What you need to know to make smart choices about caffeine

Editor’s note: Tomorrow, Deseret News looks at the use of caffeine in sports .

When Tillie Uribe feels that first twinge of a migraine coming on, she reaches for caffeine. Some of her headaches are doozies.

Her doctor suggested that caffeine’s an easy way to at least try to head off the ache before it really digs in. She’s found it often works pretty well, narrowing blood vessels in the brain and short-circuiting the misery. So when the lights appear to flicker or she sees an aura — sure signs a migraine is imminent — she says she’ll reach for coffee, tea, soda, whatever caffeine is handy.

On the other hand, Uribe, a kindergarten teacher from West Jordan, normally can’t tolerate caffeine after about 4 p.m. True for many people, caffeine late in the day keeps her awake. She also has had peripartum cardiomyopathy for decades. That’s a rare form of heart failure that can occur late in a pregnancy, so she has to be careful how much caffeine she consumes. The stimulant could be bad for her heart.

For Uribe, caffeine is both a potential blessing and curse.

For many other people, caffeine is something of a mystery. Studies — and there are scads of them — sometimes contradict each other. Products containing caffeine use positive words like “energy” and “focus,” but ignore potential downsides. The truth is, caffeine can be positive or negative, depending on how it’s used.

And also depending on how a person metabolizes caffeine and if one’s particularly sensitive to the effects and ... well, there are many factors when it comes to caffeine’s effects on individuals. Here’s some of what I learned when I asked various health practitioners about caffeine.

What is caffeine?

Caffeine is a stimulant that’s naturally found in 60 different plants, including in coffee beans, tea leaves, guarana berries, yerba mate leaves and cacao beans. It can also be manufactured with this recipe: eight carbon atoms, 10 hydrogen atoms, four nitrogen atoms and two oxygen atoms. That’s often its route into supplements, foods, beverages and medicine.

Because it’s a stimulant, caffeine’s most frequently used as a performance-enhancing drug, not only in sports but for “just work and life,” said Dr. Brett Toresdahl, board certified in family medicine, with a sports medicine certificate. He’s also an associate professor and director of research for the Division of Sports Medicine in the orthopedics department at University of Utah Health. Caffeine, he said, “reduces fatigue and improves alertness.”

Most people get caffeine by drinking it and there’s a ton of difference in how much a cup of various caffeinated beverages contain. Medline Plus reports that in general an 8-ounce cup of coffee has 95-200 milligrams of caffeine, while a 12-ounce can of cola contains 35-45 milligrams. An 8-ounce cup of green or black tea contains 14-60 milligrams. Energy drinks are all over the place; Medline Plus says they range from 70-100 milligrams for 8 ounces. But when I went shopping for caffeinated energy drinks, I found some 12-ounce drinks that noted 200 milligrams of caffeine. And that’s just the added caffeine. If the product also contains natural caffeine from coffee, tea or other plants, that may not be quantified on the label.

“I think that it’d be important for folks who are considering or reconsidering their caffeine use to understand that there are different concentrations of caffeine in beverages,” said Toresdahl. “There’s a huge range between sodas, energy drinks, different ways coffee’s prepared. It’s important that people are aware of their cumulative caffeine intake.”

Caffeine may also be in surprising places. “Caffeine can be found in unexpected products like certain gums, energy bars, some pain relievers, sports drinks, flavored waters and even in some ice creams and yogurts,” said Chris Mohr, fitness and nutrition advisor at Fortune Recommends Health . “Always read labels carefully to avoid having too much, which may lead to unwanted side effects.”

Caffeine even has unexpected effects unrelated to health. An international study in the Journal of Marketing found consuming caffeine before shopping leads people to more purchases and spending. The effect is stronger for “high hedonic products” like scented candles, cologne and decor. Caffeine doesn’t impact whether you buy a notebook or a laundry basket.

How much is too much caffeine?

People process caffeine differently, said Sarah Dehoney, a neurology clinic pharmacist at University of Utah Health. Some can drink a cup of coffee right before bed, while others who consume even small amounts early in the day struggle to sleep at night. “Metabolism in people’s bodies varies, so some may be more sensitive to side effects. We say, ‘Start low, go slow’ and watch. Someone who’s super sensitive might feel their heart is racing. They might have anxiety or nervousness, or they might be really irritable. They might get hungry, like hypoglycemic, have trouble sleeping, have an upset stomach and increased urination. Those are signs you are taking too much or your body isn’t eliminating it quickly enough and you need to decrease your dose next time.”

