The Field of Psychodietetics
- Author:
Martin F. Fritz, Ph.D.
Associate Professor of Psychology, Iowa State College, Ames, Iowa Although physicians, physiologists and biochemists have, in recent years, given a great deal of consideration to diet and nutrition, psychologists have given this field but little attention. Less than a half dozen reports are to be found in strictly psychological journals, if drugs and fasting are excluded. Most of the psychological observations have been made incidentally by specialists in other fields whose interests were primarily physiological rather than psychological. In the vast body of literature which has grown up on the question of diet we may find many suggestions of important problems which need to be investigated from the psychological angle. Valuable contributions to knowledge can be made by those who are thoroughly trained in the scientific approach to behavior, and whose interests would be fixed upon the psychological aspects. Dietary studies have rapidly assumed increasing importance and because of the popular appeal it should be possible to enlist public support for investigation. It is to be hoped that psychologists with a good background of training in biochemistry will turn their attention to this field and develop the psychological phases until they compare favorably with the contributions made by other investigators.
It would seem desirable to have some term which would refer to the psychological phases of dietary situations. To meet this need we may coin the term psychodietetics. Wood and Weeks (8) define dietetics as “the science of the feeding of an individual in sickness and in health.” Using this as a basis, we may define Psycho-dietetics as “the science of the feeding of an individual in sickness and in health with particular reference to the mental aspect.” This definition clearly designates the field which concerns the relationship between diet and mental life. Broadly speaking, the term psychodietetics may be used to cover not only those cases where diet is a factor in the direct causation of mental * Paper read before the Section on Clinical Psychology of the American Psychological Association, The University of Chicago, September 12, 1933. phenomena but also where behavior has a dietary expression as, for example, in the ease of food fads due to peculiar notions on the part of the individual.
Among the diseases now definitely attributed to dietary defects or deficiencies are certain ones which involve mental or neurological symptoms. Pernicious anemia, pellagra, sprue, nightblindness and beriberi are diseases which have dietary significance and are accompanied by symptoms of particular interest to the psychologist. Perhaps the most outstanding example is pernicious anemia. Mental symptoms were mentioned by Addison who first described the malady in 1855. Almost every writer, in giving a description, mentions symptoms suggesting a psychopathological condition as a part of the syndrome. A long array of symptoms have been mentioned by various writers but no constant psychopathological symptomatology has been worked out. However, there seems to be rather general agreement that at least 80 per cent of the patients will show definite mental involvement. It is possible that the incidence is even higher as might be discovered by more accurate methods of diagnosis. It is claimed that the mental symptoms may precede the blood picture by months or even years. These considerations point to the fact that pernicious anemia may have important legal implications, as in the case of wills. This problem has already arisen in the courts and if a case of pernicious anemia can be proved, there would seem to be good reason for setting aside the will (4). It is clear that a scientific consideration of this disease from the psychological angle, particularly with respect to the higher mental processes, would be very valuable. The etiology of pernicious anemia cannot be taken up at this time, except to say it is very doubtful that defective diet is the cause, although diet does seem to be the cure.
Pellagra, one of the deficiency diseases, is found mostly in the Southern states where it is sufficiently prevalent to constitute an important problem. It has been referred to as the disease of the three D’s?diarrhoea, dermatitis and depression. Although a variety of mental symptoms have been reported, they do not seem to present any clinical uniformity with the possible exception of depression. The disease terminates in a psychosis with a rather high degree of frequency. It has been argued that pellagra does not directly cause but merely uncovers the psychosis, but if this is true it would seem to be a rather efficient agent for uncovering psychoses. This malady awaits a thorough investigation from the psychological angle. Concerning the question of the etiology of pellagra, it seems that a vitamin Gr deficiency is the most favored hypothesis at the present time. It is interesting to note that almost from the very beginning of the study of this disease, it has been thought to have some close connection with diet and treatment has nearly always been dietary. Sprue is a disease which was formerly thought to be a purely tropical disorder. In recent years cases have been reported in the United States. Investigators have reported that it bears certain resemblances to both pellagra and pernicious anemia and that it is sometimes confused with these two maladies. The alleged presence of mental symptoms makes sprue a disease of psychological interest.
