Miércoles 25 de Junio de 2008, Ip nº 235

The coffee junkie's guide to caffeine addiction
Por Mark Adams

It’s a sunny spring afternoon in midtown, and a few hundred feet above Times Square, things are unusually calm on the 30th floor of the Viacom building. Michael Dare, the director of special events for MTV Networks, has just completed a run of twelve-hour days assembling the Night of Too Many Stars, a fund-raiser hosted by Jon Stewart on Comedy Central, and its after-party at the Mandarin Oriental hotel. Today, a Monday, Dare has a few moments to catch his breath before heading into the maelstrom of upfront sales events for cable-TV advertisers. He can just enjoy a cup of green tea, trying to detoxify from what he calls his “dysfunctional relationship” with caffeine.

Dare, 39, never drank coffee growing up in Montana. His love affair began after he moved to New York in the early nineties. “First it was mornings, and then it was afternoons, and then it was mornings and afternoons,” he says. “Lately, I’ve been kind of freaking people out. I’ve been ordering five-shot sugar-free grande soy lattes. People look at me like I’m a freak. But at least they remember my order, right?” On a really busy day, he says, he’ll take six shots. A couple of years ago, while working on a rebranding of the USA Network, he was tossing back four or five of those a day.

Dare knows that drinking 30 shots of espresso every day probably isn’t great for him. And he’s been having trouble sleeping lately, which is why this week he’s attempting to rein in his caffeine habit (For the record, green tea has a small amount of caffeine). But he knows that’s easier said than done. “I’ll quit for a month and do fine, but then I’ll be out with friends and smell coffee beans,” he says, pausing to conjure the aroma. His most recent attempt to quit ended at a cute little roadside café in Costa Rica. “It starts with a cappuccino,” he says. “And then I’m off to the races.”

Michael Dare may be an extreme example, but his story is still telling. Ever since Howard Schultz and his now-ubiquitous Starbucks outlets turned us on to the pleasures of very strong, often Venti-sized coffee, Americans have been guzzling copious, recently unprecedented, amounts of java. Per capita national coffee consumption, which had been on the decline since the forties, has risen almost 20 percent since 1995, and the amount of caffeine we consume has almost surely shot up even more than that. Starbucks and its competitors may not be Philip Morris and Brown & Williamson (companies that deliberately conspired to get us hooked on known carcinogens), but they’re certainly not shy caffeine enablers. Coffee shops now beckon from every other corner (Dare can choose from three Starbucks stores within 500 feet of his office). Serving sizes are far bigger than they used to be (a Starbucks Venti is twice the size of a traditional corner-coffee-shop cup). And a typical cup of coffee is, ounce for ounce, a lot stronger than it once was. A Wall Street Journal laboratory analysis of the caffeine levels in takeout coffees found that the coffee served at Starbucks and other gourmet coffee shops had more than 50 percent more caffeine than traditional drip coffee.

The other players in the coffee-selling business, meanwhile, have been following the Seattle giant’s lead. Innumerable coffee boutiques have sprung up in Starbucks’s wake. Dunkin’ Donuts, once famous for serving passable coffee quickly, now serves a full range of gourmet coffee drinks, and McDonald’s has begun whipping up lattes at many of its 14,000 stores. And it’s not just coffee purveyors who are peddling more and more caffeine. The twelve-ounce can of Coke has swelled into the twenty-ounce bottle. The market in energy drinks such as Red Bull has reached $4.4 billion. And you can buy caffeinated water, gum, candy bars, mints, beer, diet supplements, and lip balm.

In a relatively short amount of time, we have become a nation of caffeine addicts. Science has barely had time to study the effects of consumption at this volume. New research does, however, suggest that caffeine may not give us the instant jolt of productivity, alertness, and happiness we think it does. And most of us, it turns out, are using the drug all wrong.

Had coffee been cooked up in a university laboratory instead of evolving on an anonymous bush somewhere near the equator, it might have won someone a Nobel Prize (and made him obscenely rich). Caffeine is the world’s most widely used psychoactive substance because it works, and quickly. Caffeine enters the bloodstream almost instantaneously upon ingestion. Within 30 to 45 minutes it has permeated nearly every cell in the body. Because it slips effortlessly across the blood-brain barrier—a sort of filter that prevents bacteria, viruses, and most drugs from entering the brain—it penetrates the cerebral cortex unimpeded. Once inside the central nervous system, caffeine is believed to plug up the receptors of adenosine, a neuromodulator that acts like a brake on nerve cells firing their messages across synapses. With the neural sluice gates open, more messages flood through, resulting, it’s said, in a sense of heightened mental quickness. “It makes people feel good, it increases their arousal and alertness, and makes them more friendly and sociable and talkative,” says Laura Juliano, an American University psychology professor, coffee researcher, and substance-dependence expert. Adenosine is also linked to the onset of sleep; rats injected with it have been observed to keel over unconscious, then wake up a few minutes later. When we pull a coffee-fueled all-nighter, “we’re blocking the adenosine telling us to go to sleep because we’re tired,” says James Lane, a professor of psychology at Duke University Medical Center who has been studying the effects of caffeine since the eighties. Caffeine also greatly aids physical endurance and athletic performance, allowing one to go longer and stronger to such an extent that the International Olympic Committee once limited its use as a performance enhancer, though it lifted the restriction in 2004.