That the amount and personal tolerance is so variable leads to contradictory views of whether caffeine is helpful or harmful, said Michelle Routhenstein, a cardiovascular dietitian and author who created New York-based EntirelyNourished . Caffeine in coffee can cause one person’s heart rate or blood pressure to rocket or trigger heart palpitations. Another could have two or three cups of coffee without those effects or gastric issues.

“There’s a sweet spot,” Toresdahl said, “that’s different for everybody in terms of how much caffeine is helpful. And that line that crosses into being unhelpful is different for everyone in terms of tolerance for the substance.” He said caffeine can lead to dehydration, especially while exercising outside when it’s hot. Caffeine can also make people anxious or jittery.

Caffeine is habit-forming when used regularly, so withdrawal can trigger fairly vicious headaches that must be tolerated unless one’s willing to counter with a bit more caffeine. Some headache medicines contain caffeine. There are also concerns that the stimulant effect of caffeine can trigger an arrhythmia for those with an underlying heart condition if the heart is stressed by exercise and caffeine combined, he said.

For most pondering how much caffeine they consume, Toresdahl suggests “everything in moderation” is a mantra that makes sense. “If you’re using many cups of coffee a day, that’s probably a sign that there’s something else that needs to be addressed, like sleep patterns, sleep quality, regular exercise that can help alertness, your diet, just making sure your body’s functioning well and you’re not dependent on caffeine to get through a day.”

Otherwise, caffeine can create a vicious cycle of “poor quality sleep that makes you tired in the day, then you drink more coffee and then have worse sleep during the night. ... That’s just not the cycle to get yourself into,” he added.

Routhenstein sees three or four cups of coffee a day, up to 400 milligrams of caffeine, as a hard limit. Most research and medical advice seems to agree. For one thing, there’s a risk the beverage is replacing nutrient-rich food that’s needed. And caffeine binds to nutrients like iron, magnesium and calcium in the food supply, decreasing how much benefit folks get from them. Binding to calcium can cause bone density problems.

Dehoney prefers caffeine from natural sources and said she doesn’t take supplements containing caffeine because they may also contain undeclared ingredients. She doesn’t want to consume anything that she didn’t intend. And lots of caffeinated foods and drinks also have too much sugar.

How does caffeine affect health?

It’s possible some people should just avoid caffeine entirely, Toresdahl said, including those with uncontrolled blood pressure or heart rate issues who are sensitive to caffeine’s effects. He suggests having a discussion with your cardiologist or other health care provider to avoid problems.

Routhenstein heartily agrees. “It is just important to have a conversation with your health care provider about your caffeine consumption, because certain medications may negatively work with it. If you are trying to get pregnant, you may want to make sure that you are looking into your caffeine intake to prevent miscarriage, preterm birth, low birth weights, etc.” She notes caffeine can change insulin or blood sugar levels when consumed in a high dose.

Dehoney recommends anyone who has seizures talk to a doctor. “They may be just fine with caffeine, but check, because there can be some concerns with seizures.”

Drinking a significant amount of coffee daily could double the risk of heart death for those who have severe hypertension, per a 2022 study published in the Journal of the American Heart Association , though that wasn’t true of green tea, which also contains caffeine. And the American College of Cardiology said this summer that research showed chronic high caffeine consumption could raise risk of heart disease.

Studies have also found potential health benefits. For instance, Routhenstein said that caffeine may help liver function in some people. And natural caffeine has antioxidant properties.

Many of the studies on caffeine and health impacts look specifically at coffee, perhaps because it’s so commonly consumed, said Lucy Sorenson, an Intermountain Health registered dietitian specializing in sports medicine at Utah Tech University. She doesn’t know, she added, if it’s something else in coffee or the caffeine itself, but she noted research suggesting coffee might lower risk of certain cancers, including endometrial cancer, prostate cancer and head and neck cancer.

Pregnant women need to be moderate with caffeine, because their baby will receive a similar dose. “The current recommendations for pregnant women is to try to stay at or below 200 milligrams of caffeine a day,” said Dehoney, adding that caffeine and its metabolites can be found in breast milk, and how much depends on a lot of factors, so consulting an obstetrician about that is also important.

