Vitamin D
What is Vitamin D?
Vitamin D is a fat-soluble nutrient that is important for bone and muscle health, immune support, mood balance, and reducing inflammation. Vitamin D deficiency may increase autistic traits, while vitamin D supplementation may improve attention span, eye contact, and behavior.
The body naturally makes vitamin D in the skin whenever ultraviolet rays from the sun activate it in the skin. It can also be found in a few foods or can be taken as a dietary supplement.
Whether ingested or made in the skin, vitamin D has to be activated in order to be used within the body. There are two steps that occur to activate the vitamin D, first being in the liver converting it to calcidiol, and the second primarily in the kidney converting it to calcitriol.
Some people are inefficient in the vitamin D activation process due to certain genetic mutations, such as the Vitamin D Receptor (VDR) gene. VDR is found in many different tissues such as brain tissue and peripheral nerves. Research shows VDR may be altered in autism. [6]
Vitamin D can help increase the absorption of other minerals such as calcium and phosphorus, which are both crucial to bone health. Without enough vitamin D to enable calcium to be absorbed, individuals begin to be at risk of losing the density of their bones.
Vitamin D prevents rickets in children and osteomalacia in adults. Vitamin D paired with calcium helps prevent osteoporosis in older adults.
In addition to bone health, Vitamin D also helps with cell growth, immune function, and reduces inflammation. Many of the genes within the body depend on vitamin D to function properly.
Sources of Vitamin D
The best source of vitamin D is sunlight. Just 15-30 minutes of midday sunlight can help you reach your vitamin D needs for the day. You can also get vitamin D through food sources, though in smaller amounts:
Cod Liver Oil (see note on Fish Oil)
Egg yolks
Fortified milk & milk alternatives
Chicken breast
Mushrooms
Recommended Intake
These recommendations are based on the Recommended Dietary Allowance (RDA), which is the average daily level of intake sufficient to meet the nutrient recommendations of nearly all (97-98%) of healthy individuals.
A majority of Individuals Need at Least 600 IU/Day (Ages 1-70) and People Ages 70+ Need 800 IU/Day.
Deficiency
Vitamin D deficiency can occur when intake is low, exposure to sunlight is limited, the individual has kidney issues, of there are issues within the gastrointestinal tract preventing enough vitamin D from being absorbed.
Vitamin D deficiency can also be linked with those with a milk allergy, lactose intolerance, ovo-vegetarianism, and veganism due to the low intake of milk and other foods higher in vitamin D. Those who follow a dairy-free diet might consider supplementing with additional vitamin D.
Individuals with an increased risk of inadequate vitamin D include:
Individuals with restricted diets and poor intake
Gastrointestinal issues that lead to poor fat absorption
Vegans/Ovo-Vegetarians
Breastfed infants
Older adults
People that get limited sun exposure
Individuals with darker skin color
Individuals who are obese or had received gastric bypass surgery
Conditions Associated with Low Vitamin D
Rickets occurs in children where their bones are unable to mineralize properly and are left soft and can lead to skeletal deformities. Rickets is often seen more in infants with darker skin color due to increased melanin reducing ability to produce vitamin D from sunlight, kids who attend a daycare where an extensive amount of sunscreen is used, and children who have little sun exposure.
Osteomalacia is vitamin D deficiency in adults that results in weak bones. Symptoms include bone pain and muscle weakness.
Toxicity
Vitamin D toxicity can cause abnormal symptoms such as loss of appetite, weight loss, excessive urination and heart arrhythmias. Long-term vitamin D toxicity can cause calcium buildup in tissue, which can cause damage to the heart, blood vessels, and kidneys.
Excessive sun exposure does not lead to vitamin D toxicity. Toxicity from food is very unlikely, leaving dietary supplements being the main culprit for toxicity. Conversion of vitamin D from supplements is often ineffective, so many people who are deficient take higher levels of vitamin D without adverse health effects. If this is you, discuss with your doctor before starting mega-doses of vitamin D.
The Tolerable Upper Intake Level (UL) is the maximum daily intake unlikely to cause adverse health effects.
