caffeine | Caffeine and You

What Does Caffeine Do in Your Brain?

January 1, 2013 By Kate Heyhoe

Coffee, tea, chocolate and cola drinks are the most traditional sources of caffeine. Energy drinks and energy shots are the latest methods to boost your body with caffeine. So what happens when you perk up with one of these substances?

Throughout the day, brain cells create a neurotransmitter known as adenosine. Adenosine, often shortened to “ado,” is the first key to understanding how caffeine works. It’s what makes us sleepy and triggers hibernation in animals.

Adenosine gradually builds up throughout the day, giving us energy, until it reaches a saturation level. To stop its own activity, and keep us from being endlessly active, ado bonds to specific receptors – and this leads to deep, restorative sleep.

That is, of course, unless caffeine invades the brain.

Caffeine, The Great Imposter

To adenosine receptors, caffeine looks and acts remarkably like the real adenosine, so they say, “Okay, let’s bind to this guy” (not realizing he’s really caffeine). The binding of adenosine normally slows you down, but when it’s bouncing around in your brain, you’re energized and your nerve cells are speeded up. Along comes caffeine: your adenosine cells should be heading to bed, but caffeine has blocked the bedroom door.

So adenosine continues to party, and you feel alert. Meanwhile, caffeine works the room, chatting up the central nervous system with all sorts of stimulating conversation. Caffeine’s mere presence literally punches the brain’s happy button; it coaxes the brain’s pleasure center to release the ever-popular dopamine, a neurotransmitter that creates happy feelings of well being and good mood.

Neurotransmitters Join the Party

Once your neural pathways start firing on all cylinders, the “fight or flight” mode kicks in; adrenaline spikes, giving you that get-up-and-go boost. When adrenaline (also known as the hormone epinephrine) is released, the body goes into a heightened state of alert. Everything starts speeding up. Your blood pressure and heart rate rise, and your blood sugar spikes to release even more energy. You feel alert and your appetite is suppressed.

But as the caffeine in your brain subsides, so do these effects. Dopamine and adrenaline levels relax, and the real adenosine pushes past the withering caffeine to bond to its receptors.

Over time, everything returns to normal. Nerve cell activity slows down. But the brain remembers just how good that caffeine rush feels. And some experts say this feel-good state is what really leads to a caffeine habit.

But this is just a short story. Caffeine’s complete effects on the brain and body are far more intricate and subtle, as we’ll see later.

Caffeine Basics: Table of Contents

2. Natural Caffeine: Coffee, Tea, Chocolate, and Other Plants

January 2, 2013 By Kate Heyhoe

No one knows for sure when humans first consumed caffeine. Africa was the starting point for coffee, and probably fueled early man. Tea has its roots in Asia. Cacao, the source of chocolate, is native to Mesoamerica, while guarana and maté originated in South America. Kola nuts hail from Africa.

Today, we get our caffeine from the same plants, though in different forms, with complex processes ranging from simple steeping to grinding, fermenting, and roasting. Before jumping into energy drinks and caffeine-enhanced products, let’s start with the basics: caffeine in its natural forms as coffee, tea, cacao, guarana, and yerba mate.

Coffee Profile

January 2, 2013 By TW

Wild coffee plants originated in the same region where early humans may have been born: Ethiopia. Around 600 AD, the Oromo, a mountain tribe that still exists in Ethiopia, concocted a primitive “energy bar” by rolling up balls of ground coffee beans and ghee (clarified butter). Here’s an FAQ about coffee, starting with a few entertaining facts:

The green (unroasted) coffee beans carry a nutritious profile: 11% proteins, 8% sugars, 16% lipids, 4% minerals, and about 1% caffeine.
Green coffee beans are roasted and brewed into coffee as we know it.
Global coffee consumption is increasing at a rate of about 2 percent annually.

What is coffee? The tropical evergreen shrub known as Coffea produces red fruit with seeds, which we know as coffee beans. These red coffee “cherries” contain two seeds, and are plucked by hand when ripe. During processing, the seeds are removed from a pulpy outer covering, dried and roasted. Coffee plants thrive at higher elevations, from 1000 to 7000 feet depending on growing conditions and distance from the equator.

What are the different types of coffee beans? Thousands of species of coffee plants exist, but only two are the main sources of commercial coffee beans: C. arabica and C. robusta (also known as C. canephora). Arabica beans are considered more complex and smoother, while robusta beans are stronger in flavor. Robusta plants are hardier, more disease resistant, and grow at lower altitudes. Commercial beans are often named for their country of origin, roasting level, blend, and other flavor descriptors.

How much caffeine does coffee yield? Robusta beans contain twice the caffeine of arabica beans. But the actual caffeine in your cup varies depending on growing, roasting and brewing methods. In this book, we use 100 mg of caffeine per cup of brewed coffee as a standard. See the sidebars for other common examples. Decaffeinated coffee actually contains a small amount of caffeine, about 2-4 mg per cup. (Raw coffee beans contain 1-2% caffeine, by weight.)

Where does coffee come from? The world’s “Coffee Belt” runs between the Tropics of Cancer and Capricorn. Latin America grows 75 percent of the world’s coffee, Africa also produces coffee, and Southeast Asia has become an important coffee region. The top five coffee producers are, from most to least: Brazil, Vietnam, Colombia, Indonesia, and India. Colombia grows only arabica beans. Vietnam grows robusta beans almost entirely.

What else does coffee contain? Like all plants, coffee contains thousands of chemical compounds. Roasting and other processing can alter these compounds, making some more volatile and destroying others. Coffee is rich in antioxidants, which may provide health benefits separate from those of caffeine. Coffee’s nutrition profile: 11% proteins, 8% sugars, 16% lipids, 4% minerals, and about 1% caffeine.

