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Vitamins for Autism: A Comprehensive Guide

Various vitamin supplements with text that says "Vitamins for Autism: A Comprehensive Guide"

“Vitamins for Autism: A Comprehensive Guide” was written by Laura Ugwuoke and reviewed/edited by Gabi Abreu, BSc and Jackie Silver MHSc, RD

Medical Disclaimer: The information in this article is meant for educational purposes only. It is not intended to be personalized medical or nutrition advice. For a plan tailored to your needs, please consult with a Registered Dietitian or qualified healthcare professional.
Disclosure: This post may contain affiliate links with which I may earn a small commission but at no additional cost to you. Affiliate links help bloggers like me to provide you with free content. All opinions expressed here are genuine. 

Last updated: June 6, 2024

Vitamins for Autism: Essential Nutritional Support

Folks on the Autism spectrum live complex and intricate lives. Proper nutrition plays a crucial role in supporting autistic individuals, making it essential to focus on evidence-based dietary practices.

Various research studies have been conducted to evaluate the effects of certain vitamins and supplements for their potential benefits in supporting the health and well-being of autistic individuals.

Proper nutrition and vitamins for autism can:

  • Enhance overall wellness
  • Manage common health issues associated with autism
  • Support cognitive function and behavioral health
  • Improve digestive health and nutrient absorption

In this blog, we’ll explore the vital role that vitamins and nutrition play in the lives of autistic individuals, providing practical tips and evidence-based recommendations to help navigate this important aspect of health. 

Various vitamins for autism supplements on wooden spoons

It’s crucial to discuss any supplements with a healthcare provider before starting, as they might interact with medications or cause side effects. Additionally, we want to emphasize that we are not suggesting that vitamins can “fix” or “cure” any “symptoms” of autism. This is not aligned with our neuro-affirming approach. Our goal is simply to provide information on supplements that may be relevant to autistic individuals in supporting their overall health.

Vitamin Deficiencies in Autistic Individuals

Autistic individuals may often have lower levels of vitamins D, B6, B12, and folate. Although more research is needed to explore how these nutrients interplay with the symptoms of autism spectrum disorder (ASD), there are several known factors that can contribute to these deficiencies. 

Factors contributing to vitamin deficiencies in autism may include: 

  1. Selective Eating and Sensory Sensitivities

Many autistic individuals have specific food preferences and aversions. Sensory sensitivities to the taste, texture, color, or smell of foods can lead to selective eating habits. This limited diet can result in inadequate intake of essential vitamins and minerals. To learn more about selective eating, check out this blog post!

  1. Gastrointestinal Issues

Gastrointestinal (GI) problems are common among autistic individuals. Chronic constipation, diarrhea, and other digestive issues can impair the body’s ability to absorb nutrients efficiently. Poor nutrient absorption can lead to vitamin and/or mineral deficiencies despite a seemingly adequate diet.

  1. Restricted Diets

Some autistic individuals may follow restricted diets due to food allergies, intolerances, or behavioral issues related to eating. These restrictions can make it challenging to consume a well-rounded diet that provides all necessary nutrients.

  1. Medication Interactions

Certain medications prescribed for managing autism can interfere with the absorption or metabolism of vitamins and minerals. This can further exacerbate the risk of deficiencies.

An infographic listing the factors contributing to vitamin deficiencies in autism - vitamins for autism

Understanding Vitamins for Autism

Research on the relationship between vitamins and autism is ongoing, with limitations such as small sample sizes, and taking into consideration the complex nature of autism spectrum disorder (ASD). 

It is important to note that all of the research on vitamins for autism has been conducted in children and not adults. This is a big gap in the scientific literature and it would be helpful to conduct studies on vitamins for autistic adults. 

Additionally, much of the research on vitamins for autism has studied the effect of vitamins on autism “symptoms” such as behaviors and social communication. Research on how vitamins impact overall health in autistic individuals and the benefits of correcting nutrient deficiencies would be very helpful.

Despite these challenges, several vitamins and probiotics have shown promise in supporting the health and well-being of individuals with autism. Let’s explore a few of these below!

An infographic listing the vitamins that have been studied in autism - Vitamins for autism

1. Vitamin B12 – Some evidence suggests that vitamin B12 supplementation can help improve the severity of ASD “symptoms”. Specifically, methyl B12 (a form of vitamin B12) has been shown to enhance symptoms related to improved B12 levels in the body. Although the exact dosage used in these studies was not specified, the research indicates that methyl B12 supplementation can be beneficial without causing serious side effects. Despite these promising results, more research is needed to fully understand the effects of vitamin B12 on ASD. Overall, the strength of the current evidence supporting the use of vitamin B12 for ASD is considered strong. 

