Chapter 36
Oddly enough, a cup of hot, weak tea or coffee, with plenty of cream and sugar, will often help you to sleep, for the grateful warmth and stimulus to the lining of the stomach, drawing the blood into it and away from the head, will produce more soothing effects than the small amount of caffein will produce stimulating and wakeful ones.
The writer has often had people remark to him that while black coffee sometimes kept them awake, coffee with cream or sugar or both made them drowsy.
In the course of experiments conducted by Montuori and Pollitzer[198] it was found that coffee prepared by hot infusion when given by mouth or hypodermically with the addition of a small dose of alcohol proved an efficient means of combating the pernicious effects of low temperatures.
Coffee prepared by boiling, and tea, showed negative effects.
The value of coffee as a strength-conserver, and its function of increasing endurance, morale, and healthfulness, was demonstrated by the great stress which the military authorities, in the late and in previous wars, placed upon furnis.h.i.+ng the soldiers with plenty of good coffee, particularly at times when they were under the greatest strain. Various articles[199] record this fact; and these statements are further borne out by the data given below in the discussion of the physiological effects of caffein, to which the majority of the stimulating effects of coffee may be attributed.
According to Fauvel,[200] with a healthy patient on a vegetable diet, chocolate and coffee increase the excretion of purins, diminis.h.i.+ng the excretion of uric acid and apparently hindering the precipitation of uric acid in the organism. This diminution, however, was not due to retention of uric acid in the organism.
"Habit-forming" is one of the adjectives often used in describing coffee, but it is a fact that coffee is much less likely than alcoholic liquors to cause ill effects. A man rarely becomes a slave of coffee; and excessive drinking of this beverage never produces a state of moral irresponsibility or leads to the commission of crime. Dr. J.W.
Mallet,[201] in testimony given before a Federal Court, stated that caffein and coffee were not habit-forming in the correct sense of the term. His definition of the expression is that the habit formed must be a detrimental and injurious one--one which becomes so firmly fixed upon a person forming it that it is thrown off with great difficulty and with considerable suffering, continuous exercise of the habit increasing the demand for the habit-forming drug. It is well known that the desire ceases in a very short period of time after cessation of use of caffein-containing beverages, so that in that sense, coffee is not habit-forming.
[Ill.u.s.tration: MEN AND WOMEN LABORERS PICKING COFFEE ON A SO PAULO ESTATE]
[Ill.u.s.tration: SACKING COFFEE IN A WAREHOUSE AT THE PORT OF SANTOS]
[Ill.u.s.tration: PICKING AND SACKING COFFEE IN BRAZIL]
It has been shown by Gourewitsch[202] that the daily administration of coffee produces a certain degree of tolerance, and that the doses must be increased to obtain toxic results. Harkness[203] has been quoted as stating that "taken in moderation; coffee is one of the most wholesome beverages known. It a.s.sists digestion, exhilarates the spirits, and counteracts the tendency to sleep." Carl V. Voit,[204] the German physiological chemist, says this about coffee:
The effect of coffee is that we are bothered less by unpleasant experiences and become more able to conquer difficulties; therefore, for the feasting rich, it makes intestinal work after a meal less evident and drives away the deadly ennui; for the student it is a means to keep wide awake and fresh; for the worker it makes the day's fatigue more bearable.
Dr. Brady[205] believes that the so-called harmfulness of coffee is mainly psychological, as evidenced by his expression, "Most of the prejudice which exists against coffee as a beverage is based upon nothing more than morbid fancy. People of dyspeptic or neurotic temperament are fond of a.s.suming that coffee must be bad because it is so good, and accordingly, denying themselves the pleasure of drinking it."
The recounting of evidence, both _pro_ and _con_, relevant to the general effects of coffee could continue almost _ad infinitum_, but the fairest unification of the various opinions is best quoted from Woods Hutchinson[206]:
Somewhere from 1 to 3 percent of the community are distinctly injured or poisoned by tea or coffee, even small amounts producing burning of the stomach, palpitation of the heart, headache, eruptions of the skin, sensations of extreme nervousness, and so on; though the remaining 97 percent are not injured by them in any appreciable way if consumed in moderation.
So, if one is personally satisfied that he belongs to the abnormal minority, and has not been argued by fallacious reasoning into his belief that coffee injures him, he should either reduce his consumption of coffee or let it alone. Even those most vitally interested in the commercial side of coffee will admit that this is the logical procedure.
_Effects of Coffee on Children_
The same sort of controversy has raged around the question of the advisability of giving coffee to children as has occurred regarding its general action. Dr. J. Hutchinson[207] advocates furnis.h.i.+ng children with coffee, while Dr. Charlotte Abbey[208] is strongly against such a practise, claiming that use of caffein-containing beverages before the attainment of full growth will weaken nerve power. Nalpa.s.se[209]
observes that until fully developed the young are immoderately excited by coffee; and Hawk[210] is of the opinion that to give such a stimulant to an active school-child is both logically and dietetically incorrect.
