different colors, then get to work in the kitchen. You might try preparing something that you’ve never tasted before, or you just might create a meal that’s both beautiful to look at and delicious to eat.

And, as you digest your meal, those colorful antioxidants will start doing their own chemistry on the inside, neutralizing free radicals and keeping you healthy.

Going Deeper:

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Word Find: Antioxidants

Antioxidants

Plants can produce a variety of antioxidants. Not all of them are pigments (and not all pigments are antioxidants).

Here are some examples of potent antioxidants that can be found in various fruits and vegetables:

• Vitamin C (ascorbic acid) — oranges, tangerines, sweet peppers, strawberries, potatoes, broccoli, kiwi fruit
• Vitamin E — seeds, nuts, peanut butter, wheat germ, avocado
• Beta carotene (a form of Vitamin A) — carrots, sweet potatoes, broccoli, red peppers, apricots, cantaloupe, mangoes, pumpkin, spinach
• Anthocyanin — eggplant, grapes, berries
• Lycopene — tomatoes, pink grapefruit, watermelon
• Lutein — broccoli, brussels sprouts, spinach, kale, corn

This candy bar combines chocolate and peanuts.

Nuts contain oil, says Greg Ziegler, who studies chocolate at Pennsylvania State University. The nut oil tends to seep, or diffuse, into the chocolate. This process softens the chocolate, which also turns a chalky color. People no longer want to eat it.

Oil diffusion is just one of many problems that chocolate scientists face in creating the different kinds of chocolate sold in stores. Depending on the type of cocoa beans, processing conditions, and ingredient proportions, chocolate products can end up with different flavors, textures, shapes, sizes, and even nutritional properties.

Chocolate products of all sorts are in great demand, especially around holidays and for special occasions. In December, for example, you can buy dark chocolate Santas and crispy chocolate reindeer. Around Easter, there are hollow chocolate bunnies and cream-filled chocolate eggs. At this time of year, for Valentine’s Day, stores are filled with lots of chocolate candies.

As appetizing as these treats may be, it’s the science behind chocolate that helps determine which types people choose to eat. And, despite years of research, exactly which combinations of factors make some types tastier or more appealing than others remain a mystery.

It’s a mystery that chocolate companies are eager to solve—and one that keeps chocolate scientists busy.

“The process of making chocolate is very complex,” Ziegler says. Despite a lot of work, “there are no hard and fast answers yet.”

Work in progress

Chocolate, as we know it today, has been a work in progress for thousands of years.

People in Mexico and Central America were the first to pluck seed-containing pods from cacao trees and grind the seeds (or beans) into a powder for a spicy, frothy, bitter drink.

A cacao pod split in half reveals several cocoa beans nestled inside the tough casing.

Photo by Keith Weller, Agricultural Research, U.S. Department of Agriculture

The explorers Christopher Columbus and Hernando Cortez brought cocoa beans back to Europe early in the 1500s. Even then, no one knew quite what to do with the beans because the resulting drink tasted so bitter. Finally, Cortez had a brilliant idea: Add sugar!

Sweet drinking chocolate rapidly became a special treat for royalty across Europe. As production increased, chocolate grew cheaper and more popular. Finally, in the 1800s, advances in England and Switzerland led to the creation of solid chocolate, which people still crave today.

Making chocolate

The basic process for making chocolate hasn’t changed much since the 1800s. After beans are removed from their pods, they go through a few days of fermentation to get rid of some of the bitterness. Then, the beans are dried, either in the sun or under hot-air pipes.

Finally, the beans are shipped to candy companies, where they are cleaned, sorted, and roasted for anywhere from 30 minutes to 2 hours. Both roasting time and temperature (250 degrees F. or higher) have a big effect on how the chocolate tastes in the end. So do drying methods, bean variety, and growing conditions, including temperature, moisture, and soil composition.

Once roasting is finished, the beans are crushed and separated into three parts: a bitter liquid called chocolate liquor, a fatty, yellow solid called cocoa butter, and a powder that is often used in cakes and cookies.

