At fifty five years of age, I don’t have many active vices left; coffee, really good coffee, is pretty much it. I roast my own, from single source, organic, fair trade green beans. I’ve got a very good grinder, and an excellent drip brewing setup. Like I said, it’s really good coffee; so good that you literally start to get a buzz just breathing in the steam from a fresh cup. Caffeine – That’s what it’s all about, and that begs the question – What are the health impacts of caffeine on humans – Is it good, bad, or a little of both?
Caffeine is arguably the most widely used central nervous system stimulant in the world, with coffee and tea drinking accounting for the lion’s share. In addition to coffee beans and tea leaves, caffeine is found in cocoa beans, kola nuts, mate, guarana, and some 50+ other plants around the world. Caffeine wielding plants use it as a pesticide, to discourage competing plants from getting too close, and as a reward enhancer for bee pollinated species.
The U. S. Food & Drug Administration doesn’t require manufacturers to disclose the amount of caffeine in food products, but the European Union does. It shows up in a myriad of products, quite a few in which you might not expect to find it in, non-cola sodas, energy drinks (including energy waters), painkillers, breath fresheners, and even sunflower seeds can all pack a significant caffeine buzz.
Pure caffeine was first isolated by German and French chemists in the early 19th century, and scientists have been messing with it ever since. An alkaloid with an aromatic core, it’s a white, odorless, water soluble powder.
Before looking at caffeine’s specific effects, it’s important to note how good it is at getting into our systems. It’s a relatively fast acting drug, reaching peak bloodstream absorption as quickly as 15 minutes. Its half life, (the time it takes to lose 50% of its effectiveness), is 3 to 7 hours in adults. The next consideration is bioavailability; this is a measure of absorption, expressed as a fraction – how much of a drug reaches the blood system. A drug injected intravenously has 100% bioavailability: The bioavailability of caffeine is 95%. Thirdly, there’s protein binding, a measure of efficiency determined by the percentage of a drug that becomes bound by proteins within our blood plasma. The lower the protein binding fraction, the more unbound drug, and the greater its ability to do what it does. Protein binding for caffeine is around 30%, meaning 70% of the caffeine that hits our blood stream is available to do its thing. The bottom line? Caffeine is exceptionally active within human beings.
Caffeine is a stimulant, which it does by blocking adenosine receptors in the brain and inhibiting drowsiness. That same quality allows it to act on the autonomic nervous system, appreciably speeding up our reaction time. Additional known benefits include increased metabolism, more efficient energy use, as well as enhanced concentration and problem solving skills. There are ongoing studies to determine caffeine’s efficacy in reducing the risk of heart disease and stroke, as well as providing some level of protection against Parkinson’s disease and certain cancers.
Yet all is not wine and roses. The list of known and potential negative side effects of caffeine is easily as long as that of its benefits. Insomnia, disrupted sleep patterns, significant withdrawal issues, problems during pregnancy including miscarriage, low birth weight, and withdrawal issues for newborns, (the half life of caffeine for neonates is 60 – 120 hours). Add high blood pressure, high blood sugar, decreased bone density, anxiety, and chronic headaches, and you’ve got more than enough reasons to be careful with this stuff.
Naturally, the next question is, how much is too much? Numerous factors have bearing on the answer, from gender and age, to health, body weight, and metabolism. The general consensus indicates that an intake level under 400 milligrams a day is safe; that’s something on the order of 3-4 cups of brewed coffee, 4 shots of espresso, and up to 10 cups of tea. And For the record, yes, caffeine can be fatal at very high doses; it would take something on the order of chugging 80 to 100 cups of coffee to get there.
The obvious and sensible answer is, of course, All things in moderation. The simple solution is to avoid all that ‘energy’ crap and stick to things that allow you a reasonable degree of control over your intake.