Does Vitamin D Deficiency Cause Autism? – Part 2

Vitamin D Deficiency From: Dr. Chun Wong

Last week, I blogged about a report in Scientific American Magazine linking Vitamin D deficiency with Autism because of the rising number of autism cases in two communities of Somali immigrants who had moved from their equatorial country, with plenty of sunshine, to northern latitude countries.

You can read the Scientific American Magazine report at and click here to read my blog post on it. This week, I have decided to dig a little deeper into the vitamin D theory.

Now, many people have pointed out that these Somali communities would also have faced other changes too, not just lack of sunlight. For example, their new environment may be more toxic (pollution and heavy metals), the vaccination program in their new countries may be different, their diet would have changed etc. So I’m not sure how this preliminary study was able to rule out these other factors and make vitamin D deficiency the missing link.

However, whatever we think about this report into vitamin D deficiency and the Somali communities, there are many scientists out there who do think that vitamin D is a factor that should not be dismissed and that needs to be taken seriously.

Vitamin D – Is it a Plausible Theory?

The Vitamin D Council is an organization run by John Jacob Cannell, MD, a doctor with a special interest in clinical nutrition, and it aims to educate and inform people about vitamin D to prevent vitamin D deficiency, and the illnesses and conditions which are caused by a deficiency.

Cannell points out that at the same time that we are experiencing a vitamin D deficiency epidemic, we are also in the midst of an autism epidemic – can the two be linked? Yes, Cannell believes that sun avoidance is the root cause of both epidemics. Although this is just a theory at the moment, and has not been proven, Cannell thinks that it is a plausible theory and would explain:-

  • Why more boys suffer with autism than girls – This could be due to the different effects that the hormones, estrogen and testosterone, have on vitamin D metabolism.
  • Why more black children have autism – People with darker skins synthesize vitamin D more slowly and so have increased vitamin D requirements.
  • Why children with rickets show autism-like symptoms, including flabby muscle tone, developmental motor delays and decreased activity.
  • Why children with autism have a higher incidence of infections, just like vitamin D deficient children.
  • Why children with autism have a higher incidence of seizures – Vitamin D has been found to reduce the incidence of seizures.
  • Why there seems to be a link between vaccines, heavy metals and autism – Vitamin D increases levels of glutathione which acts as a chelating (detoxifying) agent, helping rid the body of heavy metals and decreasing oxidative stress which can lead to tissue damage, including brain damage.
  • Why there is evidence of autism rates being lower in equatorial countries – A study into the prevalence of autism in children born before 1985 (before people started to worry about sun exposure) by Dr William Grant of SUNARC (The Sunlight, Nutrition and Health Research Center) did show a strong link between the prevalence of autism and the latitudinal position of the country in which they were born.
  • Why Alabama, the southernmost state in a study into autism prevalence, had the lowest prevalence of autism and why New Jersey, the second most northern state studied, had the highest prevalence.
  • Why studies have shown that children born in winter months have a higher prevalence of autism – March, when vitamin D levels have shown to be their lowest, is the worst month of birth for autism prevalence.
  • Why some parents notice improvements in autism symptoms in summer.
  • Why multivitamins have been found to improve brain functioning.

The Vitamin D/Brain Connection

More and more scientists are concluding that vitamin D is needed for brain development. From his research into vitamin D’s role, Professor John McGrath, from Australia’s University of Queensland, concluded that vitamin D is “the neglected neurosteroid” and that it is crucial for proper brain growth and development in an unborn baby.


Studies into maternal vitamin D deficiency (deficiency in pregnancy) in rats have found that the resulting baby rats have abnormal brain cell proliferation, abnormal rates of cell death, reduced production of proteins involved in nerve structure, abnormalities in learning and memory, an abnormally increased brain size and abnormally large brain chambers. Some of these abnormalities, like a larger brain and brain chambers, are also common in autistic children.

The Sun and Autism

As I said last week, vitamin D deficiency has been linked to skin cancer prevention measures and lack of sun exposure, but are pregnant women and children now getting less vitamin D than in years gone by and is it related to sun exposure?

Yes, is the answer. Dr Cannell, from the Vitamin D Council, points out that 90% of our vitamin D stores used to come from the sun, before we started worrying about skin cancer, but in 1989 we started to be warned that sun exposure was harmful and that we needed to take precautionary measures, such as keeping small babies out of the sun. Is it coincidence that autism rates started to climb around this time? 10 years later, stricter warning were given and mothers were told to keep their babies out of direct sunlight, use sunblock or special protective clothing and minimize outdoor activities. Cannell points out that autism rates exploded around this time.

Perhaps vitamin D deficiency is a plausible theory, when you think that a pregnant woman would need to take 50 prenatal multivitamin tablets or consume 200 glasses of milk for her body to produce the same amount of vitamin D that 20 minutes of sun exposure would produce. In my opinion, it definitely warrants further research.

