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MIND ENVIRONMENT INTERACTIONS By John W. Crayton, MD, Professor of Psychiatry, The interplay between mental and physical functions of the body has been noted since ancient times, but modern researchers are developing an even greater appreciation for the interaction between physical and mental aspects of bodily functioning. Physical well-being promotes mental well-being and visa versa. Among those physical components of healthy living, which influence mental functioning, sound nutrition is clearly one of the most important. We know about numerous diseases of malnutrition, such as scurvy and beriberi. In special situations, certain individuals with inherited defects in metabolic function may recover healthy functioning with greatly increased amounts of vitamins. Others, such as those born with phenylketonuria, are substantially benefited by modifications in diet. Based on the careful studies of Wurtman1, Anderson2, Spring3, and others, we have learned that the foods we eat can influence the neurochemical substrates of behavior and can alter mood, performance and memory processes. Studies from our own lab have suggested that individuals may develop hypersensitivity to one or more foods that can also affect behavior. In a study of 23 food-sensitive individuals, 17 were shown to have statistically significant changes in mood or behavior when challenged with double-blind, placebo-controlled administrations of powdered, encapsulated foods. The most commonly incriminated foods were wheat, milk, and corn. Of particular interest was the finding that a system of proteins that circulate in the blood stream and are known to mediate some of the effects of immunologically mediated responses to foreign agents showed significant alterations following the food challenges (Crayton 4,5). These proteins have also been shown in other studies to affect brain activity and behavior. Our current studies are designed to examine the possibility that one of these substances mediates the effects of food or other foreign substances on the brain and behavior.
Each of these studies addresses the possibility that metabolic responses to environmental agents such as foods might affect brain activity and behavior. But what of the other side of the interactive mind-body equation? Studies carried out over the past decade have begun to illuminate the ways in which the activity of the mind affects a whole host of bodily functions. A rapidly growing body of research indicates that altering the psychosocial environment can alter an animal’s propensity for developing cancer. When genetically-susceptible strains of rats were housed in a crowded environment that they experienced as stressful, their rate of developing tumors increased from 10 percent in a nonstressed situation to 90 percent in a stressful one (Riley6). Of course it is more difficult to show such a relationship in humans because of the difficulty in keeping humans cooped up for extended lengths of time, but some studies have suggested that women who are depressed have a significantly higher incidence of cancer than those who are not. Perhaps mental depression also depresses the body’s capacity to fend off cancer. In another sphere, a group of studies by Besedovsky and colleagues7 has shown that the brain has a significant effect on the expression of allergic reactions. For example, experimental animals can be sensitized to a foreign antigen in such a way that any further exposure to that antigen will usually be lethal. By placing brain lesions in certain areas of the hypothalamus, the lethality of the subsequent exposure is markedly attenuated. Besedovsky has shown that the electrical activity of the brain in these critical regions is altered when an allergic reaction is occurring. In humans, alterations in brain activity that do not involve lesions have produced shifts in the expression of allergy. For example, hypnosis has reportedly altered allergic reactions to skin testing. Also, patients with multiple personality disorder (the "four faces of Eve" syndrome) may break out in hives when exposed to oranges when one personality has the upper hand and be able to eat oranges without problems when another personality is in control. Much more study is needed to document this sort of phenomenon and to understand its mechanisms.