Nutritional nightblindness, to be differentiated from idiopathic nightblindness or retinitis pigmentosa, is a disorder which was known to the ancients and, what is even more interesting, they knew the cure for it?the eating of liver. Spence (7) reports that this cure is handed down as tribal lore among the Eskimos and other primitive races. Nightblindness, attributed to defective diets, has been observed in China, Newfoundland, Labrador and other places. Administration of cod liver oil is said to result in a decided improvement within twenty-four hours. The effectiveness of liver and cod liver oil as therapeutic agents points rather forcibly to a vitamin A deficiency. This factor, along with exposure to strong light, seems to offer the most plausible etiological explanation. Kecent experimental work on rats supports this hypothesis. If nightblindness can be produced or cured almost at will by dietary methods, it would offer interesting possibilities for the psychological investigation of certain visual phenomena. Beriberi, now commonly attributed to a lack of vitamin B in the diet, is characterized by peripheral nerve degeneration which results in anesthesia, paresthesia and disturbed reflexes. There have been relatively few observations of disturbance of the higher mental processes. However, several reports of neural degeneration in the spinal cord and brain suggest the possibility that some mental effects might be found, were a careful psychological investigation made. Acrodynia is a children’s disease which has come to occupy the attention of pediatricians in recent years. The patients are said to present such a picture of abject misery that a case once seen will never be forgotten. Fortunately, acrodynia does not seem to be very common. Besides the evident pain and misery, there is photophobia and paresthesia. Some investigators have considered diet an important factor both in causation and treatment but this is not accepted by all clinicians.
Migraine is an old affliction and few disorders have had so many etiological explanations. That it is a neurosis has been suggested but apparently this hypothesis has not greatly aided in its treatment. In recent years the supporters of food allergy have claimed that in many cases it is possible to secure great benefit or even a complete elimination of the paroxysms by means of dietary control. The symptoms of migraine should make it of considerable psychological interest. The most prevalent and essential feature is a periodic headache, generally though not always unilateral, which may vary from a short attack hardly to be noticed to complete prostration lasting for days. Sometimes there are visual phenomena, vertigo, nausea and a feeling of dullness. Although the victims report that an attack means considerable shock to the body, there does not seem to be any deterioration of mentality as in the case of epilepsy. It is even a prevalent idea that only individuals of superior intellect are subject to migraine but this has been sharply challenged. Psychological tests should prove to be of value in settling this point.
The mental features of epilepsy are familiar to psychologists and so will not be given special consideration. This disease, known since antiquity, has provoked a great variety of treatments directed toward supposed causes ranging from spirits to physical pathology. In recent years, one more method of treatment has been added to the list and that is the ketogenic diet. For this reason it becomes necessary to consider epilepsy in a discussion of psychodietetics. The ketogenic diet is enthusiastically supported by some, who explain failures on the grounds that the subjects either did not adhere rigidly to the dietary schedule or else were confirmed institutional cases. It is claimed that cases of petit mal and newly developed cases are most successfully treated. Those who support food allergy as a causal factor maintain that the particular food or foods to which the individual is sensitive are accidentally withheld in the ketogenic diet. If the belief, strongly held by some, that epilepsy is a disorder of metabolism is correct, then we may have some hopes that dietary treatment will be of benefit. It seems to be widely accepted that brain lesions may lead to epileptic seizures, in which case diet could hardly be expected to have any influence. The suggestion has been made that infantile convulsions might be controlled by eliminating offending proteins from the diet and in this way avoiding future cases of epilepsy. On the whole, it may be said that dietary control in the early stages of epilepsy looks promising but much work still needs to be done. Balyeat (1) reports that allergic children have a higher mental rating than non-allergic children which he suggests may be due to greater nervous sensitivity on the part of the allergic children. The nervous sensitivity would be considered a part of the greater general tissue irritability which manifests itself as a food allergy. If this hypothesis can be verified it would open the way for studies on a possible relationship between personality and food. It is evident that there are excellent opportunities for cooperative research to be carried on by allergists and psychologists.
