Although it is a bit unusual, I have dedicated this issue to celiac disease. Our
lead article is based on this theme and constructed for the specific purpose of
raising awareness. Names of patients herein are fictional and have been changed
for complicity. In concert with our other reviews, the reader should be versed and
motivated to consider this condition as a possible co-morbid item with many
seemingly musculoskeletal entities. As with each issue, our goal is to stimulate
readers to search for expanded understanding of the concepts. I hope you enjoy it;
Bruce Gundersen, DC, FACO, Editor-In-Chief.
Dispelling Myths about Celiac Disease Leads to Better Case
Management: An Anecdotal Report
Kelly B. Jarvis Sr., DC
Journal of the Academy of Chiropractic Orthopedists
June 2015, Volume 12, Issue 2
The original article copyright belongs to the original publisher. This review is available from: http://www.dcorthoacademy.org © 2015 Jarvis and the Academy of Chiropractic Orthopedists. This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Patient held myths which the DC should “bust” to manage celiac effectively
Celiac disease, according to Peter H. Green, director of the Celiac Disease Center at Columbia University “is a multisystem disorder whose primary target of injury is the small intestine. The disease is triggered by gluten, the main storage protein found in certain grains.” The manifestations caused by the injury to the small intestine and the subsequent malabsorption syndrome that ensues are varied and complex.
My definition of a myth, for the purposes of this article, is something that once was held true, but no longer is– based upon what science knows now to be true. The modern Doctor of Chiropractic (DC) is in one of the best positions of all to help celiac patients dispel some of the myths that naturally arise regarding celiac disease because of the varied and complex manifestations. That is because the disease is best managed with a gluten-free diet not prescription drugs or other hospital or outpatient procedures. Dr. Green however, in order to help the affected individual better understand the condition, has divided celiac disease into two major categories: classic and non-classic.
My experience is that the average Medical Doctor (MD) loses interest in a condition such as celiac disease for which there is no really effective procedure (whether performed in a hospital or in an out-patient clinic) or effective prescription medication. I learned this first hand when I was invited by a celiac society to address a standing room only crowd at a well-known regional hospital near the city where I have practiced chiropractic for the past thirty-six years. Most of the 160 people in attendance did not feel that their doctors, who were mostly MDs, took an interest in helping these patients stay on or understand the reasoning behind the celiac diet. These doctors were always offering the patient a palliative prescription drug, or even a procedure to ameliorate the condition. Most of the myths about celiac for DCs concern what typical medical or chiropractic approaches do to alter the course of the disease. Some ameliorate the condition, some accomplish nothing and some are downright misleading. My most recent source was published in 2013. My oldest source was published in 1975. The real question is whether the things stated recently or a long time ago still hold true. Below in bold are statements that no longer hold true. The corroboration (explanation below the sentences seen in bold) is regarded to still be true.
1. If you don’t have diarrhea and gastrointestinal distress, you don’t have celiac.
Some people exhibit classic signs of celiac and others do not. One of the determining factors, according to peer reviewed researchers, is whether the patient was breastfed as a baby. Those not breastfed and introduced to solid foods containing the gluten grains such as wheat, rye, and barley in the first year of life exhibit more classic symptoms. Those breastfed as babies and not introduced to solid food containing the gluten grains until after 12 months old, may not exhibit gastrointestinal symptoms at all, but exhibit the non-classic symptoms and complications. The non-classic symptoms are non-diarrheal but can be neurological manifestations in the form of peripheral neuropathy, ataxia, epilepsy, and migraines. They can develop malignancies, osteoporosis, night blindness, thyroid disease, premature menopause, depression, dermatitis herpetiformis, diabetes, infertility, Sjogren’s syndrome, Addison’s disease, autoimmune liver disease, cardiomyopathy, alopecia areata, lupus, rheumatoid arthritis, fibromyalgia, aphthous stomatitis, multiple sclerosis, autism spectrum disorder, leaky gut, attention deficit, schizophrenia, dental enamel defect, Raynaud’s syndrome, and genetic disorders. So, non-classic celiac can have all the signs and symptoms and related conditions of classic except the classic gastrointestinal involvement we usually call diarrhea, cramping, nausea, and bloating.
