Vitamin C
What is Vitamin C?
Vitamin C, or ascorbic acid, is important for immune function, neurotransmitter and collagen production, as well as antioxidant status. Vitamin C deficiency has been documented clinically in children with autism with severely selective diets.
Vitamin C is a water soluble nutrient that can be found naturally within foods and as a dietary supplement. The body is not able to make vitamin C within the body, so it must be consumed from the diet.
Vitamin C is crucial for helping our body make collagen (part of connective tissue and important for wound healing), L-carnitine and certain neurotransmitters. Vitamin C also helps with protein metabolism.
A commonly known role that vitamin C plays is as an antioxidant within the body and helping regenerate other antioxidants like vitamin E. Current research is being done to see the effectiveness of vitamin C, with its antioxidant properties, for reducing oxidative stress. Lastly, vitamin C helps non-heme iron (iron from plant sources) to be absorbed.
On average, 70%-90% of moderate intakes of vitamin C is absorbed. Excess urine from high dosages is excreted in the urine, due to it being a water-soluble vitamin.
Vitamin C deficiency, or scurvy, is thought to be a rare nutrient deficiency, however we still see it clinically in children with autism with severely selective diets. [1-6]
Food Sources of Vitamin C
Citrus fruits
Tomatoes and tomato juice
Red & green peppers
Broccoli
Brussels sprouts
Cantaloupe
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.
Males
1-3 years: 15 mg/day
4-8 years: 25 mg/day
9-13 years: 45 mg/day
14-18 years: 75 mg/day
19+ years: 90 mg/day
Females
1-3 years: 15 mg/day
4-8 years: 25 mg/day
9-13 years: 45 mg/day
14-18 years: 65 mg/day
19+ years: 75 mg/day
Deficiency
Vitamin C deficiency leads to a disease state called scurvy. How long it takes to reach scurvy after vitamin C intake becomes inadequate depends on each individual. Typically, symptoms will appear within 1 month of little to no vitamin C intake. Symptoms can occur if intake is <10mg/day for many weeks.
Signs of Scurvy Include:
Fatigue
Malaise
Inflammation of the gums (may include swelling and/or bleeding)
Unexplained limp
Connective tissue weakens causing
Tiny round, brown-purple spots due to bleeding under the skin called Petechiae
Discoloration of the skin or easy bruising (Ecchymoses)
A rash of purple spots due to leaking small blood vessels called purpura
Joint pain
Poor wound healing
Thickening of the skin, called hyperkeratosis
Corkscrew hairs
Loss of teeth
Iron deficiency
Bone disease in children
Individuals at Risk of Inadequacy Include:
Individuals with low fruit/vegetable intake
Individual with restricted diets or overall poor intake
Smokers
Infants fed evaporated or boiled milk
Individuals with limited food variety
Individuals with malabsorption and certain chronic diseases such as cancer or end-stage renal disease on chronic hemodialysis
Toxicity
Vitamin C is not seen to cause any adverse health effects from large doses. The most common complaints from high doses include nausea, diarrhea, abdominal cramps, and other gastrointestinal issues.
Some studies have shown adverse effects of high doses of vitamin C, but none have been verified and/or have conflicting research. More research needs to be done to see if high doses of vitamin C will have an effect on any of the following conditions:
Vitamin C causing kidney stones in people with existing kidney issues
Hereditary hemochromatosis
Increased risk of cardiovascular disease in postmenopausal women with diabetes
Vitamin C may cause chromosomal and/or DNA damage and could contribute to cancer
Reduce vitamin B12 and copper levels in the body
Erosion of dental enamel
Males & Females
1-3 years: 400 mg/day
4-8 years: 650 mg/day
9-13 years: 1200 mg/day
14-18 years: 1800 mg/day
19+ years: 2000 mg/day
Supplements
Dietary supplements typically come in the form of ascorbic acid, which has the same ability to be absorbed as ascorbic acid from foods.
