ADHD Conference Presentation


William G. Crook, M.D.*


Upon completion of this session participants will be familiar with:
  • the relationship of food allergies/sensitivities to ADHD
  • the relationship of simple sugars (including beet sugar, corn sugar and cane sugar) to ADHD
  • the relationship of the yeast, Candida albicans to ADHD
  • the controversy surrounding these topics (including studies and reports which show that sugar and yeast play little or no role in causing ADHD or other types of brain dysfunction in children)


The child with ADHD resembles a jigsaw puzzle with several — or many — pieces out of place. Each child is unique and differs from every other child. Sometimes a child’s problem will be solved when his diet is changed and he’s given antiyeast medications.  In most children, however, other pieces of the puzzle must be put in place.

* Emeritus Fellow, American Academy of Pediatrics, American College of
  Allergy, Asthma and Immunology and American Academy of Environmental

Personal Experiences

I opened my office to practice general pediatrics in my hometown, Jackson, Tennessee in 1949.  Six years later, I read articles in the medical literature by Rowe,1 Randolph,2 Speer3 and Dees4 describing systemic and nervous symptoms caused by milk, wheat, corn and other common foods.

The relationship of foods to symptoms in these children was determined by eliminating common foods from the diet for five to seven days. If and when the child improved, the eliminated foods were eaten again, one food per day, and reactions were noted.  Using this diagnostic technique, I identified food-related problems in 50 of my patients in the late 1950s and published my observations in the May 1961 issue of Pediatrics. 

Although fatigue was the major complaint in the majority of these patients, mental and emotional symptoms (irritability, restlessness, inability to concentrate, peevishness and perversity) were noted in 49 of the 50 children, and in 26 the nervous symptoms were a major complaint.Included in my article were case reports on four of my patients and a review of the pediatric literature beginning with reports by B. R. Hoobler6 in 1916 and W. R. Shannon7 in 1923. 

During the ensuing years my interest in food-related problems continued and in the mid and late 1960s I began to see increasing numbers of children who today would be classified as ADHD.  I was pleased when I was able to help most of these youngsters using dietary changes. 

On January 1, 1973 I began a clinical study on the relationship of diet to hyperactivity and emotional, behavioral and learning problems. At the end of five years I’d seen 182 new patients with these complaints.

Seventy percent of the parents reported their child’s nervous symptoms were caused by dietary ingredients.  The causes of hyperactivity in these children included sugar (77), colors, additives and flavors (48), milk (38), corn (30), chocolate (28), egg (20), wheat (15).  However, many other foods were reported as causing trouble. 

I reported my observations in the Journal of Learning Disabilities,* in an article entitled, "Can What A Child Eats Make Him Dull, Stupid or Hyperactive."8  Forty-one parents reported an excellent response; 60 parents reported a good response; 18 parents reported a fair response; 16 reported a poor response.  Here are representative positive comments made by two parents:

Children’s Clinic Chart No. 43914: WO, age 6.  "Even a few bites of sugar, corn or eggs cause hyperactivity, nervousness, stuffy nose, hoarseness and other allergy symptoms.  Last year when WO was in kindergarten, he experienced trouble with discipline problems, paying attention to the teacher and sitting still in class.  This year he is in the top group of all of his classes, is well-adjusted and is not sick.  Diet really helps."  

Children’s Clinic Chart N. 43676:* CC, age 18 mos. when first seen.  "CC was expelled from nursery school at 18 mos. for aggressive behavior.  His worst troublemakers are red dye #2, peanuts, wheat, sugar and milk.  At the age of 4 ½ CC continues to be an extraordinary contrast to what he was 2 ½ year ago.  Instead of being the most trouble of four children he is now the least."

* A summary of this article was included in a Letter to the Editor in the New England Journal of Medicine in 1994.  For a copy of this article send a stamped, self-addressed envelope to International Health Foundation, Box 3494, Jackson, TN 38303.  