2. You can outgrow celiac disease.
The foregoing statement may have seemed at one time to have been a valid belief because celiac was once considered a food allergy. Since some children seem to outgrow their food allergies many presume that celiac is a food allergy and therefore can be outgrown. But celiac is not per se a food allergy. It is a delayed type of immune reaction. This delay is partially what makes it so hard to connect with the principal causative action, the intake of gluten. Therefore, the doctor managing a celiac case would be remiss in their duty if they gave false hope to a celiac patient that the person will eventually outgrow the disease. Instead the attending physician needs to reinforce the need to stay on the gluten-free (GF) diet for life. There is no known pro-biotic, supplement, pepdidase or drug so effective that would preclude the patient from staying on the very rigid but most effective gluten-free diet. A person risks further damage to the villi of the small intestine if they stop the GF diet because they believed they had outgrown the disease.
3. A little bit of gluten every now and then will not hurt a patient with celiac disease.
According to Dr. Green, a recognized world authority on celiac disease, “researchers have shown that ingesting as little as 100 milligrams of gluten a day will cause continued damage to the villi of the intestine. While the exact amount of gluten that can be ingested daily without causing intestinal damage has not been scientifically established, a recent study from Finland calculates it to be about 30 milligrams. Put differently, this is substantially less than a teaspoon of birthday cake.” So rather than give in to pop culture which suggests that one can meander in and out of GF compliance, the DC is in an influential position to educate the patient with celiac symptoms to obtain the necessary tests to confirm or discard a celiac disease diagnosis.
If the disease is confirmed scientifically then the doctor should motivate the patients to stay on the GF diet for life. The patient is more motivated by the certain diagnostic findings of the physician to stay on the life-long diet. In 2015, it is much easier to stay on that diet than it was in 1998. And in five more years, it will be easier because of progress in food labeling and an increase in the variety of certified gluten-free foods. This does not mean I do not hope for a cure that does not involve this most arduous compliance to a diet, but for now it is still the best way to manage the disease, so say many researchers and studies.
4. You do not need a biopsy.
While there is a movement to declare the Endomysial antibody (EMA) blood test to be as good as an intestinal biopsy for clinching the diagnosis of celiac disease, one must remember that the endoscopy is still currently the “gold standard”. This may be the consensus (though “consensus per se” isn’t really scientific) but which is arrived at by a polling of dedicated scientists in this area of medicine. Because the endoscopy involves actual inspection of the area where the patient notes the most prominent symptoms are coming from—it has especial diagnostic value. Sense perceived information is the most valid observation in science. During visual inspection, the examiner can better rule out other causes of the symptoms that may either be superimposed upon the classic finding of villous flattening/atrophy stand alone as the only visible cause of the patients epigastic complaints. This would be important to know before consigning a patient to compliance on a tough, life-long dietary regimen.
5. I can confirm or even eliminate the presence of celiac disease in a patient via Applied Kinesiology.
My answer to that is, why rely on a form of biofeedback that is rife with subjectivity when other more objective diagnostic tests are readily available? Failure to stay on the gluten-free diet when one has hereditary celiac disease has lifelong and life threatening consequences. I would not want to miss the celiac diagnosis any more than I would want to dismiss a ruptured appendix based upon the low sensitivity and low specificity of an AK challenge.
6. A person with celiac can go off the gluten-free diet as soon as the symptoms abate.
While some authors have divided this condition into 1.) gluten sensitivity 2.) gluten intolerance and 3.) celiac disease, it is important to completely rule out celiac disease before diagnosing one or both of the first two types because celiac disease is a life-long disease that requires a life-long adherence to a gluten-free diet. Diagnosis of celiac disease must include (at a minimum) the EMA immunoflourescence serum blood test and in most cases an intestinal endoscopy that involves inspection by the examiner and biopsy. And these have to be performed while the person has been consuming at least 4 slices of bread or a gluten equivalent daily for at least three months prior to the procedures.
7. But the Bible says that wheat grain is the staff of life!
The wheat of Bible times may very well have been an important, healthy staple. But the highly hybridized wheat of today has received some stiff criticism by several writers. According to William Davis MD in his book, Wheat Belly, wheat is now the unhealthy whole grain, why? The genetic changes in wheat induced by cross breeding (hybridization) and introgression have caused the gluten found in the modern semi-dwarf variety of wheat to be undigestible or nearly undigestible for up to 40% of the population. The wheat of today does not look like the “amber waves of grain” as seen in the movies, but looks more like runt stalks with ten times more buds. This type of wheat which satisfies farmers who now realize sometimes tenfold higher yields per acre, also contains a more rubbery form of gluten that is very attractive to bakers and confectioners. This motivated one observer to quip that a mother can send her child to the local supermarket to buy bread and the bread could be practically dribbled home like a basketball from the store and it still would remain intact for making sandwiches.
