Caffeine, in its thousands of years as companion to humanity, is inextricably interwoven with civilization. Worldwide consumption is estimated at 120,000 tons a year—that's more than a trillion cups of beverages, primarily coffee, tea, and soft drinks. Eighty-seven percent of Americans consume caffeine in some form, and many say they are addicted to it. Nearly two-thirds of thousands of respondents to National Geographic's online poll (posted along with a January article on caffeine) chose the response: "I need caffeine to function during the day."
Caffeine is a stimulant whose effects mimic, in some respects, the sympathetic nervous system (the body's subset of brain cells and nerves dedicated to keeping you alert, active, and ready for emergencies). It revs up metabolism, increases usage of stored fat, narrows peripheral blood vessels (decreasing blood flow in the extremities), and increases heart rate and blood pressure. The current favored theory is that it works by interfering with a naturally occurring chemical, adenosine. Adenosine binds to neurons in the brain, dampening their output and protecting against overstimulation. It gradually accumulates during hours of wakefulness, and as it does, generates a sense of fatigue and sleepiness. Caffeine, whose chemical structure is allied with adenosine's, settles into adenosine's attachment sites on neurons. That interferes with adenosine's quieting action, allowing the person to maintain an alert state.
We know from experience (and studies confirm it) that a jolt of joe or can of cola has some pretty nice benefits like boosting energy, increasing productivity, improving mood, enhancing athletic performance, and helping shed weight (if one's willpower can ride through the nagging hunger it also stimulates). But should we worry about a dark side? That question becomes ever more relevant as drinking caffeinated beverages becomes a habit not just of adulthood, but for a lifetime, starting with soft drinks among children and even toddlers.
Fortunately, the news is pretty good. Hundreds of studies have failed to associate caffeine consumption with any serious health problems, either short- or long-term, In fact, caffeine garners a lot of praise for enhancing alertness in settings where fatigue is both likely and dangerous, such as among cross-country truck drivers, emergency workers, pilots, and soldiers in battle.
Nevertheless, health authorities suggest we keep daily intake below 300 milligrams—about three cups of coffee or twice that of typical soda or tea. That's because adverse reactions start showing up at higher amounts, like the "jitters"—shakiness, restlessness, inability to concentrate, sweating, and irregular and pounding heartbeat. Excessive caffeine can cause dizziness, heart arrhythmias, cramps, diarrhea, nausea, vomiting, confusion, and occasionally, seizures. Just how much caffeine is "excessive" is vague, and varies with a person's ability to metabolize and clear it from the bloodstream (which in turn depend on liver and kidney health) and tolerance; some people are exceedingly sensitive to its effects. There is also the problem of withdrawal. Suddenly terminating one's daily dose(s) can trigger a punishing headache, lethargy, poor concentration, and irritability for a few days.
The clearest warnings about caffeine are for pregnant women and young children. Miscarriages and a lower birth weight have been associated with maternal caffeine intake of over 300 milligrams a day, and some breastfed babies of mothers who exceed that intake are abnormally restless or irritable. Caffeine metabolism is sluggish in children, especially toddlers (even more so in infants), so its effects last longer and successive consumption has more of an additive effect. (In adults, peak stimulatory effects of a single caffeinated beverage occur within an hour, but it takes four to six hours to clear half of it; most is gone after eighteen hours.)
In-school performance by soda-drinking children indicates that (like adults), they are getting hooked. Studies that had kids skip their usual sodas found they were unfocused, tired, irritable, and did worse in school for several days after stopping. In addition, the calories in those soft drinks are a contributor to childhood obesity, a serious health risk. (The same is true for adults.)
Parents should be aware that caffeine is included in some children's medicines because it works synergistically with pain relievers. Dietary sources of the drug should be minimized while using such products.