Caffeine is classified pharmacologically as a stimulant, a cousin of cocaine and amphetamines, including Adderall and other substances in the increasingly popular cognitive-improvement prescription-drug toolbox. According to one psychiatry textbook, caffeine, cocaine, and amphetamines all produce behavioral results that include “increased locomotor activity and stimulant-like discriminative stimulus effects.” In other words, not surprisingly, they pep people up. The difference between caffeine and other stimulants is, in part, a matter of degree. Like its pharmacological cousins, caffeine signals the body to release adrenaline (hence the heightened sense of energy). Caffeine also slightly raises levels of dopamine, the brain’s feel-good hormone. Cocaine and amphetamines essentially do the same thing, only they create not just a pleasant feeling but outright euphoria. Methamphetamine and crack, because they’re highly concentrated, create an even more intense feeling. But the higher a drug’s highs, the lower its lows, which is why a crack user needing a fix might rob an elderly neighbor at gunpoint while a coffee drinker might simply get snippy with co-workers.

There’s another factor at work, a more substantive difference between caffeine and related stimulants. Because the brain develops a tolerance to all of these drugs, ever-increasing quantities are required to achieve the same high. What makes caffeine more desirable, or less potentially dangerous, than other stimulants is its built-in restraining mechanism. Technically called caffeinism, it’s the state in which an overcaffeinated user hits the drug’s “dysphoric” range and is overcome by the shakes, anxiety, tension, and nausea. Caffeine, that is, is self-regulating. “That’s one of the secrets of caffeine and probably why it’s accepted worldwide,” says Roland Griffiths, professor of psychiatry and neuroscience at Johns Hopkins and the unofficial dean of caffeine researchers. “With cocaine and amphetamines, when you increase the doses, you generally get increased stimulation and well-being.” Too much cocaine makes you feel invincible; too much coffee makes you think you’re having a nervous breakdown.

Still, as with other psychoactive drugs, there’s a huge variation in how people respond to and metabolize caffeine. Just as two hits off a joint might make one person acutely paranoid while the same two hits might induce nothing more than a pizza craving in another, some people get anxious and jittery from a little caffeine while others can guzzle coffee all day with no apparent side effects. Aside from differences in body mass, no one is sure what accounts for these discrepancies. In one study, Griffiths found that some subjects perceived a buzz after ingesting the equivalent of a couple sips of coffee, while others needed almost twenty times that amount to feel anything.

Caffeine is typically flushed out of one’s system on a half-life of two to four hours, and requires five or six of those cycles to leave the body entirely, but again there are differences. Women generally metabolize caffeine faster than men. Smokers process it twice as quickly as nonsmokers do. Women taking birth-control pills metabolize it at perhaps one-third the rate that women not on the Pill do. Asians may do so more slowly than people of other races. In The World of Caffeine: The Science and Culture of the World’s Most Popular Drug, authors Bennett Alan Weinberg and Bonnie K. Bealer hypothesize that a nonsmoking Japanese man drinking his coffee with an alcoholic beverage—another slowing agent—would likely feel caffeinated “about five times longer than an Englishwoman who smoked cigarettes but did not drink or use oral contraceptives.”

New York’s first coffeehouse opened in Manhattan in 1696, and coffee drinkers have long been skeptical that the beverage could have so many welcome benefits with so few costs. In the early 1980s, a spate of negative health studies left caffeine with a particularly awful reputation. Reports linked the drug with breast lumps, pancreatic cancer, and birth defects. All of these findings were later discredited, though not before a sort of golden age of decaf came and went. Since then, considerable evidence has been compiled showing that moderate amounts of caffeine, and coffee in particular, can actually be good for you.

Studies touting newly discovered benefits of coffee and caffeine are published every few weeks. (April 8, 2008, bulletin: Caffeine may help prevent autoimmune diseases such as multiple sclerosis.) Drinking moderate amounts of coffee is believed to slash rates of Parkinson’s disease, inhibit the formation of gallstones, and ward off cirrhosis. It may help prevent Alzheimer’s. Caffeine relieves asthma symptoms by acting as a bronchodilator. Researchers who fed mice caffeinated water found that the animals were less likely to develop skin cancer. One large-scale study showed that a person’s suicide risk decreased with each cup of coffee consumed per day, up to seven cups (notably, though, eight cups or more was shown in a separate study to increase the risk substantially). Caffeine is probably not as bad a diuretic as it’s reputed to be; many nutritionists now believe that a cup of coffee hydrates people about as well as a cup of water. The doctors Mehmet Oz and Michael Roizen, authors of the popular You: The Owner’s Manual series, recommend downing 24 ounces of coffee daily. Another study showed that a serving of coffee has more antioxidants than a serving of either grape juice or blueberries.

