With a Starbucks on every corner, often adjacent to a Dunkin’ Donuts, it’s a surprise that we actually drink much less java than our grandparents — about half as much. Annual per-capita coffee consumption peaked after World War II at 46 gallons, dropping to 24 gallons in 2005.
How is it possible that our jittery, overworked, to-go coffee-cup culture is actually less caffeinated than our ancestors?
Because we aren’t. We might drink less coffee, but we’re taking in more caffeine than ever — it’s just not the coffee pot that’s providing the pick-me-up.
Now we get our kicks mainly from soft drinks (we each drank 51.5 gallons in 2005, up from 10.8 in 1946), energy drinks, gels, gums, even sprays and digestible “sheets.”
Kids are in on the trend too — nearly three-quarters of children on any given day will take in caffeine.
Caffeine is one of the only drugs Americans embrace without guilt. We — the 87 percent of Americans who ingest caffeine — boast about being “so addicted,” duck out during work to get a fix and can’t even imagine the last time we didn’t start off the day with a hit.
“It’s the only drug that’s not really seen as a real drug, that doesn’t have a stigma. It’s one that many of us feel comfortable giving to our children in small doses,” says Murray Carpenter, author of “Caffeinated,” a tenaciously researched look into the physiology, psychology and commerce of caffeine.
And it is a drug — contrary to popular misconception. Though studies suggest that it can improve mood and concentration and increase life span, caffeine has a dark side, too — upping anxiety and sleeplessness in some, and even causing psychosis in a small minority.
Carpenter’s interest in caffeine began in his senior year at University of Colorado, where he wrote a thesis on the topic. During his journalism career, he continued to write about it, ultimately deciding it deserved book-length treatment.
“It’s a fantastic drug, but it amazes me that it doesn’t get much respect,” Carpenter says. “We consistently underestimate its role in our bodies, our brains and our daily activities.” We also underestimate how much we’re actually taking in.
A Starbucks grande bought at the same store during the same day might contain anywhere from 260 milligrams to 564 milligrams, depending on who is brewing the coffee and how much caffeine the beans contain. How much we weigh, our lifestyles and our genetic tolerance also contribute to how we digest caffeine.
In fact, our love for soft drinks might not be the only cause in the precipitous drop-off of coffee drinking, Carpenter explains.
Coffee consumption has fallen in tandem with smoking rates — and with reason. Smokers, because they activate a liver enzyme that digests coffee at double the rate of non-smokers, need to drink twice the amount of coffee to get the same kick.
Women who are on birth control inhibit these same enzymes, which means they need half the amount of coffee to get their high.
“This is what I call the ‘Mad Men’ meets ‘Sex and the City’ effect,” writes Carpenter. “Both trends — fewer cigarettes and more birth control pills — have the same effect of making every milligram count.”
“These are things that underscore that it is a powerful, important drug and each of us reacts differently to it. Most of us think of it as a mild stimulant, but it really is a powerful drug.”
A little biology here: Once the liquid hits your stomach, it takes 20 minutes until caffeine hits your brain. The small molecules easily pass the blood-brain barrier, blocking the uptake of the neurotransmitter adenosine, the chemical that tells the brain it’s tired.
Meanwhile, caffeine stimulates the central nervous system, increasing alertness, decreasing reaction time and sharpening focus. Blood pressure increases, as does heart rate and muscle response.
In one study, conducted at Walter Reed Army Medical Center, 25 active-duty soldiers stayed awake for three nights and then were tested on their concentration and risk-taking skills by blowing up a simulated balloon. They received an increasing cash reward the bigger the balloon was pumped, but nada if it popped.
Those dosed with caffeine popped fewer balloons and took home more money on average than those without.
That’s one reason why so many athletes and soldiers use it — another is that it can increase athletic ability by 3 percent.
Dr. Mark Tarnopolsky at McMaster University in Canada found that caffeine increases the amount of calcium released inside our muscles, enabling them to work harder.
“So caffeine has the potential to help endurance athletes in two very different ways, in different parts of the body. The drug blocks adenosine’s ‘you’re getting tired’ mantra as it pours more coal on the intramuscular fires,” Carpenter writes.
Another byproduct of caffeine is that as it inhibits those adenosine neurotransmitters, others, like dopamine, increase.
In other words, a cup of coffee a day might help keep the shrink away.
A series of studies out of Harvard show a link between coffee drinking and depression in women, finding that those who drank the most (four or more a day) had the lowest rates of depression.
The same Harvard lab conducted another test in 2013 that examined the link between suicide risk and coffee consumption. Again they found that those who drank the most coffee had the lowest risk.
Coffee drinking might make you happier — and it also might make you live longer. Studies have shown a link between coffee-drinking and staving off Alzheimer’s and Parkinson’s. And a National Institutes of Health study revealed that those who drank three or more cups a day had a 10 percent lower risk of death than those who did not.
Is it the coffee or the caffeine — or both? This is unclear. But what was clear is that the results “provide reassurance with respect to the concern that coffee drinking might adversely affect health.”
