Vitamin C, vitamin D, and omega-3 fish oil supplements put to the test to improve the core symptoms of autism spectrum disorder.
Dietary Supplements for Autism
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Dietary supplements are commonly given to children with autism. Do they do any good? One of the most common is omega-3 fats in the form of fish oil, based on studies like this that show “a marked reduction” in omega-3 blood levels among autistic children. But maybe that’s reverse causation—instead of the low omega-3s leading to autism, maybe the autism led to low omega-3s. Maybe autistic children are just pickier eaters and not eating as much fish or flax seeds. You don’t know until…you put it to the test.
Six months of 200 mg a day of DHA, one of the long-chain omega-3s, and… no effect. So here, all these kids are taking it, despite the lack of evidence that it actually does any good. Maybe they just didn’t give enough? Okay, how about a randomized, placebo-controlled trial of 1,500 mg of long-chain omega-3s. And, a high dose didn’t work either. Put all the studies together, and omega-3 supplementation simply “does not [appear to] affect autism.”
Here is a preliminary trial that was published of vitamin C supplements for autism that suggested benefit in at least some kids, but “should not be interpreted as a blanket recommendation for [vitamin C] supplementation”—especially at the whopping dose they used, which could increase the risk of kidney stones.
Bottom line, read a 2017 review in the journal of the Academy of Pediatrics: “There is little evidence to support the use of nutritional supplements” for children with autism, though they didn’t review the vitamin D data.
The vitamin D story started out, like the omega-3 story, with clear evidence that vitamin D blood levels were “significantly” lower in children with autism compared to other kids, and lower D levels correlated with greater autism severity. But vitamin D is the sunshine vitamin. Rather than vitamin D playing some role in autism, isn’t it more likely that autistic kids just aren’t out sunbathing as much?
There were some promising case reports, though. For example, this two-year-old with autism, deficient in D, whose autism seemed to improve after vitamin D supplementation. But, you don’t know if it’s a fluke until…you put it to the test.
A study on the efficacy of vitamin D supplementation in 83 autistic children, and… 80% got better, in terms of their “behavior,…eye contact,…attention span,” concluding: “Vitamin D is inexpensive, readily available,…safe,” and “may have beneficial effects.” But, this was an open-label trial, meaning no placebo control group. So, we don’t know how much of the improvement was just the placebo effect. Now sometimes, open-label experiments are unavoidable. Like, if you’re studying the effects of physical therapy or something, it’s hard to come up with like a placebo massage. But, you can stick vitamin D in a pill. Why not then do a proper randomized, double-blind, placebo-controlled trial?
The typical excuse you get is that it wouldn’t be ethical. If you have a kid who was vitamin D-deficient, how could you just stand by and give them a sugar pill? Yeah, but if vitamin D actually works, how many kids are you condemning to continue to suffer unnecessarily by publishing a less-than-ideal study design?
There are a bunch of “various tenable mechanisms” by which vitamin D could potentially help in children with autism: improvement in “DNA repair, anti-inflammatory actions,…mitochondrial protection,” etc. That’s why “randomized controlled trials are urgently needed.” But there haven’t been any such studies…until now.
A “[r]andomized, controlled trial of vitamin D supplementation in children with autism,” and it’s about time. They gave kids up to 5,000 international units a day, depending on their weight, versus a placebo. The drugs we have for autism really just help with some of the “associated symptoms.” Like, we can give kids sleeping pills or something, but there’s no drug that really touches “the core symptoms” of autism.
So, research groups around the world are looking for something better, and this group appeared to find it. “[V]itamin D supplementation revealed significant effects on the core manifestations of [autism spectrum disorder],” “significant improvements in [not only] irritability [and] hyperactivity [but] social withdrawal,” and repetitive behaviors, “and inappropriate speech”—the first double-blinded, randomized, controlled trial proving the efficacy of vitamin D in autism…patients.”
Please consider volunteering to help out on the site.
- Vancassel S, Durand G, Barthélémy C, et al. Plasma fatty acid levels in autistic children. Prostaglandins Leukot Essent Fatty Acids. 2001;65(1):1-7.
- Mankad D, Dupuis A, Smile S, et al. A randomized, placebo controlled trial of omega-3 fatty acids in the treatment of young children with autism. Mol Autism. 2015;6:18.
- Voigt RG, Mellon MW, Katusic SK, et al. Dietary docosahexaenoic acid supplementation in children with autism. J Pediatr Gastroenterol Nutr. 2014;58(6):715-722.
- Horvath A, Łukasik J, Szajewska H. ω-3 Fatty Acid Supplementation Does Not Affect Autism Spectrum Disorder in Children: A Systematic Review and Meta-Analysis. J Nutr. 2017;147(3):367-376.
- Saad K, Abdel-Rahman AA, Elserogy YM, et al. Randomized controlled trial of vitamin D supplementation in children with autism spectrum disorder. J Child Psychol Psychiatry. 2018;59(1):20-29.
- 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.
