Whether it is grabbing a Guayakí Yerba Mate from the Arbor before hitting the library or downing a cup of coffee in an attempt to stay awake for an 8 a.m. class, many UC Santa Barbara students rely on caffeine to help them focus.

Studies have shown that caffeine enhances cognitive performance by improving energy, alertness and reflexes. Caffeine binds to adenosine receptors and blocks adenosine, the neurotransmitter responsible for making us sleepy. It also boosts positive feelings by increasing the flow of dopamine in our brains. Caffeine is also associated with other mental benefits such as helping to consolidate learning, reducing cognitive decline and decreasing the risk of depression. Registered Dietician Carrie Flack at UC Santa Barbara Student Health discusses research in caffeine’s possible prevention of some diseases.

“Caffeine is studied in relation to the possible treatment of neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases,” Flack explained. “In epidemiological reports, caffeine consumption was associated with significantly lower risk of developing them.”

These benefits are promising, but what happens if you drink too much coffee? The Food and Drug Administration (FDA) recommends no more than 400 mg of caffeine per day — about three or four cups of brewed coffee. Regular consumption of caffeine past this limit poses a potential risk to physical and mental health. For reference, a venti-brewed coffee from Starbucks contains about 415 mg of caffeine, a Celsius energy drink contains 200 mg and a can of Guayakí Yerba Mate contains anywhere from 60-150 mg of caffeine. Despite its benefits, too much caffeine can have undesirable side effects such as restlessness, insomnia, rapid heartbeat, agitation and headaches. 

At high doses of caffeine, you might experience the “jitters,” characterized by shakiness, nervousness and anxiety. People with underlying mental health issues such as anxiety and panic disorders might be more susceptible to these symptoms and experience them more intensely. Many side effects are also experienced by people with caffeine sensitivity at doses as low as 10 mg. Consuming too much caffeine too often can also cause dependency. 

“It is possible to become addicted to caffeine in the sense that individuals regularly consuming caffeine may become physically dependent on it to function optimally or feel normal,” Flack said. “The body adjusts to caffeine intake by becoming less responsive to it or by developing tolerance to it.”

People with a caffeine addiction can experience withdrawal symptoms such as headaches, fatigue, drowsiness and irritability if caffeine intake is stopped abruptly. Therefore, it is more beneficial to ease off of caffeine rather than quitting cold turkey when someone is caffeine-dependent.

Intake of caffeine close to bedtime can also affect the quality of sleep due to its half-life of four to six hours. This means that for up to six hours after drinking that cup of coffee, half of the caffeine consumed is still present in the bloodstream. Although it does help you stay awake at night by delaying the increase of melatonin levels, the hormone that promotes sleep, it can contribute to feeling groggy in the morning. A study has shown that caffeine affects your circadian rhythm — not only does it cause you to fall asleep later, but it also causes you to wake up later. 

People who choose to avoid caffeine but still enjoy the taste of coffee might turn to decaffeinated coffee, which typically contains only two to five mg of caffeine. 

Decaffeinated coffee uses the water processing method, or Swiss Water Process. It water instead of solvents and is a natural, reusable process. A mixture of water and extract from green coffee beans is used to soak the beans, which removes the caffeine. The leftover caffeine-rich solution is then passed through activated charcoal that absorbs the caffeine. This is then used for the next batch of beans to be decaffeinated. Water processing typically preserves the flavor profile of the beans which go on to be dried and roasted. 

Another method is the direct solvent method which uses ethyl acetate or methylene chloride to directly dissolve caffeine from the coffee beans. Ethyl acetate is a natural byproduct of sugar production and is also commonly used in paints, perfumes and nail polish. Methylene chloride is a harmful chemical whose residues are removed through the drying and roasting process of decaffeination. The use of this chemical is not usually advertised, so it has likely been used if the product does not say “water processed” or “natural/sugar processed.” Methylene chloride in decaffeination is deemed safe by the FDA, but it typically produces coffee with low-quality flavor.

The indirect solvent method is common in Europe and also uses ethyl acetate or methylene chloride. Coffee beans are boiled to extract the coffee oil and flavors, which are collected in the water. The beans are treated with the solvent and then heated, which evaporates both the caffeine and the solvent. They are then combined with the initial water solution, restoring flavor and oils to the coffee beans.

Lastly, the carbon dioxide method soaks coffee beans in highly compressed liquid carbon dioxide. This method removes only the caffeine from the beans, preserving their flavor profile. Activated carbon filters are then used to separate the coffee beans from the carbon dioxide, which is reused for the next batch. Decaffeinated coffee is overall safe, but you may want to know what you’re buying before you purchase another batch. 

If you want to consume regular coffee but limit your caffeine intake, there are a few things you can do. It is recommended to not have any caffeine within an hour of waking up, which will help maintain a normal circadian rhythm. Caffeine during this time is unnecessary because our bodies produce cortisol after waking up — a natural energy booster. To help with sleep hygiene, drink caffeine no less than six hours before bedtime. Lastly, if you are not caffeine-dependent, consider drinking it more sparingly and only when you really need an energy boost. Although coffee is a best friend to many of us, don’t underestimate the power of caffeine the next time you brew a cup!

A version of this article appeared on p. 9 of the Oct. 19, 2023 print edition of the Daily Nexus.