Tiny red flecks — rayon fibers — will soon identify the only BPA-free thermal-printed store receipts in North America. Credit: Appleton

Appleton Paper, a company in Wisconsin, makes the kind of paper used for sales receipts. Starting in the first two weeks of November, the company’s receipt paper comes with something new — tiny flakes of red fibers on the back. Next time you come across a receipt, flip it over and see whether you can see red.

If you do, rest easy — because Appleton’s receipts do not contain bisphenol A (BPA), a chemical that has been in the news. Recent studies show BPA could be hazardous to your health. BPA is called a hormone disruptor, which means it enters the body and acts like a hormone, a chemical that can control body processes. When BPA acts like hormones, the body’s real hormones may have trouble doing their job.

Studies have turned up a link between BPA and heart disease, and exposure to the chemical might make a person more likely to develop diseases such as diabetes. In roundworms, which are often used in the laboratory as a model for humans, BPA interferes with reproduction. That could mean bad news for human reproduction, too.

In three separate studies last year, conducted all over the world, researchers discovered BPA in cash register and ATM receipts. Worse yet, further studies showed that the BPA rubs off easily onto a person’s hand. A recent report from the French government says this BPA is quickly absorbed into the skin and then the bloodstream.

“I won’t touch receipts now,” Frederick vom Saal told Science News. He is a scientist at the University of Missouri in Columbia who investigated receipts as part of a study by the nonprofit Environmental Working Group. He is now working on a study that looks not only at how BPA travels from receipt to skin, but also at how much of that BPA later turns up in a person’s urine or blood.

A recent study of pregnant American women found that cashiers, who work with receipts all day, have higher levels of BPA in their blood and urine. Since BPA passes so easily into the body, it may also pass easily into the fetus, which means a mother’s BPA exposure could be hazardous to her children.

Receipts are not the only source of BPA — far from it. BPA is used in the production of plastic. Plastic is everywhere, which means BPA is all around us. The BPA travels from the plastic into the body when the plastic is heated — in a dishwasher or microwave, for example — or when it is scratched.

In addition to water bottles and other containers, plastic shows up in places you wouldn’t expect: bike helmets, telephones, computers. As a quick example, consider a typical automobile: plastic is used in the seats, dashboard, parts of the body and some engine parts.

BPA is in receipts and in plastic, and a recent study turned up BPA in yet another alarming source: food. In a recent study, scientists in Texas tested 31 types of canned foods or foods packaged in plastic. They discovered measurable amounts of BPA in 60 percent of the food products.

The Environmental Protection Agency recommends people consume no more than 50 micrograms of BPA per kilogram (2.2 pounds) of body weight. The food-based BPA measured by the Texas scientists is far below that guideline.

Scientists are still trying to determine both the real risks of BPA, and how much of the chemical is too much. To be on the safe side, check your receipts — and your plastic.

POWER WORDS (from the Yahoo! Kids Dictionary and the National Institutes of Health)

plasticizer Any of various substances added to plastics or other materials to make or keep them soft or pliable.

plastic Any of various organic compounds produced by polymerization, and capable of being molded, extruded, cast into various shapes and films, or drawn into filaments used as textile fibers.

BPA A chemical produced in large quantities for use primarily in the production of plastics.

hormone A substance produced by one tissue that travels through the bloodstream to another tissue to effect physiological activity, such as growth or metabolism.

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

Most kids already have a ton of energy, but kids who drink a lot of cola often end up even more wired than usual. The soda’s high sugar content is partly to blame, but cola also usually includes an energy-sparking chemical called caffeine.

Drinking caffeinated soda can give kids a burst of hyperactive energy.

iStockphoto.com

Like cola, coffee is full of caffeine. That’s why many adults drink it first thing in the morning to help them wake up. The chemical is also naturally found in tea, chocolate, and hot cocoa. Because people crave the caffeine kick—and may even become addicted to it—food manufacturers add the chemical to many other sodas as well as to energy drinks and snacks.

Parents and teachers usually try to keep kids away from caffeine. But is this chemical actually bad for your health? The answer is complicated.

Good caffeine, bad caffeine

First the plus side. Some studies have shown that caffeine might help people respond to things more quickly and even run longer. Scientists have also recently found evidence that caffeinated coffee and tea can help protect the heart, brain, and other organs from disease.

On the other hand, too much caffeine can make people anxious and unable to sleep. A 2003 survey of more than 200 students in grades seven through nine found that kids who drank a 16-ounce bottle of cola slept less, woke up more often, and felt more tired the next day than kids who drank less caffeine. This is worrisome because sleeping well is an important part of staying healthy (See “Getting Enough Sleep”).

