Is Caffeine Safe for Kids? Ask Canada, U.S. Has No Guidelines

April 30, 2013 By Kate Heyhoe

Kids and Caffeine? Turn to Canada’s Guidelines

Remarkably, the U.S. government has no official guidelines for children’s caffeine consumption, but Canadian guidelines say:

Preschoolers should be limited to 45 mg of caffeine per day – about the amount of caffeine found in a 12-ounce (355-milliliter) can of Diet Coke or four small (1.5-ounce/43-gram) milk chocolate bars.

Health Canada also recommends:

For ages 12 and younger: no more than 2.5 milligrams per kilogram of body weight, per day. Or, based on average body weights, no more than these caffeine amounts:

Ages 4-6: 45 mg
Ages 7-9: 62.5 mg
Ages 10-12: 85 mg

Why We Love Caffeine

January 1, 2013 By Kate Heyhoe

People Love Caffeine, But Why?

Japanese pachinko machines work like regular pinball machines, except instead of playing one large steel ball at a time, they shoot off dozens of smaller balls, clattering loudly through the playing field, bouncing, racing and ricocheting into obstacles, bumpers and rabbit holes. Lights flash, whistles blow, bells ding, all the while the balls are in play. Until they gradually exit the playing space and everything stops. Kind of like your body on caffeine.

Caffeine churns through your entire system like steel balls in a pachinko machine, lighting up different responses throughout your body. Part of this has to do with the fact that adenosine doesn’t reside only in your brain. (Adenosine is the neurotransmitter responsible for energy, among other things.) Your body is full of adenosine and adenosine receptors. Caffeine has the same ability to block those receptors wherever it finds them, which can lead to some pretty interesting effects in organs other than the brain.

Adenosine, though, is only one link in the chain. Caffeine creates a domino effect among neurotransmitters, making us love it all the more.

Just as some players keep the pachinko balls in play longer than others, caffeine bounces around in some people longer than others. And as we’ll see in the coming pages, the human genome is like the Wizard of Oz: it’s the chief programmer behind long- and short-term caffeine highs.

The Caffeine Rush

When caffeine blocks adenosine reabsorption, it puts a chain reaction of neurotransmitters into effect. The caffeine-adenosine synergy amps up the levels of dopamine, norepinephrine, acetylcholine, epinephrine, serotonin, and glutamate. And collectively, these substances are responsible for how you feel, act, and think on caffeine.

For instance, caffeine sparks an adrenaline rush. When caffeine stirs up the brain’s neural activity, the pituitary gland gets confused and thinks there’s an emergency. It dispatches hormones to the adrenal glands, telling them, “Yikes, guys! Create more adrenaline!” (also known as epinephrine).

What happens when adrenaline fires off?

Pupils dilate
The heart beats faster
Breathing tubes open up
Blood flow to the skin increases
Blood flow to the stomach slows
The liver releases sugar for extra energy
Blood pressure rises

It’s almost like falling in love. In fact, the caffeine rush is a lot like falling in love. In both cases, adrenaline and dopamine elevate our moods and our heartbeats, though it takes a few other neurotransmitters to spark true love. (Still, if you meet someone over coffee or a chocolate dessert, you may want to re-evaluate your relationship after the caffeine rush subsides.)

Warning: Caffeine Is Not for Everyone

Caffeine can cause bad reactions in some people, often at doses higher than 300 mg. Symptoms include restlessness, a loss of fine motor control, headaches, dizziness, insomnia, nausea, agitation, tremors, palpitations, and rapid breathing. Hand tremors, high blood pressure and anxiety are other common reactions. As we’ll see later, overuse of caffeine can also lead to serious abnormal behavior in some people, and caffeine withdrawal sparks a series of unfriendly experiences in the habitual user. Caffeine overdoses do happen, but deaths from caffeinated beverages are rare, and more likely in people with certain health conditions. Women and caffeine have a particularly roller-coaster relationship, affected by their cycle, aging hormones, pregnancy, and birth control pills. Infants and unborn children can retain caffeine in their systems for days. (More on this later.)

Caffeine is Addictive, in its own special way

Caffeine can have drawbacks, especially when mixed with alcohol and when taken in unsafe doses. It can be habit-forming, and is considered mildly addictive. It doesn’t create substance addiction the way other stimulants like nicotine and heroine do, but there’s a reason why people need their morning jolt of coffee or tea. Most people can overcome withdrawal effects of their habit, but people whose brains are already prone to addiction can face severe clinical-addiction symptoms while kicking their caffeine habit.

