Influence Of Mind On Food Digestion
With the progress of biological chemistry, digestion came to be
considered a purely chemical process. Now we realize that even more
important than the chemical factors of digestion is the individual
liking for particular kinds of food, and the mental attitude of the
patient toward digestion.
Not only may mental factors interrupt or hamper digestive processes
generally but, as the investigations of Pawlow
t the Imperial
Institute of St. Petersburg show, they may modify very materially the
chemical processes within the stomach. If, for investigation purposes,
a stomach pouch be experimentally segregated in a dog from the rest of
the stomach, and the dog be fed food that he has a particular liking
for, the gastric juice manufactured will be especially strong and
effective. If the food given be less to the dog's liking, the gastric
juice is not nearly so efficient in its activity. Finally, if food be
consumed for which the dog does not care, but which he takes because
hunger compels him, the gastric juice manufactured for its digestion
is quite weak and the process of digestion is slow. If this is true
for an animal like the dog, whose psyche is comparatively of much less
importance than that of human beings, the corresponding influences in
men and women will be even more emphasized. This is only what common
experience has always shown us. The human stomach is not a test-tube
in which mere chemical processes are carried on, but its vital
activity is of great importance. That vital activity depends to a
large extent on the state of mind, on the relish with which food is
eaten, on the individual likes and dislikes, and on the emotional
condition during digestion.
Prejudices and Digestion.--Perfectly good food materials may become
difficult or impossible of digestion as the result of learning
something about their mode of preparation. In the country this is
often noted, with regard to butter, milk, and even eggs. The story of
the farmer's wife who wanted to trade her own butter for an equivalent
amount made by someone else illustrates the influence of mind over
relish for food. She was candid enough to say that the reason she
wanted to exchange the butter was that a mouse had been seen in the
cream, and her children could not, therefore, eat it. She took
back home with her exactly the same butter in another crock, and there
was no further difficulty, though before this the children would have
been actually sick if compelled to eat the butter. I once saw a family
of three women who had vomited because they heard that the dishes had
been washed in a slop pan, though this proved to be a mistake. Such
occurrences emphasize the necessity for properly predisposing the
mind, and for removing unfavorable suggestion, if digestion is to
proceed properly.
Mental States and the Stomach.--The typical example of the influence
of the mind on the digestive tract is to be found in the experiences
of Flaubert, the French novelist, while writing "Madame Bovary." When
he was writing the scene in which he describes the effects of the
arsenic which Madame Bovary takes, he himself suffered from
practically all the symptoms due to the drug. In order to describe it
faithfully he had studied it carefully. He had the pains, the
vomiting, the burning feeling and even the garlicky, metallic taste in
his mouth. Such an incident is extremely exceptional, yet its
possibility is recognized, and it illustrates how sensitive some
people are to the action of mental states upon the body, and how large
a role a strongly excited imagination can play in producing definite
physical symptoms. There are many more such realistic imaginations
than we have, perhaps, been inclined to suspect. It is over these
particularly that the psychotherapeutist can exert his influence by
helping to modify the cause of their symptoms, the mental attitude
which exists, rather than by trying to change the symptoms which are
only effects, for diseases must, as far as possible, be treated in
their causes.
Disgust and Disturbance of Digestion.--Max Mueller's story, told in
his book on "Language," to show how language might have been a human
invention from imitation of natural sounds, illustrates the influence
of an unfavorable state of mind in disturbing digestion. An
Englishman, traveling in China, fearful lest he should not be able to
obtain food that he cared for, because of his lack of knowledge of the
language of the country, was rather surprised on his first day's
journey into the interior, to be served with a stew made of some kind
of dark meat that tasted very well indeed and with which he was so
much pleased that he asked for a second helping. Just as he was about
to eat the second portion, he thought it well to ask the waiter what
sort of meat it was, as he wished to be able to obtain the same kind
at other places. Calling the waiter to him, he said, pointing to the
dish of meat with a questioning tone, "Quack, quack?" The waiter at
once shook his head and said, "Ugh! bow wow!" The Englishman pushed
the second portion away and got up from the table.
Tinder the same circumstances nearly everybody would feel the same
qualmishness--at least all who had been brought up according to our
Western notions. Reason has little or nothing to do with it. It is a
question of feeling. The dog is much more cleanly in its habits than
the hog, but we in the West are used to the idea of eating hog-meat
just as they in the East are used to eating dog-meat. The objection,
of course, might be urged that the difference between the hog and the
dog is that we do not eat carnivorous but only herbivorous animals.
