Xjyuk

Treatment Ratings for Autism claims that basically any special diet is an effective treatment of autism. Is this true?

From the study: "The following data have been collected from the more than 27,000 parents who have completed our questionnaires designed to
collect such information. For the purposes of the present table, the parents responses on a six-point scale have been combined into three
categories: “made worse” (ratings 1 and 2), “no effect” (ratings 3 and 4), and “made better” (ratings 5 and 6). The “Better:Worse” column
gives the number of children who “Got Better” for each one who “Got Worse.”"

The study presents results such as this one:

Removed Chocolate:

Got worse: 2%
No Effect: 46%
Got Better: 52%

The claim merely quotes statistics about what parents thought happened. The trouble is that once someone has decided that a special diet is worth the effort, and has gone to the effort of implementing that diet, then they are likely to experience confirmation bias leading them to see an improvement where none exists.

Complicating the matter is that the subjects of the experiments are children, and children, even autistic ones, do develop mentally as time goes on. Hence it is possible that these parents are interpreting continuing mental development as an improvement due to the diet.

None of this is evidence that these treatments are not efficacious, its just that the statistics listed don't really prove anything either way.

According to Sathe N, Andrews JC, McPheeters ML, et al. Nutritional and Dietary Interventions for Autism Spectrum Disorder: A Systematic Review. Pediatrics.
2017;139(6):e20170346:

Is any special diet a treatment of autism?

Yes:

... many families, if not a majority of families, pursue dietary and
nutritional approaches as components of treatment. (Footnotes 1–11)

Is any special diet is an effective treatment of autism?

Maybe; there's some evidence that this may be the case, but the Strength-of-Evidence (SOE) is generally rated as insufficient:

RESULTS: Nineteen randomized controlled trials (RCTs), 4 with a low
risk of bias, evaluated supplements or variations of the
gluten/casein-free diet and other dietary approaches. Populations,
interventions, and outcomes varied. Ω-3 supplementation did not affect
challenging behaviors and was associated with minimal harms (low SOE).
Two RCTs of different digestive enzymes reported mixed effects on
symptom severity (insufficient SOE). Studies of other supplements
(methyl B12, levocarnitine) reported some improvements in symptom
severity (insufficient SOE). Studies evaluating gluten/casein-free
diets reported some parent-rated improvements in communication and
challenging behaviors; however, data were inadequate to make
conclusions about the body of evidence (insufficient SOE).

(Emphasis added above.)

In conclusion:

Despite their widespread reported use, little evidence supports the
effectiveness of nutritional supplements or the GFCF diet for
improving ASD symptoms. Harms reported in studies were generally
considered mild, but the long-term effects of these therapies are not
well understood.

[...]

Even without a clear evidence base documenting safety and
efficacy, many families of children with ASD use diet and nutritional
approaches.

To split your question into 3 parts:

1. What other conditions are highly comorbid with autism?


2. For each of those conditions, is there a special diet that is effective?


3. If the symptoms of the other condition are treated, does that reduce the symptoms of autism?

For #1, there is a huge list of symptoms that appear to be correlated, but there are a few that jump out at me:

• Mitochondrial disease


• various gastrointestinal problems (including but not limited to acid reflux and Crohn's disease)


• Immune system problems (and thus allergies)

These are each known to be strongly affected by diet, passing #2. But treatments are often not completely effective.

For #3, not having to constantly deal with discomfort means there is more mental effort available for coping with situations.

So, depending on the percentage of people that pass #1, and the strength of #3 given the efficiency of #2, it seems reasonable in some cases.

But the source you linked is almost certainly bogus; finding the right diet would require very specific analysis of what particular nutrients should be avoided/supplemented for the particular comorbidities (including ones I didn't list above).

It may be tricky to find a medical professional who specializes in autism (and can be expected to keep up with studies altering the comorbidity list); in my experience there are only a handful even in a densely-populated state, and American healthcare often doesn't cover them.