- Stubbs G, Henley K, Green J. Autism: Will vitamin D supplementation during pregnancy and early childhood reduce the recurrence rate of autism in newborn siblings?. Med Hypotheses. 2016;88:74-78.
- 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):341-350.
- Cannell JJ, Grant WB. What is the role of vitamin D in autism?. Dermatoendocrinol. 2013;5(1):199-204.
- Jia F, Wang B, Shan L, Xu Z, Staal WG, Du L. Core symptoms of autism improved after vitamin D supplementation. Pediatrics. 2015;135(1):e196-e198.
- Dolske MC, Spollen J, McKay S, Lancashire E, Tolbert L. A preliminary trial of ascorbic acid as supplemental therapy for autism. Prog Neuropsychopharmacol Biol Psychiatry. 1993;17(5):765-774.
- Sathe N, Andrews JC, McPheeters ML, Warren ZE. Nutritional and Dietary Interventions for Autism Spectrum Disorder: A Systematic Review. Pediatrics. 2017;139(6):e20170346.
- Stewart PA, Hyman SL, Schmidt BL, et al. Dietary Supplementation in Children with Autism Spectrum Disorders: Common, Insufficient, and Excessive. J Acad Nutr Diet. 2015;115(8):1237-1248.
- Hanson E, Kalish LA, Curtis C, et al. The Use of Complementary and Alternative Therapy for Children on the Autism Spectrum. JDBP. 2004;25(5):380-381.
- Chen X, Shen L, Gu X, et al. High-dose supplementation with vitamin C--induced pediatric urolithiasis: the first case report in a child and literature review. Urology. 2014;84(4):922-924.
Image credit: CC0 Public Domain via pxhere. Image has been modified.
Motion graphics by Avocado Video.
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Dietary supplements are commonly given to children with autism. Do they do any good? One of the most common is omega-3 fats in the form of fish oil, based on studies like this that show “a marked reduction” in omega-3 blood levels among autistic children. But maybe that’s reverse causation—instead of the low omega-3s leading to autism, maybe the autism led to low omega-3s. Maybe autistic children are just pickier eaters and not eating as much fish or flax seeds. You don’t know until…you put it to the test.
Six months of 200 mg a day of DHA, one of the long-chain omega-3s, and… no effect. So here, all these kids are taking it, despite the lack of evidence that it actually does any good. Maybe they just didn’t give enough? Okay, how about a randomized, placebo-controlled trial of 1,500 mg of long-chain omega-3s. And, a high dose didn’t work either. Put all the studies together, and omega-3 supplementation simply “does not [appear to] affect autism.”
Here is a preliminary trial that was published of vitamin C supplements for autism that suggested benefit in at least some kids, but “should not be interpreted as a blanket recommendation for [vitamin C] supplementation”—especially at the whopping dose they used, which could increase the risk of kidney stones.
Bottom line, read a 2017 review in the journal of the Academy of Pediatrics: “There is little evidence to support the use of nutritional supplements” for children with autism, though they didn’t review the vitamin D data.
The vitamin D story started out, like the omega-3 story, with clear evidence that vitamin D blood levels were “significantly” lower in children with autism compared to other kids, and lower D levels correlated with greater autism severity. But vitamin D is the sunshine vitamin. Rather than vitamin D playing some role in autism, isn’t it more likely that autistic kids just aren’t out sunbathing as much?
There were some promising case reports, though. For example, this two-year-old with autism, deficient in D, whose autism seemed to improve after vitamin D supplementation. But, you don’t know if it’s a fluke until…you put it to the test.
A study on the efficacy of vitamin D supplementation in 83 autistic children, and… 80% got better, in terms of their “behavior,…eye contact,…attention span,” concluding: “Vitamin D is inexpensive, readily available,…safe,” and “may have beneficial effects.” But, this was an open-label trial, meaning no placebo control group. So, we don’t know how much of the improvement was just the placebo effect. Now sometimes, open-label experiments are unavoidable. Like, if you’re studying the effects of physical therapy or something, it’s hard to come up with like a placebo massage. But, you can stick vitamin D in a pill. Why not then do a proper randomized, double-blind, placebo-controlled trial?
The typical excuse you get is that it wouldn’t be ethical. If you have a kid who was vitamin D-deficient, how could you just stand by and give them a sugar pill? Yeah, but if vitamin D actually works, how many kids are you condemning to continue to suffer unnecessarily by publishing a less-than-ideal study design?
There are a bunch of “various tenable mechanisms” by which vitamin D could potentially help in children with autism: improvement in “DNA repair, anti-inflammatory actions,…mitochondrial protection,” etc. That’s why “randomized controlled trials are urgently needed.” But there haven’t been any such studies…until now.
A “[r]andomized, controlled trial of vitamin D supplementation in children with autism,” and it’s about time. They gave kids up to 5,000 international units a day, depending on their weight, versus a placebo. The drugs we have for autism really just help with some of the “associated symptoms.” Like, we can give kids sleeping pills or something, but there’s no drug that really touches “the core symptoms” of autism.