Vitamin C is water-soluble, which can affect its absorption. Liposomal (or fat-soluble) vitamin C is available, which increases absorption significantly and may have additional therapeutic benefits. “Buffered” vitamin C means that it has been combined together with buffering minerals such as magnesium, potassium, or calcium to consume higher levels without causing stomach upset.
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.
Research
Vitamin C & Autism in the Research
Scurvy Due to Picky Eating
Vitamin C deficiency (scurvy) is seen within individuals with autism or other neurologic conditions. The most common presenting symptom was an unexplained limp. [1-6]
Three children with ASD who presented with refusal to walk and gingivitis who underwent comprehensive evaluations before establishing the diagnosis of vitamin C deficiency (scurvy). The symptoms resolved after treatment with vitamin C. [1]
Case study: A 17-year-old male with autism spectrum disorder and a diet severely deficient in ascorbic acid due to textural aversion and food preferences. He presented with recurrent arthritis, hemarthrosis, bruising, and anemia. His vitamin C level was low, and his symptoms improved promptly after treatment with ascorbic acid. [7]
Vitamin C Intake
Children with autism often have restricted diets from a number of reasons. Vitamin C deficiency is possible when the diet is restricted. [3]
Children with autism typically consume less vitamin C than typically developing children. [8]
Vitamin C Supplementation
Research shows that vitamin C can be beneficial for sensorimotor behaviors and can reduce autism severity behavior. [8]
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[1] Swed-Tobia R, Haj A, Militianu D, Eshach O, Ravid S, Weiss R, Aviel YB. Highly Selective Eating in Autism Spectrum Disorder Leading to Scurvy: A Series of Three Patients. Pediatr Neurol. 2019 May;94:61-63. doi: 10.1016/j.pediatrneurol.2018.12.011. Epub 2018 Dec 28. PMID: 30795887.
[2] Gulko E, Collins LK, Murphy RC, Thornhill BA, Taragin BH. MRI findings in pediatric patients with scurvy. Skeletal Radiol. 2015 Feb;44(2):291-7. doi: 10.1007/s00256-014-1962-y. Epub 2014 Aug 12. PMID: 25109378.
[3] Ma NS, Thompson C, Weston S. Brief Report: Scurvy as a Manifestation of Food Selectivity in Children with Autism. J Autism Dev Disord. 2016 Apr;46(4):1464-70. doi: 10.1007/s10803-015-2660-x. PMID: 26590972.
[4] Golriz F, Donnelly LF, Devaraj S, Krishnamurthy R. Modern American scurvy - experience with vitamin C deficiency at a large children's hospital. Pediatr Radiol. 2017 Feb;47(2):214-220. doi: 10.1007/s00247-016-3726-4. Epub 2016 Oct 24. PMID: 27778040.
[5] Niwa T, Aida N, Tanaka Y, Tanaka M, Shiomi M, Machida J. Scurvy in a child with autism: magnetic resonance imaging and pathological findings. J Pediatr Hematol Oncol. 2012 Aug;34(6):484-7. doi: 10.1097/MPH.0b013e318236c519. PMID: 22258350.
[6] Andrews SL, Iyer S, Rodda C, Fitzgerald J. Scurvy: A rare cause for limp in a child with autism spectrum disorder. J Paediatr Child Health. 2018 Dec;54(12):1375-1377. doi: 10.1111/jpc.14098. Epub 2018 Jun 27. PMID: 29947447.
[7] Amos LE, Carpenter SL, Hoeltzel MF. Lost at Sea in Search of a Diagnosis: A Case of Unexplained Bleeding. Pediatr Blood Cancer. 2016 Jul;63(7):1305-6. doi: 10.1002/pbc.25980. Epub 2016 Apr 8. PMID: 27062477.
[8] Bjørklund G, Waly MI, Al-Farsi Y, Saad K, Dadar M, Rahman MM, Elhoufey A, Chirumbolo S, Jóźwik-Pruska J, Kałużna-Czaplińska J. The Role of Vitamins in Autism Spectrum Disorder: What Do We Know? J Mol Neurosci. 2019 Mar;67(3):373-387. doi: 10.1007/s12031-018-1237-5. Epub 2019 Jan 3. PMID: 30607900.
