What If Vitamin D Deficiency Is a Cause of Autism?

A few researchers are turning their attention to the sunshine vitamin as a culprit, prompted by the experience of immigrants that have moved from their equatorial country to two northern latitude locations
April 24, 2009

As evidence of widespread vitamin D deficiency grows, some scientists are wondering whether the sunshine vitamin-once only considered important in bone health-may actually play a role in one of neurology's most vexing conditions: autism.

The idea, although not yet tested or widely held, comes out of preliminary studies in Sweden and Minnesota. Last summer, Swedish researchers published a study in Developmental Medicine and Child Neurology that found the prevalence of autism and related disorders was three to four times higher among Somali immigrants, than non-Somalis in Stockholm. The study reviewed the records of 2,437 children, born between 1988 and 1998 in Stockholm, in response to parents and teachers, who had raised concerns about whether children, with a Somali background were overrepresented in the total group of children with autism.

In Sweden, the 15,000-strong Somali community calls autism "the Swedish disease," says Elisabeth Fernell, a researcher at the Karolinska Institute in Stockholm and a co-author of the study.
In Minnesota, where there are an estimated 60,000 Somali immigrants, the situation was quite similar: There, health officials noted reports of autism among Somali refugees, who began arriving in 1993, comparable to those found in Sweden. Within several years of arrival, dozens of the Somali families whose children were born in the U.S. found themselves grappling with autism, says Huda Farah, a Somali-born molecular biologist who works on refugee resettlement issues with Minnesota health officials. The number of Somali children in the city's autism programs jumped from zero in 1999 to 43 in 2007, says Ann Fox, director of special education programs for Minneapolis schools. The number of Somali-speaking children in the Minneapolis school district increased from 1,773 to 2,029 during the same period.

Few, if any, Somalis had ever seen anything like it. "It has shocked the community," Farah says. "We never saw such a disease in Somalia. We do not even have a word for it."
What seemed to link the two regions was the fact that Somalis were getting less sun than in their native country-and therefore less vitamin D. The vitamin is made by the skin during sun exposure, or ingested in a small number of foods. At northern latitudes in the summertime, light-skinned people produce about 1,000 international units (IUs) of vitamin D per minute, but those with darker skin synthesize it more slowly, says Adit Ginde, an assistant professor at the University of Colorado Denver School of Medicine. Ginde recommends between 1,000 to 2,000 IUs per day, calling current recommendations of 200 IUs per day outmoded.

And again Scientific American headlines,
Vitamin D deficiency, soars, in the U.S, study says,
New research suggests that most Americans are lacking a crucial vitamin.
Three-quarters of U.S. teens and adults are deficient in vitamin D, the so-called "sunshine vitamin" whose deficits are increasingly blamed for everything from cancer and heart disease to diabetes, according to new research.

The trend marks a dramatic increase in the amount of vitamin D deficiency in the U.S., according to findings set to be published tomorrow in the Archives of Internal Medicine. Between 1988 and 1994, 45 percent of 18,883 people (who were examined as part of the federal government's National Health and Nutrition Examination Survey) had 30 nanograms per milliliter or more of vitamin D, the blood level a growing number of doctors consider sufficient for overall health; a decade later, just 23 percent of 13,369 of those surveyed had at least that amount

And from Magazine Psychology Today
Autism and Vitamin D
The sun is not the enemy
Published on April 25, 2011
In recent ,we have been told to avoid the sun. Anyone reading women's magazines, in fact, will have been advised to put on sunscreen on face and hands "just in case" as those few moments walking from the car to the workplace or grocery store might be enough to cause aging and cancer cells to go nuts in our vulnerable skin.

We slather on sunscreen and sunblock, which for the most part completely blocks the UVB sun rays that increase our cancer protective vitamin D and allows in some cancer causing UVA - to me that sounds like a silly thing to do!

Why not get enough sun to get a little color, obtain a healthy amount of the essential vitamin D and then cover up to avoid sunburn and further problems? It is certainly what our ancestors, absent suncreen, must have done for hundreds of thousands of years.
Vitamin D is minimal in the diet (fortified dairy products and cod liver oil provide a small amount), and we have historically obtained 90% or so of our vitamin D through our skin. In fact, someone with fair skin in the midday hours of the summertime can make up to 12,000 IU vitamin D within 20 minutes or so with arms and legs exposed. A more typical amount in someone with an adequate blood level of vitamin D would be 4,000 IU - a cup of milk has 300 IU. So you can see you have to drink an awful lot of milk to make up for sun avoidance.

