ARI Publication 40 – 2013 Version
of steak, which is not a significant concern. Common adverse effects include diarrhea and fishy
Several studies have suggested that mitochondrial disorders are common in children with autism –
see review by Rossignol DA and Frye RE, Mitochondrial dysfunction in autism spectrum disorders: a
systematic review and meta-analysis. Mo/ Psychiatry. 2012 Mar;17(3):290-314.
Note that the term “mitochondrial disorders” is used to denote a generalized impairment of
mitochondrial function, and are generally not as severe as “mitochondrial disease,” which involves
specific severe genetic abnormalities. One important factor for normal mitochondrial function is
carnitine, which transports fatty acids into the mitochondria for energy production. However,
mitochondrial disorders can be caused by many factors, and carnitine deficiency is only one
One study found decreased levels of carnitine in children with autism (Filipek et al 2004); however,
that study only compared against laboratory reference ranges, which are of limited validity.
A/ipek et al, Relative carnitine deficiency in autism. l Autism Dev Disord. 2004 Dec;34(6):615-23.
A recent double-blind, placebo-controlled 3-month study (n=30) found that supplementation with
carnitine was beneficial. Specifically, that study found significantly greater improvements in the
Childhood Autism Rating Scale (CARS) and Clinical Global Impressions (CGI) scores in the treatment
group compared to the placebo group. In addition, scores significantly improved in cognition,
marginally in speech, and non-significantly in total and sociability scores on the ATEC. L-carnitine
therapy significantly increased serum carnitine concentrations, and significant correlations between
changes in serum free-carnitine levels and positive clinical changes were observed. Study subjects
generally tolerated L-carnitine therapy.
Geier DA etal, A prospective double-blind, randomized clinical trial oflevocarnitine to treat autism
spectrum disorders. Med Sci Monit 2011 Jun;17(6):PI15-23.
Overall, the literature suggests that mitochondrial disorders are common in autism, and carnitine
supplementation may help improve mitochondrial function. Other supplements for mitochondrial
therapy include vitamins, minerals, CoEnzyme Q10, and essential fatty acids, which work together
to improve mitochondrial function.