Food For The Brain: What Is the Evidence for Allergy or Intolerance Testing in Children

Back in February I took up Holford’s challenge to search through the medical literature so that I could see for myself that, “[t]he evidence for IgG antibody reactions as a basis for food intolerances continues to grow”. But, like McCavity, the strength of evidence wasn’t there.

Dr. Glenis Scadding, Consultant Allergist of the Royal Nose, Throat and Ear Hospital, recently gave evidence at a House of Lords investigation into allergy and allergic diseases and she declared that IgG tests for the diagnosis of food intolerance are a waste of money. Dr. Scadding also gave an interesting overview of how allergy and intolerance kits can provide results that lead to the misdiagnosis of allergy and inappropriate allergen avoidance.

I have many reservations about the relevance of IgG tests to the diagnosis of food intolerance but, exercising fairmindedness, I thought that I should consult Holford’s Food for the Brain (FFTB) information site and learn what they had to say on the matter. I had hoped that any information on FFTB would include specialised literature about children. I read a number of claims about the incidence, significance and presentation of allergies and intolerance in children: however, there were no references for these claims. Fortunately, FFTB provides a search and question-answering facility. [Update: 10 May. This has now been removed from the site until July*. None of the links to the FFTB paper summaries work any longer.]

To find an answer to your questions all you have to do is enter your question and it will search a database of every question I’ve ever answered.

I entered the question, “Why do you recommend IgG tests for food intolerance and what is the evidence?”. In return, I was given the following.

“why do you recommend igg tests for food intolerance and what is the evidence” found the following entries: Result Page: 1
B. O’Reilly, Hyperactive Children’s Support Group Conference, London, June 2001
B. Starobrat-Hermelin and T. Kozielec, ‘The effects of magnesium physiological supplementation on hyperactivity in children with attention deficit hyperactivity disorder (ADHD): Positive response to magnesium oral loading test’, Magnes Res, Vol 10(2), 1997, pp. 149-56
M. D. Boris and F. S. Mandel, ‘Foods and additives are common causes of the attention deficit hyperactive disorder in children’ Ann Allergy, Vol. 72 (1994), pp. 462-468
R. M. Sapolsky, ‘Why stress is bad for your brain’, Science, Vol 273(5276), 1996, pp. 749-50

I had hoped for some form of answer to my question but was willing to accept that clicking on the links would take me to a summary that would provide some guidance. However, the links to neither the O’Reilly nor Sapolsky paper provided any further detail, far less a summary. The other papers did lead to a summary. However, magnesium supplementation is not relevant to any part of my question; the study did not involve allergies or intolerances. I didn’t find the FFTB summary of the Boris and Mandel paper to be particularly helpful so I located the abstract on Entrez PubMed. The paper discussed a multi-item elimination diet and a double blind placebo controlled food challenge but not blood tests, IgG antibodies or anything that I’d asked about.

As an aside on the Boris and Mandel paper, it is mentioned in passing in a Quackwatch overview of the Feingold diet that has some popularity among parents of children on the autistic spectrum or with ADHD. Barrett quotes a review committee that examined several studies of food additives and children and found:

no more than 2% of children respond adversely to dye additives, and even that statistic was questionable [5]. Since that time, experimental findings have been mixed. Some researchers have reported little or no adverse effect during challenge experiments [6-7] and some have reported worsening behavior during such experiments [8-10 [includes the Boris and Mandel]]. However, it remains clear that the percentage of children who may become hyperactive in response to food additives is, at best, very small. Sugar and aspartame (an artificial sweetener) have also been blamed for hyperactivity, but well-designed studies have found no evidence supporting such claims [11-13].

More recently, Cruz and Bahna reviewed the evidence for the possible role of foods or additives in causing behavioral disorders in children, particularly ADHD. The review addresses widespread beliefs about the influence of diet on childhood hyperactivity:

Despite the very limited scientific evidence to support a relationship between food additives and behavioral changes, many parents continue to believe they exist. With the increasing acceptance of natural and homeopathic therapies, some parents may seek dietary management instead of pharmacologic agents. Foods devoid of food additives appeal to parents who may be averse to commercial food processing. Media sources, especially the wide use of the Internet, unfortunately tend to perpetuate information that may appeal to the public without scientific evidence…

When parents seek professional help regarding a child’s behavioral disorder for possible relationship to foods, additives or sugar, it would be prudent to first establish the diagnosis of a behavior disorder…Therefore, such parents should be counseled with empathy about the limited evidence of such a relationship. The family often expects “allergy testing” to reveal the specific agent. However, routine allergy skin testing or blood tests are primarily for immunoglobulin E-mediated reactions, but there is no evidence for such mechanism in behavioral disorder.

