Does Vitamin D Deficiency Cause Autism? - Part 2

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 http://www.scientificamerican.com/article.cfm?id=vitamin-d-and-autism 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 - http://www.vitamindcouncil.org/health/autism/ - The articles make interesting reading.