Gettysburg Medical News
 The Clinical View
 by P.E. Hoffsten, MD
 5 October 2005

COFFEE AND CAFFEINE  -  THE GOOD AND THE BAD

            Depending on how you define the word, the most commonly used “drug” in the world is caffeine.  It doesn’t require a prescription.  It comes in all manner of drinks including coffee (50 -150 milligrams), tea (40-80 milligrams), cola drinks (100 milligrams), and a variety of “energy drinks”.  It is present in chocolate bars (50 milligrams) and cocoa.  It comes as an over-the-counter constituent of weight loss pills, energy pills, pain pills, and products to keep you awake such as Nodoze (200 milligrams).  A single dose of 1000 milligrams of caffeine will predictably cause over-stimulation and a single dose of 10,000 milligrams (50 Nodoze tablets) has been reported to be fatal.   Fatalities from caffeine overdose are very rare.  It has been touted as the product that kept armies going in times of war and the product that kept you awake on a long driving trip.  It is present in virtually every office in the country.  Large amounts of shelf space are taken up in all of our variety stores and novelty stores selling coffee makers, coffee itself and the various things to put in it.

            A patient came in recently stating that they wanted to change their lifestyle and get themselves “straightened out”.  The gentleman felt that he drank too much coffee and wondered if it was something that he should stop or if it was harmless after all.  Using a search engine through the National Library of Medicine, I found that there are more than 20,000 medically related articles pertaining to coffee in the past ten years. I did not read them all but below is a summary of what I told this gentleman.

            The first point to make is that there are two types of individuals in our society.  One of these is the people that drink coffee all the time and become habituated to its effect.  The other is a group of people who drink coffee infrequently and are not habituated to it.  Coffee and caffeine have a much greater stimulant effect on individuals who are not used to it.  Attention span and physical endurance in a time of fatigue are improved by coffee in the individual who is not used to it.  The opposite seems to be true of those who have become habituated to coffee.  The telling effect on them is what happens if they don’t get coffee.  Their performance goes down and they fatigue more easily than if they have their coffee.  Thus in both groups of people, coffee is definitely a stimulant.

            The gentleman questioned whether or not coffee raised his blood pressure which was already somewhat elevated.  Caffeine and coffee definitely raise blood pressures between 5 and 10 mm of mercury.  Thus if your resting blood pressure resting is 120/70, after a cup of coffee, it is about 130/70-80.  This would seem to be a detrimental effect on people’s health and especially on those individuals who have high blood pressure to begin with.  But in all of those 20,000 articles about coffee at the National Library of Medicine, there is no data that says that coffee causes strokes or heart attacks.  This is strange because we believe that high blood pressure contributes to strokes and heart attacks.  The answer seems to be that the problem is “sustained” high blood pressure.  When a person drinks coffee, the blood pressure goes up for a brief period of time and then the blood pressure drops back down again relatively quickly within the hour.  Strokes and heart attacks come in those individuals whose blood pressures are elevated all of the time.  Coffee doesn’t seem to cause that.  And as strange as it seems, there is not information that has shown that coffee is more dangerous in a hypertensive individual.  It just makes sense that it would be but all the life expectancy statistics have not shown a detrimental effect from coffee.

            There is a misconception on why coffee raises blood pressure.  The commonly held view is that coffee is a heart stimulant that makes the heart pump harder and put out more blood to serve the body.  In fact, studies have shown that coffee constricts blood vessels.  The reason that the person’s blood pressure goes up is that the resistance of the blood vessels in the hands and the feet gets bigger and it is even harder to pump blood out to your hands and feet than it was without coffee.  If you think about it, this just makes sense because coffee does make your hands and feet colder.

            The gentleman next asked about coffee effects on the stomach.  He noted that sometimes if he quit drinking coffee for a day or two, his stomach got better.  Coffee is definitely a stimulant for the person to make more stomach acid.  This doesn’t bother some individuals but for others it can cause definite abdominal discomfort and irritation of the stomach.  Surprisingly, even decaffeinated coffee is a stimulant for stomach acid.  It is not just the caffeine that makes coffee a gastric irritant.

            The next question had to do with the gentleman’s “touch of diabetes”.  I first told him that there is no such thing as a “touch of diabetes”.  Diabetes is like pregnancy.  Either the person is pregnant or they are not; but there is no such thing as “a touch of pregnancy”.  Diabetes is the same way.  Either the person is diabetic or they are not: but, there is no diabetic tendency.  He wanted to know if coffee was bad for diabetes.  The very surprising answer is that coffee drinkers seem to have a lower incidence of diabetes.  This surprising answer has now been confirmed in three separate studies.    Thus coffee does not seem to be a problem for diabetics.

            Lastly, the gentleman asked about whether coffee made him more irritable.  He said that he knew that sometimes “good, strong” coffee would make him “shaky and irritable”.  The answer is that coffee and caffeine lead to the release of adrenalin from the various body stores.  Adrenalin definitely makes the person more shaky and for some people “more irritable”.  For some people, a strong cup of coffee will lead to perspiration which is an effect of the adrenalin release.

            In summary, I told the gentleman that coffee by itself was not going to shorten his life.  Most of the effects that coffee has on the body are related to the amount of caffeine.  This is related to how strong the person brews the coffee.  Some people kind-of turn the water brown and other individuals make coffee that would corrode the spoon.  These are matters of personal taste and how much “jitteriness” the individual is willing to put up with.  I told him that if he wanted to change his lifestyle, the absence of an “upper” type stimulant like coffee would be something to consider.  But coffee is not something that shortens the person’s life by any measure that we have thus far.