When I had the responsibility, with my sister, of going to the bakery to buy bread in the 1950’s, we were instructed that bread had to be carried level and cradled in our arms like a baby or the loaf would be nothing but crumbs by the time we walked the block and a half to our home. The semi-dwarf variety of wheat was developed after that. Many researchers have claimed that this is the variety that causes the bulk of the gastrointestinal symptoms today. Dr. Davis says, “such
fundamental genetic changes, as you will see, have come at a price.” While it seems most have been looking out for the interest of the farmer, confectioner, and baker in all of this, it does not appear that anyone has been looking out after the interests of the consumer, or if you will— the person who must digest and assimilate this highly altered form of wheat bread.
8. As long as the main ingredient is not wheat, other ingredients in the product won’t really bother a celiac patient.
Actually there is a long list of well over 2,000 ingredients that could be in the product but which are not displayed on the label. Those ingredients can come from a source that is not gluten-free. These are known as GRAS additives or Generally Recognized As Safe additives. In addition there are other additives that are allowed by the FDA to be ingredients in foods we eat that by their name don’t immediately convey to the consumer that they do or do not contain gluten. These are: caramel color, citric acid, dextrin, dextrose, flavorings, malt, modified food starch, and a host of other ingredients that may not be gluten-free. For example, maltodextrin should theoretically be gluten-free even if it is made from wheat starch because it is assumed that it is so highly processed that all traces of the storage protein–gluten would be left out of the final product. But if some mistake in the processing of the maltodextrin should result in a certain residue of gluten being found in the maltodextrin, would that be noted on the packaging if detected in an ELISA test for gluten of the final product in a certain batch? Similarly, can airborne traces of gluten be found in products that are labeled “GF” but which traces are not detected either because the product was tested before the crosscontamination occurred or the concentration of the trace did not exceed the arbitrary 20 ppm standard the FDA has set? It is quite evident that a 20 ppm standard ignores that many immune systems detect antigens and react to them in concentrations well below 20 ppm. Internet chat sites on prescription drugs are loaded with commentary from anxious patients who know they are sensitive to wheat gluten in concentrations as low as 3-5 ppm.
Food manufacturers are not under the same scrutiny as drug manufacturers. A well-known baker of a popular brand of wheat bread in the mountain states area of the U.S. told me a few years ago that when a 1,500 pound loaf of dough is ready to be divided and placed into 1,500 1 pound loaf pans for baking, the bakery must be prepared to have the loaves set up just right or the entire run would have to be thrown out. The additives used to assure proper set up are rarely listed on the packaging because most are classified as GRASBut the baker told me, “Even if they were not GRAS additives which are exempt from having to be listed on the label, the bakery has no way to list extra additives added to a single batch of product because the bags each loaf will go in are printed well in advance of specific production before extra chemicals are added to the bread.
9. The gluten-free movement is mostly a `chic’ fad.
Actually one of the earliest bakers that catered to customers who noticed they did not tolerate white flour in baked goods was Pamela’s Cookies based in San Francisco. Pamela told me years ago that this is a consumer driven movement if there ever was one. People just wanted to feel good after eating. Like wearing tennis shoes with a tuxedo, many writers have defined the gluten-free craze as “chic” at best but unhealthy food faddism at worst. Popular magazines mostly characterize it as a passing fad.
Celiac disease is a `hidden’ epidemic throughout the world because so few cases have been diagnosed compared to what is occurring. Celiac is increasing in prevalence and it is worsened by unwise, hyperhybridization (cross breeding) which results in genetic modification of the storage protein gluten found in the wheat grain. Once sensitized by indigestible wheat gluten, celiacs are then forced to avoid rye and barley, two other gluten grains. All other patients having any kind of intolerance or sensitivity to gluten should be screened for celiac disease because management of celiac requires a lifelong adherence to a strict gluten-free diet. More and more food purveyors are making it easier to adhere to the diet.