Bottom Line: Moderation is Okay!

The good news is most everyone agrees that caffeine in moderate consumption is safe for most people (a big change from the attitudes of the 1980s, when dubious research linked caffeine to all sorts of health problems). Since almost every person in the world consumes caffeine, this is very good news indeed. We’re not drinking ourselves into mass extinction (though some species on earth surely wish we were). And we may even be extending our lives and living healthier because of caffeine. But caffeine isn’t fully understood, and for some people, it can still be risky.

Fickle, Flighty and Evasive: Caffeine and Research Results

One thing I can say with certainty: Caffeine is quirky – fickle enough to confound its researchers. Perhaps this is just an indication of how little we know, errors in methodology, and contaminated research results. On the other hand, caffeine research results may be inconsistent because the substance itself is far more complicated than we’ve been able to pin down. Epigenetics, botany, and sociobiology are just some of the sciences pursuing the depth of caffeine’s mysteries.

One of the most difficult things about summarizing caffeine’s effects is that, depending on the circumstances, it can cause opposite responses. Scientists now believe the differences in research results may be due to genetics: some people are genetically more sensitive to caffeine than others. Studies that take these genetic differences into consideration (mostly conducted after 2010) may prove more reliable than previous ones.

Another hiccup in research results: regular vs. non-regular users. People who consume caffeine on a regular basis build up a tolerance to it, and their reactions, even when caffeine is not actively in their system, may be markedly different from people who never consume caffeine. If a study testing the effects of caffeine doesn’t control for this, the results may be inaccurate or not replicable. Even though caffeine has been tested on humans for decades, the results of early studies may lead to different conclusions when re-examined.

So don’t be surprised if you hear a wide range of claims about caffeine’s effects. Results that are consistent and replicable tend to be the most reliable. As a species, we are remarkable in our ability to question our own physiology. Even if we’re not always right at first, we keep trying, and changing our course or conclusions are an essential part of the ongoing scientific process. It took hundreds of years, and meticulous observations, for the earth to go from flat to round. With caffeine research, the next dozen years may be just as illuminating.

Coming Up…

This section on How Caffeine Works highlights only the top caffeine effects. Research is hot on the trail of more complicated results, from living longer to living healthier, as we’ll see later…

Caffeine Basics: Table of Contents

Profile: Energy Drinks and Shots

January 3, 2013 By Kate Heyhoe

We tend to think that more is better, but that’s not the case with caffeine.

Caffeine is a biphasic drug; low to moderate doses are considered safe, while high doses can create adverse effects. Energy drinks range from moderate to extremely high levels of caffeine.

What are energy drinks? The term “energy drink” is a beverage-marketing category. The FDA classifies energy drinks (and energy shots) as “dietary supplements.” They contain caffeine and other ingredients intended to boost physical and/or mental energy.

What’s the difference between energy drinks, energy shots, and sports drinks? All three are designed to boost or restore energy. Energy drinks are like carbonated soft drinks, but more caffeinated. Energy shots typically come highly concentrated in 2-ounce bottles, and are not carbonated. Sports drinks contain ingredients to rehydrate, like electrolytes and nutrients lost in exercise, and contain no caffeine.

How much caffeine do energy drinks and shots contain? There is no standardized amount of caffeine for these products, and no limit. Energy drinks go from 80 mg of caffeine, which is comparable to coffee, up to 500 mg. They come in containers ranging from 8 to 20 fluid ounces. Formulas matter, too: Rockstar, for instance, makes more than a dozen varieties, with caffeine ranging from 120 to 240 mg per can. Energy shots span 100 to 500 mg of caffeine – as much caffeine as one to five cups of coffee, but swallowed in two gulps.

How much sugar do energy drinks and energy shots contain? Most energy drinks are sweeter than 12-ounces of Coca-Cola Classic (with 39 grams of sugar), and also come artificially sweetened. Energy shots are artificially sweetened, though some contain up to 7 grams of sugar.

What else do energy drinks and shots contain? All contain caffeine; some add guarana and yerba mate for their caffeine content. Other ingredients, like taurine and B vitamins, are shown in the next section. Their impact in energy drinks is questionable; quantities are usually small, and research on energy drinks has been sparse.