Support from academic colleagues:  Although many, and perhaps most, of my pediatric colleagues paid little attention to my observation I made a few "converts," including the late William Deamer, Professor of Pediatrics, University of California, San Francisco.  Here’s an excerpt from his 1971 article published in Pediatrics,

"Despite an extensive bibliography (the allergic tension-fatigue syndrome ) may be one of the most underdiagnosed syndromes in practice. Dr. William Crook finds such patients to be numerous in his general pediatric practice.  I agree, but it took me a long time to become fully aware of the fact."9

John W. Gerrard, Professor of Pediatrics, University of Saskatchewan, became interested in food allergies and sensitivities in the 1960s.  In his 1973 book, Understanding Allergies, he told the story of one of his patients who . . .

". . . used to be a restless, inattentive lad who was so fidgety in the classroom that he infuriated his teacher and upset most of the other children.  After milk was eliminated from his diet, his teacher said, ‘He now concentrates on his work.  He sits still as a statue and is a model to everyone else.’

"At first I found it hard to believe that harmless foods could so change a child’s personality; but many parents have made confirmatory, unsolicited observations.  I’m now convinced that in ways we do not yet understand, the allergic child’s, and adult’s too, behavior can be altered and modified as dramatically by foods as it can be altered by drugs."10

The late Frank A. Oski, M.D., in a chapter of his book, Don’t Drink Your Milk, discussed milk and the tension-fatigue syndrome.  Here’s an excerpt of his comments,

"There’s a growing body of evidence . . . to suggest that certain allergies may manifest themselves primarily as changes in personality, emotions, or in one’s general sense of well-being . . . These children will appear restless and in a constant state of activity.  They fidget, grimace, twist, turn, jump and just never seem to sit still.  Many of these children are also excessively irritable and can never be pleased . . . 

"An example of the magnitude of this problem is provided by the experiences of Dr. William Crook. 

In a group of 41 children he found that each child was allergic to an average of three foods. . .  28 were sensitive to milk.  Sensitivity to cane sugar was equally frequent.  Sensitivity to eggs, wheat and corn were also common."11

Walter W. Tunnessen, Jr., M.D.,* Oski’s colleague in New York and subsequently at Johns Hopkins, published an article about food allergies in 1979.   Here are excerpts,

"Over the past ten or so years ‘the voice crying in the wilderness’ that has caught my attention concerning this disorder, the tension-fatigue syndrome, is that of William Crook, M.D. of Jackson, Tennessee.  His article, ‘Food Allergy the Great Masquerader,’ (Pediatric Clinics of North America, 222-238, 1975), is worth reading and digesting. . .

"Motor symptoms may include overactivity, restlessness and clumsiness, sensory tension may be reflected in irritability, insomnia or hypersensitivity to pain or noise. . . The proof of the pudding is in some simple dietary elimination . . . the culprits I find most common are milk, chocolate and eggs, although cane sugar, corn and wheat should also be considered . . .

"I, too, had been a ‘doubting Thomas’ until my son responded to dietary elimination. . .  Do we need ‘hard data’ in a form of laboratory confirmation to support every diagnosis?  I think not.  ‘Soft data,’ subjective signs and symptoms can be applied just as rigorously to reinforce our hypotheses."12

In 1978, Doris Rapp, a pediatric allergist and a member of the clinical faculty at the University of Buffalo, published an article on the relationship of diet to hyperactivity in the Journal of Learning Disabilities.13  Since that time she has carried out scientific studies and made movies  documenting her observations and has published several books which focus on these topics.  

* CC was a National Merit Scholarship semi-finalist and received a four-year, all expenses paid scholarship at a major university.

*Dr. Tunnessen is now the Senior Vice President of the American Board of Pediatrics, 111 Silver Cedar Ct., Chapel Hill, NC 27514-1651.  

My Comments:   Only a small minority of my professional colleagues agree observations on the relationship of food to behavioral and learning problems in children. 

In an effort to encourage additional research studies, I sent a letter to Pediatrics, which was published in January 1982.  Here are excerpts,

"Although investigating the effects of sugar (or any dietary ingredient) on the behavior of children is difficult and complex . . . the time has come for carefully designed studies to be undertaken to throw more light on this controversial subject.   However, before such studies are done . . . the following pre-requisites should be met: 
  1. The study should be funded by an impartial body (not by the sugar or fabricated food industry).
  2. The scientists who undertake the study should go out ‘into the field’ and spend time with physicians who’ve been working with hyperactive children using the dietary approach.
  3. Those conducting the study should carefully review the large volume of medical literature relating to sensitivity reactions to foods. (There are more than 175 scientific articles and 25 books on the subject.)