So, research groups around the world are looking for something better, and this group appeared to find it. “[V]itamin D supplementation revealed significant effects on the core manifestations of [autism spectrum disorder],” “significant improvements in [not only] irritability [and] hyperactivity [but] social withdrawal,” and repetitive behaviors, “and inappropriate speech”—the first double-blinded, randomized, controlled trial proving the efficacy of vitamin D in autism…patients.”
Please consider volunteering to help out on the site.
- Vancassel S, Durand G, Barthélémy C, et al. Plasma fatty acid levels in autistic children. Prostaglandins Leukot Essent Fatty Acids. 2001;65(1):1-7.
- Mankad D, Dupuis A, Smile S, et al. A randomized, placebo controlled trial of omega-3 fatty acids in the treatment of young children with autism. Mol Autism. 2015;6:18.
- Voigt RG, Mellon MW, Katusic SK, et al. Dietary docosahexaenoic acid supplementation in children with autism. J Pediatr Gastroenterol Nutr. 2014;58(6):715-722.
- Horvath A, Łukasik J, Szajewska H. ω-3 Fatty Acid Supplementation Does Not Affect Autism Spectrum Disorder in Children: A Systematic Review and Meta-Analysis. J Nutr. 2017;147(3):367-376.
- Saad K, Abdel-Rahman AA, Elserogy YM, et al. Randomized controlled trial of vitamin D supplementation in children with autism spectrum disorder. J Child Psychol Psychiatry. 2018;59(1):20-29.
- 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.
- Stubbs G, Henley K, Green J. Autism: Will vitamin D supplementation during pregnancy and early childhood reduce the recurrence rate of autism in newborn siblings?. Med Hypotheses. 2016;88:74-78.
- 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):341-350.
- Cannell JJ, Grant WB. What is the role of vitamin D in autism?. Dermatoendocrinol. 2013;5(1):199-204.
- Jia F, Wang B, Shan L, Xu Z, Staal WG, Du L. Core symptoms of autism improved after vitamin D supplementation. Pediatrics. 2015;135(1):e196-e198.
- Dolske MC, Spollen J, McKay S, Lancashire E, Tolbert L. A preliminary trial of ascorbic acid as supplemental therapy for autism. Prog Neuropsychopharmacol Biol Psychiatry. 1993;17(5):765-774.
- Sathe N, Andrews JC, McPheeters ML, Warren ZE. Nutritional and Dietary Interventions for Autism Spectrum Disorder: A Systematic Review. Pediatrics. 2017;139(6):e20170346.
- Stewart PA, Hyman SL, Schmidt BL, et al. Dietary Supplementation in Children with Autism Spectrum Disorders: Common, Insufficient, and Excessive. J Acad Nutr Diet. 2015;115(8):1237-1248.
- Hanson E, Kalish LA, Curtis C, et al. The Use of Complementary and Alternative Therapy for Children on the Autism Spectrum. JDBP. 2004;25(5):380-381.
- Chen X, Shen L, Gu X, et al. High-dose supplementation with vitamin C--induced pediatric urolithiasis: the first case report in a child and literature review. Urology. 2014;84(4):922-924.
Image credit: CC0 Public Domain via pxhere. Image has been modified.
Motion graphics by Avocado Video.
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Dietary Supplements for Autism
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Content URLDoctor's Note
UPDATE: The vitamin D RCT has since been retracted for data irregularities and should be not be considered reliable.
This is the latest of an extended series on natural treatments for autism (for those who want to be treated). Please check out the others if you’re interested:
- Fever Benefits for Autism in a Food
- Fighting Autism Brain Inflammation with Food
- Best Foods for Autism
- Autism & Casein from Cow’s Milk
- Does A2 Milk Carry Less Autism Risk?
- Gluten-Free, Casein-Free Diets for Autism Put to the Test
- Are Autism Diet Benefits Just a Placebo Effect?
- Double-Blind Clinical Trial of Diet for Autism
- Pros & Cons of Gluten-Free, Casein-Free Diets for Autism
- Is Autism Really on the Rise?
- The Role of Pesticides & Pollution in Autism
- Heavy Metal Urine Testing and Chelation for Autism
- The Role of the Gut Microbiome in Autism
- Alternative Treatments for Autism
The disappointing results with fish oil mirror what we now know about their use for heart disease. See, for example, Is Fish Oil Just Snake Oil? and Omega-3s & the Eskimo Fish Tale.
What’s that about vitamin C and kidney stones? See Do Vitamin C Supplements Prevent Colds but Cause Kidney Stones?
For more on what vitamin D can and can’t do, check out:
- Will You Live Longer If You Take Vitamin D Supplements?
- Do Vitamin D Supplements Help with Diabetes, Weight Loss, and Blood Pressure?
- How Much Vitamin D Should You Take?
- The Optimal Dose of Vitamin D Based on Natural Levels
- The Best Way to Get Vitamin D: Sun, Supplements, or Salons?
- The Risks & Benefits of Sensible Sun Exposure
- Should Vitamin D Supplements Be Taken to Prevent Falls in the Elderly?
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