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 at 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


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


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


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


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


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.

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