Although caffeine comes in pill form over the counter, most people enjoy it in beverages or food. The most popular caffeine vehicles are coffee, tea, and soft drinks, and the amount of caffeine in each varies greatly. Coffee's content depends on bean type and preparation method; an average of 100 milligrams per 8-ounce of brew is commonly cited, though people often drink more than that. (A single shot of espresso, at a diminutive 2 ounces, has about 100 milligrams.)
Caffeinated tea, whether green, oolong, black (also called red), or flavored concoctions like chai, all are from the same plant, Camellia sinensis. Black tea is dried longest and has more caffeine, roughly 50 milligrams per 8-ounce cup, though a long-dunked bag or extra leaf can offer the same as the average cup of joe.
Caffeine content of soft drinks varies from about 30 to 50 milligrams per 12-ounce serving. No longer linked to caffeine-containing extracts of the cola nuts, today's "colas" are synthetic look-alikes with caffeine added from the massive surplus generated by production of decaffeinated coffees and teas. Many soft drinks of other colors besides cola-brown are also caffeinated.
Energy drinks like Red Bull, Full Throttle, Rock Star, Monster, and No Fear are skyrocketing in popularity (though are banned in some countries), especially among college students, hard-driving professionals, fitness and exercise devotees, and all-night dance clubbers. Some contain green tea extract and guarana (see later), offering a caffeine whammy of up to 400 milligrams per serving (the FDA limits the addition of purified caffeine to six milligrams per ounce of beverage, but guarana and green tea extract are thus far unregulated). A printed warning accompanies them in the US: "Not recommended for children, pregnant or breast-feeding women, caffeine-sensitive persons." Red Bull, the leader of the pack, has a tarnished reputation in Europe because of a few deaths linked with consuming multiple servings, though other ingredients are as suspect as caffeine.
There is a lot of confusion about whether chocolate has caffeine. A careful chemical analysis found virtually none in raw cacao from which chocolate is made (.03 percent by weight compared to coffee beans at 1-2 percent caffeine). Chocolate does naturally contain theobromine, a chemical relative of caffeine but with much milder stimulatory effects. (Note that theobromine is highly toxic to animals, so don't feed chocolate to your pets!) But some chocolate products have added caffeine. Dark chocolate typically has the most (a Hershey's Special Dark Chocolate Bar has 31 milligrams in 1.5 ounces) and milk or white chocolate has about a fourth that in the same size bar. Chocolate milk or hot chocolate has only about five milligrams per eight-ounce serving.
There also are coffee-flavored foods like yogurt and ice cream that harbor caffeine (e.g., 85 milligrams per cup of Ben and Jerry's No Fat Coffee Fudge Frozen Yogurt, a little less than a cup of coffee). Some "energy bars" contain guarana, cola nut, or green tea—or combinations of these, though many, like PowerBar, the original in its genre, are packed with caffeine-free nutients. Energy gels are a newer edible product that sometimes have caffeine-containing ingredients. They come in single serving packets, meant to give a speedy energy boost, especially during exercise.
Certain bottled waters have caffeine and/or guarana, in spite of names like "vitamin water" and "Fruit2O." The latter, described as a "citrus energy boost" on its label, has no fruit, but does have 80 milligrams of caffeine per 16-ounce bottle.
What may seem like newer members of the stimulants club—guarana and maté (or yerba maté)—are actually ancient medicinal plants from South America, now finding their way to the US. Guarana bears orange-red fruit whose seeds are roasted, peeled, and made into a paste used for hot beverages or soft drinks. As popular today in Brazil as coffee, guarana was crowned the "national beverage" in 1940. Maté is a holly-like shrub whose dried leaves are added to hot water, often with spices, sweeteners, or milk. It is preferred in Argentina seven to one over coffee and boasts an impressive list of vitamins, minerals, and antioxidants that serve as Argentinean cowboys' "liquid vegetable."
The primary stimulant in both guarana and maté is caffeine. Guarana is the highest natural source of such stimulants currently known, with double to triple that of coffee beans. Maté is often said to contain "mateine" instead, but it's chemically identical to caffeine. Its content is far less by weight (it's a leaf), but Guayaki brand maté products contain a wide range, from about 25 to 135 milligrams caffeine per serving.
