Differing Opinions On Coffee, Effect On Brain, Heart, Kidney
( Originally Published 1936 )
We all drink a great many things which do not come under the heading of food. None of them being necessary to sustain life, opinions are sharply divided as to their effect.
At one end of the list is the verdict which instinctively comes to certain mindsó"Dangerous, very bad for you." In the middle isó"Silly thing to do, but harmless." And at the other endó"Positively beneficial to health."
All of these opinions, as you know, are expressed about coffee.
If a representative group of people were to be polled for their views on the subject, it may be imagined that they would compose the following essay on coffee:
"Coffee keeps you awake. It increases mental efficiency and is a good thing to drink when preparing for an examination, etc. It is bad for the kidneys. Too much of it makes you nervous. Three cups of it a day is too much and I am going to cut that down to one cup at breakfast. But it all depends on how you make it."
In order to evaluate all this, let us first inquire into the action of its active ingredientócaffeine. The one thing we are certain the caffeine does is to increase the blood, flqwpcwliy through the brain, the heart and the kidneys. Whether this is due to direct stimulation of the" heart -muscle or dilation of the small blood vessels, is not agreed. Some physicians believe that this increased blood supply is the explanation of its stimulating actionóit keeps you awake because it brings more blood to the brain. Others postulate a specific stimulating action on the brain cells. Whichever is right, the action is there.
The dose of caffeine in an average cup of coffee is from one and a half to three grains, and this is an average medical dose of the drug. Like all other drugs, however, tolerance is established confirmed coffee drinkers require larger doses to get the effect.
As to the general results of the coffee habit, too much of it certainly makes for nervousness. Everybody agrees that it is bad for children. They do not need the stimulation and there is good evidence that coffee interferes with digestion.
For older people, on the contrary, it may be a positive benefit. It may pump just enough extra blood through their hearts to keep them going. The best authorities say that coffee in the amounts used for beverage purposes has no permanent effect on the kidneys one way or the other.
It is a matter of common observation that people drink coffee for years without shortening their lives.