Dr. Vaughn[211] advances this scientific argument against the drinking of coffee by children under seven years of age:
In proportion to body weight the young contain more of the xanthin bases than adults. They are already laden with these physiological stimulants, and the additional dose given in tea or coffee may be harmful.
In a study of the effects of coffee drinking upon 464 school children, C.K. Taylor[212] found a slight difference in mental ability and behavior, unfavorable to coffee. About 29 percent of these children drank no coffee; 46 percent drank a cup a
As a refutation to this experimental evidence is the practical experience of the inhabitants of the Island of Groix, off the Brittany coast, whose annual consumption of coffee is nearly 30 pounds per capita, being ingested both as the roasted bean and as an infusion. It is reported that many of the children are nourished almost entirely on coffee soup up to ten years of age, yet the mentality and physique of the populace does not fall below that of others of the same stock and educational opportunities.[213]
Pertinent in this connection is Hawk's[214] statement that young mothers should refrain from the use of coffee, as caffein stimulates the action of the kidneys and tends to bring about a loss from the body of some of the salts necessary to the development of the unborn child as well as for the proper production of milk during the nursing period. The caffein of coffee also increases the flow of milk, but the milk produced is correspondingly dilute and a later decreased secretion may be expected.
Furthermore, some of the caffein of the coffee may pa.s.s into the mother's milk, thus reaching the child, so that the use of coffee during the nursing period is undesirable on this ground also. Naturally, the question arises as to whether this arraignment is purely theoretical or based upon a.n.a.lytical and clinical data.
It is a difficult matter definitely to set an age below which coffee should not be drunk, as the time of reaching maturity varies with climate and ancestral origin. Yet, from a theoretical standpoint, children before or during the adolescent period should be limited to the use of a rather small amount of tea and coffee as beverages, as their poise and nerve control have not reached a stage of development sufficient to warrant the stimulation incident to the consumption of an appreciable quant.i.ty of caffein.
_Coffee Drinking and Longevity_
There are many who would have us believe that the use of coffee is only a means toward the end of quickly reaching the great beyond; but it is known that the habitual coffee drinker generally enjoys good health, and some of the longest-lived people have used it from their earliest youth without any apparent injury to their health. Nearly every one has an acquaintance who has lived to a ripe old age despite the use of coffee.
Quoting Metchnikoff[215]:
In some cases centenarians have been much addicted to the drinking of coffee. The reader will recall Voltaire's reply when his doctor described the grave harm that comes from the abuse of coffee, which acts as a real poison. "Well", said Voltaire, "I have been poisoning myself for nearly eighty years." There are centenarians who have lived longer than Voltaire and have drunk still more coffee. Elizabeth Durieux, a native of Savoy, reached the age of 114. Her princ.i.p.al food was coffee, of which she took daily as many as forty small cups. She was jovial and a boon table companion, and used black coffee in quant.i.ties that would have surprised an Arab.
Her coffee-pot was always on the fire, like the tea-pot in an English cottage (Lejoncourt, p. 84; Chemin, p. 147).
The entire matter resolves itself into one of individual tolerance, resistivity, and const.i.tution. Numerous examples of young abstainers who have died and coffee drinkers who have still lived on can be found, and _vice versa_, the preponderance of instances being in neither direction.
Bodies of persons killed by accident have been painstakingly examined for physiological changes attributable to coffee; but no difference between those of coffee and of non-coffee drinkers (ascertained by careful investigation of their life history) could be discerned.[216] In the long run, it is safe to say that the effect of coffee drinking upon the prolongation or shortening of life is neutral.
_Coffee in the Alimentary Tract_
When coffee is taken _per os_ it pa.s.ses directly to the stomach, where its sole immediate action is to dilute the previous contents, just as other ingested liquids do. Eventually the caffein content is absorbed by the system, and from thence on a stimulation is apparent. Considerable conjecture has occurred over the difference in the effects of tea and coffee, the most feasible explanation advanced being one appearing in the London _Lancet_.[217]
The caffein tannate of tea is precipitated by weak acids, and the presumption is that it is precipitated by the gastric juice and, therefore, the caffein is probably not absorbed until it reaches the alkaline alimentary tract. In the case of coffee, however, in whatever form the caffein may be present, it is soluble in both alkaline and acid fluids, and, therefore, the absorption of the alkaloid probably takes place in the stomach.
This theory, if true, goes far toward explaining the more rapid stimulation of coffee.