You can read more about Vitamin D and its possible link to Autism in articles at the Vitamin D Council website – – The articles make interesting reading.


8 thoughts on “Does Vitamin D Deficiency Cause Autism? – Part 2

  • Connie

    My son is autistic and we have been using nutrition to heal him. In addition to being currently on the gfcf diet, he also takes probiotics, and vitamins. He has made remarkable leaps and bounds, but he was still having bad days. I decided to keep a log of everything he consumed and when. I also kept track of his moods, vitamin intake, and bowel movements. I was certain there was something I was missing, but I just couldn’t see it. I went back to the drawing board and started researching again. That’s when I found the information about vitamin D. We started taking my son out every day for 20 minutes without sunscreen. Within two days, we saw a HUGE leap in his communication and social skills! It was amazing! I realized that what made the difference between his good and bad days, was the sun! I’m not saying that this is scientific proof that these children are deficient in vitamin D, but there’s definitely something there. And for the other parents out there looking desperately for answers: You’ve tried everything else, we not try this?

  • Where you live it may be the case that lifelong support for people with Autistic Spectrum Disorders is at a level that cannot be bettered but where I live resources  are by no means perfect and support provided is generally too little and too late.

    Research Autism gives a reasonable picture of the prospect for many autistic young people here. They are trying to tighten up the legislation preventing schools from expelling children with SEN but the fact is that if resources are limited then those children who require disproportionate amounts of support and resources will inevitably be more difficult to place in fully supportive schools.
    Given the low cost of vitamin d repletion and it’s absolute safety it seems to me foolish not to opt on the side of safety and having human breast milk flowing replete with vitamin d from vitamin d replete mothers seems to me entirely natural. I suspect that telling pregnant and nursing women they should dress as this Kitava native is not going to get much support if any in modern society so the next best alternative is an effective amount of vitamin d3 daily to equate to the natural amount this Kitava native would obtain.  

    There are plenty of good reasons to remain Vitamin D replete (by which I mean around 50ng/mL) even if in future, it is found that the link between low vitamin D status and increased incidence is not supported.
    Vitamin D Deficiency Linked to Bacterial Vaginosis
    Maternal vitamin D intake during pregnancy is inversely associated with asthma and allergic

     …Association between vitamin D deficiency and primary Cesarean section

  • @TedHutchinson – here is another possibility – 

    “Autism: the role of cholesterol in treatment.
    Aneja A, Tierney E.
    Department of Psychiatry and Behavioral Sciences, Division of Child and Adolescent Psychiatry, Johns Hopkins University School of Medicine, and Department of Psychiatry, Kennedy Krieger Institute, Baltimore, MD 21211, USA. [email protected]

    Cholesterol is essential for neuroactive steroid production, growth of myelin membranes, and normal embryonic and fetal development. It also modulates the oxytocin receptor, ligand activity and G-protein coupling of the serotonin-1A receptor. A deficit of cholesterol may perturb these biological mechanisms and thereby contribute to autism spectrum disorders (ASDs), as observed in Smith-Lemli-Opitz syndrome (SLOS) and some subjects with ASDs in the Autism Genetic Resource Exchange (AGRE). A clinical diagnosis of SLOS can be confirmed by laboratory testing with an elevated plasma 7DHC level relative to the cholesterol level and is treatable by dietary cholesterol supplementation. Individuals with SLOS who have such cholesterol treatment display fewer autistic behaviours, infections, and symptoms of irritability and hyperactivity, with improvements in physical growth, sleep and social interactions. Othuseer behaviours shown to improve with cholesterol supplementation include aggressive behaviours, self-injury, temper outbursts and trichotillomania. Cholesterol ought to be considered as a helpful treatment approach while awaiting an improved understanding of cholesterol metabolism and ASD. There is an increasing recognition that this single-gene disorder of abnormal cholesterol synthesis may be a model for understanding genetic causes of autism and the role of cholesterol in ASD”

    I have found hundreds of “studies” about what COULD cause autism…seriously – we could go on and on and on…how about focusing on the early intervention that DOES work…give these kids a fair shake…it is not a disease…it is not curable…it is treatable…and the likelihood of having a mother know in advance that there is a possibility that her kid could have autism during any prenatal testing…that there is some genetic link from five generations ago…I don’t disagree that vitamen D is essential to any persons health…however…the resources that you quote…well it is only one…the research shows that autism is genetic and that the trigger “could” be a thousand different things – a difference of opinion I might say but I live with this everyday…my other kids live with it everyday…I am a voice for my son – plain and simple…he doesn’t need to be cured of anything…he is healthy and strong and happy and very bright and in time we will know if he will be able to have a job or live on his own.  He gets what he needs and then some…and he is a pretty cool kid. 