"What a child eats can make him hyperactive.  And truly impartial, carefully designed scientific studies are urgently needed to document this relationship for the benefit of parents, children, physicians, teachers and everyone concerned with the health and welfare of children." 14

In 1979 I learned about yeast-related problems: I read an article by C. Orian Truss, M.D., an internist and allergist who described the relationship of the common yeast, Candida albicans to mental and nervous symptoms.15

Because of an explosion of interest in yeast-related problems, I wrote and published a hardback edition of  The Yeast Connection in 1983 and a paperback edition in 1986.  This book, which sold over one million copies, spread the yeast story all over the world.  Although my initial book is seriously out of date, I’ve published other books which include a discussion of yeast-related problems including Help for the Hyperactive Child and The Yeast Connection Handbook.

Other publications which discuss the relationship of yeast to health problems which affect children include The Missing Diagnosis by C. Orian Truss, M.D., Yeast Problems by Ray C. Wunderlich, M.D., The Candida Related Complex by Christine Winderlin and Keith Sehnert and Allergy Relief and Prevention by Jacqueline Krohn and colleagues. 

In spite of the observations by Dr. Truss and a number of other physicians, including professionals with impeccable academic credentials, the relationship of yeast to a number of chronic disorders was labeled "speculative and unproven" by a major medical organization in the mid 1980s.  Many physicians continue to cite this report.16  

Support for the relationship of sugar and yeast to ADHD and other types of brain dysfunction in children
  1. Data obtained by Bernard Rimland, Ph.D., Autism Research Institute.  Rimland summarized  information obtained from 8700 parents who filled out questionnaires about prescription drugs given to their autistic children.

    Forty-nine percent of the 208 parents found that their child was "better" on antifungal medication  (nystatin or Nizoral).  Only 4% said their child was "worse."   (The better/worse ratio was more than 12:1.)  

    None of the other prescription medications showed a better/worse ratio of more than 2:1 in 1161 children who were given stimulants the better/worse ratio was only 0.5:1.17  
  2. William Shaw, Ph.D. and colleagues in studies of children with brain dysfunction found elevated fungal metabolites and other abnormal acids in the urine of children with autism and ADHD.  Following treatment with the antifungal medications (nystatin or Diflucan) and dietary changes, all of the autistic children improved.18  

    In his recent studies on the relationship of yeast (and bacterial metabolites) to ADHD, Shaw found elevations in a number of compounds, including citramalic acid and furancarbonylglycine.19  
  3. Clinical Data July/August 1999: I sent questionnaires to 16 practicing physicians interested in the management of children with ADHD.  Eleven of the responders said that avoiding sugar was "very important," three said it was "somewhat important," and two said it was "not important."

    Five of the responders said that antiyeast therapy was "very effective" in managing these children and eight said it was "somewhat effective" in managing these children.  One responder said it was "not effective" and another responder said he had not tried this therapy.  
  4. Patricia K. Hardman, Ph.D., Tallahassee, FL, said, "In over 25 years of working with severely hyperkinetic and dyslexic children in our school, we’ve never recommended or needed to have one child on Ritalin.  Our regimen for these children includes the elimination of cow’s milk and sugar."  (Personal communication.)
  5. Ralph Campbell, M.D., FAAP, Polson, MT, said, "In over 30 years of practice I’ve only had to prescribe Ritalin for three children.  Most of these kids have trouble with only two substances — table sugar and cow’s milk."  (Personal c  6. Linda P. Rodriguez, M.D., FAAP, "I’ve encountered many children with ADHD.  In the past I was frustrated with the traditional approach until I learned about the relationship of yeast to these problems.  Since then, I’ve been able to help these children with positive results." 

What are some of the mechanisms which suggest the relationship of sugar and yeast to ADHD?
  • Children with ADHD often give a history of repeated ear infections in infancy.
  • Such ear problems are usually treated with amoxicillin and/or other broad spectrum antibiotic drugs.
  • A research study found that 69% of children being evaluated for school failure who were receiving medication for ear infections. By contrast, only 20% of non-hyperactive children had more than ten infections.20     

  • Antibiotics wipe out friendly bacteria in the gut while they’re knocking out enemies, as a result, the usually benign microorganism, Candida albicans, multiplies.

