The original randomized controlled trials of gluten-free and casein-free diets may have been hampered by parental expectation bias.
My video Are the Autism Diet Benefits Just a Placebo Effect? begins with graphics showing the results of the first randomized, controlled trial to test a gluten-free and casein-free diet for children with autism. Major improvements were reported with attention problems, and there was less aloofness, less need for routines and rituals, and improved response to learning after a year of dieting. In contrast, no significant differences were reported in the control group before and after the one-year trial period. There were also improvements in social and emotional factors in the group on the gluten-free and casein-free diet, with the children having significantly fewer problems in relationships with their peers, less fear, more empathy and more acceptance of physical contact. No significant changes were reported in the control group either. In the diet group, too, there were significantly fewer communication problems with more facial expressions, better eye contact and improved responsiveness as well as fewer occurrences of “linguistic peculiarities” such as meaningless repetitions of words, while again no significant changes in the control group. Finally, in terms of cognitive factors and exercise, after a year of dieting there was a significant improvement in the children’s ability to assess dangerous situations, expanded personal interests, and decreased the likelihood of being overly restless or passive.
However, the study was problematic in that the researchers relied primarily on the parents’ report. You asked the parents a series of questions before and after the year-long process to see if they could see any differences in their children, which you see at 1:20 in my. can see Video.
Is that really a problem? Who knows the everyday life of children better than their own parents? Yes, the researchers could have had each child assessed by an impartial observer before and after the trial period, blind to whether they were in the diet group or the control group, but these assessments would only be snapshots. Who knows better than parents what is wrong with their children? Well, there really is one problem with parental assessment: the problem is the placebo effect. “After this to implement After up to a year of intervention, the parents had invested considerable time and effort in maintaining the diet and possibly looking for improvements in their children’s behavior. ”So many products contain wheat and dairy that they can be omitted from the diet can be a major adjustment for most families. So while the families in the control group did nothing special that year and reported no significant changes before and after the trial period, the families in the diet group had done all of this work. When asked if their children were looking better, their opinions may have been influenced by their expectations of benefit. In other words, “placebo effects may have been involved”.
Are Parents Really That Gullible? Well, “the power of parenting suggestion” can Be very strong in situations that affect their children’s behavior. ”For example, there was a famous study where all children were given an artificial sweetener drink, but half of the parents were told the drink was sweetened with sugar. Parents who thought their children had received the sugar-sweetened drink rated their own children’s behavior significantly worse.
In these types of autism studies, “it is possible that the parents in placebo effects” search look for positive behavioral changes and ignore negative ones or explain them away. ”Ideally, we need double-blind studies in which children are given foods that look and taste the same, but one food contains gluten and casein while the other is gluten and casein free. The children do not know what is what, and neither do the parents. Even the researchers don’t know what if they break the code by the end of the study. “In this way, the behaviors recorded after the food challenges could not be influenced by preconceived ideas or prejudices.”
Well, then why wasn’t the study double-blind? “In terms of design,” the researchers say conceded, “One could argue that a double-blind crossover study would have been ideal. Gluten and casein could have been given to all children on a diet, for example in capsules during certain changeover times. Parents and carers would have been blind to who was on the diet and who was on a normal diet, “they secretly got gluten and casein without their knowing it. Then they could have eliminated the placebo effect and this expectation bias. So why not?
The researchers were so convinced that gluten and casein are harmful that – “from an ethical point of view” – they simply couldn’t bring themselves to give these children gluten or casein. The children in the diet group appeared to be doing so much better, and the researchers had seen cases where the children appeared to relapse when these proteins were reintroduced into the diet so they just couldn’t bring themselves to something to swallow children secretly.
I understand, but if they were really that certain gluten and casein were bad by designing a less than ideal study then they would potentially cause many other children to fail by not providing the strongest evidence. Fortunately, four years later, other researchers stepped in and released the first double-blind clinical study on nutrition and autism, which I describe in detail in my video Double-blind study of nutrition in autism.
This article discusses the fourth video in a six-part series on the role of gluten and dairy-free diets in the treatment of autism. If you missed the first three, check out:
The last two videos in this autism series are Double-blind clinical study on nutrition in autism and Pros and cons of a gluten-free, casein-free diet for autism.
Stay tuned to all of my autism related videos Here.
Videos about gluten-free diets in general can be found at:
In health,
Michael Greger, MD
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