In recent decades, near-complete sun-avoidance is what we've been told to do (particularly in the midday, which is when we make the most vitamin D.)
Health-conscious folks blocked those dangerous rays from our vulnerable hides and definitely protected the soft skin of our most precious children. But could that increased vigilance have a terrible cost? Could a lack of sunshine and suboptimal amounts of vitamin D be a possible cause of autism spectrum disease in our children?
Dr. Cannell's major points (he has several more, but I'll note the more compelling ones):

1) Autism is increasing, as is vitamin D deficiency, and the autism epidemic came upon us at the same time the major health authorities advised us to eschew the sun.

2) Vitamin D is likely central to brain development as a key helper in neural development, and neuroprotection. In addition, autism is likely mediated by inflammation, and vitamin D is a key player in anti-inflammatory processes. Also, vitamin D enables glutathione, the "master antioxidant," to clear our system of free radicals, and glutathione also acts as a chelating agent to bind toxic heavy metals such as mercury, which kids with autism have a tough time clearing from their systems.

3) Williams syndrome, a chromosomal disease which (among other things) results in abnormally high levels of circulating active vitamin D in early childhood, results in kids who are especially social and overfriendly - rather the opposite of autism symptoms.
And how many friendly online pseudoskeptics have you met ?

4) During pregnancy, boys' brains are bathed in testosterone, and girls' brains in estrogen. Estrogen is known to have many vitamin D enhancing properties. This could account for the 4:1 ratio of boys to girls suffering from autism.
(As Susan Blackmore points out in Wikki, that pseudo-skeptics are a large group of dysfunctionally timid men. All men.)

5) Studies show autism births occur most often in March, at the end of winter, when vitamin D levels would be lowest.

6) African Americans seem to suffer from a higher rate of autism, and they also have a higher rate of vitamin D deficiency than people with lighter skin. In Europe, the children of darker-skinned immigrants have higher rates of autism also.

7) Rickets, due to vitamin D deficiency, is characterized by hypotonia (poor muscle tone) and developmental delay, as is autism.

8) Autism seems to be higher among the kids of highly educated women, and they are more likely to follow guidelines for sun restriction for themselves and their children.

All told, it makes for a compelling theory, and Dr. Cannell has a point in that "this theory deserves immediate attempts to disprove it." My only major issues with it, are that rickets is not autism, and that there may not be a new autism epidemic, after all, but we are only now recognizing how prevalent the disorder actually has been all this time. But I could certainly be wrong about that second bit. And, by all means, let's please give pregnant women guidelines for sufficient vitamin D and get the kids to play outside! And let's study vitamin D and autism directly.

Dr. Cannell touches on this next part in his 2010 article - we have a lot to learn from history. If vitamin D deficiency is the cause of autism, then all of this has happened before. Rickets, characterized mostly by bone growth abnormalities in children, became endemic during the industrial revolution, when people in cities, especially, seemed to spend very little time outdoors, diets were poor, and many children died, as there was no cure. Eventually, cod liver oil and sunbathing were shown to prevent and improve the disease.

Here is Dr. Cannell's quote: "If adequate amounts of vitamin D prevent autism, one would expect children with rickets to have an increased risk of autism. To my knowledge, the neuropsychiatric symptoms of rickets have not been studied in the modern era. However, at least two old papers have addressed it, both published before Kanner described autism in 1943. Both papers describe 'weak mindedness,''feeble minds,''mental dullness,' unresponsiveness and developmental delays. Even more intriguing, both papers report that the mental condition in rickets improved with vitamin D." Those broad symptoms are repeatedly observed, in online pseudo-skeptics, the James Randi Brigade.

In Nutrition and Physical Degeneration, first published in 1939, a writer named Laird had the following to say about the state of mental health at the time - keeping in mind this was published without a thought for political correctness, and certainly researchers or bloggers would phrase some things quite differently these days! (1):

The country's average level of general ability sinks lower with each generation. Should the ballot be restricted to citizens able to take care of themselves? One out of four cannot. . . . The tail is now wagging Washington, and Wall St. and LaSalle Street. . . . Each generation has seen some lowering of the American average level of general ability.

Although we might cite any one of nearly two dozen states, we will first mention Vermont by name, because that is the place studied by the late Dr. Pearce Bailey. "It would be," he wrote, "safe to assume that there are at least 30 defectives per 1000 in Vermont, of the eight-year-old mentality type, and 300 per 1000 of backward or retarded persons, persons of distinctly inferior intelligence. In other words, nearly one-third of the whole population of that state is of a type to require some supervision.

Dr. Weston Price summarized the thinking about medicine and disease at the time thusly:

The problem of lowered mentality and its place in our modern conception of bodily diseases has not been placed on a physical basis, as have the better understood degenerative processes, with their direct relationship to a diseased organ, but has generally been assigned to a realm entirely outside the domain of disease or injury of a special organ or tissue. Edward Lee Thorndike, of Columbia University, says that "thinking is as biological as digestion." This implies that a disturbance in the capacity to think is directly related to a defect in the brain.