Caffeine can also raise your blood pressure, increase your heart rate, and make you feel more stressed, which may eventually lead to heart disease and other health problems.

“If you feel a lot of pressure at school, caffeine is going to make you feel even more anxious,” says Jim Lane, a psychologist at Duke University Medical Center in Durham, N.C.

Roasted coffee beans, like these, are ground and brewed into steaming cups of coffee. The fragrant beverage is the main source of caffeine for most adults.

Wikipedia

Love it or hate it, caffeine is hard to avoid. Coffee shops crowd city streets and malls. Vending machines offer caffeinated sodas in schools. And even though caffeine-free versions of coffee, tea, and cola are widely available, more than 80 percent of adults consume caffeine regularly in North America, according to a 2004 study, mostly in the form of coffee. And kids today are drinking more and more soda, caffeinated or not.

Some 30 percent of 8-to-13-year-olds surveyed by researchers at the University of Minnesota said that they drink soft drinks every day, according to a study published last year. And more probably would if they could: 95 percent of kids in the survey said they “like” or “strongly like” the taste of soda.

You’re feeling sleepy . . . NOT!

Caffeine works by blocking the effects of a sleep-inducing substance produced by your body called adenosine. The substance accumulates inside you throughout the day.

As adenosine levels rise, you become calm and drowsy. Later, as you sleep, adenosine levels drop. When you wake up, the cycle starts again. By not allowing adenosine to build up, caffeine keeps you feeling fired up—as if you’re ready to face a tiger attack.

Human brains aren’t the only ones that feel the effects of caffeine. These images show how an extreme amount caffeine affects the brain of a tiny creature. In this case, the top picture shows how a spider spins its web before caffeine and after (bottom).

NASA; Wikipedia

Caffeine raises the amount of sugar in your bloodstream, even if there is no sugar in your caffeinated drink. That’s what gives you extra energy. The chemical also increases your blood pressure, which may make you feel as if your chest is pounding. But if you consume too much caffeine, you will probably feel nervous and sick.

Caffeine claims for brains

People say they like caffeine because it makes them feel alert. In experiments, people who are given caffeine say they feel more awake than do people who have been given a caffeinefree pill or beverage instead, says psychologist Peter Rogers of the University of Bristol in England.

The caffeine in cola beverages like this one affects your brain and nervous system in ways that have nothing to do with sugar or other ingredients.

National Cancer Institute/Wikipedia

In other studies, caffeine appears to shorten reaction times: People press a button more quickly after seeing a symbol appear on a computer screen after they’ve had some caffeine.

On the basis of such findings, it’s tempting to conclude that caffeine helps people respond more quickly and pay better attention. However, says Rogers, there is another, more likely, conclusion.

Studies show that the people who do better on tests after taking caffeine tend to be regular caffeine users already. In other words, they are probably addicted to the chemical.

Taking caffeine away from habitual users causes them to have symptoms of withdrawal, such as headaches and sleepiness. It also slows their reaction times. So, when these people are given their daily dose of caffeine, they feel better and perform better on reaction-time tests than they do without it.

Coffee and other caffeinated beverages can be addictive, even for children.

iStockphoto.com

People who aren’t addicted, on the other hand, may feel jittery and more awake after taking caffeine, but the chemical doesn’t improve their performance on reaction-time tests. And regular caffeine users who get caffeine before the tests aren’t any more alert or quicker to react than people who don’t normally use the chemical and haven’t taken any.

Giving athletes a jolt

Caffeine has become popular with exercisers looking for an extra boost of energy. Research shows, however, that caffeine helps only athletes who are already in top condition and only when they are pushing themselves as hard as possible, says Terry Graham, a caffeine researcher at the University of Guelph in Canada.

In one study, Graham challenged nine runners to run on a treadmill at a very fast pace. On average, these athletes were able to run for about 32 minutes without caffeine. With caffeine in their systems, they ran 7 to 10 minutes longer.

Athletes often take caffeine for an extra boost of energy. But the chemical doesn’t necessarily make them faster or stronger.

iStockphoto.com

Though caffeine may help the performance of world-class athletes, it may harm the health of people who are overweight. Graham’s other research has shown that caffeine interferes with the body’s ability to process sugars, which may lead to a disease called type 2 diabetes.

Kids, who tend to be smaller than adults, feel the various effects of caffeine more strongly than adults do. And just like adults, kids and teens can become addicted to the chemical.

A can of caffeinated soda every now and then is probably OK, nutritionists say, but sip carefully!

The following list shows how many milligrams (mg) of caffeine are contained in some popular products. All beverages refer to an 8-ounce (1-cup) serving, unless otherwise noted.

