That is, what do we do while we wait for all the hundreds of studies that need to be done to see if the vitamin D theory is correct? The studies will take years. If we do nothing but just wait, we are continuing an unplanned naturalistic experiment on pregnant women, the brains of their unborn children, and upon autistic individuals. A risk/benefit analysis tells us the risk of doing nothing is potentially great while the risk of treating vitamin D deficiency is minimal, simply good medicine, and the better choice.

So until we know for sure, pregnant women, infants, children, everyone—especially autistic children—should receive sensible sun exposure daily: around noon or 1:00 p.m., expose as much skin as possible, 10–30 minutes duration, depending on how easily one sunburns. In the winter, use a suntan parlor once a week, with the same precautions—or better yet, purchase an ultraviolet vitamin D lamp for home use.

I Prefer to avoid sunlight, what should I do?

You and your child should have a vitamin D blood test, called a 25-hydroxyvitamin D . Then take enough vitamin D to achieve adequate (natural summertime) levels. Given what we do know, adequate 25(OH)D levels are now thought to be somewhere above 40 ng/mL (100 nmol/L) and probably closer 50 ng/mL (125 nmol/L). Ideal levels are unknown but they are probably close to levels that were present when the human genome evolved. Natural levels (levels found in humans who live or work in the sun) are around 50–80 ng/mL (125–175 nmol/L). These levels are obtained by only a small fraction of modern humans.

How much vitamin D should I take?

The Food and Nutrition Board set the current Upper Limit for medically-unsupervised intake by infants and babies (up to the age of 1 years-old) at 1,000 units/day. This means the government says it is safe to give infants and babies up to 1,000 units a day without getting a blood test. Of course, with correct sun exposure in the summer this is not necessary, but it will be in winter. Children over 1 years of age, according to the Food and Nutrition Board, may safely take 2,000 units/day—again, without requiring a blood test.

For adolescents, pregnant women, and other adults, the government’s Upper Limits are a problem. While a 2,000-unit Upper Limit is entirely appropriate for younger children, such limits in heavier adolescents, adults, and pregnant women limit effective treatment of vitamin D deficiency. However, these limits no more impair a physician’s ability to treat vitamin D deficiency with higher doses than comparable Upper Limits for calcium or magnesium impair their ability to treat calcium or magnesium deficiencies with higher doses, should those deficiencies be diagnosed.

In the absence of sun exposure and in winter, heavier children, adults, and pregnant women may require doses above 2,000 units daily (depending on pre-existing blood levels, body weight, degree of skin pigmentation, age, and latitude of residence) in order to obtain and maintain levels of 50–80 ng/mL. For example, Professor Heaney at Creighton University has estimated that about 3,000 units/day is required simply to assure that 97% of adult Americans obtain levels greater than 35 ng/mL. Healthy adult men utilize up to 5,000 units of vitamin D per day, if present in the body. Professors Bruce Hollis and Carol Wagner, in South Carolina, have been giving pregnant women 4,000 units/day for years. Professor Vieth, at the University of Toronto, found that actual vitamin D toxicity, with systemic symptoms, is exceedingly rare and requires much higher doses than those discussed above. When exceeding the Upper Limit, periodic serum 25(OH)D and calcium levels will reassure both physician and patient that such amounts are safe as well as convince all concerned that the government should revise their 10-year-old (yet most current) recommendations—the sooner the better.

Is Autism Iatrogenic

If the vitamin D theory of autism is correct, then to the extent it is correct, the current plague of autism is an iatrogenic disease, caused by modern sun-avoidance and the organizations that promulgated it. Long before we worshipped our current gods, primitive humans venerated an older god, the sun. Much as we have shunned our modern gods, 20 years ago we shunned the sun, hiding from it under buildings, cars, shade, and sunblock. We told the sun she was damaging us, and banished her from our lives—and from the lives of our pregnant women and our children. Tragically, we relied on medical knowledge instead of human traditions, government recommendations instead of common sense, the latest science instead of basic instincts. The ancient Greeks, who loved the sun, knew the gods seldom reward such hubris.

In addition to the current epidemic of vitamin D deficiency, say another epidemic—an epidemic of autism—was upon our children? What if the autism epidemic began at the same time the epidemic of vitamin D deficiency began? What if both epidemics had worsened in unison? What if one theory explained all the unexplained facts about autism? What if both epidemics had the same root cause: sun avoidance? What if both were iatrogenic, that is, medical advice to avoid the sun had caused both epidemics? Be warned, what follows is not light reading—autism is not a light disease.

Does The Vitamin D Theory Best Autism?

The theory that vitamin D deficiency, during pregnancy or childhood, causes autism is just a theory. However, the theory has a plausible mechanism of action, explains all the unexplained facts about autism, subsumes several other theories, implies simple prevention, and is easily disprovable—all components of a useful theory. A genetic lesion (abnormality) in some component of the vitamin D system—a lesion vitamin D’s unique pharmacology could overcome—would explain why monozygotic (identical) twins are highly affected while fraternal twins are not. Varying brain levels of activated vitamin D during later life would explain why some identical twins get severe disease while others are barely affected. Falling vitamin D levels over the last 20 years due to sun-avoidance explain autism’s rapid increase in incidence during that same time. The very different effects estrogen and testosterone have on vitamin D metabolism may explain why boys are much more likely to get it than girls are. Lower vitamin D levels in blacks may explain their higher rates of autism. The vitamin D theory has tenable explanations for all the epidemiological features of autism.

What’s The Risk of Going in The Sun?

The window of opportunity to affect brain development is limited. Time is of the essence if the vitamin D theory of autism is correct. Ask yourself, what is the risk of taking your autistic child outside to play in the sun? What’s the risk of pregnant women sunbathing for a few minutes every day? Children always played in the sun before the epidemic of autism; your pregnant grandmother spent time in the sun as well. Physicians considered that sunshine was healthy before the sun-scare, that is, before autism became an epidemic.