But the slop-fed hogs from the neighborhood of our large cities,
constituting a goodly portion of those brought to market, eat meat
quite ravenously. They certainly are not exclusively herbivorous.
There is no principle behind our objection to dog meal
then--only the unfamiliarity of the idea of eating it.
The treatment of patients with digestive disturbances requires a
careful analysis of the conditions of mind towards foods. If prejudice
exists with regard to certain foods, there will be no relish for them,
and unless these prejudices can be removed, the foods either will not
be taken, though they represent important nutritional elements, or
else they must be taken in such small quantities and digested with so
much consciousness of their presence and such difficulty as to be a
disturbing factor for health. Persuasion, the custom of the country,
habit, training, mean much for this modification of mental attitude.
Custom and Food.--In recent years many parts of animals, not
generally eaten before, have come to be consumed with a relish because
of the removal of prejudices against them. It might be thought that
organs like the kidney, the essential function of which is excretory,
and through which so much of the offensive waste products of the body
pass, could not be a relished article of food. But it has become quite
a dainty. The liver, owing to the peculiar nature of its function, its
very special flavor, and the staining with bile, might be expected to
be objectionable. It is not, but, strange to say, a third organ of the
abdominal cavity, the spleen, which has none of the external
objectionable features of kidney or liver, is not yet eaten, and most
people would probably find it rather difficult to eat it. This
difficulty would result, not because of anything in the organic
substance itself, but because of the lack of accustomedness to it.
There are a number of people who now have trained themselves to eat
it. Such apparently impossible portions of the animal as the
intestines, even those of the hog, are eaten with relish by a great
many people, though there are others who have never been able to get
used to them. The dainties of some peoples are utterly repulsive to
others. The French like brains and other special portions of animals
that are not much eaten by Anglo-Saxons. Fried brains in black butter
sauce are enough to turn the stomach of some people by the very
thought of it, though it is a highly prized dish in the south of
France.
In Italy most visitors eat snail soup with relish before they know
what it is. It seems to be a special kind of gumbo soup. Down at
Marseilles, gourmets occasionally eat angle-worms and find them to be
a very appetizing dish. In all of these things the question of relish
and peaceful, happy digestion depends entirely on the attitude of
mind. The first men who ate eels must have been looked upon with
considerable suspicion by their neighbors as viper eaters, and
probably they themselves were not comfortable over the feat. It has
been said that the first man who ever swallowed an oyster performed as
great a feat as any of our important inventors or discoverers.
Gastric Antipathies.--To the great majority of mankind the idea of
eating horseflesh is repulsive. Numbers of people in various parts of
Europe have found, however, that after the initial repugnance is
conquered, it is quite as pleasant to eat as cow's meat. To my taste,
at least, it is much more palatable than venison or bear meat. At the
beginning, its sweetish taste has a curious reflex effect. Taken in
connection with the thought that this is horse meat, the taste is apt
to produce a sensation of nausea. This is readily overcome, though the
first time it is necessary to keep constantly inhibiting the
mind from acting unfavorably upon the stomach during the course of
eating and digestion. Custom, I learned from many, soon made it quite
as savory as beef.
Food Varieties and the Mind.--How easy it may be to overcome many
prejudices in the matter of food digestion under the stress of
necessity and the influence of example, was well illustrated during
the siege of Paris. The Parisians, though a most delicate people in
the matter of eating, were able to accommodate themselves to the
conditions, and practically every kind of animal was eaten with a
relish. Before the siege, to most of them it would have seemed quite
impossible, that they should sit down with complacency to the dishes
which afterwards were so appetizing. At the beginning there was a
definite attempt to conceal the eating of rats, mice, cats and dogs
under various names, and by various modes of preparation. But it was
not long before there was an end of this pretense. The animals in the
zoological garden proved a veritable life-saving store of meat. Every
one of them was eaten, people were glad to get them, and paid high
prices for them. Camel steaks, elephant cutlets, lion and tiger stews,
appeared under their own names, even at the banquets of the wealthy.