Maurer and Tsai (5, 6) report pronounced bad effects upon the learning ability of white rats when vitamin B is withheld during the nursing period only. These findings do not necessarily conflict with those of Fritz (3) who found but little effect on mature rats even with a combination of salt defectiveness and vitamin B deficiency. That vitamin B deficiency results in nervous degeneration is hardly open to question, but what the psychological effects may be has received little attention.
It has been supposed for a number of years that intestinal toxemia is responsible for a great many alarming symptoms including profound mental effects. Some physicians, and no doubt the majority of the public, believe thoroughly in the horrible effects of intestinal toxemia. A few have flatly challenged these beliefs. Studies on voluntary constipation (2) suggest that the bad effects are reflexive and due to a packing of the colon with fecal material rather than a toxic condition. The difficulty of stating exactly what is meant by intestinal toxemia and how it would be produced, along with the scarcity of well-controlled experimental investigations, still leaves this field a “free for all.” However, if it is as prevalent as is generally thought and the nervous and mental symptoms are as profound as it is often claimed, then there can be no doubt that scientific information would be of the greatest practical value.
It seems very probable, judging from rather careful experimental work, that vitamin B deficiency will result in anorexia. Clinically, it is found that feeding infants a high vitamin B diet stimulates appetite.
It is not possible at this time to take up all of the situations which should receive consideration in a discussion on psychodietetics. Some of these can only be mentioned. Neurasthenia, hyperexeitability, “nervousness,” sexual virility and fatigability are found by some to be related to diet. Racial vigor and temperament have not been clearly established as a function of food although this interpretation has been strongly defended. Instinct as a guide to food has received experimental consideration and the results would seem to point to an ability of both animals and humans to select food according to nutritional requirements. In conclusion, it may be stated that perhaps the findings in the field of psychodietetics should, for the most part, be considered tentative. One of the conspicuous faults in most of the reported observations is the complete absence of control groups. While it is certainly true that in many cases it would be difficult, if not impossible, to secure a control group, we can hardly lower our standards of scientific accuracy because of this. The clinician must act according to the most plausible hypothesis and he can scarcely withhold treatment just to find out what will happen. It must be recognized that the clinician is treating to cure and not performing an experiment. More laboratory work is needed and a partial solution may lie in the experimental use of animals. Only a few specific references to literature have been made m this paper since a review and fairly complete bibliography on psychodietetics up to 1933 will be published later.
References
Balyeat, R. M. The general health and mental activity of allergic children, Amer. J. Dis. Child., 1929, 37, 1193-7.
2. Donaldson, A. N. Relation of constipation to intestinal intoxication, J. Amer. Med. Asso., 1922, 78, 884-8. 3. Fritz, M. F. Maze performance of the white rat in relation to unfavorable salt mixture and vitamin B deficiency, J. Comp. Psychol., 1932, 13, 365-90. 4. Hulett, A. G. The psychological and medicolegal aspects of pernicious anemia, Med. J. and Eec., 1928, 127, 1-6. 5. Matjrer, S., & Tsai, L. S. Vitamin B deficiency and learning ability, J. Comp. Psychol., 1930, 11, 51-62. 6. Maurer, S., & Tsai, L. S. The effect of partial depletion of vitamin B complex upon learning ability in rats, J. of Nutrition, 1931, 4, 507-16. 7. Spence, J. C. A clinical study of nutritional xerophthalmia and nightblindness, Arch. Dis. in Childhood, 1931, 6, 17-26. 8. Wood, B. M., & Weeks, A. L. Fundamentals of dietetics, W. B. Saunders Co., 1930.
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