Dietary supplementation and autism (and the horror of a GFCF diet)

As perhaps expected, the results reported by Patricia Stewart and colleagues [1] suggesting that: "Few children with ASD [autism spectrum disorder] need most of the micronutrients they are commonly given as supplements, which often leads to excess intake" has generated some interesting media headlines given their mention of the words "gluten/casein-free diet (GFCF)".

A case in point is an article titled: 'Autism Diets' Do Not Provide Children With Adequate Supplementation, Can Lead To Overuse which aside from making little sense (do not provide children with adequate supplementation?) seems to be using the Stewart paper to take pot shots at the mention that GFCF diets have some research (yes, peer-reviewed research) history with autism in mind. Bearing in mind that I have something of an interest in this area, I'm gonna go through some of the findings reported by Stewart et al with a slightly different mindset albeit based on the science to hand.

Drawing on participants with autism (N=288) recruited via the Autism Speaks Autism Treatment Network (ATN) researchers set about examining "dietary supplement use and micronutrient intake in children with ASD." This was accomplished by analysing data from 3-day diet/supplement records "relative to GFCF diet status."

There were a few important results to mention following analysis of [trained] caregiver food/supplement diaries for children based on the reported data and other write-up of the findings:

• Overall, children with ASD were consuming similar amounts of micronutrients as children without ASD. "They also had the same deficits in vitamins D, E, calcium, potassium, and choline as the general pediatric population." I'll come back to some of the details of this shortly.
• Children receiving GFCF diets (~20%) had similar micronutrient intake to those not following a GFCF diet. Indeed: "Children on the GFCF diet consumed more magnesium and vitamin E" and "Children on this diet were more adequately supplemented with vitamin D." These findings hark back to other research suggestions that the 'horror' that is a GFCF diet might not be as poor in nutrition as some people might imagine (see here). I might add that if readers look elsewhere on this blog, you might notice that yours truly has written a book about how a GFCF diet can be implemented safely and nutritiously without the requirement for high levels of supplementation when it comes to autism (sorry for the blatant self-publicity).
• "Dietary supplements, especially multivitamin/minerals, were used by 56% of children with ASD." Using a GFCF diet seemed to be associated with greater supplement use (78% vs 56%) compared with those not following such a diet. I assume this is because of the perception that a GFCF diet is 'nutritionally inadequate' when it comes to important minerals such as calcium for example. That being said: "Calcium supplementation was equally inadequate in those on and off the diet." This is interesting and perhaps relevant to other work on diet, calcium, bone health and autism (see here).
• "Despite different eating behaviors, children with ASD received much of their needed micronutrients from food consumption." The authors suggest that this might have something to do with the various food fortification strategies in place these days, but likewise "may also be responsible for the overconsumption of certain nutrients by children with ASD."
• "Even when supplements are used, careful attention should be given to adequacy of vitamin D and calcium intake." Coming back to the idea that deficiencies noted in this sample of children with autism are not so dissimilar from that seen in the general population, the suggestion that issues such as vitamin D deficiency or insufficiency might be over-represented when it comes to autism continues an emerging research theme (see here).

There are some important points to take from the Stewart paper bearing in mind that 3-day food / supplement diaries are really only providing a snapshot of food / supplement intake and say nothing about the biological levels of various nutrients when it comes to autism. As per the numerous entries on this blog about where eating habits can go wrong with autism in mind (see here) and what happens when vitamin/mineral supplementation in autism is put to the double-blind test (see here) I'd be slightly guarded about drawing too many sweeping conclusions from the new data.

"In clinical practice, each patient needs to be individually assessed for potential nutritional deficiencies or excess." So says Dr Stewart in the press release accompanying the study. I'd be minded to agree with that sentiment given the idea of plurality in autism (see here) and the potential for various biochemistry that can follow a diagnosis (see here and see here) potentially impacting on food and feeding habits. As I've said many times before, receipt of the label of 'autism' or 'autism spectrum disorder' should be a starting point for quite a bit more clinical inspection and not the finishing line...

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[1] Stewart PA. et al. Dietary Supplementation in Children with Autism Spectrum Disorders: Common, Insufficient, and Excessive. Journal of the Academy of Nutrition and Dietetics. 2015. June 4.

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Patricia A. Stewart, Susan L. Hyman, Brianne L. Schmidt, Eric A. Macklin, Ann Reynolds, Cynthia R. Johnson, S. Jill James, & Patricia Manning-Courtney (2015). Dietary Supplementation in Children with Autism Spectrum Disorders: Common, Insufficient, and Excessive Journal of the Academy of Nutrition and Dietetics