Vitamin D deficiency in pregnancy: does it increase the risk of autism in the child?

According to recent research in Australia, vitamin D deficiency in pregnant women may increase, by up to 4 times, the risk of giving birth to children with autism. Consuming vitamin D supplements during gestation could, therefore, be a cheap and easy way to reduce the incidence of the disease. In support of this hypothesis, another study reported that vitamin D3 supplements may improve symptoms in children with autism.

The study, which was conducted by researchers at the University of Queensland (Australia) and the 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 comprise a cluster of developmental deficits (such as autism and Asperger's Syndrome), characterized by symptoms involving the social, communicative and behavioral domains. Signs of the disease usually manifest around the age of three years. These disorders are chronic and disabling and affect about 4 children per 1,000 in Italy, with a higher incidence in males, representing a significant public health problem. Autism is a neurodevelopmental disorder with unknown causes, but it is probably due to both genetic and environmental factors. The latter could include prenatal and early life exposures to infections or toxins or obstetrical complications. Another potential environmental risk factor for autism spectrum disorders is vitamin D deficiency during gestation. Vitamin D is known for its role on bone health; however, optimal concentration is also necessary for a number of other functions such as brain function; in fact, the vitamin plays an important role in Calcium signaling and in the maturation and differentiation of neurons. There are now several scientific evidences highlighting the link between vitamin D insufficiency and autism; several studies have found a relationship between vitamin D deficiency in children and the onset of symptoms of the condition.

Vitamin D deficiency increases the risk of autism

Research conducted by Australian and Dutch researchers has shown that a vitamin D deficiency in pregnancy is linked to an increased risk of autism in children, by age six. Specifically, children born to women with low vitamin D in their blood at mid-pregnancy were 4 times more likely to suffer from autism spectrum disorders, compared to babies born to women with normal vitamin D levels. The findings add to those suggesting a link between vitamin D deficiency and brain growth dysfunction or neurodevelopmental disorders, but, with this study for the first time the association between autism and vitamin D deficiency during pregnancy was examined.

Some details of the research 

The effects described were obtained by analyzing 4229 blood samples from women at 20 weeks of pregnancy, and later from that taken from their infants, who were taking part in another long-term study at the University of Rotterdam. After about 6 years, the children involved in the research were tested specifically to determine any symptoms of autism, revealing that women who had low vitamin D levels in pregnancy were more likely to have 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 directed the research, just as folic acid consumption in pregnancy reduced cases of spina bifida, the information obtained suggests that prenatal vitamin D supplementation could reduce the incidence of autism. The use of supplements, again according to McGrath, is an inexpensive, affordable and safe strategy to reduce the prevalence of this new risk factor for autism. Although, in fact, sunlight stimulates vitamin D synthesis in the epidermis, excessive sun exposure without adequate protection can be a cause of skin cancer. The next step will be to determine with more in-depth research what biological mechanisms link vitamin D deficiency with brain growth and to various neurodevelopmental disorders.

Vitamin D supplements: help improve symptoms in children with autism 

Vitamin D supplements would be useful not only during pregnancy for preventive purposes, but also in autistics; the results of another recent scientific paper revealed, in fact, that supplements containing vitamin D3, the most important form of vitamin D, can improve autism symptoms in children affected by the disorder. The research, published in the Journal of Child Psychology and Psychiatry, which involved a total of 109 autistic children between the ages of 3 and 10 years, living in Egypt, showed that signs of autism improved significantly after four months of daily supplementation with vitamin D3. These data add to those of previous studies that have suggested an association between the risk of autism spectrum disorders and low levels of vitamin D in the blood. Studies published in 2015 revealed that 57 percent of children with this type of disorder showed severe vitamin D deficiency, and another 30 percent of them had vitamin insufficiency in relation to symptom severity. According to the researchers from the University of Assiut (Egypt) who conducted the study, the results will still need to be validated by large-scale research confirming how vitamin D supplements, along with other therapeutic strategies, can help improve the lives of children with autism. Indeed, at present, autism remains a disease that cannot be cured but can be managed with supportive therapy and behavioral and educational strategies.

What doses of vitamin D are considered safe? 

The daily supplement doses used in this study are 300 international units (IU) of vitamin D3 per kg of body weight. In 2016, the European Food Safety Authority (EFSA) set 15 micrograms (600 IU) per day as the adequate intake of vitamin D from food for both adults and children. These recommendations are based on data published by experts from EFSA in 2012, in which for children aged 11 to 17 years the tolerable intake was set at 100 micrograms per day (4,000 IU), and for younger children at no more than 50 micrograms per day (2,000 IU).

Vitamin D supplements: Omegor D3 drops

D3 drops Is a dietary supplement of vitamin D3. D3 drops contains 400 IU of vitamin D3 in each drop and can be used in all cases of increased need or decreased dietary intake of vitamin D3, and is especially indicated 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.