Males & Females
1-3 years: 2500 IU/day
4-8 years: 3000 IU/day
9+ years: 4000 IU/day
Supplements
There are two different forms of vitamin D: D2 (ergocalciferol) and D3 (cholecalciferol). Vitamin D2 comes from plant sources, while vitamin D3 comes from animal sources. Vitamin D2 is both cheaper to produce and less absorbable. While more expensive, vitamin D3 is more efficiently absorbed, and ideal to take orally.
Examples
Note: All supplements are linked to Amazon for convenience, however, buying supplements on Amazon does not guarantee quality, as there are many “unverified resellers” selling nutrition supplements. To buy supplements that are verified to be sent directly to the consumer, you can create an account on the Autism Dietitian FullScript and search for the respective supplement under “Catalog”.
DISCLAIMER: Before starting any supplement or medication, always consult with your healthcare provider to ensure it is a good fit for your child. Dosage can vary based on age, weight, gender, and current diet.
Vitamin D & Autism in the Research
Vitamin D Supplementation Decreases Symptoms
Research shows that vitamin D supplementation for individuals with autism shows improved behavior, stereotypy, eye contact and attention span, especially when the final serum level is more than 40 ng/ml. [1,2]
Vitamin D Deficiency in Autism
Vitamin D deficiency or inadequacy is seen quite often in individuals with autism, and at a higher rate than typically developing individuals. [1-9]
A combination of vitamin D and vitamin A deficiencies may exacerbate the symptoms of children with ASD. [4]
Vitamin D and iron deficiencies are more common in children with ASD. [5[
Severity of vitamin D deficiency has been found to correlate with the severity of autism. [1-2]
Research shows vitamin D deficiency in those with autism producing increased autism-related traits. [4, 9]
Maternal Vitamin D
Low mid-gestational vitamin D levels are associated with increased risk of autism. [8, 10-11]
Vitamin D Receptors (VDR)
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[1] Saad K, Abdel-rahman AA, Elserogy YM, et al. Vitamin D status in autism spectrum disorders and the efficacy of vitamin D supplementation in autistic children. Nutr Neurosci. 2016;19(8):346-351.
[2] Feng J, Shan L, Du L, et al. Clinical improvement following vitamin D3 supplementation in Autism Spectrum Disorder. Nutr Neurosci. 2017;20(5):284-290.
[3] Arastoo AA, Khojastehkia H, Rahimi Z, et al. Evaluation of serum 25-Hydroxy vitamin D levels in children with autism Spectrum disorder. Ital J Pediatr. 2018;44(1):150.
[4] Guo M, Zhu J, Yang T, et al. Vitamin A and vitamin D deficiencies exacerbate symptoms in children with autism spectrum disorders. Nutr Neurosci. 2019;22(9):637-647.
[5] Bener A, Khattab AO, Bhugra D, Hoffmann GF. Iron and vitamin D levels among autism spectrum disorders children. Ann Afr Med. 2017;16(4):186-191.
[6] Altun H, Kurutaş EB, Şahin N, Güngör O, Fındıklı E. The Levels of Vitamin D, Vitamin D Receptor, Homocysteine and Complex B Vitamin in Children with Autism Spectrum Disorders. Clin Psychopharmacol Neurosci. 2018;16(4):383-90.
[7] Cannell JJ. Vitamin D and autism, what's new?. Rev Endocr Metab Disord. 2017;18(2):183-193.
[8] Wang T, Shan L, Du L, et al. Serum concentration of 25-hydroxyvitamin D in autism spectrum disorder: a systematic review and meta-analysis. Eur Child Adolesc Psychiatry. 2016;25(4):341-50.
[9] Guo M, Li L, Zhang Q, et al. Vitamin and mineral status of children with autism spectrum disorder in Hainan Province of China: associations with symptoms. Nutr Neurosci. 10.1080/1028415X.2018.1558762
[10] Vinkhuyzen AAE, Eyles DW, Burne THJ, et al. Gestational vitamin D deficiency and autism-related traits: the Generation R Study. Mol Psychiatry. 2018;23(2):240-246.
[11] Wu DM, Wen X, Han XR, et al. Relationship Between Neonatal Vitamin D at Birth and Risk of Autism Spectrum Disorders: the NBSIB Study. J Bone Miner Res. 2018;33(3):458-466.
[12] Cieślińska A, Kostyra E, Chwała B, et al. Vitamin D Receptor Gene Polymorphisms Associated with Childhood Autism. Brain Sci. 2017;7(9)