Though caffeine has few black clouds of health dangers over it, we could do better in our choice of stimulants, counsels Bob Lesnow, Doctor of Chiropractic and Certified Dietician-Nutritionist from Accord. "When you are taking caffeine on an ongoing basis, you are depleting your system. By mimicking the activity of our sympathetic nervous system, caffeine creates a physiological loop that stimulates the adrenal gland, which impacts a lot of other physiological parameters. It alters glucose control, suppresses appetite, tends to increase insulin resistance, and can set people up for eating high sugar, high glycemic index foods." In addition, Lesnow says adrenal overstimulation can impair immune functioning.
Instead of caffeine, Lesnow explains, "there is a whole other category of substances that do fight fatigue and increase alertness, mental performance, well being, and energy." These are called adaptogens. Rather than deplete organs, the complex mixtures of natural compounds in adaptogenic plants help tone them, returning the system to normal under stress. To earn the designation of adaptogen, a plant must be able to bring diverse types of maladaptive physiological change back to a healthful balance without harmful effects of their own.
"Adaptogenic herbs keep the adrenal gland from going into the stages by which they burn themselves out," says Lesnow. "Many studies support this. Years and years ago the first adaptogenic herb that was very much sought after was Siberian ginseng [Eleutherococcus senticosus; Eleuthero for short]. It improves the body's ability to enhance performance under stressful circumstances." Russian cosmonauts and Olympic athletes used Eleuthero as a general tonic and to reduce physical and mental stress. Asian ginseng (Panax ginseng), also called Chinese and Korean, and American ginseng (Panax quinquefolium), are prized adaptogens as well.
Rhodiola rosea (golden root, roseroot) is another adaptogen that's been a traditional medicine in Russia and Scandinavia for centuries. It is widely used and commercially available in those regions today, and in health food stores here. It fights fatigue and depression, and increases physical endurance (The Vikings imbibed it—look where it got them.) Studies show it enhances cognition, memory, and learning by increasing levels of several brain neurotransmitters. Rhodiola comes as an alcohol-based extract, typically taken as 5-10 drops on an empty stomach a few times daily.
Another favorite Lesnow suggests is licorice. "It helps to increase energy, resist fatigue, and support the body under stress." Two other adaptogenic plants, astragalus and schizandra, are featured in energy capsules or tinctures offered by health food stores and Chinese herbal experts. Some are teeming with added vitamins and minerals. The catch is they can be very expensive. And if one is addicted to the behavior of sipping a nice warm beverage, a pill just isn't the same. But drinking an herbal tea with ginseng or licorice can be enjoyed daily to maintain a healthful energy.
Vicki Koenig, Registered Dietitian and Nutritional Consultant with offices in New Paltz and Kingston, has another reminder about stimulants: what you eat makes a difference in energy level. She tells you how in a Stonyfield Farm Wellness Moosletter called "Minding Your Moods with Foods." "The key to quickly shifting your mind into a more alert and motivated mindset is to have protein with small amounts of fats and carbohydrates. For most people, three to four ounces of protein is enough. The best sources are lean protein with almost no carbs." Fats tend to decrease alertness, so use them sparingly.
Heed that advice at lunch especially, when the brain's alertness neurotransmitters dopamine and norepinephrine, both protein-based, are beginning to wane. Good lunch choices would be a Caesar salad with grilled chicken, salmon, or shrimp; or lightly sautéed fish, tofu or chicken fillet with vegetables (keep grain servings small). Visit Stonyfield's website for specific food and menu recommendations, www.stonyfield.com.
Koenig enjoys a bit of java, too. "I'm not immune to an occasional cappuccino when out, but I'm picky about what I drink. My personal choice is a locally roasted organic coffee mixed 50 percent with decaf."