  • @Masonsmom – 

    As I have explained  3000IU/day for 7 months may not have been sufficient. The type of supplement you take may also be critical for success. D3 is the only reliable form, some people simply cannot use D2, Dr Davis has found that the OIL based gel caps are most effective. Others find the dry powder filled capsules from Biotech are also reliable, many people have found solid large capsules unreliable.
    While Dr Davis finds 5000iu/daily is the average female requirement there is a huge variation in response to D3. For some people 1000iu/d is sufficient and others may require nearer 10,000iu/daily. If you were serious deficient then the standard amount to correct vitamin D deficiency is 50,000iu/ EACH WEEK (approximately 7000iu/daily) for at least 8 weeks and then 5000iu/daily. 
    The average human uses between 3000~5000iu/daily so in order to correct deficiency states it is necessary for a short while to consume MORE each day than your body actually uses daily. If you only take 3000iu and your body actually ideally uses 5000iu/daily then you are still not meeting your body’s daily needs therefore you remain deficient.
    There is a great deal of misunderstanding on the amount of skin exposure to UVB required for Vitamin d repletion. This paper explains how when they measured outdoor workers who spend all day every day out in the sun, they found that over the year they averaged only 2800iu/daily over the year and were insufficient in winter. If you were to lay nearly naked in the midday sun for 20~30minutes then it’s possible you would make sufficient vitamin D, but the “official” guidance applies only to obtaining the “official” RDA which is clearly insufficient as those who religously take the “official” RDA and then find they are deficient has been proved regularly over the last few years. It is also the case that what some doctors/reporting labs consider “normal” may not be “sufficient” for some individuals to operate optimally. If you watch YouTube – Whats a Vitamin D Deficiency?you will better understand what an ideal vitamin d level should be. Perhaps if you could get checked again by and organisation like Grassrootshealth D Action and reported back your current 25(OH)D it will be easier to see where the problem may lie.
    I forgot the mention the association between low vitamin d status and obesity. There certainly is a connection and it appears to be both cause and effect so creating a vicious spiral. 

  • @TedHutchinson – so a typical response is here – I was tested and the levels were low and on dr’s orders took 3000IU/day for 7 months.  I failed to include that in my response – I apologize.  It is a standardized test where I live and all pregnant women are required to be tested, it is added into all of our dairy products and in the summer we have about 18 hours of daylight for most of the summer and 15 minutes of sun is all you need according to the American study of whatever (I am drawing a blank to actual name of the institute) and well…a general practice of that has certainly served us well.  Anyway…long story short – testing for levels of vitamen D is a standardized test for everyone actually and part of a routine panel when any blood work is being done, as well with babies when they are born and each week in the first 6 weeks and then at each checkup.  I apologize in advance for failing to share this important information.  I forget that not everyone lives where I live.  cheers.

  • The problem with Vitamin D deficiency is not tested for before or during pregnancy so most people are not aware that they are deficient.  Masonsmom is typical. She assumes that because she took vitamin D supplements during pregnancy and gave them to her son then neither could be vitamin D deficient. 

    That simply isn’t the case. Most vitamin D supplements stick to the “official” RDA amounts and these are simply inadequate. If we take an example from recent research we see that at latitude 54 when they used 3200iu/daily they just about got the study participants above the insufficiency threshold. Vitamin D supplementation enhances the beneficial effects of weight loss The problem is that most supplement have only around 200~400iu and as such only raise 25(OH)D levels a trivial amount. Too low to show any difference to any risk indicators.
    Dr Davis of the Heartscanblog, working at latitude 43 Wisconsin, finds that most of his female patients require 5000iu/daily and males 6000iu/daily. But he is aiming to get his heart patients in just above 60ng/mL. 
    For both magnesium and Vitamin d there is a trend from the early 1900’s of ever lower magnesium and vitamin D levels. Something about the way we live (maybe omega 6 oils, increasing sugar/fructose, refined flours, is depleting our vitamin D and magnesium reserves, maybe the increase in pro inflammatory foods is causing our bodies to use up anti inflammatory agents at a faster rate while we are being encouraged to stay out of the sun and use sunscreens.
    Really the only way to be sure you’ve achieved a safe 25(OH)D status is to get tested. But because the safety of vitamin d is so good it is perfectly all right to take 5000iu/daily for 3 months to see how well your body responds to that intake then when you are tested you will then be in a better position to know if your body needs more or less and adjust your intake accordingly. 

  • Does vitamen D deficiency also explain the rise in childhood obesity, reducing sun exposure would prevent our kids from playing outside…just as valid and equally serious and completely preventable…I took vitamen D supplements during pregnancy because it was in the winter, gave my baby vitamen D because he was not formula fed, continued to give all of my children vitamen D supplements during the winter…and in the summer they play outside with sunscreen on…this has nothing to do with the “cause” of autism…my kid was born with it…and I will keep on saying this until someone listens. 

  • I think it’s plausible to say that it would definitely contribute to something like that. Nutritional deficiencies are the primary cause of over 90% of illnesses, so you know, I wouldn’t say that there’s not the potential for it. 

    Nonetheless, a multivitamin is good for pretty much everyone. 


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