Vitamin D Deficiency During Pregnancy: Does It Increase Autism Risk in Children?

According to recent research conducted in Australia, vitamin D deficiency in pregnant women may increase the risk of having children with autism up to 4 times. Taking vitamin D supplements during pregnancy could therefore represent an economical and simple method to reduce the incidence of the condition. Supporting this hypothesis, another study reported that vitamin D3 supplements can improve symptoms in autistic children.

The study, conducted by researchers from the University of Queensland (Australia) and Erasmus Medical Centre in Rotterdam (Netherlands), was published in the journal Molecular Psychiatry.

Autism: A Widespread Problem Affecting Children and Their Families

Autism spectrum disorders include a range of developmental deficits (such as autism and Asperger's Syndrome), characterized by symptoms affecting social, communicative, and behavioral areas. Signs usually appear around the age of three. These conditions are chronic and disabling, affecting about 4 children per 1,000 in Italy, with a higher incidence in males, representing a significant public health issue. Autism is a neurodevelopmental disorder of unknown cause, but it is likely due to both genetic and environmental factors. The latter may include prenatal and early life exposures to infections, toxins, or obstetric complications. Another potential environmental risk factor for autism spectrum disorders is vitamin D deficiency during pregnancy. Vitamin D is known for its role in bone health, but optimal levels are also necessary for a range of other functions such as brain function, where it plays an important role in calcium signaling and neuron maturation and differentiation. Scientific evidence increasingly highlights the link between vitamin D insufficiency and autism; several studies have found a relationship between vitamin D deficiency in children and the onset of autism symptoms.

Vitamin D Deficiency Increases Autism Risk

Research by Australian and Dutch scientists has shown that vitamin D deficiency during pregnancy is associated with an increased risk of autism in children by age six. Specifically, children born to women with low vitamin D levels at mid-pregnancy had a 4-fold higher likelihood of developing autism spectrum disorders compared to children born to women with normal vitamin D levels. These findings add to evidence linking vitamin D deficiency with brain growth dysfunctions and neurodevelopmental disorders, but this study is the first to examine the association between autism and vitamin D deficiency during pregnancy.

Research Details

These effects were observed by analyzing 4,229 blood samples taken from women at the twentieth week of pregnancy and subsequently from their newborns, who were part of another long-term study at the University of Rotterdam. Approximately six years later, the children involved underwent specific tests to assess autism symptoms, revealing that women with low vitamin D levels during pregnancy had a higher chance of having autistic children.

Positive Implications of the Discovery

The study identifies gestational vitamin D deficiency as a modifiable risk factor associated with autism. According to Professor John McGrath, who led the research, just as folic acid intake during pregnancy reduced spina bifida cases, these findings suggest that prenatal vitamin D supplementation could reduce autism incidence. Supplement use, McGrath adds, represents a cost-effective, accessible, and safe strategy to lower the prevalence of this emerging autism risk factor. While sunlight stimulates vitamin D synthesis in the skin, excessive unprotected sun exposure can cause skin cancer. The next step will be to determine through further research the biological mechanisms linking vitamin D deficiency with brain development and various neurodevelopmental disorders.

Vitamin D Supplements: Helping Improve Symptoms in Autistic Children

Vitamin D supplements may be useful not only as a preventive measure during pregnancy but also for autistic children. Results from another recent scientific study revealed that vitamin D3 supplements, the most important form of vitamin D, can improve autism symptoms in affected children. The research, published in the Journal of Child Psychology and Psychiatry, involved 109 autistic children aged 3 to 10 years, residing in Egypt. It showed that autism symptoms significantly improved after four months of daily vitamin D3 supplementation. These data add to previous studies suggesting an association between autism spectrum disorder risk and low blood vitamin D levels. Some studies published in 2015 found that 57% of children with this condition had severe vitamin D deficiency, and another 30% had vitamin insufficiency related to symptom severity. According to researchers from Assiut University (Egypt) who conducted the study, these results need to be validated by larger-scale research confirming that vitamin D supplements, together with other therapeutic strategies, may help improve the lives of autistic children. Currently, autism remains an incurable condition but can be managed with supportive therapy and behavioral and educational strategies.

What Are Considered Safe Vitamin D Dosages?

The daily supplement doses used in this study were 300 international units (IU) of vitamin D3 per kilogram of body weight. In 2016, the European Food Safety Authority (EFSA) set the adequate intake of vitamin D from food at 15 micrograms (600 IU) per day for both adults and children. These recommendations are based on data published by EFSA experts in 2012, which established a tolerable upper intake level of 100 micrograms per day (4,000 IU) for children aged 11 to 17 years, and 50 micrograms per day (2,000 IU) for younger children.

Vitamin D Supplements: Omegor D3 Drops

D3 drops is a vitamin D3 dietary supplement. D3 drops contains 400 IU of vitamin D3 per drop and can be used in all cases of increased need or reduced dietary intake of vitamin D3, and is especially suitable during growth.

Sources: J McGrath, et al., “Gestational vitamin D deficiency and autism-related traits: the Generation R Study,” Molecular Psychiatry. Khaled Saad et al., “Randomized controlled trial of vitamin D supplementation in children with autism spectrum disorder,” Journal of Child Psychology and Psychiatry.