Does Vitamin D Deficiency Cause Autism?

Vitamin D Deficiency From: Dr. Chun Wong

There have been a couple of reports about Vitamin D in “Scientific American” magazine which both have bearings on autism.

Vitamin D Deficiency Affects the US

The first report was about how Vitamin D deficiency is soaring in the US, according to a study published in the “Archives of Internal Medicine”. The study claimed that a whopping three quarters of US teens and adults have a deficiency of vitamin D – that’s quite an incredible figure and makes you wonder why.

The study’s author, Adit Ginde, from the University of Colorado Denver School of Medicine, puts this vitamin D deficiency down to skin cancer prevention measures such as wearing long sleeves and using sunscreen ( sun protection of just factor 15 can cut the skin’s ability to manufacture vitamin D by 99%) and points out that there are actually very few dietary sources of vitamin D. Vitamin D is known as the “sunshine vitamin” because the skin produces vitamin D when it is exposed to the sun. By protecting ourselves from sun exposure, to reduce our risk of melanoma, we are cutting our levels of vitamin D. 

Is There a Link between Lack of Sun and Autism?

But what has all this got to do with autism? Doesn’t a vitamin D deficiency lead to bone problems, such as rickets, osteoporosis and arthritis, not autism?

Well, yes, but experts are now wondering if a growth in vitamin D deficiencies has got something to do with the growth in autism. This theory is the result of two preliminary studies in Minnesota and Sweden, and the findings of these studies are discussed in the second article in “Scientific American” magazine.

Both Sweden and Minnesota have large Somali immigrant communities who seem to be overrepresented in the total number of children with autism in each area. In Minnesota, Somali families began arriving in 1993 and the number of children with autism in their community has jumped from 0 out of 1,773 in 1993, to 43 out of 2,029 in 2007. In Sweden, records of Somali children born in Stockholm between 1988 and 1998 have been studied and researchers concluded that Somali children in Stockholm were 3-4 times more likely to suffer with autism than non-Somali children in the city.

The Somali communities in both cities just can’t understand it. In Stockholm, the Somali people call autism “The Swedish Disease” because they had never seen it in Somalia, and Huda Fara, a Somali molecular biologist working in Minnesota, says “We never saw such a disease in Somalia. We do not even have a word for it.”

So why is autism hitting the Somali community so badly?


The only link that researchers could see was to do with sunlight. Both Minnesota and Stockholm are northern latitude countries and so have less hours of sunlight than equatorial Somalia. This means that the Somali communities were having less sun exposure in their new countries and therefore less vitamin D. Adit Ginde also points out that people with darker skins synthesize vitamin D more slowly. It has also been noted that Somali women (including pregnant women) were covering themselves completely when going outside in their new communities, much more than they would have done back in Somali where their whole community was Muslim. Their dress obviously affected their sun exposure levels.

Some experts are arguing that the increase of rates of autism in the Somali communities is just because autism was not being diagnosed in Somalia, due to a lack of awareness, but others are arguing that there may be a vitamin D link with autism. Proponents of this theory put forward the findings of a 2007 review, by Tulane University’s Allan Kalueff, on 20 different studies on animals and humans. Kalueff concluded that vitamin D was essential in gestation and early infanthood for “normal brain functioning”.

Further Evidence

Another study that backs up the vitamin D theory is research carried out by Cornell University and published in “Archives of Pediatrics and Adolescent Medicine” in November last year. This study found that children who lived in counties in Washington, Oregon and California, where there were more overcast days and more rain, were twice as likely to have autism than children living in drier counties in the same state. Michael Waldman, co-author of the study, said “Our research is sufficiently suggestive of an environmental trigger for autism associated with precipitation, of which vitamin D deficiency is one possibility. Further research focused on vitamin D deficiency is clearly warranted.”

Research into vitamin D and autism is ongoing, including a pilot study by Gene Stubbs (associate professor emeritus of psychiatry and pediatrics at Oregon Health & Science University) with pregnant women. Stubbs is giving 5,000 IUs of vitamin D3 to pregnant women who already have at least one child with autism. He is then going to give the women 7,000 IUs while they are breastfeeding. It will be interesting to see the results of this study.

What Can You Do?

If you are pregnant, you may want to consider taking a special pregnancy supplement which contains vitamin D and making sure that you eat plenty of vitamin D rich foods, such as milk, fatty fish and eggs. However, the best source of vitamin D is the sun, so try and get a little sun each day. Experts agree that 10-15 minutes of sunlight a day, at breakfast time or in the evening when the sun’s rays are not so damaging, can boost vitamin D levels without harming the skin.


11 thoughts on “Does Vitamin D Deficiency Cause Autism?