  • Based on the research studies by Iwata in the 1970s, candida puts out toxins which affect the nervous system, the immune system and other parts of the body.21

  • A study from St. Jude Children Research Hospital and the Department of Pediatrics, University of Tennessee showed that gastrointestinal growth of Candida albicans was approximately 200 times greater in mice who received dextrose than in a control group.  Dextrose availability allows C. albicans to colonize in the GI tract in an enhanced degree compared to xylitol and control groups. (P=0.001)."22

  • Changes in the gut flora play a part in causing increased permeability in the intestinal membrane (a "leaky" gut).  As a result, endotoxins, enterotoxins and food allergens are more apt to be absorbed, leading to further symptoms.

In 1987, W. Allan Walker, M.D., of Harvard University Medical School, discussed the role of the intestinal mucosal barrier in handling antigens.  In a comprehensive review of antigen handling by the gut, he said,

"Increasingly experimental clinical evidence suggests that large antigenically active molecules can penetrate the intestinal surface not in sufficient quantities to be of nutritional importance, but in quantities that may be of immunological importance."

"This observation could mean that the intestinal tract represents a potential site for the absorption of bacterial breakdown products, such as endotoxins and enterotoxins, proteolytic and hydrolytic enzymes or other ingested food antigens that normally exist in the intestinal lumen."23

A British physician, J. O. Hunter, FRCP, presented a hypothesis to explain the mechanisms that take place in people who experience adverse food reactions, including those with eczema and hyperactivity.  In his discussion he said that patients with food allergies have an abnormal gut flora, even though pathogens are not present.  And he stated,

"If food allergy is not an immunologic disease, but a disease of bacterial fermentation in the colon, it might be more appropriately named an ‘enterometabolic disorder.’ ... Modern microbiology has opened the way to the manipulation of bacterial flora to allow the correction of food intolerances and thus the control of disease."24


Sugar, Yeast (Candida albicans) and ADHD  


Sugar, Yeast and ADHD: Opposing Points of View

Here are reports from professionals who disagree with me-often strongly.

Mark L. Wolraich, M.D., Vanderbilt University School of Medicine, in a 1995 article in JAMA concluded,

"The meta-analytic synthesis of the studies to date found that sugar does not affect the behavior or cognitive performance of children.  The strong belief of parents may be due to expectancy and common association. However, a small effect of sugar or effects on subsets of children cannot be ruled out."25

In a subsequent report he stated,

"The main beneficial treatment (for ADHD) are two nonspecific treatments, stimulant medication and behavioral intervention, preferably in combination . . . Diets that restrict sugar have not been proved to be efficacious."26

D. W. Hoover and R. Milich, in a 1994 article stated,

"This study tested the hypothesis that commonly reported negative effects of sugar on children’s behavior may be due to parent expectations . . . Mothers in the sugar expectancy condition rated their children as significantly more hyperactive."27

D. A. Krummel and associates commented,

"Adverse behavioral responses to ingestion of candy have been reported repeatedly in the lay press. Parents and teachers alike attribute excessive motor activity and other disruptive behaviors to candy consumption . . . Although sugar is widely believed by the public to cause hyperactive behavior, this has not been scientifically substantiated. [emphasis added]

"Twelve double blind, placebo-controlled studies of sugar challenges failed to provide any evidence that sugar ingestion leads to untoward behavior in children with ADHD . . . For children with behavioral problems diet-oriented treatment does not appear to be appropriate."28 [emphasis added]

In his 1996 book, Taking Charge of ADHD, The Complete Authoritative Guide For Parents, Russell A. Barkley, Ph.D., Director of Psychology and Professor of Psychiatry and Neurology at the University of Massachusetts Medical Center, discussed a number of "myths" under the heading, "What does not cause ADHD."  Here are excerpts,

"Is It Sugar That Causes ADHD As I So Often Hear?  "Not a single scientific study has been provided by proponents to support these claims." [emphasis added]

Barkley reviewed the observations of Wolraich, Milich and others cited above and said,

"Most studies have failed to find any effects associated with sugar ingestion and the few studies that have found effects have been as likely to find sugar improving behavior as making it worse.  How can this be the case when nearly half the parents and teachers queried in one of these studies stated their child appeared to them to be quite sugar sensitive?"