At too-high doses, though, many of the positives are reversed. Take a fatal dose — a mere tablespoon of pure caffeine — and the results, for a drug that is “generally recognized as safe” by the FDA, are startling: “arrhythmia, tachycardia, vomiting, convulsions, coma and death.”
Withdrawal has its own familiar side effects, among them: inability to concentrate, headaches and flu-like symptoms. And it only takes a little — a mere daily regimen of 100 milligrams a day (or one chai-tea latte).
Thirteen percent of those who experience withdrawal reported “clinically significant distress or functional impairment.”
Carpenter breaks this down in disaster terms, showing what would happen if our coffee supply were suddenly cut: “Since about 80 percent of Americans take caffeine daily, these results suggest that 125 million people would have headaches and 32 million of us — nearly the entire population of California — would be experiencing distress or functional impairment.”
How can we fight the zombie apocalypse if the population of California is suffering from “serious” withdrawal from coffee?
Sleep disturbances is one of the most chronically harmful side effects of caffeine use. Caffeine’s half life — or the time it takes for levels to reach 50 percent — is four to five hours. That means if we have a cup at 12 p.m., we might still be feeling its effects if we try to get to bed at 10 p.m.
The youngest caffeine users feel this effect the most severely. Five- to 7-year-olds who drank 52 milligrams of caffeine a day (less than two cans of Coke) were the most sleep-deprived of any group studied.
Anxiety in those with genetic predispositions is another widespread result of coffee use.
Brazilian doctor Antonio Nardi gathered three groups: one made up of healthy controls, the second with a history of panic disorders and a third of people with no history of panic attacks but who had a first-degree relative who did. When given high doses of caffeine — about 480 milligrams (about six Red Bulls), none of the healthy subjects suffered attacks, while 52 percent of those with panic disorders did. The surprising part? Forty-one percent of the first-degree relatives (with no history) suffered from attacks, too.
It begs the question, of the 40 million American who suffer from anxiety disorders, how many would improve by cutting out the morning latte?
On the extreme and rarest end of the spectrum, excessive caffeine use can also lead to psychosis.
Olfactory hallucinations — the taste of “plastic or burnt coffee” — occurred in patients injected with 250 milligrams of caffeine in 1993. Another experiment, led by a team of Greek researchers, found that when a man with a history of panic disorder was injected with 400 milligrams of caffeine, he had an auditory hallucination.
“He could hear vividly and repeatedly, in an echo-form, the last words of each thought he had,” Carpenter writes. “The patient strongly believed he was ‘going crazy.’”
Researchers concluded that “further caution needs to be advised with the use of this overtly ‘safe’ drug.”
The most cited example of “caffeine-induced psychosis” was of a successful, 47-year-old male farmer. Though he had no history of psychiatric issues, he developed the belief that people were “plotting against him to drive him off his farm and take his land,” the study reads. He installed security cameras, stopped bathing and was placed on a slew of anti-anxiety meds.
He also drank between 12 and 36 cups of coffee a day. Once he kicked that habit, all of the psychiatric symptoms stopped.
A few people have tried to blame caffeine for their violent crimes — with varying successes.
Kentucky’s Woody Will Smith, who strangled his wife with an extension cord, blamed it on sleep deprivation and caffeine intoxication. The jury didn’t buy it and sentenced him to life in prison.
Dan Noble, who hit and injured two pedestrians with his gold Trans Am after washing down his daily dose of two Starbucks coffees in Washington state, was acquitted of all charges due to “insanity, caffeine-induced.”
No matter what you believe about his defense, the take-home message is clear, writes Carpenter: “Caffeine can really mess with your head.”
Psychology professors Laura Juliano of American University and her collaborator Roland Griffiths of John’s Hopkins so believe in the serious psychiatric and physical effects of the drug that they’ve devoted a decade trying to land caffeine in the Diagnostic Statistical Manual of Mental Disorders (DSM), psychiatry’s key diagnostic tool.
The work paid off. In the new DSM-5, published in 2013, “caffeine withdrawal” is a real, albeit temporary, mental disorder. The inclusion of caffeine withdrawal — where one must experience headache, fatigue, depressed mood and muscle pain to the point that it “interferes in some significant way in their physical or emotional functioning” — places it on par with other drugs with listed withdrawal symptoms, like cocaine, nicotine and opiates.
But their bid for inclusion of “caffeine dependence disorder” — those so addicted to caffeine that they’re unable to quit — was not included. It was, however, listed by the DSM-5’s editors as an area that deserves further research.
They are doing just that. Right now Juliano and Griffiths are at work on an energy drink study — in light of the string of deaths and hospital visits (20,783 in 2011 alone) — that will examine the drinks’ effects on sleep, blood pressure and addiction patterns.
So, in light of this, as well of his three years of research, how does Carpenter now feel about his morning coffee?
“I have a coffee right next to me on my desk,” he said during an interview last week. “I’ve lowered my consumption a little bit, but I still drink about three to four cups a day.”