The gold standard for diagnosis remains the endoscopy because it is believed there is less chance of error, because endoscopy involves visual inspection. But EMA blood testing also helps verify the diagnosis. After discarding celiac as a diagnosis based on endoscopy and EMA, the diagnostician may need to repeat those tests throughout the life of the patient as early stage celiac is not always positive on either endoscopy (visualization and biopsy) or EMA. Genetic testing of the HLA II DQ2 and DQ8 lymphocytes can confirm celiac when it is in the early stages and doesn’t yet show the telltale signs on the endoscopy or EMA. There is no drug, enzyme, probiotic, vitamin, supplement, or herb known that substitutes for adherence to the gluten-free diet once celiac is diagnosed. If doctors and professionals would focus more on the compliance with the diet rather than on experimentation with unproven products that are alleged to provide some measure of relief from one or more symptoms of celiac, they would be better serving the long term interests of the patient in managing and even surviving this disease.
10. A person who feels or believes they have celiac disease can simply take a digestive enzyme before a meal to deal with the problem.
Damage to the villi will still ensue by taking a digestive enzyme because it is improbable that a digestive enzyme will break down all the ingested gluten before it enters the small intestine. Once the small intestine is damaged, the gall bladder may begin to malfunction since cholecystokinin, the messenger hormone that makes the gall bladder contract and empty, will be disrupted by the damaged villi where cholecystokinin is produced. Certain absorption of nutrients especially those absorbed in the upper small intestine will be disrupted. Deficiency diseases stemming from that may not be noticed at first such as pernicious anemia, vitamin A deficiency, potassium deficiency, and iron deficiency among others. It only takes as little as 30 mgs of gluten to get into the small intestine of a celiac patient for damage to the villi to occur.
Anecdotal Report- multigenerational
This case study involves the children, grandchildren, and great grandchildren of two sisters, Audrey and Jeri.
A sixty-seven year old white caucasian multi-para female named Audrey presented to her chiropractor’s office in July of 1987 for nutritional advice on celiac sprue. She had been diagnosed with it in 1976 by her family doctor after about fifteen years of seeing him for increasing digestive complaints including moderate to severe diarrhea after meals, cramping, reflux, and bloating. In the preceding eleven years she had experienced a measure of success adhering to a banana-rice diet. But Audrey felt that perhaps obtaining an exogenous source of pancreatic enzymes would help her body breakdown the gluten that was apparently entering her small intestine undigested and was therefore inflaming the small intestine. The condition appeared to run in her family as her father had had many symptoms of classic celiac including many of its known complications before he passed away four years before her diagnosis. She had done enough research on celiac sprue (as it was called then by most medical doctors) to know that she had to avoid the gluten grains of wheat, rye, barley, and oats. It has since been established that oats are not per se a gluten grain, but are often insinuated with wheat gluten during planting, harvesting, transport, and/or packaging.
In 1987 Audrey’s choices were limited for pursuing alternatives to wheat bread, however there were some health food stores in her neighborhood that carried bread made from potato, rice, tapioca and other flours. Without gluten, such breads were brittle, dry, and sometimes tasteless. However Audrey tried to conform to the diet in order to relieve or at least minimize her symptoms. Her chiropractor recommend two different kinds of pancreatic enzymes. Audrey settled on a product called Pan-8. Over an eight week period, Audrey reported that taking the product when away from home helped minimize gluten reactions from meals containing uncertain ingredients. While at home, there was little need for the digestants as Audrey was quite dutiful with staying on the GF diet.
After her diagnosis of celiac malabsorption and osteoporosis with kyphotic deformity by her medical doctor, Audrey felt it important (since celiac was known in the 1970s to occur in families) to warn her own siblings, children, and nieces and nephews of the possibility that they would develop celiac in adulthood just like she had.
