Autism and Vitamin D Connection

Autism – or autism spectrum disorder – appears during early childhood and interferes with a person’s ability to communicate with others and interact socially. According to the Autism Society, the prevalence of autism is growing. Between 2000 and 2010, the incidence of autism increased by 119.4 percent. Although the exact cause of autism is not known, research studies have uncovered a connection between autism and vitamin D during pregnancy and in autistic children’s degree of symptoms.

Following are the results of two of those studies.

Autism and Vitamin D Connection During Pregnancy

Autism and Vitamin D Connection During Pregnancy

Brain scans of children diagnosed with autism typically show differences in the shape and structure of their brains. A growing body of evidence connects vitamin D deficiency during pregnancy with altered brain development.

In a study of 4,229 children and their birth mothers, doctors measured mothers’ vitamin D levels halfway through pregnancy and in the umbilical cord blood at birth. When the children turned six years of age, parents in the study completed behavioral questionnaires.

The findings?

Mothers whose vitamin D levels were lower than 10 nanograms per milliliter of blood (ng/ml) during pregnancy were more likely to have a child with autistic traits compared to mothers whose vitamin D levels were sufficient. Doctors defined sufficient vitamin D levels at or above 20 ng/ml. Children whose birth mothers were deficient in vitamin D at mid-pregnancy were 3.8 times more likely to exhibit autistic traits compared to kids of mothers with sufficient vitamin D levels.

The number of women deficient in vitamin D more than doubled from mid-pregnancy to birth – from 16 percent to 36 percent. This finding is particularly important because the developing baby depends entirely on his or her mother for its vitamin D supply. Doctors concluded that supplementing with vitamin D while pregnant is a safe, accessible and inexpensive way to reduce the chances of children developing autism spectrum traits.


Autism and Vitamin D Connection in Children with Autism

The good news is that early diagnosis and intervention can make a big difference in a child’s development.

In a placebo-controlled study to measure the effects of vitamin D supplements on autism symptoms in children, 85 boys and 24 girls, ages 3 to 10, took a placebo or up to 5,000 IU of vitamin D3 per day. Doctors defined normal vitamin D levels at or above 30 ng/ml and deficient vitamin D levels below 20 ng/ml.

After four months, vitamin D levels had increased from 26 to 46 ng/ml in the vitamin D group, and from 27 to 28 ng/ml for the placebo group. Autism symptom scores decreased 17.7 percent for the vitamin D group and 1.9 percent for the placebo group. The vitamin D group also improved in social responsiveness compared to the placebo group.


As continued research uncovers more links into the causes and treatments of autism spectrum disorder, families and individuals affected by autism have hope and support.

FDA Disclaimer
These statements have not been evaluated by the FDA. They are not intended to treat, diagnose, cure or prevent any disease.