If you have less than 100 mg of caffeine in your system while you're reading this, then you are in the minority. Caffeine is undoubtedly the world's (yes, world) most popular drug, with over 450,000,000 cups of coffee consumed in the United States alone every day. I'm sure many of you are like me, and simply have trouble believing that something with such noticeable energy/mood/focus/endurance enhancing effects could possibly be as perfectly healthy as it seems to be. I decided that I was going to get to the bottom of this, so I emailed my Indian virtual assistant from ihabilis.com and asked him to research the in depth effects of caffeine in the body. Specifically, I wanted to know what happens in your body when you drink caffeine, what the studies say it is good for, and what the studies say it is bad for. He came back to me in 5 hours with a 26 page word document containing what appeared to be 5 to 7 different websites' information pasted into a word document with no indication of which site was which. Over the next 3 days I read the whole thing, and started thinking to myself, "Oh man, this blog is going to be fun." So here we go.

Before we get into the details, I would like to point out that the internet is full of folks who insist on having empirical evidence for everything before they will give it any credibility. While I can't blame them for wanting information to be correct, this generally means a study where scientists were able to isolate caffeine and test whether or not it was the single determining factor in whether or not someone experienced a reported symptom. If isolated caffeine does not cause the symptom directly, caffeine is deemed to have little to no effect on that symptom. Unfortunately, this is somewhat unrealistic in my opinion. As you will soon find out, 50% of the human population would die if we all ingested 10,000 mg of caffeine at once (50 strong cups of coffee). This is called the LD-50 for those who like scientific terms, which stands for Lethal Dose - 50% and is determined using rats. But who is to say that a liter of alcohol, 3 super sized french fries, 1000 mg of caffeine and 4 cigars wouldn't kill 50% of people as well? My guess is that study has yet to be done (at least in a lab). So just keep this in mind when it appears that we've come to the conclusion that caffeine is been deemed as "healthy in moderate doses."

Now that the disclaimer is over with, it's time to hear the fun stuff!  

The Basics

While coffee is clearly the most common source of caffeine in the world, there are over 60 plants that naturally contain caffeine. It turns out plants developed caffeine for their own personal reasons and not to help us pass our final exams. Caffeine is a natural pesticide because it has a very bitter taste and is toxic to the system of an insect given the volume to weight ratio (it literally paralyzes and kills them). It can be equally toxic to humans when consumed in large quantities as you read above. Ordinary human consumption of 500 mg per day is generally accepted to have low health risks, and even has a protective effect against some diseases. 

What Does Caffeine Do to Me?

I'm sure you all know the basic effects of caffeine: energy, clear thinking, jitters, increased heart rate, etc. and it may even be relatively clear to you that these types of effects can be very harmful when doses are taken to the extremes, but what is really going on inside your body? 

Caffeine literally tricks your brain and blocks it from telling you that you are drowsy. Here's how it works. When you have a thought, your brain uses energy. Just like when an alkaline battery produces battery acid, any energy producing process will have an acid byproduct. In this case, neurons firing in your brain produce adenosine as a byproduct. Your nervous system constantly monitors your adenosine levels through receptors in your brain and spinal chord to determine when you have used too much energy and it needs to release a number of drowsiness chemicals to nudge you toward sleep. 

Caffeine is a chemical relative of adenosine and the receptors in your nervous system can't tell the difference between the two. So when you ingest caffeine, it is accepted by the adenosine receptors as a kind of "placeholder" and serves to block the real adenosine from getting in. Not only does your nervous system not get the depressant effect of adenosine, the caffeine actually stimulates the nerves and puts the body into a state of emergency (hence, stimulant). This causes the pituitary gland to release hormones telling your adrenal glands to fire up your "fight or flight" response. 

This master of disguise can also mimic epinephrine within your heart. The effects of this on the heart are very similar to those on the nervous system, but it is more of a complicated multi-step process. Basically, epinephrine normally binds with receptors in your heart to tell them to release enzymes that block cAMP (cyclic adenosine monophosphate) which would in-turn activate a protein kinase which produces the adenosine triphosphate (ATP) needed for muscle contractions and relaxation of the heart. To make a very long story short, your heart rate increases because caffeine has tricked your nervous system again. 

Read more: Why Does Caffeine Raise the Heart Rate? | eHow.com http://www.ehow.com/how-does_5185453_caffeine-raise-heart-rate_.html#ixzz2FjUlKqlI

Is Caffeine Addictive?

In the United States the average daily intake among adult caffeine drinkers is 280 mg, which is the equivalent of 17 ounces of brewed coffee (Folgers not Starbucks, Starbucks has more) or 84 ounces of coca-cola. Anyone that goes through life with their eyes open, even if their squinting a lot, can tell that caffeine is addictive. The question then becomes what is really going on inside your brain that causes this? 