That’s the good news. And now the bad. A study published earlier this year demonstrated that pregnant women who consume 200 milligrams of caffeine or more per day (that’s less than one Tall Starbucks drip coffee or three six-ounce cups of traditional coffee) are more than twice as likely to have a miscarriage as those who don’t use any. Too much caffeine during gestation may also contribute to low birth weights in children and result in babies born with a caffeine dependence. Large daily doses may also be a factor in female infertility. A study released in late May found that drinking coffee before breakfast could cause blood-glucose levels to rise sharply, which can be dangerous for people with type 2 diabetes. Drinking large amounts of caffeine has been found to exacerbate osteoporosis. And despite the popular idea that caffeine can relieve migraines, doctors say it more often causes them (Caffeine withdrawal seems to be the trigger). “Starbucks has been a big boon to our business,” says Alexander Mauskop, director of the New York Headache Center.

The most serious negative effects of hypercaffeination involve stress and sleeplessness. Because the drug is linked to the production of adrenaline and cortisol, hormones which are in turn associated with the fight-or-flight response, says Duke’s James Lane, “for someone with a busy, stressful job, little stresses elicit big responses on caffeine, and big stresses elicit huge responses.” Lane once did a study in which he compared caffeine’s effects on type-A versus type-B personalities. “Caffeine tended to make type Bs into type As,” he says. “Their blood pressure went up. They rose to challenges.” The type As didn’t get any more ambitious; they just became more excitable. Stress has been linked to everything from cancer to sexual dysfunction to depression. Before she prescribes an antianxiety drug like Xanax, Juliano advises her patients to quit coffee.

Caffeine’s ability to delay the onset of sleep is, of course, one of its chief selling points. But while caffeine can keep us awake, says Lane, “it doesn’t make the brain any less tired.” That’s why it’s possible to lie awake at 3 a.m. clicking through infomercials but still feel mentally exhausted. Depending on one’s caffeine metabolism, just one strong cup of morning coffee can be enough to disrupt sleep at night; an afternoon recharge is that much more likely to do so. “We routinely ask patients who are insomniacs to discontinue the use of caffeine, or reduce it to a cup or two in the morning,” says Charles Pollak, director of the Center for Sleep Medicine at the New York Weill-Cornell Medical Center. “And no caffeine after noon.” The United States Centers for Disease Control reports that sleep disorders are more pervasive than ever. Americans, on average, are getting 6.7 hours of sleep per night, the lowest amount since records have been kept, and are racking up an hour or more of sleep deficit per day. Sales of Ambien, Lunesta, and other prescription sleep aids have more than doubled in the past few years. “You have people drinking caffeine all day and taking sleeping pills at night,” Juliano says.

The effects of sleep deprivation are wide-ranging. The body’s ability to fight off disease is weakened. The body produces less leptin, a hormone that regulates appetite, leaving a sufferer hungrier than she would normally be. For that reason, sleep loss is increasingly seen as a major factor in the obesity epidemic. The sleep-deprived are more susceptible to depression and tend to have less control over their emotions. Sleep loss also weakens problem-solving and decision-making skills and, naturally, leaves a sufferer exhausted—all of which are conditions that caffeine is called upon to solve. “If we drink coffee all day long, it’s harder to sleep at night, and we need more coffee to get up and go to work the next morning,” says Lane. “The cycle repeats itself.”

No one can say for sure how much caffeine is safe, but just about everyone preaches moderation, and 300 milligrams seems to be the upper limit of what’s considered a moderate daily intake. That translates to about one Starbucks Grande drip coffee, four and a half six-ounce cups of traditional coffee, eight and a half twelve-ounce Cokes, or six eight-ounce cups of tea. Doctors note that pregnant women and nursing mothers and those who suffer from any of the health problems associated with caffeine would probably do well to drink little or none of the stuff.

That all said, what if the uptick in energy, alertness, and smarts we feel after drinking a cup of coffee isn’t a real uptick at all? What if it’s an illusion? A group of cutting-edge caffeine researchers believes that might be the case.

