By Jennifer Copley (Last Updated 30 May 2011)
Those who are deficient in vitamin C suffer from confusion and depression, conditions often afflicting people with autism and a variety of other disorders as well. Such parallels caused many researchers to become interested in exploring the potential of vitamin C for treating various conditions.
Why Vitamin C Helps
There are several theories regarding vitamin C’s benefits for those with autistic spectrum disorders. The first is that children with autism are deficient in vitamin C or need more of it than neurotypicals (non-autistics).
Another theory is that vitamin C’s benefits are due to its effects on the brain’s response to the neurotransmitter dopamine. Vitamin C supplementation has a calming effect on people and reduces stereotyped behaviour among animals. Stereotyped behaviour is a symptom of autistic spectrum disorders among humans.
A third theory regarding vitamin C’s effects focuses on the benefits of its antioxidant properties. Some researchers believe that those with autism have more difficulty managing free radicals. Free radicals can damage the immune system, the brain, and other areas of the body. As an antioxidant, vitamin C provides some protection against the effects of free radicals.
It is likely that all three beneficial effects of vitamin C play a role in mitigating some of the problematic symptoms associated with autistic spectrum disorders.
Effectiveness of Vitamin C in Treating Autistic Symptoms
A study of autistic adults and adolescents found that a dose of 8,000 mg of vitamin C a day generated significant improvement (Tolbert, 1991). Another study that aimed to discover whether vitamin C could be beneficial for those with autism found that while it was not as effective as vitamin B6, a high dose could produce favourable results (Dolske et al., 2003). These findings were confirmed by a 2004 study of autistic children, which found reduced gastrointestinal problems and significantly improved sleep in the vitamin C group (Adams & Holloway, 2004).
While these results are encouraging, it should be noted that the subject pools were quite small and more research is required to confirm these findings. However, given that vitamin C is relatively safe and provides additional benefits as a result of its antioxidant properties, supplementation may be worthwhile.
Of the Autism Research Institute’s 2,390 parent ratings of the use of vitamin C for treating autism symptoms, 43% saw improvements, 55% no change, and 2% a worsening of symptoms. Of the 201 parent ratings of vitamin C for treating Asperger’s syndrome symptoms, 46% reported improvements, 51% saw no change, and 2% said that their children grew worse.
As well as helping the immune system fight off colds and flus more rapidly, vitamin C has a beneficial effect on a variety of conditions, ranging from schizophrenia to depression. Because many of those with autism also suffer from depression, vitamin C supplementation may be useful even if it does not directly reduce autistic symptoms. The ability of high doses of vitamin C to improve the social functioning of those with schizophrenia is also of interest because although the two conditions are quite different from one another, autistic people also suffer from deficits in social functioning (Rimland, 1997).
In addition, vitamin C supports adrenal function, which is critical to coping effectively with stress, and chronic stress can deplete vitamin C levels on the body (Bourne, 2005). Sensory overload, social pressure, and other issues can trigger anxiety symptoms such as withdrawal, agoraphobia, panic attacks, tantrums, and stereotypies (repetitive movements) in those with autistic spectrum disorders. Therefore, vitamin C may help with the stress and anxiety that often plagues those on the autistic spectrum.
Vitamin C is among the safest of the supplements commonly available when used responsibly, but it can have adverse effects at very high doses. If considering supplementation, consult a doctor before proceeding.
Other Autism Supplements
For more on the effectiveness of various supplements for treating autistic spectrum disorders, see the main Autism Supplements page. For a full list of articles on autism and Asperger’s syndrome, visit the main Autistic Spectrum Disorders page.
This article is not intended as a substitute for medical consultation or care. Health concerns should be referred to a doctor.
- Adams, J.B., & Holloway, C. (2004). “Pilot Study of a Moderate Dose Multivitamin/Mineral Supplement for Children with Autistic Spectrum Disorder.” Journal of Alternative & Complementary Medicine, 10(6), 1,033-1,039.
- Autism Canada Foundation. (2011). “Nutritional – Vitamin C.” AutismCanada.org.
- Autism Research Institute Parent Ratings of various interventions for Autism and Asperger’s Syndrome.
- Autism Research Institute. (1998). “Vitamin C in the Prevention and Treatment of Autism.” Autism Research Review International, Vol. 12, No. 2, page 3.
- Bourne, Edmund J., PhD. (2005). The Anxiety and Phobia Workbook. Oakland, CA: New Harbinger Publications.
- Dolske, M.C.; Spollen, J.; McKay, S.; Lancashire, E.; & Tolbert, L. (1993). “A Preliminary Trial of Ascorbic Acid as a Supplemental Therapy for Autism.” Progressive Neuro-psychopharmacology & Biological Psychiatry, 17, 765-774.
- Tolbert, L.C. (1991). “Ascorbic Acid: Therapeutic Trial in Autism.” Autism Society of America Annual Conference, Indianapolis, Indiana, July 10-13, 1991.