Regular brewed coffee: 135 mg
Red Bull (8.5 oz): 80 mg
Black tea: 40-70 mg
Java Water: 62 mg
Starbucks Coffee Ice cream (1 cup): 40-60 mg
Espresso (1 oz): 30-50 mg
Green tea: 25-40 mg
Mountain Dew and Diet Mountain Dew: 37 mg
Diet Coke: 34 mg
Hershey’s Special Dark Chocolate Bar (1 bar – 1.5 oz): 31 mg
Pepsi: 28 mg
Diet Pepsi: 27 mg
Coca-Cola Classic: 26 mg
Snapple Iced Tea: 24 mg
Jolt gum (1 piece): 20 mg
Hershey’s Milk Chocolate Bar (1 bar – 1.5 oz): 10 mg
Hot cocoa: 5 mg
Chocolate milk: 5 mg
Decaffeinated coffee: 5 mg
Decaffeinated black tea: 4 mg

Going Deeper:

Additional Information

Questions about the Article

Word Find: Feel the Buzz

Researchers have now found that microbes living under the ocean floor appear to produce propane and another gas called ethane. These microbes chew up ancient organic material, such as leaves and twigs buried in the sand, and they generate the gases as waste products.

That’s a surprise. Scientists had thought that propane and ethane could be produced only in the same way that petroleum is—by great heat applied to ancient, buried material.

Kai-Uwe Hinrichs examines a sample taken from a cylinder of sediment drilled out of the ocean floor.

Ocean Drilling Program Leg 201 Science Party

A team led by Kai-Uwe Hinrichs of the University of Bremen in Germany went on a research ship equipped with an enormous drill that dug out cylinders of sand or rock thousands of feet long. When the researchers examined these cylinders, they found traces of ethane and propane locked in the sediment.

Normally, to generate these gases, Earth’s heat cooks organic material in sand for many thousands of years. This can happen only at spots above cracks in Earth’s crust, where heat can leak out from inside Earth, and where thick layers of sediment would act like a blanket.

But the samples that Hinrichs and his coworkers had looked at contained thin layers of sediment. Some cylinders had also been obtained from places far from any cracks in Earth’s crust. So where could the gases be coming from?

Scientists already knew that microbes could break down organic material to produce a related, simpler gas called methane. So, undersea microbes were the only thing that made sense.

“When you can’t come up with any geologic source, then biology is an obvious candidate,” Hinrichs says.

The finding may someday lead to practical applications. Propane is valuable as a fuel, and ethane is used to make plastics. Pulling propane and ethane out of sediment is too difficult to be practical. But if scientists can better understand how microbes create the gases, they might be able to use the microbes’ methods to make ethane and propane directly from organic material.—J. Rehmeyer

Going Deeper:

Rehmeyer, Julie. 2006. Gassy bugs: Microbes may produce propane under the sea. Science News 170(Sept. 30):213. Available at http://www.sciencenews.org/articles/20060930/fob4.asp .

You can learn more about propane at en.wikipedia.org/wiki/Propane and ethane at en.wikipedia.org/wiki/Ethane (Wikipedia).

Cutraro, Jennifer. 2006. Microbes at the gas pump. Science News for Kids (April 12). Available at http://www.sciencenewsforkids.org/articles/20060412/Feature1.asp .

Sohn, Emily. 2006. Plant gas. Science News for Kids (Jan. 18). Available at http://www.sciencenewsforkids.org/articles/20060118/Note2.asp .

______. 2004. Drilling deep for fuel. Science News for Kids (Sept. 29). Available at http://www.sciencenewsforkids.org/articles/20040929/Note3.asp .

ScienceFairZone
Harvesting Biogas from Manure
www.sciencenewsforkids.org/articles/
20050504/ScienceFairZone.asp

Take a look at the cosmetics and beauty products on display when you shop: hair gel, lipstick, nail polish, shimmer, lip gloss, mascara, eye shadow, face powder, hair spray, eye liner, glitter, face cream, body lotion, and more. Every one of these items is a chemical concoction.

EyeWire

“Formulating cosmetics is a cross between—it sounds nasty—real chemistry and cooking,” says Steve Hasher. He works at Estee Lauder, a major makeup company in New York.

The men and women who create cosmetics have to know science, especially chemistry, Hasher says. But a product’s success also depends a lot on how it looks and feels.

“When you’re cooking, you throw in a little bit of garlic, and the food comes out different,” Hasher says. “When you’re developing a product, you play with chemicals and balance ratios to get it to feel right. Basically, it’s trial and error.”

All that tinkering adds up. Makeup sales are big business.