Anyone who consumes caffeine on a regular basis—especially someone who consumes a lot of it—knows what happens if he skips his morning coffee: fatigue, difficulty concentrating, irritability, headaches. Research has shown that drinking just 100 milligrams of caffeine a day (an eight-ounce cup of almost any type contains at least that much) is enough to develop a dependence and trigger withdrawal symptoms. The escape from the clutches of withdrawal is a big part of what makes the day’s first cup of coffee so wonderful. “Feeding that dependence feels really good,” Juliano says. The implication: The positive feelings we associate with drinking coffee don’t represent a net gain in energy or alertness; they’re really the result of withdrawal maintenance.

When Griffiths and Juliano teamed up to review 170 years of caffeine research, much of which confirmed the drug’s reputation as a brain booster, they noticed a pattern: Most studies had been done on caffeine users who, in the interest of scientific rigor, were deprived of the stimulant overnight. Because caffeine withdrawal can commence in just twelve hours, by the time each study’s jonesing test subjects were given either caffeine or a placebo, they had begun to suffer headaches and fatigue. For the half that received the stimulant—poof!—their withdrawal symptoms vanished. The other half remained uncaffeinated, crabby, and logy, and guess which group scored higher on cognitive tests time after time? The boost the test subjects who got the caffeine felt may have simply been a function of having been deprived of the drug. “They were restoring performance and mood that was degraded from low-grade withdrawal,” Griffiths says. Without the withdrawal, the caffeine may not have had any effect.

“You seem to get the most beneficial effects if you don’t use caffeine often,” says one researcher. “But that’s not how people generally consume it.”

At least one researcher is certain that’s true. Jack James, head of the school of psychology at the National University of Ireland, Galway, has been studying caffeine for 25 years and is probably the biggest skeptic of the drug’s positive effects. “Considerable scientific effort has gone into clarifying to what extent benefits generally attributed to caffeine represent genuine net effects of the drug or reversal of withdrawal effects,” he says. “In short, although caffeine is widely believed to be beneficial to mental performance and mood, controlled studies show that these perceived benefits are largely illusory.” Even caffeine’s reputation as a sleep-fighter is overrated, James believes; fatigue, he notes, is just another symptom of withdrawal. So the extra alertness we feel after drinking a cup of coffee may be another withdrawal-maintenance mirage.

In keeping with this heretical thinking, researchers have been tinkering with new ways to maximize caffeine’s benefits while minimizing the drug’s unwanted side effects and health risks. Recent studies, some of them funded by the military in order to calibrate peak performance of combatants, have demonstrated that instead of dosing ourselves with caffeine bombs two or three—or in Michael Dare’s case, six—times daily, we’d probably get better results from caffeine by taking in multiple small amounts throughout the day. One experiment conducted by Harvard researchers found that subjects given the caffeine equivalent of two ounces of coffee every hour maintained their alertness, scored well on cognitive tests, and suffered little detriment to their nighttime sleep—even though they continued to ingest it up until 90 minutes before bedtime. Troops in Iraq are given Stay Alert gum, which comes in 100-milligram doses. The upside of slow-drip consumption is that your body isn’t subjected to caffeine’s roller-coaster ride. You get the highs without the lows, or the withdrawal. Another novel idea is to use caffeine not as a faithful companion but on an as-needed basis only. Most of the researchers I spoke with use caffeine this way, taking small doses (say, 50 milligrams) occasionally, and not every day. “You seem to get the most beneficial effects if you don’t use it often,” says Duke’s Lane. “But that’s not how people generally consume it.”

He’s right, of course. Coffee isn’t just a drug-delivery system. It’s a social and cultural phenomenon. It’s a totem of a new day’s potential, a business-meeting staple, an excuse to linger after dinner and talk. And it tastes good. All of which makes it difficult to quit. One survey found that 13 percent of caffeine users had been told by a doctor or therapist to cut back or eliminate caffeine because it was causing them medical or psychological problems but had been unable to do so.

A couple of weeks after my first chat with Michael Dare, I checked in to see how he was faring with his green-tea-only regimen. He’d made it through the upfronts with only a single relapse, triggered by a walk through his neighborhood’s gauntlet of Starbucks on an especially sunny day. “I did manage some restraint and limited myself to a tall four-shot soy sugar-free dolce latte with two Splenda, rather than my megashot usual,” he reported. Since all but quitting caffeine, he reported, he’d been dozing off faster and sleeping more soundly at night, with no measurable drop-off in productivity during the day. “I’ve been alert and able to concentrate in a seemingly smoother fashion,” he said. “Coffee seems to be more frantic on the system.”

I thought back to our first conversation, in which Dare had described in mesmerizing detail the joy he found in the ritual of removing the top of his freshly poured latte and swirling in his sweetener. Despite his success so far, I couldn’t help but wonder if he was just one stressful premiere party away from slipping back into his old, bad relationship. In an e-mail he later sent me, he seemed to be reading my mind: “Don’t hold it against me,” he wrote, “if one of these days I fall prey to the daily coffee grind again.”


  01/06/2008. New York Magazine.