What is true of the mental attitude for meats influencing not only the
relish for them, but their digestion, is also true for many
vegetables. There are unfavorable suggestions in the minds of many
with regard to the supposed indigestibility of potatoes, turnips,
carrots, beans and occasionally with regard to tomatoes, lettuce, or
the like. A few definite physiological idiosyncrasies against these
vegetables, or certain of them, do actually exist. The attitude of
mind, however, is largely responsible for the discomfort that occurs
after the consumption of most of them. Patients who ought to consume
more starchy substances, or whose bowels need the residual materials
that are contained in these vegetables, for the sake of their effect
upon peristalsis, should be persuaded to take these vegetables, first
in small quantities and then in gradually increasing amounts. Many of
them can thus be brought to a diet at once more nutritious and more
likely to help out intestinal function. Their objection to them is
usually but a fancy.
Genuine Food Idiosyncrasies.--There are certain genuine idiosyncrasies
with a physiological basis which prevent the taking of certain kinds
of food, or cause disturbance if they are taken, but these are rare.
Their presence should never be considered as demonstrated by
subjective signs alone for these are eminently fallacious. In certain
cases, however, so rare as to be almost always curiosities in medical
practice, there are definite objective symptoms of the idiosyncrasy.
These consist of urticarial rashes, tendencies to vomiting, or
diarrhea, or both. Sometimes these result from the most bland and
nutritious of foods. I have notes of the cases of two children--whose
father could not eat eggs without vomiting--and to whom fresh eggs fed
at the age of two and three years, always produced this same effect.
Even small portions of egg would cause it. It mattered not how the egg
was prepared, nor even whether it was carefully concealed in custard
or in cake provided there was a certain amount of it, the food eaten
with it would be vomited. There are many such idiosyncrasies for shell
fish, cheese, and such fruits as strawberries, pineapples,
pomegranates and the like, but they are demonstrated by objective
signs. But by far the greater number of food dislikes are entirely
subjective and the subjective feelings can probably always be
overcome by habit and training.
Food Dislikes.--Milk.--Nothing makes more clear the absolute
dominion of the mind over the stomach than the likes and dislikes of
people for various kinds of milk. Most Americans can take cow's milk
with good relish, though there are a few to whom it is distasteful. In
this country we have not had much experience with the milk of other
animals. Even goat's milk is not commonly used. The very thought of
taking it disturbs many people, and to take it with other food would
almost surely produce disturbance of digestion. I have seen people
while traveling quite upset over the discovery that goat's milk had
been put into their tea or coffee. Mare's milk is commonly used in
some parts of Europe and in many parts of Asia, but it would be quite
impossible to most of our people. Sheep's milk is used in some places.
Ass's milk is commonly used in parts of Asia and may be obtained in
Spain and is said to be less likely to disagree with children in
summer than cow's milk. Most American mothers would rather not hear of
it.
The same thing is true of the milk products. Some people find certain
kinds of cheese quite out of the question though other people relish
them. It requires special training, not of stomach but of mind, to
enable one to eat certain cheese, though once the habit has been
acquired such articles are delicious. It is only in recent years that
some forms of cheese with greenish tints have become popular in
America. To serve them at a dinner a generation ago disgusted many
people. Now a dinner does not seem complete without them.
The beverages of various countries illustrate this same principle. The
wines the Spaniards care for are not palatable to the Italians, and
vice versa. Beer, as the result of familiarity, is now drunk
everywhere in Europe, but when it was first introduced into Italy from
Germany, it was considered impossible to understand how anybody could
take it and pretend that its taste was pleasant. The question is said
to have been once asked of one of the Congregations at Rome whether it
was permissible to take beer on fast days. The Cardinals who tasted it
declared that not only did it seem to them permissible but that it was
a mortification to drink it and therefore it was proper Lenten
exercise.
Eggs.--Many people have a supposed natural repugnance for eggs which
they are sure indicates that these are not good for them. As a result,
the physician gets all sorts of stories with regard to the supposed
effects of eggs. One person tells you that more than two eggs a day
makes him bilious. Another will tell you that they are too heavy for
him. A third will tell you that they are distinctly constipating. A
fourth will tell you that they produce a tendency to diarrhea. Here,
as with regard to milk, the experience of the tuberculosis sanatoria
has shown that there are but few people who cannot, when properly
persuaded and when eggs are given in various forms, take from four to
six eggs in the day without injury, and even without inconvenience. In
these cases, it is largely a matter of mental attitude towards the
food. In many instances, it will be found that the disinclination
began in some experience in childhood when an egg was not very good,
or when it was served insufficiently cooked, or when, perhaps, eggs
always cooked one way were made a staple of the diet for a
considerable period. There are over one hundred ways of cooking
eggs and this variety of preparation will often make them palatable,
and nearly always digestible.