Caffeine Basics: Table of Contents

Chocolate Profile

January 2, 2013 By Kate Heyhoe

Who knew such a luscious flavor would also be a stimulating food? Ancient peoples of the Americas did.

Cacao, cocoa, and chocolate are different terms, but all come from the same tree. The word cocoa is an Anglicized version of cacao, and the word “chocolate” has roots in native languages of the Americas.

What is chocolate? Chocolate is obtained from the cacao tree, a tropical evergreen known as Theobroma cacao (which translates from Greek as “food of the gods”). Each large cacao pod yields about 40 seeds or “beans” which are fermented, dried, and roasted. They’re then processed into cocoa solids, non-alcoholic cocoa liquor (a mix of solids and fat), and cocoa butter, the essential ingredients in chocolate products. Cocoa butter is the fat, with no caffeine or other stimulants. Cocoa liquor and solids are processed into eating chocolates and cocoa powders, sometimes with cocoa butter added back in.

What are the typical types of eating chocolate? Solid chocolate is basically finely ground cocoa solids suspended in cocoa butter. The more solids, the darker the chocolate, and the more stimulants contained. Milk chocolate includes milk and sugar, with less cocoa liquor or solids. White chocolate isn’t true chocolate; it contains cocoa butter and no cocoa solids or liquor.

Many dark chocolate bars promote the high percentage of cacao on their label, as in 72% chocolate (the combined weight of the cocoa solids and cocoa butter; the rest is usually sugar). Mass market chocolates often contain almost no real cacao, as little as 10% chocolate liquor which is the minimum required by U.S. regulations.

Cocoa powder is dried cocoa liquor, ground and unsweetened, and used in cooking and beverages. Instant cocoa powder has sugar added. Unsweetened chocolate is mainly for baking and cooking, and is known as bitter, baking, or unsweetened chocolate. Semi-sweet or bittersweet chocolate contains a high percentage of cocoa liquor and solids, and some sugar. Cocoa nibs, or cacao nibs, are the crunchy inner bits of roasted cocoa beans, and are added to recipes for texture and flavor.

Where does chocolate come from? Cacao trees are native to tropical rainforests in South and Central America, but now grow in equatorial zones around the globe. West Africa produces 70% of the world’s cacao, led by Ivory Coast, and followed by Ghana, Nigeria, and Cameroon. Indonesia is the world’s second-largest producing country. Producers in the Americas include Brazil, Ecuador, Dominican Republic, Colombia and Mexico.

How much caffeine does chocolate contain? A 1-ounce portion of chocolate averages about 20 mg of caffeine and 130 mg of theobromine; the combined effect is similar to that of a cup of tea with 40 mg of caffeine. Why? Chocolate contains a small amount of caffeine, and seven to ten times more theobromine than caffeine. Caffeine is the more potent of the two stimulants, but theobromine’s greater quantity makes it the predominant buzz in chocolate. Together they pack a punch: the combined impact of caffeine and theobromine in chocolate is roughly twice that of caffeine alone. (Theobromine also occurs in small amounts in tea, guarana, mate, and kola nut; and when caffeine is metabolized by the liver, it releases theobromine as a byproduct.)

What else does chocolate contain? Some people say they’re addicted to chocolate, and there may be some truth to that. Chocolate sparks several feel-good chemicals in the brain. Anandamide is a mood-altering substance in chocolate, and also occurs naturally in the brain. It’s related to THC, the psychoactive compound in marijuana. Chocolate causes the brain to release the neurotransmitter phenylethylamine (PEA), known as the love-drug because it’s released when we fall in love. Chocolate has a small amount of tryptophan, which stimulates serotonin, and in high quantities promotes good feelings. Flavenoids and antioxidants in chocolate have been linked to cardiovascular health benefits.

Caffeine Basics: Table of Contents

Guarana Profile

January 2, 2013 By Kate Heyhoe

Scan the label on an energy drink or energy shot, and you’ll likely see guarana: an ingredient twice as caffeinated as coffee, and a natural product of the Amazon. For centuries, natives there have used it medicinally, to suppress appetite, and for extending physical endurance.

What is guarana? The substance hails from the seeds of the guaraná plant, hence the name. Guaranine is the term for the caffeinated element in guarana, which is chemically identical to caffeine in coffee, tea and chocolate.

Where does guarana come from? Native to the Amazon basin, guaraná vines bear clumps of grape-size, Christmas-red berries and can climb as tall as 35 to 40 feet. When the three-sided guaraná fruits ripen, the capsule splits to reveal a black seed poking out of a white aril – they look like arm-length clusters of Muppet eyes. (Native legends say that the first guaraná plant sprouted from the eye of an infant god.) Native tribes have harvested guarana for centuries. The seeds are dried, ground, and brewed into tea or processed into an extract. Brazil is the leading supplier of guarana extract and powder, which are added to foods and beverages as a caffeine-boost.

How much caffeine does guarana yield? Guarana seeds are twice as caffeinated as coffee beans, about 4% caffeine by weight (coffee has 1-2% caffeine). But it’s difficult to know how much guarana a product contains. Like coffee and tea, guarana is naturally caffeinated, so U.S. regulations do not require the amount of guarana to be listed. If caffeine is listed separately, it typically does not include the extra caffeine that comes from guarana or guaranine.

What else does guarana contain? Guarana also contains the caffeine-related stimulants theobromine and theophylline. Some studies show guarana yields antioxidant effects. It’s classified as GRAS, generally recognized as safe, by the U.S. Food and Drug Administration (FDA).

For more about guarana, check out:

Children of Guarana: Tribe, Legend, Plant

Guarana Soda: Brazil’s National Buzz

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Caffeine Basics: Table of Contents