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Studies show that a gluten-free casein-free diet has no discernable effect on autism. So why are many parents continuing with the treatment?
By Nathan Ackroyd | Assistant Professor of Chemistry, Mount Royal University | The Mark
Months of concern had brought us to this doctor’s office, where my two-year-old was scrambling into corners and under tables, looking for the source of his distraction, his frustration. “What is that?” he asked again and again. It wasn’t until he at last asked, “What is that sound?” that I was finally able to satisfy him – the faint hum of the fluorescent lighting was driving him crazy.
We learned that Evan has Sensory Integration Dysfunction, a condition often associated with either autism or giftedness. For someone like Evan, everyday sensation such as touch, taste, or sound is not perceived in the normal way. Sounds that most of us tune out continue to force their way into Evan’s attention. Every one of his senses appears to be over- or under-sensitive, and trying to correct the imbalance sometimes leads to behaviour problems. Searching for a treatment more effective than earplugs his ears are too sensitive for led us to a possible solution – the gluten-free, casein-free diet. This diet has been in the news recently as a potential treatment for autism after a January 2010 review in the journal Pediatrics re-affirmed that it doesn’t work. Gluten, a protein found in various grains, and casein, a milk protein, are harmless for most people. So why would anyone think that the proteins in white bread and a glass of milk contribute to autism? In 2003, Ann-Mari Knivsberg and Karl L. Reichelt tested several fragments of gluten and casein that can be found in the urine of autistic children at much higher levels than with normal children. When they injected specific fragments of partially digested protein into rats, the rats showed specific autism-like symptoms. Believers in the so-called Neuropeptide Hypothesis claim this finding demonstrates that it is these partially digested remains of bread and milk in the brain that cause the sensory-related characteristics of autism and sensory integration dysfunction. Remove them from the diet, and autism should go away. This hypothesis makes sense because our brains are filled with large proteins called receptors – docking stations for the chemicals our bodies use to send signals back-and-forth. Many drugs work because they bind to receptors to either block or strengthen the messages our bodies are trying to send. Researchers have found that these gluten and casein protein fragments bind to opioid receptors, the same receptors that dock morphine and heroin. These drugs cause an intense disconnection from the world. Since autism is characterized by poor response to the outside world, the connection between opioid receptors and symptoms of autism seems reasonable, though we lack the firm evidence that would prove the Neuropeptide Hypothesis.
Knivsberg and Reichelt conducted their rat study to explain the results of a 2002 study, in which they tracked the progress of ten autistic children who were on a gluten-free, casein-free diet. Compared to a control group, the kids on the new diet were reported by parents to have a marked increase in test scores related to symptoms of autism, such as aloofness, repetitive behaviour, and need for routine. But because the parents knew which diet their children received, skeptics can object that the observed improvement was due to a parental placebo effect rather than an actual change in their children.
A placebo is any treatment, be it medication, diet change, or counseling, that works because the patient expects that it will, rather than because of any effectiveness of the procedure itself. In the case of children on an altered diet, however, it is the parents who believe it will be effective. Because the children are unaware of the potential benefits, any placebo effect must be purely due to perception. The parents see a change because they are looking for one, a change that someone who is less hopeful would not see.
Jennifer Elder, a researcher at the University of Florida, improved on the Knivsberg study in 2006, this time keeping parents unaware of their children’s diet. Fifteen autistic children took turns in six-week shifts, eating either a regular diet or one that was gluten-free and casein-free. Improvements in the children’s symptoms were judged by external evaluators, using standardized tests. When asked to guess, 85 per cent of parents thought they could tell when the diet changed, though they were correct only at the same rate as random chance. The measured changes in the severity of symptoms showed no significant difference between the weeks on the control diet and the weeks on the test diet, demonstrating that the new diet has no value on its own as a treatment for autism. In spite of this, several parents reported seeing behavioural changes that weren’t supported by standardized test results and 70 per cent of the parents who finished the study planned to continue the diet. This despite of the potential health risks of a restrictive diet and firm evidence the diet had made *no* difference to their child.
Evan’s sensory integration is only part of what influences his behaviour. He is complex and has required a complex response from us. As he has grown, so has his ability to say what bothers him. Evan can tell us what is too loud, too scratchy, too much. He says gluten gives him headaches, and I believe him – partly because gluten gives me headaches too. A headache makes everything feel worse, whether diet has actual direct effects on sensory perception or not.
Studies aside, my own experience with the diet suggests that, other than a headache, our sensory perception of the world doesn’t change with what we eat. It appears that any observed change this particular diet has on autistic children is due to their parent’s perception of them, not the child’s perception of the world. Even so, the majority of the parents in the Elder study chose to continue a diet that science has shown to have no effect. It appears that when the choice is between hope and science, many find that hope in a placebo is the more attractive option.
Source: http://www.themarknews.com/articles/980-autism-and-the-placebo-diet
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