In 1982, when Audrey’s only sister, Jeri, was 59 years old, Jeri was rushed to the hospital in extreme distress and was found to have a perforated duodenal ulcer. She underwent emergency surgery and recovered. Audrey suggested to Jeri that the ulcer had occurred as a result of a chronically inflamed duodenum due to celiac disease. Jeri had had other signs of the disease such as abdominal cramping, loose stools intolerance to certain foods, and dental enamel defects. Like John F. Kennedy who was suspected of having celiac disease, doctors prescribed for Jeri the ice cream, milk, and cream diet. Jeri’s dental enamel defects from birth resulted in a large number of dental visits and by the time she was in her twenties most of her molars were either crowned or extracted and bridges put in the place of many of the extracted teeth. Jeri often complained of “side aches” during vigorous activity such as dancing, playing volleyball, and jogging. During the emergency surgery on the perforated ulcer, Jeri’s gallbladder was found to be diseased and was removed. The surgeon also snipped the vagus nerve. It was believed that such a procedure would reduce future excess in stomach acid production that would ward off another ulcer in the future. Jeri’s recovery was good except that in 1984, she was referred by Audrey to Audrey’s chiropractor with complaints of itchy scalp with eczematous lesions having the appearance of a blistering rash, and the DC was asked by Audrey to evaluate whether a nutritional product would help. Because of Audrey’s celiac diagnosis and knowing that it runs in families, Audrey’s DC concluded that Jeri might have dermatitis herpetiformis.
Dermatitis herpetiformis is celiac disease of the skin. According to Peter Green, the eruptions are often mistaken for other skin conditions such as mosquito bites, eczema, contact dermatitis, allergies, heat rash, diabetic pruritis, psoriasis, hives, nerves, unexplained dermatitis, or regular herpes. `Herpetiform’ means ‘like herpes’.
The DC encouraged Jeri to attempt a glutenfree diet, but Jeri did not feel that the rash was bad enough to go on something so restrictive as a gluten-free diet at that time. However, Jeri did start taking bile salts and pancreatic enzymes for digestive problems she felt were related to the removed gallbladder. For two years after Jeri’s emergency surgery, she experienced sudden dumping syndrome, a common occurrence following vagotomy. When it occurred away from home it was most embarrassing and disconcerting for Jeri.
In 1992, one of Audrey’s nephews, Kelly, began to experience right upper quadrant distress after eating and the symptom would last for several hours. This prompted Kelly to consult a specialist who ran an ultrasound on the abdominal area and a Hydascan (gall bladder function test). The gallbladder was found to contain sludge and to empty incompletely. Kelly started taking bile salts before heavier meals and always after meals if he noticed the distress. Kelly was later diagnosed with celiac disease in 1998.
Later in 1992, Jeri asked Audrey’s DC to make a house call to the home of Jeri’s eight year old grandson named Charlie, who had just experienced a grand mal seizure. Charlie had lost consciousness, had severely chewed his tongue during the seizure and was still delirious when the DC arrived at the scene. Charlie had been suspected by Audrey of having celiac disease in 1983 after Charlie’s mother had reported to Audrey his concerning symptoms which, back then, included petite mal seizures involving shuddering and rolling back of the eyes. The symptoms also included Charlie’s exhibiting voluminous pale, pasty stools (steatorrhea), severe bloating, digestive distress, vomiting, and crying. The parents consulted their family doctor who agreed with Audrey that the child might have celiac disease. The parents elected not to pursue the recommended endoscopy which includes visualization and pinch biopsy of the upper small intestine, but decided to pursue immediately placing Charlie on a gluten-free diet. Since Charlie’s symptoms were greatly reduced after putting him on the diet, over time, the parents became more and more lax about his gluten free diet until, by the time he reached the age of four, Charlie was no longer on a strict gluten free diet. Charlie experienced a second grand mal seizure two years later (1994). This prompted the parents to pursue neurological consultation with a specialist who diagnosed a type of “Jacksonian Epilepsy” and urged that Charlie go on medication if he experienced another seizure. The parents noted that both seizures occurred within hours of applying a well-known brand mosquito repellent and urged Charlie to avoid any future contact with mosquito repellent. What they didn’t learn until later is that celiac patients are more sensitive to mosquito repellents because of the leaky gut that celiac disease produces. This prevents toxins discharged by the liver through the bile from being fully eliminated but rather recirculated through the blood stream. In high enough thresholds the active ingredient of the repellent penetrates the blood-brain barrier and produces seizures.