Over and over again I have seen people who had thought that eggs made
them bilious, and who accordingly had for long refused to eat them,
put in circumstances (from tuberculosis, diabetes, or obesity) where
eggs had to form a considerable portion of the diet. Then there was no
difficulty about eating and digesting eggs. In three cases in my
experience patients with an objection they thought constitutional,
developed glycosuria, and then nearly all their desserts were
custards, and eggs became a standing dish in their daily diet. In
every case not only was there no trouble, but they got to like the
eggs and wondered why they should ever have had any prejudice against
them. Two of the patients were women, the third a man who had not
touched eggs for many years. His wife's comment was: "Eggs always made
him bilious when he did not take them, but now that he is taking them
freely they no longer make him bilious."
Mental Changes and Digestion.--The change that has come over the
public mind with regard to sour milk is a typical illustration of how
much a difference in the mental attitude towards a food product may
mean for its satisfactory consumption by many people. Sour milk,
though many farmers and working people thought it a pleasant acid
beverage, was for long looked upon as a product fit at most to be fed
to the pigs, if, indeed, there might not be question even of the
advisability of this. Only the very poor who craved the nutritious
value there was in it, continued to take it to any extent. Even if the
milk still tasted sweet, but broke when it went into the tea, that was
enough to make it quite impossible for many sensitive stomachs.
Lactic Acid as a Bactericide.--Then came Metchnikoff's announcement
that his studies showed sour milk to be an extremely valuable food
material, but much more than that, an important auxiliary for the
lessening of microbic life in the intestines. He seemed to be able to
demonstrate that a great many bacteria, whose products, absorbed from
the intestines, hastened that process of deterioration in the tissues
that we call old age, were inhibited when sour milk or lactic acid
bacteria were present. The general health of the person who took sour
milk was, as a consequence, much better. Not only this, but processes
of deterioration being lessened, prolonged life and even old age could
be promised to those who drank sour milk in sufficient quantities.
Metchnikoff had been brought to the study of this question by what he
had seen on the Steppes of Russia. Among the nomad tribes a principal
part of whose diet consists of soured mare's milk, he found a large
proportion of very old people. In looking for the reason for this
disproportionate longevity, he came to the conclusion that the sour
milk had something to do with it. Then laboratory observations and
experiments as to the influence of the bacillus, that causes the
souring of the milk, on the growth of other bacteria, and especially
such bacteria as are usually found in the human digestive tract,
seemed to show that the lactic bacteria had a strong inhibitory effect
on nearly all the pathologic flora of the intestines.
As the result of these studies, all the world is now quite willing to
take its share of sour milk. We no longer hear the complaint that
uncomfortable feelings in the digestive tract are the result of taking
milk that was a little sour.
Since this doctrine of Metchnikoff's has come to be popularly known,
fewer patients have insisted that they could not take milk in such
quantities as the physician thought desirable for them. Before that, a
persuasion with regard to the ease with which milk becomes
contaminated with microbes, and the dread that it might thus be a
source of disease, or at least of disturbance of digestion, made it
very difficult of digestion for many people. Now that they have a good
authority who insists that, even if it should become somewhat soured
in the ordinary way, this, far from making it a pathological article
of diet, rather adds to its value from a therapeutic standpoint, has
changed the attitude of mind of these people.
We need a similar feeling with regard to eggs in order that they may
be eaten by many people who now refuse them because they fear the
possible evil results of taking even a slightly tainted egg. Our
recent pure food investigations have shown that the bakers in our
large cities have been for many years using canned eggs, and that
these would be quite impossible of consumption except disguised as
they are in the midst of baker's products. Sometimes these eggs have
been kept for several months before being canned. All the cold storage
eggs that cannot be disposed of otherwise are thus treated. In spite
of the common use of these canned eggs by a large proportion of the
city population no serious results have come from them. The change
that comes over eggs in time does not apparently spoil their nutritive
quality, but only disturbs their taste. The main element in the change
is the production of hydrogen sulphide. This gas has a very unpleasing
odor, but its presence is not of pathological significance. This gas
is a common ingredient in those mineral waters that are known as
sulphur waters, and that have a reputation for curing many forms of
digestive disturbance, especially chronic cases of nervous
indigestion. What is true of sour milk, then, would seem to be true of
eggs that have been, to some degree, spoiled, and at least no serious
results may be expected from them. If serious results were to be
expected, we should have had many evil reports of them in recent
years. Whether considerations of this kind will help patients, who
need to get over qualminess with regard to eggs, because they are
always suspicious lest they should not be fresh, will depend a good
deal on the suggestive value of such information as presented by the
physician.