Caffeine consumption can add up, because it’s in so many products, from the tiny amount in an Oreo cookie, dark chocolate bar or chocolate pudding to the megadose in certain energy drinks and weight-loss supplements. Dehoney was surprised to learn that labels on products like energy drinks or supplements may not include all the caffeine they contain. “They only have to list the added caffeine. The point is people may experience side effects because there’s more caffeine than they intended to take.”

Medication efficacy can be changed by caffeine, said Sorenson, noting an interaction with some antidepressants and antipsychotics that increases medication potency. Caffeine can reduce the effectiveness of some thyroid medications, while boosting the effect of some blood thinners.

People who choose to use caffeine should ask, “Does caffeine have any interactions with my meds?” Dehoney said, while Sorenson noted the answer could suggest changing the timing of using caffeine or taking medicine to avoid problems.

“It needs to be individualized and we need to understand the whole picture of things,” Routhenstein said. “There’re a lot of other nutrients that will support heart health and brain health and mental alertness that have antioxidants in them. It’s not just caffeine. But “with caffeine, there is an amount that’s appropriate to confer benefits without giving potential harm.”

“I think there are a lot of considerations to take into account that we probably aren’t knowing,” she said. She hopes people will consider their caffeine use in a broader context of their lives to be sure it’s not substituting for something important to health like sleep or nutritious food.

Is caffeine used as medicine?

Dr. Raj Dasgupta, quadruple board certified in internal medicine, pulmonology, critical care and sleep medicine and a medical reviewer for the National Council on Aging, does not prescribe caffeine now, he told me by email. “However, I’ve had patients in the past who used caffeine as a backup treatment for ADHD.” Formerly, he said, “caffeine was considered less effective than medications like methylphenidate or amphetamines but better than a placebo for ADHD. I think people with ADHD might be more likely to use caffeine, possibly to help manage their symptoms on their own.”

While reporting this story, I heard as well from people who are prescribed caffeine for an underactive thyroid (hypothyroidism) and for symptoms of attention deficit hyperactivity disorder (ADHD). While Dehoney said she hasn’t encountered that use, “I could make that leap, just because it’s a stimulant and Adderall and Ritalin have been hard to get your hands on.”

A 2022 study from Spain bolstered the idea that caffeine could treat some ADHD symptoms, based on a systematic review of preclinical studies. The study, in the journal Nutrients by experts at the Universitat Oberta de Catalunya, concluded that “a prescribed consumption of caffeine can increase attention and retention capacity in adolescents and adults suffering from this psychiatric disorder.”

Dasgupta has also had asthma patients who used caffeine to improve lung function, reduce muscle fatigue and act as a mild bronchodilator. “But caffeine isn’t as strong or fast-acting as rescue inhalers like albuterol, so it should never be used as a substitute.” And the amount it would take to improve lung function would likely create side effects that would outweigh any possible benefit, he added.

Dehoney said caffeine can be prescribed to help patients. The U.S. Food and Drug Administration has approved oral use for different types of headaches, including the kind that can follow having a spinal tap. Caffeine may be given for a headache after surgery or prescribed for tension headaches, she said.

A caffeine infusion is sometimes prescribed for premature babies who have sleep apnea that makes them breathe too slow or stop breathing entirely.

Fatigue is another place where caffeine can be medicine, in prescription or over-the-counter form. “That’s where you’re going to see the products at pharmacies like NoDoze and Vivarin and those marketed to help with mental alertness,” said Dehoney.

Weight-loss supplements and cold medicines may also contain caffeine.

New uses are being tested in both studies and practice, Dehoney said. “When we get into things like improving memory, improving diabetes and everything else under the sun, the evidence is all over the place.” When her patients want to see if caffeine helps them, she tells them to decide how long they’re going to try it.

Because of the unpredictability, getting a doctor’s advice is a good idea. And some products are not recommended for long-term use.

Caffeinated medicine is usually only suggested for those 12 and older, Dehoney said. “We don’t really have good data for kids under that age I’m aware of. The FDA doesn’t feel like there’s good enough data to be routinely recommending it for those under 12 .”

In fact, last year a study in Substance Use & Misuse concluded that children ages 9 and 10 who frequently drink caffeinated sodas are at higher risk of alcohol consumption in the future. The study also found that young daily caffeinated soda drinkers were more impulsive and had poorer working memory.