Are energy drinks and shots safe? The biggest danger comes from overconsumption of caffeine, and mixing with alcohol. Many, but not all, of the added ingredients are recognized as safe by the FDA.

Caffeine Basics: Table of Contents

Supplements in Energy Drinks

January 3, 2013 By Kate Heyhoe

The “energy” in energy drinks and energy shots comes from two sources: caffeine (including the caffeine in guarana, yerba mate, and kola nut) and glucose, or sugar. The following ingredients are also common in energy drinks and “dietary supplement” products.

Taurine

Taurine is an amino acid, obtained in meats and fish, and helps regulate water and mineral salt levels in the blood. Studies on rats suggest caffeine and taurine have a synergy, enhancing caffeine’s stimulant properties, but not enough research on humans has been done. European nations once banned Red Bull out of concern over taurine’s safety, but continued research has not shown any ill effects. Taurine is not included on the FDA’s GRAS list (generally regarded as safe). At best, taurine’s impact in energy drinks is unknown.

Ginseng

Ginseng is an herb. Traditional herbalists say it enhances mental wellbeing, boosts the immune system, and improves stamina. In energy drinks, ginseng probably won’t improve athletic performance. One study did show 200 mg of ginseng gave cognitive test-takers a mental boost, but only at that dose. Ginseng is shown to lower blood glucose and may interact with blood-thinning drugs like wayfarin, so consumers should consult their doctor before use.

Inositol

Inositol is a nutrient found in plants and animals that plays a role in brain, heart, muscle, and nerve cell functions. Insufficient evidence exists to support functional claims in dietary supplements, and quantities in energy drinks are too small to make an impact. The FDA lists it as “generally regarded as safe.”

B Vitamins

B vitamins help regulate metabolism, convert food to energy, and include thiamin, niacin, riboflavin, and cobalamin among others. They’re also believed to help maintain mental function. People get plenty of B vitamins in a normal diet, and excess is usually flushed from the system. But some amounts can be unsafe. B-6 is known to cause numbness and nerve damage in hands and feet when taken in large quantities over time. The FDA recommends 1.3 mg per day for most adults, and sets the tolerable upper limit for B-6 at 100 mg per day, but supplements often exceed that amount. (A 5-Hour ENERGY shot contains 40 mg of B-6.)

Ginkgo Biloba

Ginkgo biloba has been a favorite traditional herbal medicine for thousands of years, even though it’s not on the FDA’s GRAS list of safe ingredients. It’s taken to enhance memory and improve circulation. It can interact with other drugs and cause unwanted side effects, especially with anti-depressant medications and blood thinners. Energy drinks generally contain too small an amount to be of benefit.

L-Carnitine

L-Carnitine, a nutrient synthesized by amino acids in the body, converts food into energy, and helps move fat into cells to burn as energy. Some studies suggest it boosts metabolism, energy levels, and athletic endurance, but research is not conclusive. Most people on a normal diet produce adequate amounts, but physical stress may reduce available L-carnitine. It may cause gastrointestinal distress in some people.

Bottom line: Some of these ingredients may provide health or performance benefits, but probably not in the amounts found in energy drinks. People with health conditions or on medications should consult a doctor before consuming these substances.

Caffeine Basics: Table of Contents

5-Hour ENERGY Shot: More amps than advertised?

January 3, 2013 By Kate Heyhoe

“It contains about as much caffeine as a cup of the leading premium coffee,” say the ads for 5-Hour ENERGY shot. But how much caffeine is that? The company won’t reveal how many milligrams of caffeine each 2-ounce shot contains, but CBS News had a bottle analyzed by ConsumerLab.com. The result: 207 mg – far more caffeine than in a cup of coffee. For comparison:

207 mg caffeine:

= 5-hour ENERGY Shot

= 2 cups average brewed coffee

= more than a Starbucks “short” (180 mg/8 ounces)

= six-pack Coca Cola

Want a bigger buzz? Extra-Strength 5-Hour ENERGY claims to have as much caffeine “as a 12-ounce cup of coffee.” No lab results are available, so it’s unclear how much caffeine this version actually contains.

Warning: 5-Hour Energy has come under federal scrutiny as a contributing factor in 13 deaths, due to the high caffeine content and other ingredients. The company claims its product is safe, but the Center for Science in the Public Interest issued a 2012 report warning consumers to avoid it until the FDA can resolve safety issues.

Caffeine Basics: Table of Contents