Chemists and engineers such as Hasher are constantly working to create new products and improve old ones. Every tube of lipstick, face powder, and anti-wrinkle lotion contains a finely tuned mixture of ingredients—the product of intensive research with advanced technologies.

Ancient foundation

Makeup has been around for a long, long time.

More than 4,000 years ago, ancient Egyptians had a variety of beauty aids, including body oils, face creams, perfumes, eye makeup, face paint, hair dyes, and lipstick. Women in ancient Greece applied a white powder to lighten their skin and used powdered charcoal as eye shadow.

Recently, archaeologists from Bristol University dug up a pot of grayish cream in south London dating back to the second century A.D. At that time, Great Britain was part of the Roman Empire, and many Romans lived in the area where London now stands.

The plain little pot was just 6 centimeters wide and 5 centimeters tall, and there were still finger marks on the lid and fingerprints in the cream. The cream inside the container was amazingly well preserved.

A Roman cosmetic cream in its original container (left) and a modern version of this concoction created by scientists (right).

Nature

“Such discoveries from the Roman world are rare,” Richard Evershed and his coworkers wrote last November in the scientific journal Nature. “This is the only one to be found so far with its lid and contents—a whitish medicinal or cosmetic cream—providing a unique opportunity to study this ancient formulation.”

At first, the researchers suspected that the substance, dubbed Londinium cream, might be toothpaste or even a ritualistic smear for goats that were about to be sacrificed. After analyzing the cream, however, they concluded that Roman women used it as a type of face makeup called a foundation cream.

Fashionable Roman women valued an unnaturally fair complexion, and it would have taken a special cream to achieve the white appearance they were aiming for.

To get the necessary white color, the Romans must have taken some care in formulating the cream from animal fat, starch, and a chemical called tin oxide. The fat came from animal carcasses, and it was probably heated to remove any color. The starch was obtained by treating roots or grains with boiling water. Tin oxide was produced by heating tin metal in air.

Once the scientists finished analyzing the ancient cream, they made their own version using fresh ingredients and tried it out.

“This cream had a pleasant texture when rubbed into the skin,” the Bristol University researchers reported. “Although it felt greasy initially, owing to the fat melting as a result of body heat, this was quickly overtaken by the smooth, powdery texture created by the starch: remarkably, starch is still used for this purpose in modern cosmetics.”

Building a cosmetic

Nowadays, just about every cosmetic product on the market has a unique formula created to meet specific needs. Some are designed for people with dry skin, others for oily skin. Colors vary widely. And companies have to keep up with a constantly changing sense of style.

EyeWire

“We’re always looking for something new,” Hasher says. “We want to make something that feels different from what everyone else has.”

Many modern foundations start with a combination of water and silicone, a very stable type of chemical. Substances called emulsifiers are then added to hold the water and silicone together. This keeps the ingredients from separating.

To the base, cosmetic formulators then add pigments for color. The Romans used tin oxide, Hasher says, because that was just about the only thing available. Today, iron oxides produce crisper colors.

Modern makeup companies also steer clear of ingredients that come from animals. Today’s materials come from plants instead, or they’re created in the lab.

One of the biggest advances in the past decade or so, Hasher says, involves synthetic materials called pearls and micas. These are tiny round particles that change the way light bounces off the face. The result is a soft, blurring effect that supposedly makes people look better.

New techniques that allow scientists to grind ingredients into extra-small pieces have also fed a trend toward more comfortable, longer-lasting foundations.

Londinium cream would have been thick and cakey, Hasher says. Like other ancient makeup, it probably cracked after a while and hurt to wear. Today’s products don’t have that problem.

Testing

One of the most important steps in producing makeup these days is something the Romans probably never did: Testing.

EyeWire

Before cosmetics companies can sell new products, they put them through all sorts of harsh trials—heating, freezing, and keeping them at high altitudes to see how they hold up, for example. The companies also hire people to wear the makeup for a while to make sure it interacts with skin in the way it’s supposed to. Sometimes, cosmetics are tested on animals to make sure they are safe for people.

And even though makeup is purely for appearance, makeup scientists draw from discoveries in other fields, Hasher says.

At Estee Lauder, researchers work with companies that study street-sign technology, for example, to find better ways to make bright colors that glow at night even in dim light. They talk with people in the car industry about the science behind paint colors. And they follow research on the eye, to better understand how people see makeup on others.

Still, despite all the advances that have changed makeup formulas during the last 2,000 years, some things haven’t changed. Just like in Roman times, many people today think that covering their faces with creams and colors will make them look better. In the end, though, the old adage is probably true: It’s what on the inside that really counts.

Going Deeper:

Additional Information

Questions about the Article

Word Find: Makeup Science