DEAR DR. BLONZ: I had to stop my caffeine intake due to a health condition. It took a few days to stop the annoying headaches, and I wondered what caused them. Things have now settled, but I do miss my coffee. I have a question about a caffeine-free energy drink: The ingredients list shows "guarana," which has me wanting some clarification before trying it. Thanks for any advice you might provide. -- T.I., San Jose, California
DEAR T.I.: The headaches you experienced relate to the way caffeine works: how the body adapts to its chronic presence, and what happens with abrupt withdrawal, which is what you went through. In addition to caffeine, a key biochemical in this scenario is adenosine, a compound found in all living cells that plays many roles and is part of the genetic building blocks of DNA and RNA. As a neurotransmitter, higher levels of adenosine cause feelings of sleepiness. Receptors on cell surfaces bind to adenosine to make this happen. Caffeine blocks the adenosine receptors, which keeps us alert. After days of regular caffeine intake, the body compensates by adjusting the number and sensitivity of its adenosine receptors. Not everyone responds to this process with the same efficiency, which explains how some people can consume coffee with dinner without it affecting their ability to fall asleep at night.
When a regular caffeine user abruptly stops, the body becomes hyper-responsive to adenosine because caffeine is no longer present. It is believed this is responsible for the withdrawal headache and other discomforts associated with the sudden absence of caffeine. People who stop their regular caffeine consumption when fasting for blood tests, medical procedures or religious holidays know this sensation. Consuming caffeine, of course, would reverse it, but that's not always an option. It has been suggested that continued caffeine consumption may be as much about avoiding the withdrawal effects as any enjoyment of the caffeinated beverage itself. As a coffee drinker who enjoys my morning brew, I find this a bit disingenuous, but I acknowledge a bit of subjectivity here.
As for your energy drink: Guarana (Paullinia cupana) comes from the seeds of this South American climbing shrub. Guarana seeds have a high concentration of caffeine -- more than twice that of coffee beans, the kola nut or cacao (cocoa), which makes it a useful ingredient in energy drinks. Often referred to as guaranine, or natural caffeine, guarana is misleadingly characterized as "caffeine-free." The seeds of the guarana shrub produce caffeine as part of their phytochemical defense against insects and animals dining on the plant and its seeds. For these tiny natural poachers, the level of caffeine in one seed can be deadly, but our size provides us with greater tolerance. Marketing guarana as "caffeine-free" is deceptive. Glad you checked things out.
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