The statement has sometimes been made that milk or cream causes the coffee liquid to become coagulated when it comes into contact with the acids of the stomach. This is true, but does not carry with it the inference that indigestibility accompanies this coagulation. Milk and cream, upon reaching the stomach, are coagulated by the gastric juice; but the casein product formed is not indigestible. These liquids, when added to coffee, are partially acted upon by the small acid content of the brew, so that the gastric juice action is not so p.r.o.nounced, for the coagulation was started before ingestion, and the coagulable const.i.tuent, casein, is more dilute in the cup as consumed than it is in milk. Accordingly, the particles formed by it in the stomach will be relatively smaller and more quickly and easily digested than milk _per se_. It has been observed that coffee containing milk or cream is not as stimulating as black coffee. The writer believes that this is probably due to mechanical inclusion of caffein in the casein and fat particles, and also to some adsorption of the alkaloid by them. This would materially r.e.t.a.r.d the absorption of the caffein by the body, spread the action over a longer period of time, and hence decrease the maximum stimulation attained.
In a few instances, a small fraction of one percent of coffee users, there is a certain type of distress, localized chiefly in the alimentary tract, caused by coffee, which can not be blamed upon the much-maligned caffein. The irritating elements may be generally cla.s.sified as compounds formed upon the addition of cream or milk to the coffee liquor, volatile const.i.tuents, and products formed by hydrolysis of the fibrous part of the grounds. It may be generally postulated that the main causation of this discomfort is due to substances formed in the incorrect brewing of coffee, the effect of which is accentuated by the addition of cream or milk, when the condition of individual idiosyncrasy is present.
Without enlarging upon his reason, Lorand[218] concludes that neither tea nor coffee is advisable for weak stomachs. Nalpa.s.se,[219] however, believes that coffee taken after meals makes the digestion more perfect and more rapid, augmenting the secretions, and that it agrees equally well with people inclined to embonpoint and heavy eaters whose digestion is slow and difficult. Thompson[220] also observes that coffee drunk in moderation is a mild stimulant to gastric digestion.
Eder[221] reported, as the result of an inquiry into the action of coffee on the activity of the stomachs of ruminants, that coffee infusions produced a transitory increase in the number and intensity of the movements of the paunch, but that the influence exercised was very irregular.
An elaborate investigation of the action of tea and coffee on digestion in the stomach was made by Fraser,[222] in which he found that both r.e.t.a.r.d peptic digestion, the former to a greater degree than the latter.
The digestion of white of egg, ham, salt beef, and roast beef was much less affected than that of lamb, fowl, or bread. Coffee seemed actually to aid the digestion of egg and ham. He attributed the r.e.t.a.r.ding effect to the tannic acid of the tea and the volatile const.i.tuents of the coffee--the caffein itself favoring digestion rather than otherwise. Tea increased the production of gas in all but salt foods, whereas coffee did not. Coffee is, therefore, to be preferred in cases of flatulent dyspepsia.
Hutchinson, in his _Food and Dietetics_, opines:
As regards the practical inferences to be drawn from experiences and observations, it may be said that in health the disturbance of digestion produced by the infused beverages (tea and coffee) is negligible. Roberts, indeed, goes so far as to suggest that the slight slowing of digestion which they produce may be favored rather than otherwise, as tending to compensate for too rapid digestibility which refinements of manufacture and preparation have made characteristic of modern foods.
Regarding increase in secretory activity, Moore and Allanston[223]
report that in their experience meat extracts, tea, caffein solution, and coffee call forth a greater gastric secretion than does water, while with milk the flow of gastric juice seems to be r.e.t.a.r.ded. Cus.h.i.+ng[224]
and others support this statement. This action is partially explained by Voit on the grounds that all tasty foods increase gastric secretion, the action being partly psychological; but Cus.h.i.+ng observed the same effects upon introducing coffee directly into the stomachs of animals.
In general, a moderate amount of coffee stimulates appet.i.te, improves digestion and relieves the sense of plenitude in the stomach. It increases intestinal peristalsis, acts as a mild laxative, and slightly stimulates secretion of bile. Excessive use, however, profoundly disturbs digestive function, and promotes constipation and hemorrhoids.[225] There is much evidence to support the view that "neither tea, coffee, nor chicory in dilute solutions has any deleterious action on the digestive ferments, although in strong solutions such an action may be manifest."[226] After conducting exhaustive experiments with various types of coffee, Lehmann[227]
concluded that ordinary coffee is without effect on the digestion of the majority of sound persons, and may be used with impunity.
_Coffee in the Dietary--Food Value_
There are three things to be considered in deciding upon the inclusion of a substance in the dietary--palatability, digestibility without toxicity or disarrangement, and calorific value. Coffee is as satisfactory from these viewpoints as any other food product.
The palatability of a well-made cup of good coffee needs no eulogizing; it speaks for itself. It adds enormously to the attractiveness of the meal, and to our ability to eat with relish and appet.i.te large amounts of solid foods, without a subsequent uncomfortable feeling. Wiley[228]