Can a Deficiency in this Common Vitamin Increase Autism Risk?

Can a Deficiency in this Common Vitamin Increase Autism Risk?

A growing body of evidence is finding a link between vitamin D levels and autism. New research in a 2019 edition of Molecular Psychiatry found that mothers with low levels of vitamin D at 11 weeks of pregnancy were associated with 1.58 greater odds of their child developing autism spectrum disorder (ASD). For this study, vitamin D insufficiency was defined as 25-<50 mmol/L on a blood test called 25-hydroxy vitamin D.

Similarly, in this same study, infants with vitamin D levels under 25 mmol/L were 1.33 times as likely to have ASD as newborns with vitamin D levels of 50 mmol/L or higher. When both the mother and baby had low levels, the odds were even higher—1.75 times increased risk of autism.

These findings are consistent with a 2017 study in British Journal of Psychiatry Open, which found that children born to mothers with mid-pregnancy vitamin D deficiency had more than twice the risk of developing ASD.

Another study from 2018 that focused on 3-year-old children found that those in the bottom 25% of vitamin D levels were at a 260% increased risk of ASD.

The exact mechanism of how vitamin D deficiency impacts the risk of autism remains unclear, but the important nutrient plays a vital role in overall brain development.

The Neuroprotective Qualities of Vitamin D

On the flip side, newborns with high levels of vitamin D have reduced odds of autism compared with infants with low levels, according to the largest study to explore the connection between the vitamin and ASD. This study, presented at the 2018 International Society for Autism Research involved a blood analysis of 3,370 infants.

Vitamin D has many other neuroprotective qualities. Called the “sunshine vitamin,” it is actually a steroid hormone, and it activates receptors on neurons in regions important to the regulation of behavior. It also protects the brain by acting in antioxidant and anti-inflammatory capacity.

The sunshine vitamin also plays a critical role in the production of the neurotransmitter serotonin, which is involved in mood control, shifting attention, and cognitive flexibility. And it has a powerful influence on cognitive and mental health, in addition to physical health. Low levels of vitamin D have been associated with depression, cognitive impairment, and psychosis, as well as heart disease, cancer, obesity, and all causes of mortality.

The Vitamin D Crisis

A report in JAMA Internal Medicine that looked at vitamin D levels for American adults in 1988-1994 compared with 2001-2004 showed that our levels are dropping. The percentage of people with levels of 30 ng/mL or more fell from 45% to 23%. This means that 3 out of 4 Americans have low levels of this important vitamin.

Some of the reasons for the dramatic rise in vitamin D deficiency include the fact that people are wearing more sunscreen when outside and spending more time inside while working or sitting in front of the television or computer.

The following groups are more likely to experience vitamin D deficiency:

  • Older adults
  • People with darker skin (reduced ability to make vitamin D from sunlight)
  • People with limited sun exposure (think Northern latitudes)
  • People taking certain medications, such as antihypertensives, antidiabetics, or benzodiazepines
  • People with fat malabsorption syndrome, such as liver disease, cystic fibrosis, and Crohn’s disease
  • People who are obese or who have undergone gastric bypass surgery

Optimizing vitamin D levels (especially vitamin D3) has been associated with improvements in a number of areas. If you are pregnant or trying to conceive, you may want to get your vitamin D level checked and optimize it if it is low.

Similarly, if you have a child with autism, have their vitamin D level tested and optimize it if necessary. One study in Pediatrics found that supplementation with vitamin D improved symptoms of autism. In addition, here are some other things you can do for your autistic child.

At Amen Clinics, we have seen more than 1,000 people with ASD and have used brain imaging in combination with blood tests and lab work as part of a comprehensive evaluation to get an accurate diagnosis and provide targeted treatments that minimize symptoms. If you want your child to join the many others who have improved their autism symptoms at Amen Clinics, speak to a specialist today at 888-288-9834. If all our specialists are busy helping others, you can also schedule a time to talk.


  1. Many, many people with autism have a MTHFR gene mutation. MTHFR gene mutations limit your body’s ability to detox well and put enormous stress on the liver. Since Vitamin D is metabolized in the liver, doesn’t it seem that the MTHFR gene mutation is causing both vitamin D deficiency and the toxic overload leads to Autism, especially after being over exposed to toxins? So, it seems, the MTHFR could be causing both the Vitamin D deficiency and autism.

    Comment by Barbara — February 12, 2020 @ 5:53 AM

  2. how much Vit D3 supplementation is too much?

    Comment by Barbara Garrison — February 12, 2020 @ 10:45 AM

  3. A blood test revealed I have a deficiency in Vitamin D. How can that be possible. I had returned from a holiday at a nudist beach, I don’t use sunscreen often, I work regularly in my garden and I live in a place with around 300 days of sunshine. There must be another factor.

    Comment by Christel Hauri — February 12, 2020 @ 3:44 PM

  4. Thank you for the information on Vitamin D. What is the best time of day to take the Vitamin D supplement?

    Comment by Marcella — February 12, 2020 @ 3:48 PM

  5. This is a semi-educated guess: Could your magnesium levels be too low? I’ve heard that magnesium and vitamin D are closely related.

    Comment by Jean-Philippe Suter — February 23, 2020 @ 10:11 AM

  6. What’s the best time to take Vitamin D?

    Comment by ginny kompst — March 2, 2020 @ 8:22 AM

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