Cruz and Bahna provide a useful summary of a number of investigations. The authors provide an overview of studies that suggest that there is a relationship between food additives, sugar and ADHD and those that refute such a connection. Cruz and Bahna conclude their review as follows:

a critical review of the literature provides very limited support for such a relationship. On encountering such cases, the healthcare professional should first establish an accurate diagnosis of the suspected “abnormal” behavior based on specific standard criteria. It is important to counsel the family regarding the standard of care practice and about the limited evidence of a role of foods and additives in causing behavior problems. If parents strongly suspect a specific dietary item, a trial of elimination may be warranted. If the child’s behavior show definite improvement, a challenge in a double-blind, placebo-controlled fashion under the supervision of an experienced physician would be necessary to verify the relationship.

Cruz and Bahna do not suggest that there is a role for diagnosing allergies or food sensitivities with blood tests. They do emphasise the need for an accurate diagnosis and for collaboration with a child’s doctor to validate a suspected allergen.

I didn’t find the response to my first question helpful but I was willing to consider that the question might have been inappropriate, so I entered the search terms “allergies intolerance”. The results for that were:

1. M. Ash and E. Gilmore, Modifying autism through functional nutrition, paper given at Allergy Research Group conference, London, January 2001
2. M. D. Boris and F. S. Mandel, ‘Foods and additives are common causes of the attention deficit hyperactive disorder in children’ Ann Allergy, Vol. 72 (1994), pp. 462-468

I’ve dealt with the Boris and Mandel paper above and there was no further information about the Ash and Gilmore paper. Obviously, the latter does not explore the use of the recommended allergy and intolerance tests and it isn’t possible to comment on the former.

FFTB limits a ‘non-friend’ to three questions. Feeling a little as if I were trapped in a fairytale with a cranky genie I gambled that searching on “allergies autism” must return some useful results. The response was two pages of references. Sadly, the top 3 were:

1. B. Rimland et al., ‘The effect of high doses of vitamin B6 on autistic children: A double-blind crossover study’, Am J Psychiatry, Vol 135(4), 1978, pp. 472-5
2. Gut disorders are more prevalent in children with developmental disorders. A. J. Wakefield et al., ‘Enterocolitis in children with developmental disorders’, Am J Gastroenterol, Vol 95(9), 2000, pp. 2285-95
3. J. G. Bell et al., ‘Red blood cell fatty acid compositions in a patient with autism spectrum disorder: a characteristic abnormality in neurodevelopmental disorders?’, Prostaglandins Leukot Essent Fatty Acids, Vol 63(1-2), 2000, pp. 21-5

The Wakefield paper involved endoscopic examination and tissues biopsies, and enterocolitis rather than allergies. I should also mention that some of Wakefield’s fellow researchers later partially retracted their endorsement of some of the work that they had published with him. Neither the Vitamin B6 nor the fatty acid paper addressed the issue of allergies. Having glanced through some of the other references, they did not seem to be relevant.

I have no idea what the search engine algorithm on that site was doing but I doubt that I could have had less relevant or helpful ‘answers’ if I had been sticking my hand in some truthiness and referenciness tombola and pulling out solutions.

I shall examine some of the unsubstantiated claims about allergies, intolerance and diagnostic testing on the FFTB site at another time. I was particularly intrigued to read:

Early reports back in the 1980′s, confirmed by recent double-blind controlled trials, have found that allergies can affect any system of the body, including the central nervous system. They can cause a diverse range of symptoms including fatigue, slowed thought processes, irritability, agitation, aggressive behaviour, nervousness, anxiety, depression, ADHD, autism, hyperactivity and learning disabilities. These types of symptoms can be caused by a variety of substances in susceptible children, though many have reactions to common foods and/or food additives.

Following FFTB’s recommendations for allergies and intolerances may have substantial financial and social implications for a family and the way in which they accommodate the needs of family members. It would probably be very helpful for parents who are interested in exploring some of FFTB’s recommendations for their children if FFTB explained some of their recommendations more fully and provided references to the scientific literature that directly support those recommendations.

*The Evidence part of the FFTB site no longer has the search facility and just offers this message:

Please accept our apologies but this part of the site is under re-construction at present. We hope to have the research and search database facility back on-line in July this year.

Thank you for your patience and your continued support.

None of the links to FFTB’s summaries of the research that they do cite are active any longer.