ARI Publication 40 – 2013 Version
Duration: Very little is known about optimal types and dosages of probiotics. We recommend
gradually increasing to a high dose until benefit is observed, and then consider a lower maintenance
Testing: One simple and very useful test is to look at the stool, since half of the stool is bacteria.
The stool should be a medium/dark brown and well-formed, with 1-3 bowel movements/day.
Use antibiotics only with great caution: One round of oral antibiotics typically kills off over
99% of beneficial gut bacteria, but has little or no effect on yeast or many types of bad bacteria,
which then thrive due to lack of competition from beneficial bacteria. Oral antibiotics often cause
overgrowths of bad bacteria and yeast, and are suspected as the cause of many of the gut
problems in autism. Several studies have shown that children with autism had, on average, a much
higher usage of oral antibiotics than typical children in their first few years of life.
Lab Testing: A Comprehensive Digestive Stool Analysis (available from Genova Diagnostics or
Doctor’s Data) will reveal the amount of some types of normal and abnormal bacteria and yeast.
Some labs offer individualized susceptibility testing, to determine which anti-fungals are most
effective against the patient’s particular yeast.
Urinary organic acid testing can be done to check for abnormally high levels of metabolites from
yeast, although the reliability of this test is unclear.
Individuals with chronic gastrointestinal problems should consider a consult with a
gastroenterologist (a doctor who specializes in gastrointestinal problems), who may recommend an
endoscopy or other testing. Endoscopies should include a biopsy to evaluate digestive enzymes
(see Digestive Enzyme section) – this testing is now widely available.
ARI Survey of Parent Ratings of Treatment Efficacy:
|% Worse||% No Change||% Better||Number of Reports|
|Antibiotics (not recommended)||33%||50%||18%||2507|
Research – Oral Antibiotics Over-used
Five studies have reported much higher usage of oral antibiotics during infancy of children with
autism vs. controls, usually for treating ear infections (possibly suggesting an impaired immune
system). Commonly used oral antibiotics eliminate almost all of the normal gut bacteria, which play
an important role in the breakdown of plant polysaccharides, promoting gastrointestinal motility,
maintaining water balance, producing some vitamins, and competing against harmful bacteria. Loss
of normal gut flora can result in the overgrowth of harmful bacteria/yeast, which can in turn cause
constipation and other problems.
Konstantareas MM, Homatidis S: Ear infections in autistic and normal children. Journal ofAutism and
Developmental Disorders 1987, 17(4):585-594.
Niehus R, Lord C: Early medical history ofchildren with autism spectrum disorders. Journal of
Developmental and Behavioral Pediatrics 2006, 27(2):S120-S127.
Adams JB et al., Analyses of Toxic Metals and Essential Minerals in the Hair ofArizona Children with
Autism and their mothers, Biol Tr El Res 2006, 110:193-209.
Adams JB et al., Mercury, Lead, and Zinc in Baby Teeth ofChildren with Autism vs. Controls J Toxicol
Environ Health 2007, 70(12):1046-51.
Adams JB et al., Mercury in First-Cut Baby Hair ofChildren with Autism vs. Typically-Developing Children.