Another very important line of study has been explored by Robert Ader and colleagues at the University of Rochester 8,9. Ader has shown that an experimental animal can "learn" to suppress its immune system in much the same manner that Ivan Pavlov’s dogs could learn to salivate at the sound of a bell. In Adler’s studies, rats were given an immunosuppressant agent at the same time they were given saccharin. The rats seemed to associate the sweet taste of the saccharin with the suppressing effects of the cyclophosphamide on immune functions. When the animals were subsequently given saccharin, they developed immune suppression even though they did not get another dose of the cyclophosphamide. This remarkable finding has far-reaching implications for the study of the mental and physical effects of exogenous agents. Is it possible that a person could "learn" to have headaches, inflammatory reactions in bowels or joints, or flare-ups of skin disorders so that the exposure to a generally innocuous agent (which had previously been paired with a noxious one) could produce the adverse reaction? This question must be considered when assessing the reactions that individuals have to foods, chemicals, and environmental antigens. What mechanisms might mediate these effects of the brain on immunity? One set of studies by Kiecolt-Glaser, Kennedy, and colleagues at Ohio State University 10,11,12 suggests that stress has an immunosuppressant effect on certain cells critical to a healthy immunological response to foreign antigenic substances. In several groups of subjects, e.g., medical students during exam week or the caretakers of patients with Alzheimer’s disease, these workers have found deficits in the expected reactions of white blood cells to standardized antigenic stimulation. Perhaps further studies of this type of effect will clarify how a mental process can lead to altered reactivity of the immune system.
Over the past several years, many people interested in the effects of allergens, particularly dietary ones, on the brain and body function have sequestered themselves in two, frequently antagonistic camps, one group claiming that individuals with altered brain functioning – from anxiety to depression and schizophrenia – are reacting to foreign antigens, the other group claiming that such patients are simply neurotic. Attacks from one side or the other have frequently become vicious, with concerted attempts to thwart the solid, legitimate findings of the other side or with ad hominem attacks on the character or mental health of opponents. But the principal fault in both groups’ arguments is the failure to appreciate the intricate interaction between brain and immune system. The fact, for example, that white blood cells have receptor sites on their surface which bind all the brain neurotransmitter chemicals suggests that both nerve cells and white blood cells are capable of responding to many of the same signals. Other factors, such as good nutrition, undoubtedly have direct and indirect effects on both the immune system and the brain.
Much more research is needed on the interaction of brain and immune system. Only then can we arrive at a solid understanding of the ways in which dietary and other allergens affect the brain and how much mental processes modulate those reactions. _________________________ 1Wurtman, R.J., "Effects of dietary amino acids, carbohydrates, and choline on neurotransmitter synthesis," Mt. Sinai Journal of Medicine 55(1):75-86, 1987. 2Anderson, G.H., "Diet, neurotransmitters and brain function," British Medical Bulletin 37:95-100, January 1981. 3Spring, B., "Recent research on the behavioral effects of tryptophan and carbohydrate," Nutrition and Health 3:55-67, 1984. 4Crayton, J.W., "Immunologically mediated behavioral reactions to food," Food Technology 40:153-57, 1986. 5Crayton, J.W., "Adverse reactions to foods: Relevance to psychiatric disorders," Journal of Allergy and Clinical Immunology 78:243-50, 1986. 6Riley, V., "Psychoneuroendocrine influences on immunocompetence and neoplasia," Science 212:1100-09, June 5, 1981. 7Besedovsky, H.O., A.E. del Rey, and E. Sorkin, "Immuneneuroendocrine interactions," Journal of Immunology 135 (2 Suppl.):750s-54s, August 1985. 8Ader, R., and N. Cohen, "Behaviorally conditioned immuno-suppression," Psychosomatic Medicine 46:4-14, January-February 1984. 9Ader, R., and N. Cohen, "High time for psychoimmunology (letter)," Nature 315:103-04, May 9-15, 1985. 10Kiecolt-Glaser, J.K., W. Garner, C. Speicher, G.M. Penn, J. Holliday, and R. Glaser, "Psychosocial modifiers of immuno-competence in medical students." Psychosomatic Medicine 46:7-14, January-February 1984. 11Kiecolt-Glaser, J.K., R. Glaser, E.C. Shuttleworth, C.S. Dyer, P. Ogrocki, and C.E. Speicher, "Chronic stress and immunity in family caregivers of Alzheimer’s disease victims," Psychosomatic Medicine 49:523-35, September-October 1987. 12Kennedy, S., J.K. Kiecolt-Glaser, and R. Glaser, "Immunological consequences of acute and chronic stressors: mediating role of interpersonal relationships," British Journal of Medical Psychology (England) 61:77-85, March 1988. Article from NOHA NEWS, Vol. XIII, No. 4, Fall 1988, pages 3-4. |
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