When I finally confronted my dependency and gave up coffee three months ago, my body wasn’t happy. In the mornings during the time that I would normally have my espresso, my thoughts tried to bargain with me to find some way to consume caffeine: How about just one cup? Maybe I could stop by the cafe on the way home and order a small one? Each day for nearly a week when I didn’t succumb to the temptation, a pounding headache took over instead. I was moody and irritable, sensitive to loud noises and the slightest inconvenience.
Caffeine appears in so many foods, drinks and we even allow children to freely consume it. But it doesn't take long to develop a dependency on it and, for me, the withdrawal was so strong, I started to question: Is caffeine actually the harmless drug we all say it is?
“For healthy adults, caffeine consumption is relatively safe, but for some vulnerable populations, caffeine consumption could be harmful, including impairments in cardiovascular function, sleep and substance use,” according to a 2017 review on caffeine’s safety.
Caffeine and coffee in particular has been credited with “changing the world.” The rise of coffee essentially coincides with the rise of capitalism, as people would gather in coffeehouses to exchange ideas and do business in the 16th and 17th centuries. Soon after, colonists started taking over Indigenous lands and enslaving people to cultivate their coffee plantations.
Today, between 80 and 90% of the population consumes some form of caffeine every day. People rely on it to stay up all night, get through the workday, or even boost their exercise performance by guzzling preworkout drinks. Arguably, our work culture has become completely dependent on caffeine, but this substance isn't without risks.
Between 80 and 90% of the population consumes some form of caffeine every day.
Like with any substance, the safety of caffeine depends largely on the dose. Decades of research has shown that up to 400 milligrams a day, or the equivalent of roughly two or three cups of coffee, is safe for the general population. However, a portion of the population drinks more than that, especially with the proliferation of energy drinks and other supplements that may have extremely high caffeine content.
Additionally, certain people, like those with mental health disorders, underlying health conditions, or even about half of the population with a certain genetic predisposition, may experience negative effects of caffeine, like heart arrhythmias or increased anxiety. Because of some negative impacts on fetal development shown with consuming high levels of caffeine, it is recommended that pregnant people limit caffeine intake, drinking a maximum of just 200 milligrams a day. But there are not different recommendations for other vulnerable groups.
Caffeine is often linked to health benefits. In several studies, it was associated with increased cognitive performance in aging populations and even a reduced risk of Parkinson’s disease and Alzheimer’s disease. Another 2012 study published in the New England Journal of Medicine following a group of coffee drinkers and a group of non-coffee drinkers over 13 years found those who did drink it were less likely to die from heart disease and diabetes.
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It has also been shown to decrease inflammation and is even sometimes used as a medical treatment. For example, caffeine is sometimes used to help premature babies breathe, said Dr. Shannon Kilgore, a neurologist at Stanford University School of Medicine. Excedrin brand migraine medication contains caffeine, in addition to acetaminophen and aspirin, because it helps constrict blood vessels in a process called vasoconstriction, enhancing pain relief.
“That is related, of course, to people who stop drinking caffeine and their withdrawal symptom is often a headache,” Kilgore told Salon in a phone interview. “That is a response to that lack of vasoconstriction.”
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Caffeine is a psychostimulant that works by blocking the adenosine receptors in the brain, which are linked to sleep, memory and learning. Blocking these receptors leads to a more wakeful state that can increase focus, said Dr. Oliver Grundmann, who studies how plants affect the brain at the University of Florida. It can also increase dopamine signaling in the brain.
Like many psychostimulants, including amphetamine or prescription drugs, caffeine can also increase heart rate. This could be positive for certain people who have a low heart rate, which has been linked to depression — and may be why some people report feeling less depressed with caffeine, in addition to the increased dopamine. In others who are more sensitive to caffeine, however, it could lead to heart problems like an abnormal heart beat.
“For somebody who already has cardiovascular issues, an increased heart rate, or high blood pressure, that can be detrimental and lead to sustained cardiovascular damage that we really don’t want,” Grundmann told Salon in a phone interview. “For example, cardiomyopathies can occur, but that is usually if somebody is a really heavy consumer of caffeinated beverages.”
This sensitivity is in part due to a genetic predisposition estimated to exist in up to 50% of the population that determines whether people metabolize caffeine faster or slower. Essentially, those with a certain expression of an enzyme that makes them metabolize caffeine more slowly will feel a greater effect, as it stays in the body longer. In contrast, those with a different expression who metabolize it faster will likely not feel its effects as strongly, Grundmann said.
In one study published in the journal Hypertension, people who had the “slow” caffeine metabolizing gene allele were at an increased risk of hypertension compared to those who had the “fast” gene allele.
Interestingly, people with the genetic predisposition to metabolize caffeine more quickly report consuming more caffeine, according to research conducted by Dr. Marilyn Cornelis, who studies genetics and caffeine at Northwestern University.
“They're probably trying to consume more in order to compensate for that increased metabolism so that they can maintain the psychostimulative effects of caffeine,” Cornelis told Salon in a phone interview.
Smoking tobacco also increases the activity of this enzyme and can accelerate the metabolism of caffeine, meaning people who smoke may be more likely to consume more caffeine. Relatively little is known about how caffeine interacts with some other substances like cannabis, although one study in rats showed that caffeine worsened memory lapses induced by THC, the main drug in marijuana.
In another study comparing the effect of drinking four versus eight cups of coffee a day, Cornelis found that endocannabinoids in the body decreased as people consumed more coffee, which is typically something that happens as a response to stress. This is generally the opposite of what happens when using cannabis.
“Perhaps the heavy coffee consumption was a stressor, though it’s all speculative,” Caornelis said.
Similar to tobacco, the body can also develop a tolerance to caffeine, where repeated exposure to this blockage of the adenosine receptors makes them less sensitive to the substance and more caffeine is needed to accomplish the same effect. The official Diagnostic and Statistical Manual of Mental Illnesses (DSM-5) does not include any official diagnosis for caffeine use disorder, although a decade ago it was acknowledged as something that requires further study. However, the manual does include caffeine withdrawal as an official diagnosis.
It took me years to work up the courage to give up coffee. I knew it was making me feel anxious and sleep more poorly, and I even sometimes had heart palpitations when I drank too much. Since abstaining, I have noticed I’m sleeping better and feel less anxious. I might not accomplish tasks as rapidly as I did after a double shot of espresso — but is that necessarily a bad thing? In my experience, I am able to approach my day with more intention and presence, using the energy I have and resting when it runs out, instead of outsourcing more of it from a cup of Joe.
But my experience is likely dependent on my genes and sensitivity to caffeine, which will be different for everyone.
"It's not black-and-white, like it’s clearly great or it's clearly bad,” Kilgore said. “It has to be taken in the context of the person, though it's probably fine for most healthy people.”
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