Another Organic Acid.--Sauerkraut has shared the fate of sour milk,
and because of its acid bacteria has been accepted by Metchnikoff as
an ally. Yet sauerkraut used to be thought quite out of the question
for invalids, especially those suffering from digestive disturbances.
I recall the case of an old German shoemaker who had lived very much
on sauerkraut when he was a young man and then, having made money in
the manufacture of shoes, had not had much of it for thirty years,
pleading with me, when he was old and it was rather hard to get
anything to stay on his stomach, that he should be allowed to have
sauerkraut. On the principle that what a man craves is usually what
does him good, I allowed it. The physician with whom I was in
consultation was perfectly sure there would be trouble, and the family
were confident that his physicians evidently had given up all hope and
were quite ready to yield to his caprices and let him take anything
that he cared for. He not only took the sauerkraut without any
trouble, though I must confess to some misgivings myself (for I am of
those who unfortunately do not care for it and, therefore, was
prejudiced), but after having eaten a large plateful of sauerkraut
twice a day for several days, he began to crave other things that
would not stay down before, retained them well, digested them without
difficulty, and got over that attack of indigestion and lived for
several years afterwards. His own mental attitude was a better index
than our supposed knowledge, though science has now come to confirm
his state of mind.
Bacon and a Change in Suggestion,--Another food material with regard
to which there has been a complete change of view in recent years, is
bacon and hog products generally. Pork in all forms used to be
considered quite indigestible, and was one of the first things that
people suffering from indigestion--or the fear of it--eliminated from
their diet. Now we know how valuable a food product it is, especially
for those inclined to suffer from constipation, or who are under
weight. Many people still look surprised when advised to eat it
regularly. Here we have a typical example of the change in the mental
attitude toward a particular article of food bringing about a
corresponding difference as regards not only the appetite for it, but
also its digestibility. Many persons, who used to have no appetite for
breakfast, now find that after eating a crisp piece or two of bacon,
they develop an appetite for other foods. Bacon has become a fetish
for some people and is considered a help, not a detriment to
digestion.
I recall a case in which I had very nearly the same experience with
bacon as I related with regard to sauerkraut. The patient was an
elderly woman, probably nearly ninety years of age, who, because of a
crippling deformity, had not been able to get outside of the house for
many years. She sat in a wheel chair, transported herself from one end
of an apartment to another, spent most of her time by the window, but
was very helpful in many little things about the house and occupied
her hands with knitting and sewing. In spite of her condition, she was
cheerful, pleasant, happy, and all her life had had a good digestion,
her only trouble being a tendency to asthma as she grew old. I came
back to the city after a summer vacation to find that she was not
expected to live because nothing would stay on her stomach. She was
sinking, and the end seemed not far off. I was asked to see her more
because I had been her regular physician for some years, and it was
thought that it would console her to see me than with any real hope of
betterment. It had been extremely hot weather and this seemed to be an
unfortunate circumstance. At my visit, I asked her if there was
anything that she cared for. She shook her head and yet there seemed a
hesitancy. I urged her to tell me if there was anything that she
wanted, but only after considerable urging did she venture to say that
there was something, only that she knew that she could not have it.
Putting her thumb on the top of her little finger, she said, "Oh, I
would like so much to have just a teenie-weenie bit of bacon." I said
that she should certainly have it. Then taking courage, she asked if
she could not have a little cabbage with it. I said, "Certainly." Her
friends thought that it was just a yielding to one of the last wishes
of an invalid with the idea that nothing could much harm her, since
she was so near the end. She had eaten cabbage and bacon all her life;
she ate it again with a relish, and in spite of the heat kept it down
and digested it well. She had bacon and cabbage next day, and for
several days; she gradually got strong and lived several more years of
her happy contented life.