I won't get too in-depth on the subject of brain plasticity, but if you like the stuff you're reading, I recommend The Brain That Changes Itself by Norman Doidge. Basically, it was long believed that the brain is a static machine that cannot be changed, and after years of controversy, neuroscientists finally agree that the brain does in fact change itself to adapt to it's environment. As it turns out this happens extremely fast too, like in a few training sessions on Sudoku or a week of consuming caffeine. 

This process is extremely applicable to caffeine consumption in the body and is entirely responsible for both tolerance building and withdrawal symptoms. Our brains are a bit smarter than we gave them credit for when they got tricked by the caffeine molecules. After a few days of drinking coffee, your brain literally restructures itself to better exist in the environment that you have built for it. It increases the amount of receptor cells so that it can handle the load of the caffeine and still have room for the adenosine. This works out okay if you have a way to keep your caffeine levels consistent, but caffeine has a half-life of about 6 hours and it's pretty difficult to keep the levels the same all the time. This means that if you have 100 mg of caffeine in the morning, there will be 50 mg in your system 6 hours later, and 25 mg in your system 6 hours after that. Unfortunately, when your caffeine levels get low, those extra receptors detect too much adenosine and make you drowsy. The good news is that the brain will also remove the extra receptors after about 2 weeks with no caffeine, but they will be busy messing with your nervous system in the meantime causing headaches, nausea, drowsiness and more of the familiar side-effects of caffeine withdrawal. It is recommended not to go cold turkey when you decide to cut back, and just reduce by about 50 mg per day.  

Caffeine in Sports:

I don't want this blog post to get too long for fear of people not reading it all, but I just had to include this part. 

Anyone who plays sports and drinks caffeine has without a doubt noticed that it has some effects on your ability to do things, and in most cases enhances it, but I stumbled across this study that was extremely interesting to me. It was published in the Journal of Applied Physiology and compared the effect of coffee and caffeine on run time to exhaustion. A group of nine men took part in five trials. The following is taken directly from the article summary:

Sixty minutes before each run, the men took one of the following:

  • A placebo
  • Caffeine capsules
  • De-caffeinated coffee with caffeine added
  • Regular coffee
Performance times were up to 10 times longer in subjects using the caffeine capsules, with no differences in times among the other trials. Since the level of caffeine absorption was similar during the caffeine trials, researchers concluded something in the coffee itself that interferes with caffeine's performance-enhancing effects. This makes sense considering that there are literally hundreds of compounds dissolved when coffee beans are roasted, ground and extracted.

Results of this research suggest that if benefits of caffeine on endurance times are desired, caffeine capsules work better than coffee.

Interesting huh? Recognizing that this was a pretty small number of test subjects, it still seems to have pretty overwhelming result. Personal experience with coffee before work outs compared to energy drinks (the healthy-ish kind like Hi-Ball Energy which is carbonated water and caffeine only) has shown me the same type of results but to a lesser extent than the ridiculous factor of 10 mentioned above.

Is Caffeine Healthy?

If you read my disclaimer, you are probably already aware that most of the research I came across does say that caffeine is perfectly safe for long term use in moderation, and it generally is. You will have to deal with the roller coaster of drowsiness that we have generally become accustomed to, but it is "safe." I'll go through a few quick specifics without too much detail.

There are claims that caffeine leads to osteoperosis because it increases the amount of calcium in urine. While these have been debunked by the Mayo Clinic, it was on the basis that this is not "enough" calcium to cause osteoperosis. As I said before though, it is contributing to the overall cumulative effect of calcium depletion, and could contribute if combined with other things. 

There are also promising claims that caffeine has an moderate protective effect on Alzheimer Disease, but the evidence is generally deemed inconclusive on the basis that there are a large number of factors thought to cause the disease. This might be another example of the cumulative effects mentioned above. 

A study recently showed that coffee drinkers have an average of 20% less cases of Cirrhosis in the liver among heavy long term alcoholics. This was actually a large sample size with conclusive results, but they could not determine whether the results were due to caffeine itself, or the other compounds in coffee. Either way, this is somewhat encouraging for coffee.

A report from the National Research Council on Diet and Health stated, "evidence linking coffee consumption to the risk of coronary heart disease...is weak and inconsistent."

According to a 1989 report from the Framingham Heart Study: "Caffeine does not cause chronic hypertension or any persistent increase in blood pressure. Some individuals sensitive to caffeine may experience a short-lived rise in blood pressure, usually not lasting more than several hours. Studies show any rise in blood pressure is modest and less than that normally experienced when climbing stairs."


It would appear that Michael Pollan's 7 words for eating "Eat food, not too much, mostly plants" pretty much sums this one up again. Caffeine is perfectly acceptable to drink every day in moderation, but much like cacao leaves vs cocaine and so many other refined things in today's society, it's definitely not a good idea to extract active ingredients of food and take a bunch of it all at once. It's hard to drink enough coffee to kill you before you throw up, but you could definitely hurt yourself with a mega shot of caffeine that has been extracted and concentrated. So drink up and have a Merry Christmas!  

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