Is Autism a Vitamin D-Deficiency Disorder?

Autism is increasing exponentially and is related to vitamin D deficiency. As I have pointed out in my book, both children and adults with autism typically show difficulties in verbal and non-verbal communication, social interactions, and leisure or play activities.”[1]

The cost of autism is about $35 billion annually, and the societal cost for each case is about $3.2 million.[2] The most alarming increase in autism is observed over the past few decades, and its incidence is currently growing at the rate of 10-17% per year.39 Dr. John Cannell wrote a compelling paper on how autism could be caused, at least in part, by lack of vitamin D during brain development.[3] Much of this post discusses his primary arguments.

Cannell points out that in 1989, about the time autism began its most rapid increase in incidence, the American Medical Association Council on Scientific Affairs first warned of the perceived dangers of sun exposure and advised keeping infants out of the sun as much as possible.[4] In 1999, when autism risk began to really skyrocket, the American Academy of Pediatrics advised to keep infants out of direct sunlight and to make sure activities minimized sun exposure.[5] In 2002 the Centers for Disease Control reported that the efforts had been quite successful.5

It is quite possible that the result of all of this “protection” has been an increase in autism, since the increase in the incidence of autism has closely paralleled the increase in “sunscare efforts.” Vitamin D is absolutely essential for brain development[6] [7] and that children are deficient because of sun “protection” measures that lower vitamin D levels. My opinion is that this is the major reason for the surge in the rate of autism.

Here are more of Dr. Cannell’s autism/vitamin D-deficiency links:

Both autism and vitamin D deficiency are associated with abnormally high inflammation.[8] [9]
Low consumption of vitamin D-rich seafood in pregnant women correlates to increased risk of their children’s low verbal IQ’s, poorer social performance, communication and motor skills.[10] [11]

Dark-skinned people are far more likely to be vitamin D deficient because they require more sun exposure to produce it. If the theory is correct, the rate of autism among black children would be higher than that among white children due to maternal vitamin D deficiency and fetal insufficiency that would influence brain development. This is exactly the case; children of mothers who have emigrated from Uganda to Sweden, for example, have an autism rate of 15%, which is 200 times that of the general population.[12] Far less sunlight is available in Sweden than Uganda, and the season available for vitamin D production is much shorter in Sweden. This puts the Ugandan women at a severe disadvantage in producing enough vitamin D for the developing fetus.

There is a close correlation between latitude and autism among countries; the higher the latitude, the higher the rate of autism.[13] High-latitude countries have higher rates of vitamin D deficiency due to a shorter season in which UVB is available to stimulate its production in the skin. The same relationship of latitude to autism exists within the states of the USA, with northern states having higher rates of autism.[14] [15]

In winter, when vitamin D production is low, birth rates of autistic children peak.[16]
Rickets and autism show similar urban/rural distribution rates. Rickets is an accepted vitamin D-deficiency disease, and urban children have significantly higher rates of both diseases.[17] Pregnant rural women and their children tend to be outside in the sunshine more their urban counterparts, and in urban settings, more air pollution blocks out UVB light, the wave length that stimulates vitamin D production; poor air quality is directly correlated with autism[18] and with profoundly lower serum levels of vitamin D.[19] It is also interesting to note that the Amish of Pennsylvania—mostly rural farmers—have extremely low rates of autism.[20] According to Dr. Heng Wang, who treats Amish people in rural Ohio, their rate of autism is 1 in 1,500, compared to 1 in 166 nationally.[21]

Finally, where precipitation rates are high, rates of autism are also high,[22] [23] suggesting a link with sunlight deprivation. Cloudy, rainy weather blocks the UVB light necessary to produce vitamin D.

The argument that autism is a vitamin D-deficiency disorder is compelling, but until the theory is proven, it would certainly be prudent to assure that pregnant women and young children maintain optimal levels of vitamin D. There is no downside, and the potential to halt an unnecessary disease that is devastating to youngsters, their parents and society.


[1] Autism Society of America web site, accessed January 29, 2008
[2] Ganz, M. The lifetime distribution of the incremental societal costs of autism. Arch Pediatr Adolesc Med 2007;161:343-39.
[3] Cannell, J. Autism and vitamin D. Med hypothesis Oct 24, 2007. Epub ahead of print
[4] JAMA 1989;262:380-84. No authors listed
[5] Cannell, J. Vitamin D newsletter, May 2007.
[6] Eyles, D. et al. Vitamin D3 and brain development. Neuroscience 2003;118:641-53.
[7] McGrath, J. et al. Vitamin D3-implications for brain development J Steroid Biochem Mol Biol 2004;89-90:557-60.
[8] Ashwood, P. et al. The immune response in autism: a new frontier for autism research. J Leukoc Biol 2006;80:1-15.
[9] Cantorna, M. . Vitamin D status, 1,25-dihydroxyvitamin D3, and the immune system. Am J Clin Nutr. 2004 Dec;80:1717S-20S.
[10] Cantorna, M. . Vitamin D status, 1,25-dihydroxyvitamin D3, and the immune system. Am J Clin Nutr. 2004 Dec;80:1717S-20S.
[11] Hibbeln, J. et al. Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study. Lancet. 2007 Feb 17;369(9561):578-85.
[12] Gillberg, C. Et al. Autism in immigrants: children born in Sweden to mothers born in Uganda. J Intellect Disabil Res. 1995;39:141-4.
[13] Grant, W. Epidemiological evidence for supporting the role of maternal vitamin D deficiency as a significant risk factor for the development of infantile autism in those born prior to 1985. Unpublished manuscript.
[14] McNally, R. et al. An infectious aetiology for childhood brain tumors? Evidence from space-time clustering and seasonality analyses. Br J Cancer 2002;86:1070-77.
[15] Centers for Disease Control and Prevention. Prevalence of autism spectrum disorders–autism and developmental disabilities monitoring network, 14 sites, United States, 2002. MMWR Surveill Summ 2007;56:12–28.
[16] Stevens, M. Season of birth effects in autism. J Clin Exp Neuropsychol 2000;22:399–407.
[17] Williams, J. et al. Systematic review of prevalence studies of autism spectrum disorders. Arch Dis Child 2006;91:8-15.
[18] Windham, M. et al. Autism spectrum disorders in relation to hazardous air pollutants in the San Francisco Bay area. Environ Health Perspect 2006;114:1438-44.
[19] Agarwal, K. et al. The impact of atmospheric pollution on vitamin D status of infants and toddlers in Delhi, India. Arch Dis Child. 2002;87:111-13.
[20] Waldman M, et al. Does television cause autism? National Bureau of Economic Research Working Paper 12632, 2006. http://www.econ.cudenver.edu/mocan/data%20for%20courses/Autism%5B1%5D.w12632.pdf (accessed Feb 2, 2008.).
[21]Wang, H. Quoted by Dan Olmsted in The Age of Autism: One in 15,000 Amish. UPI June 8, 2005. Available online at http://pittsburgh.indymedia.org/news/2005/06/18948.php.
[22] Waldman M, et al. Does television cause autism? National Bureau of Economic Research Working Paper 12632, 2006. http://www.econ.cudenver.edu/mocan/data%20for%20courses/Autism%5B1%5D.w12632.pdf (accessed Feb 2, 2008.).
[23] Waldman,M. Autism prevalence and precipitation rates in California, Oregon, and Washington counties. Arch Pediatr Adolesc Med. 2008 Nov;162(11):1026-34