Dark chocolate has just three main ingredients: chocolate liquor, cocoa butter, and sugar. The liquor, which is not alcoholic, is the bitter part. Sugar counters the bitterness, and the cocoa butter adds fat. Milk chocolate also contains milk solids. White chocolate is just sugar, milk solids, and cocoa butter, with no liquor.

Dark chocolate is made from chocolate liquor, cocoa butter, and sugar.

Less than one percent of a finished chocolate product is made up of flavorings, such as vanilla and salt. There’s also often a small amount of an emulsifier, such as soy lecithin, which keeps the sugar suspended and spread out in the solid. If you check the ingredients label on the back of a chocolate bar, you might see soy lecithin in the list.

Flavor experiments

Playing with the ratios of the main ingredients and adding fillings are two major ways in which manufacturers experiment with flavors. One look at the candy aisle shows how far chocolate research has come. Modern chocolate bars include everything from almonds and raisins to caramel and cookies. Some bars are crispy; some are chewy; some are frozen.

With each new flavor or texture combination, however, comes a new puzzle. Edges are one major challenge, Ziegler says. Coatings tend to thin out at the corners of a bar.

Then, there’s the nut problem. After years of research, scientists have come up with strategies for making nutty chocolate last longer. Some companies, for example, create bars that place a physical barrier, such as a candy coating, between the chocolate and the nuts or peanut butter.

Being selective about the type of cocoa butter is another way to slow diffusion. Varieties of cocoa butter that are extra-solid work best. It also turns out that there are six different kinds of crystals that can form inside cocoa butter. Some of these forms are more resistant to oil diffusion than others.

Still, plenty of questions remain. Ziegler is pretty sure that nut oil actually dissolves in cocoa butter. This process, he suggests, is what ruins the chocolate’s texture and color. Other scientists propose that chocolate acts more like a sponge, sucking up the oil through a process called capillary infiltration.

This chocolate product has a peanut-butter filling and a milk-chocolate coating.

“Right now,” Ziegler says, “the most important thing is just to get a handle on what physical phenomena are involved.” He and his colleagues have used special equipment to get detailed images of what goes on over time inside a piece of nut-filled chocolate.

Eventually, he hopes to come up with a mathematical equation that predicts how nuts and chocolate behave (or misbehave) together. This information could then be used to create products that last longer.

“We might find out that it’s not only different crystal types but also the size of crystals in the fat that are important in determining how quickly the oil dissolves,” he says. “Then, we could change the crystal proportions.”

Good taste

While Ziegler is hard at work on the nut quandary, other researchers are trying to breed cocoa beans that are resistant to disease but still taste good. Their biggest challenge is to figure out why some beans have hints of flowers, fruits, or raisins, among other flavor notes, and why some beans produce superb chocolate and others don’t.

Still others are busy experimenting with textures and sensations. That melt-in-your-mouth quality may in fact be what you crave more than the way the food itself tastes.

In one study, scientists showed that swallowing chocolate-filled capsules didn’t satisfy cravings for chocolate nearly as much as actually chewing pieces of chocolate. The researchers concluded that the special sense of well-being that comes from eating chocolate has more to do with the experience itself than with anything actually in the chocolate.

The feel of eating chocolate rather than the chocolate itself has a lot to do with how much people enjoy chocolate.

Yet, even though its chemical makeup may not fuel your cravings, the way chocolate affects your body has become a major focus of chocolate research in recent years. Scientists have discovered that chocolate contains compounds called flavonoids, which might protect against heart attacks, keep you from getting sick, even help cure coughs. Yes, it’s true. Eating chocolate can actually be good for you!

So, have a happy Valentine’s Day, and eat up. Just make sure to keep your portions reasonable. Despite the wonders of chocolate, it’s still loaded with sugar and fat, and no one should eat too much of those.

“It tastes good, and it makes you happy,” Ziegler says. “In moderation, it’s okay.”

Better yet, consider becoming a chocolate scientist. “It’s a dream job,” Ziegler says. “I like science and figuring things out and understanding nature. But for me, my specific work on chocolate seems to open a lot of doors. It makes people happy. When I tell them what I’m working on, they smile.”

Spread the joy. Don’t just eat chocolate. Study it!

Going Deeper:

News Detective: Emily goes to a chocolate show

Word Find: Chocolate

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