  • August 25, 2009 at 10:48 am

    The author above encourages morning or evening exposure to the sun when in fact, skin produces the most vitamin d when exposed to the noon-day sun.    Plus, calling sun exposure damage is akin to calling exercise damaging to your muscles.   It’s natural and healthy in moderation….it’s not “damage” at all.   What IS damaging, obviously, considering the topic of this article and the other deseases linked to Vitamin D deficiency, is NOT getting sun exposure.   Research suggests that for every 1 person that dies of skin cancer, 200 die from Vitamin D deficiency….while 1,000’s more suffer more profoundly with lingering ailments like osteoperosis and apparently, autism. 

  • July 27, 2009 at 9:15 am

    Vitamin D and cancer mini-symposium: the risk of additional vitamin D.This paper shows there is absolutely no possible danger from consuming less than 10,000iu/daily vitamin D3 and also getting regular sun exposure. As has been stated previously keeping vitamin D status between 50ng and 60ng/ml should take no more than 5000~6000iu/daily. Regular 25(OH)D testing will enable you to discover how much extra vitamin d your body requires to keep within that optimum range. Age, Skin colour, latitude and time outdoors when uvb<>uva ratio is optimum will make big difference to the amount of supplemental D3 your body requires. Correcting magnesium deficiency at the same time as improving vitamin d status is also a good idea. 

  • July 15, 2009 at 3:00 pm

    We have been seeing a lot of interest about vitamin D and about vitamin D deficiency at the search engine through The Vitamin Shopper website.  The more science learns, the healthier we will all eventually be.

  • July 15, 2009 at 11:04 am

    @hoosierville –  Sorry that you feel the need to say ‘its just not true’ which is a euphemism for the fact you think I’m lying just because you don’t know the name of the disease and I can’t remember it.  That really wasn’t called for.

    I didn’t post any links because I don’t have any, I have personal experience of it, since my ex husband had it once and has it again and its quite common around here, especially among the fishermen and farmers. I think a common name for it, but not here, is sand disease, but I don’t have a link for that either.  Its a red growth, thin, that grows on the sclera and the doctors tell you that it is excess vitamin D caused by exposure to sunlight. If you lived in the tropics you might also have encountered it.

  • July 13, 2009 at 9:53 pm

    @Skinny_Iwill_Be@xanga –  Macular degeneration is quite a different disease and has nothing to do with sunlight as far as I am aware. This is a visible growth caused by, as you say, excessive sunlight, but from sunlight engendering the over-production of vitamin D.  I can’t remember its name, sorry.  My ex husband has had it twice (still has it actually).  

  • July 13, 2009 at 9:11 pm

    @SavonDuJour@xanga – Eye diseases are not caused by excessive VIT D, but by excessive sunlight without protection (UVA & UVB rays). Macular Degeneration or as known as ARMD/AMD is a very common disease.

  • July 13, 2009 at 1:54 pm

    Very interesting – lack of Vitamin D and/or Sunlight, compared with Autism.

  • July 13, 2009 at 12:23 pm

    Excess vitamin D is not good at all. I live in the Caribbean and there are various eye diseases caused by it..  What you could do is look at the statistics between the UK and the US.  In the UK vitamin D is added to bread, margarine and milk and I think (but I may be wrong, breakfast cereals and yoghurts). 

    If vitamin D deficiency is linked to autism then it should be greater in the US than the UK and greater in dark-skinned people, those living in less-sunny climes, and Islamic women.  All these populations naturally receiving less than light-skinned people getting sun exposure on faces, arms and maybe legs regularly and eating (at least in the UK) fortified foods.  Also vegans (not in the UK) who don’t take vitamin supplements and don’t get a lot of sun might have a problem as vit. D is only found in animal products. 

  • July 13, 2009 at 9:58 am

    One thing Dr. Chun Wong did not mention was the research on mice and rats showing that vitamin D deficiency during mice/rat pregnancy led to abnomal social behaviours during the offsprings later life. 

    Grassrootshealth D Action offer postal Vitamin D 25(OH)D testing at cost price as part of a 5yr trial. Until such time as there is firm evidence it isn’t expensive either to get tested or to supplement with an effective amount of vitamin D3 to keep your vitamin D status roughly around the level at which human breast milk naturally flows replete with the vitamin

    Unless you spend 20~30 minutes laying naked in the midday sun, it is likely you will require something in the region of 4000~6000iu/daily depending one weight, skin colour latitude, altitude and other variables. There are very many other reasons why everyone should aim for the level of Vitamin d status associated with the least incidence of chronic disease (50~60ng). Here are just a few of particular importance for those pregnant.Vitamin D Deficiency Linked to Bacterial VaginosisAssociation between vitamin D deficiency and primary Cesarean sectionVitamin D, infections and immune-mediated diseasesVitamin D Supplementation and Reduced Risk of Preeclampsia in Nulliparous Women.

  • July 13, 2009 at 2:36 am

    My son was born in California by Gestational Surrogate, so this is interesting to me.  Also, he CRAVES sunlight.  May be a natural reaction to the autism. Most autistic kids do love the sunlight and swimming in a pool or at the beach.


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