Also, Barkley poses and answers this question, Can Yeast Cause ADHD?  Here’s an excerpt of what he had to say,

"Dr. William Crook, a pediatrician and allergist from Jackson, Tennessee has been a vocal proponent of yeasts . . . as a major cause of many different learning, behavioral and emotional problems, especially ADHD. . . Presently not a shred of sound scientific evidence supports Dr. Crook’s theory. Given that the American Academy of Allergy and Immunology have found the theory of yeast sensitivity unproven, parents are encouraged to ignore any advice based on it."29 [emphasis added]

In a widely publicized 1998 book, Running on Ritalin, Lawrence H. Diller, M.D., a California psychiatrist in discussing dietary theories said,

"I share with many parents, discomfort with today’s standard medical approach to ADD, especially its emphasis on the use of Ritalin for their children’s problems. . .  No one can legitimately claim they have the right answer for every child’s behavior problems. . . For the most part, those who explore natural alternatives are representing a descending minority, many of whom return to Ritalin when other methods fail.

"Eliminating foods that contain refined sugar, food additives and/or dyes, or salicylates . . . or all of the above, has led to improvement in many cases studies showing that dietary interventions worked with only a very small percentage of children."

In a paragraph entitled, "Antifungal and the role of candida," Diller said,

"A chief component of this theory recommends treatment and includes a control diet, elimination of environmental toxins, nutritional supplements and antifungal medication, especially for children with a history of antibiotic use.  Scientific support is lacking."30 [emphasis added]

A Closing Comment:

No single intervention, including the removal of sugar or antiyeast medications, provides a quick fix for the child with ADHD.  In my experience, and that of a number of professionals and nonprofessionals, these interventions can and do help many children. Here’s what I tell my patients, "Helping your child with ADHD can be compared to taking bundles of straw off of the back of an overloaded camel."

Further research is urgently needed to evaluate the clinical observations described in this report.

Questions and Answers:

True or False:
  1. Allergy prick tests are the best way to determine the presence or absence of sensitivity to milk, wheat, sugar or other common foods. (F)
  2. The presence or absence of a yeast-related disorder can best be determined from the history of the child receiving repeated or prolonged courses of antibiotic drugs and the child’s response to a comprehensive treatment program.  Such a program includes the avoidance of simple carbohydrates (especially corn, cane and beet sugar) and the administration of antifungal medications and probiotic supplements. (T)
  3. Children who consume diets which lack magnesium, zinc, Omega-3 fatty acids and other nutrients, are prone to develop behavior and learning problems.  (T)  
  4. Parents and professionals should be concerned about the exposure of children pollutants in homes and schools.  These include insecticide sprays, tobacco smoke, perfumes, odorous carpets  and other outgassing chemicals. (T)