Charlie was compliant with avoiding mosquito repellent until Charlie suffered a third grand mal seizure a few hours after liberally applying mosquito repellent offered to him by his father-in-law. Later, the family realized that that the can of repellent was an older can of the product which contained nearly double the amount of the active ingredient, DEET that was allowed in products produced in 2006. Three years ago, Charlie’s daughter began experiencing petite mal seizures and later grand mal seizures. She was evaluated by a pediatrician. In view of the history, however, Charlie’s wife elected to put the daughter on a gluten-free diet. She had no seizures until a pre-school teacher accidentally gave her a cookie. She had a mild seizure following. Celiac seizures can be caused by the damage to the small intestine caused by gluten. This damage allows toxins that normally would be eliminated to be reabsorbed through the blood stream even if they are not the active ingredient in mosquito repellent called DEET. Charlie’s daughter has had no seizures since adhering to the GF diet. The EPA has received thousands of complaints about the chemical DEET and its link to seizures. So far, manufacturers of mosquito repellent have only reduced its concentration but have not eliminated DEET in insect repellents.
Kelly, who was Jeri’s son ended up having a cholecystectomy in 1998. Kelly developed no duodenal ulcers like his mother, Jeri. But following a head-on collision with a drunk driver in 1996, Kelly began to experience severe classic celiac symptoms. While hospitalized for the injuries caused by the drunk driver, a neighbor brought Kelly a large Mexican burrito having a double wrap made from white flour tortillas. Kelly’s gastrointestinal distress from the white flour product was so severe that Kelly was scanned while in the hospital to see if he had developed a blockage of the bowel. By late 1998, Kelly told a gastroenterologist that the gall bladder surgery earlier that year had done little to ease his frequent distress. Kelly recalled his Aunt Audrey’s comments in 1976 about the family’s celiac disease history and made contact with Audrey who urged him to be tested. Kelly underwent blood testing and endoscopy with biopsy. He was found to have villous flattening with no atrophy and no complicating ulcers but did have a high EMA count. Kelly was referred to John Zone at the University of Utah Hospital who helped coach Kelly through the celiac GF diet as well as monitoring of his emerging dermatitis herpetiformis lesions, the first of which in 1995. The lesions were confused at first with mosquito or other insect bites from camping in the Park.
More than twelve of Audrey’s descendants or descendants of one of her siblings have now been diagnosed with celiac disease and are trying to conform to the tough but rewarding gluten-free diet. Two of Audrey’s near relatives have autoimmune thyroid disease, two have epilepsy, two have had melanoma, three have autoimmune rheumatoid arthritis flare-ups, four have dental enamel defects, three have developed diabetes and one is infertile. Those with autoimmune disease were diagnosed with it first before later being diagnosed with celiac disease. Having one autoimmune disease increases the risk of getting another. But all of the above maladies are linked to celiac disease. And all have improved by going on the gluten-free diet, except for Kelly’s brother who experienced sterility related to his early diagnosed celiac disease. Kelly, who characteristically had more than ten cavities every time he went for his six month dental check-ups, is now (while faithful on the GF diet) only having 1-2 small cavities during each check-up. Those with epilepsy have not experienced further seizures after staying on the gluten-free diet. Those with thyroid disease have seen their blood indicators return more to normal if not completely normal after going on the glutenfree regimen.
Kelly is the only one of the family besides Audrey who had true, classic celiac symptoms first.
Both classic celiac with related conditions and non-classic celiac with related conditions respond to a standard gluten-free diet. This prompted one well known writer to say, “Celiac disease is a disease with a constellation of symptoms that involve management by nearly all medical specialties, but which symptoms nearly all improve after going on a gluten-free diet.” Increases in mortality compared to the general population due to celiac returns to normal after a period of about five years when one adheres to the gluten-free diet. The diet is the only therapy currently known to be effective for uncomplicated celiac disease.
1. Perlmutter, David MD with Kristin Loberg, “Grain Brain” Little Brown & Co, Sept 2013.
2. Davis, MD, “Wheat Belly”, Rodale Books, 2011.
3. Green, Peter H.R. Green MD & Rory Jones, “Celiac Disease, A Hidden Epidemic”, Harper Collins Publishers, Revised & updated 2010.
4. Hagman, Bette “The Gluten-free Gourmet”, Henry Holt & Co Publishers, 1999.
5. Weissberg, Steven M, MD & Joseph Christiano, APPT, “The Answer is in Your Bloodtype”, Personal Nutrition USA, Inc., 1999.
6. Gershon, Michael D. MD, “The Second Brain” The scientific basis of gut instinct, Harper Collins Publishers, 1998.
7. Gardner, Robert W, Ph.D, “Chemical Intolerance”, CRC Press, Inc, 1994.
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