Experts Explore Link Between Vitamin D and Childhood Disorders

Experts Explore Link Between Vitamin D and Childhood Disorders
By Nora Tarte
Kirkman Group, Inc.

Recent studies suggest that there may be a correlation between vitamin D levels and autism diagnoses. While there may be some truth to the theories, experts are calling for more research to be done.

Multiple studies show that children diagnosed with autism have lower vitamin D levels than those without; and lower vitamin D levels were associated with more severe autism, according to a study in Saudi Arabiai.

“Higher quality studies must be done to see if there is a causal effect,” a spokesperson from the Vitamin D Council said.

John Cannell, MD, executive director of the Vitamin D Council, has been administering vitamin D supplements to children diagnosed with autism at their vitamin D clinic to see if it would have any effect on the symptoms related to autism.

Dr. Cannell estimates that 25 percent of autism-diagnosed children taking these supplements showed dramatic improvement (classified as signs and symptoms of the disease disappearing), while 50 percent saw significant improvement (classified as improvements of signs and symptoms). The remaining 25 percent saw no significant changes.

There’s not enough research to speculate whether or not, vitamin D supplements could decrease symptoms of autism, according to a Vitamin D Council spokesperson. “Whether vitamin D could help a person lose their diagnosis hasn’t been studied,” she said.

Rebecca J. Schmidt, Ph.D., assistant professor at the University of California Davis, said she believes there could be a link between vitamin D and autism.

“If there is a link, it is most likely maternal vitamin D status during pregnancy and perhaps the child’s early postnatal development that is most relevant.”

She explained this correlation by noting that maternal vitamin D levels influence the developing fetus’s vitamin D levels during times of critical brain development.

Dr. Schmidt is conducting studies to that effect, including a study in which she looked at the relation between women who took prenatal vitamins and autism diagnoses.

“We found that mothers of children with autism (and autism spectrum disorder) were significantly less likely to report taking a prenatal vitamin in the three months before and the first month of pregnancy,” she said.

The study, however, did not evaluate the relationship between autism and vitamin D specifically, though most prenatal vitamins do contain vitamin D in lower levels. The levels that exist in most prenatal vitamins do not compare to those a person receives through vitamin D supplements and sunlight exposure, Dr. Schmidt explained.

Additionally, Dr. Schmidt said the research did not show an association with multi-vitamins, which typically contain similar amounts of vitamin D.

Dr. Schmidt is planning to continue her research with a new study that will focus on maternal vitamin D intake. Although the study is still preliminary, Dr. Schmidt explained its premise:

“The idea is to evaluate vitamin D status during the relevant time period (early development) in populations where you will have enough clinically determined cases of autism to appropriately test for associations,” she said.

In addition, Dr. Schmidt and her team are conducting other work to examine the genotypes of children with autism and their parents in comparison with families of children with typical development to determine if there are genetic factors that could affect how vitamin D is utilized.

One of the reasons Dr. Schmidt believes the conducted studies do not yet prove a relationship between vitamin D and autism is due to the lack of studies done on humans.

“The studies to date do not provide definitive evidence for a connection in humans,” she said. “Most of the evidence on vitamin D’s role in brain development is based on animal models, so there is a question of whether it will translate to humans.”

The studies that found lower vitamin D levels in humans diagnosed with autism still don’t provide enough evidence for Dr. Schmidt.

“These differences could be explained by many factors, including as a consequence of the disorder,” she said.

“Other studies with weaker designs have made speculative links based on differences in autism rates by geography or skin color of populations, but these studies should be interpreted with caution given the multitude of other factors that differ across populations.”

Dr. Cannell pointed out the misconception about vitamin D, which isn’t really a vitamin at all. Instead, vitamin D is the only known precursor to a steroid hormone (which is classified as having a molecular basis of cholesterol and turns genes on and off) called calcitriol, or activated vitamin D.

Activated vitamin D has the potential to regulate specific genes in the brain making it important to brain development.

“Trials have shown that vitamin D can be taken in doses of 2,000 IU or 4,000 IU daily during pregnancy and have healthy pregnancies,” according to a spokesperson. (Most prenatal vitamins contain only 400 IU.)

The Vitamin D Council recommends an even higher dose, which has not been specifically studied yet.

“Of what we know about vitamin D, it is believed to be a safe, healthy and
adequate dose,” she says.

“Always work with your doctor,” she says. “Vitamin D is a fat soluble, so you can take too much.”

The Vitamin D Council suggests taking no more than 10,000 IU/day for adults and 2000 IU/day per 25 lbs. for children.

But supplements aren’t the only way to get vitamin D.

“A little bit of moderate and safe sunshine cannot hurt, either, and will help getting adequate vitamin D during pregnancy,” a spokesperson for the vitamin D council advised.

i. Mostafa, Gehan A., Al-Ayadhi, Laila Y. (2012). Reduced serum concentrations of 25-hydroxy vitamin D in children with autism; Relation to autoimmunity. Journal of Neuroinflammation. 2012, 9:201.