  1. Rowe, A.H., "Allergic Toxemia and Migraine Due to Food Allergy: Report of Cases," Calf. West Med., 33:785, 1930.
  2. Randolph, T.G., "Allergy as a Causative Factor of Fatigue, Irritability and Behavior Problems of Children,:"
    J. of Pediatrics, 31:560, 1947.
  3. Speer,  F., "The Allergic Tension Fatigue Syndrome,"
    Pediat. Clin. N. Amer., 1:1029, 1954.   
  4. Dees, S.C., "Neurologic Allergy in Childhood,"
    Pediat. Clin. N. Amer., 1:1017, 1954.  
  5. Crook, W.G., et al, "Systemic Manifestation Due to Allergy.  Report of Fifty Patients and a Review of the Literature on the Subject, (Allergic Toxemia and the Allergic Tension- Fatigue Syndrome), Pediatrics, 27:790, 1961. 
  6. Hoobler, B.R., "Some Early Symptoms Suggesting Protein Sensitization in Infancy,"
    American J. of Dis. Child., 12:129, 1916.  
  7. Shannon, W.R., "Neuropathic Manifestations in Infancy and Children as a Result of Anaphylactic Reactions to Foods Contained in their Dietary," Am. J. Dis. Child, 24:89, 1922.
  8. Crook, W.G., "Can What A Child Eats Make Him Dull, Stupid or Hyperactive?,"
    Journal of Learning Disabilities, 13:1358, 1980.  
  9. Deamer, W.C., Pediatric Allergy: Some Impressions Gained Over a 37-year Period," Pediatrics, 48:930-938, 1971.  
  10. Gerrard, J.W., Understanding Allergies, pp 14-16, Charles C. Thomas Publishers, Springfield, IL, 1973. 
  11. Oski, F., "Milk and the Tension Fatigue Syndrome," in Oski, F., Don’t Drink Your Milk, Mollica Press Ltd.,
    Syracuse, NY 1977. 
  12. Tunnessen, W. W., "An 8-year old boy with lethargy and fatigue," CliniPearls, Dista Products Company, Division of Eli Lilly and Company, Indianapolis, Vol. 2 No. 6,
    July/August, 1979.
  13. Rapp, D., "Does Diet Affect Hyperactivity?," J. of Learning Disabilities, 11:56-62, June/July 1978 
  14. Crook, W.G., "Food and Behavior Studies Needed," Pediatrics, Vol. 69:128, January 1982. (Letter)  
  15. Truss, C.O., "Tissue Injury Induced by C. albicans: Mental and Neurological Manifestations,"
    J. of Ortho. Psych., 7:17, 1978.
  16. The Practice Standards Committee, American Academy of Allergy and Immunology: "Candidiasis Hypersensitivity Syndrome," J. Allergy Clin. Immunol., 78:273, 1986.
  17. Autism Research Review International, 4182 Adams Ave., San Diego, CA 92116, October 1994.
  18. Shaw, W., Chaves, S.E. and Luxem, M., "Abnormal Urine Organic Acids Associated with Fungal Metabolism in Urine Samples of Children with Autism: Preliminary Results of a Clinical Trial with Antifungal Drugs," Annual Meeting of the Autism Society of America, 1995.  
  19. Shaw, W., Personal communication, Great Plains Laboratory, 9335 W. 75th St., Overland Park, KS 66204, June 16, 1999,  Fax: 913-341-6207. 
  20. Hagerman, R. J. and Falkenstein, A.R., "An Association Between RecuMedia in Infancy and Later Hyperactivity," Clinical Pediatrics, 26:253-257, 1987.  
  21. Iwata, K. and Yamamoto, Y., "Glycoprotein toxins produced by Candida albicans," Proceedings of the Fourth International Conference on the Mycoses, June, 1997,
    PAHO Scientific Publication #356. 
  22. Vargas, S.L., Patrick, C.C., Ayers, G.D. and Hughes, W. T., "Modulating Effect of Dietary Carbohydrate Supplementation on Candida albicans Colonization and Invasion in a Neutropenic Mouse Model,"
    Infection and Immunity, 61:619, 1993.
  23. W. A. Walker, in Brostoff and Challacombe, Food Allergy and Intolerance, London, Balliere Tindal, Philadelphia,
    W. B. Saunders, 1987, pp 209-222.
  24. Hunter, J.O., The Lancet, 338:495-96, August 24, 1991.
  25. Wolraich, M.L., Wilson, D.B., White, J.W., "The Effects of Sugar on Behavior or Cognition in Children. A Meta-Analysis," JAMA, 1995, November 22/29; 274(20):1617-21.  
  26. Wolraich, M.L., Professional Care of Mother & Child, 1998; 8(2): 35-7.  
  27. Hoover, D.W., Milich, R., "Effects of Sugar Ingestion Expectancy on Mother-Child Interactions,"
    J. Abnorm. Child Psychol., 1994, August 22(4): 501-515.
  28. Krummel, D. A. et al, "Hyperactivity: Is Candy Causal?,"
    Crit. Rev. Food Sci. Nutr., 1996, January, 36(1-2): 31-47.
  29. Barkley, R. A., Taking Charge of ADHD, The Complete Authoritative Guide For Parents, The Guilford Press,
    New York, NY., 1996.  
  30. Diller, L.H., Running on Ritalin: A Physician Reflects on Children, Society and Performance in a Pill,, pp.140-144, Bantam Books, New York, 1998.
  31. Munoz, K.A., et al, "Food Intakes of U. S. Children and Adolescents Compared to Recommendations,"
    Pediatrics, 100:323-329, Sept. 1997.

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