Please note that B12 levels can be checked in bloodwork and people who are low in B12 would likely benefit from taking a B12 supplement. Always check with a healthcare professional before starting any new supplement. 


2. Vitamin B6 and Magnesium – While there is a perception that Vitamin 6 and Magnesium supplementation could have an effect in reducing ASD “symptoms”, there is no solid evidence that supports this. One study tested various doses of vitamin B6 ranging from 30 mg per kilogram of body weight per day, up to a maximum of 1 gram per day. They also tested magnesium lactate at 10–15 mg per kilogram per day. 

Although some improvements in overall behavior ratings related to ASD were reported, the strength of the evidence is very low. No significant side effects have been observed with these supplements, but it’s important to note that high doses of vitamin B6 carry a risk of nerve damage, and high doses of magnesium can cause diarrhea.


Foods high in vitamin b6

3. Vitamin D – Vitamin D is known for its role in bone health and immune function. Research has found that autistic individuals may often have lower levels of vitamin D compared to the general population. 

However, the specific effects of vitamin D supplementation on ASD is not clearly established, and more research is needed to fully understand its potential benefits. 

In one study, 109 children aged 3–10 years with ASD were given 300 IU of vitamin D3 per kilogram of body weight per day. The results showed improvement in behavior and social responsiveness among the children receiving this treatment. Additionally, little to no harm was recorded from this high dose of vitamin D supplementation. Despite these promising results, the current evidence supporting the use of vitamin D for improving behavior is considered weak.

Overall, while there are some indications that vitamin D supplementation may help improve certain ASD “symptoms”, such as behavioral functioning, the evidence is not strong enough to draw definitive conclusions.

Similarly to B12, vitamin D levels can be checked in bloodwork and people who are low in vitamin D would benefit from taking a vitamin D supplement. Always check with a healthcare professional before starting any new supplement.


Foods that are high in Vitamin D - vitamins for autism

4. Omega-3 Fatty Acids – Omega-3 Fatty Acids are essential nutrients found in seafood and fish oil, to name a few sources. Omega-3s are important for brain health and function in all stages of life. 

Some research with small sample sizes has shown improvements in ASD-related characteristics with omega-3 supplementation. However, more research is needed to understand the relationship between omega-3 supplementation and ASD symptoms. It is hypothesized that omega-3 may play a role in autism by reducing inflammation but this connection has not been proven. In one study, participants (autistic children) were given 840 mg per day of eicosapentaenoic acid (EPA) and 700 mg per day of docosahexaenoic acid (DHA) for six weeks. The results showed improvements in reducing repetitive behaviors, inappropriate speech, and hyperactivity. While no severe side effects were observed, mild side effects such as gastrointestinal symptoms, rash, and agitation were often reported. 

Other studies with omega-3 supplementation in autistic children showed improvement in hyperactivity, irritability, stereotyped behaviors, and social communication.

The strength of the evidence supporting the use of omega-3 supplements for ASD is considered moderate. Overall, while there are indications that omega-3 fatty acids may help with certain ASD symptoms, further research is needed to draw definitive conclusions.


Foods that are high in Omega-3

5. IronIndividuals with ASD often have lower levels of iron compared to the general population. Iron is an important mineral for optimal body functions, growth and development for all individuals.

Autistic children are at higher risk for iron deficiency if they are selective eaters (ie. they may not eat iron-rich foods due to sensory reasons), have food sensitivities or GI issues.

Research has shown that iron supplementation can improve ASD behaviors related to increased iron levels in the body. However, more research is needed to fully understand how iron supplementation affects ASD symptoms. Some studies have also shown that iron supplementation may improve sleep in autistic children.

While the specific dosage used in studies was not specified, no serious side effects were observed with iron supplementation. Overall, while there are promising indications that iron may help alleviate certain ASD behaviors and sleep, further research is necessary to draw definitive conclusions.

As with vitamin B12 and vitamin D, a blood test can check for an iron deficiency. Taking an iron supplement can help resolve this nutrient deficiency so it would be helpful for autistic individuals to know if they are low in iron. If you are concerned you may be iron deficient, please ask your doctor for a blood test. 

Foods that are rich in iron - vitamins for autism

6. Probiotics – Probiotics are often referred to as the “good” or “friendly” bacteria. They help maintain a healthy balance in your gut by counteracting harmful bacteria. Probiotics can be found in foods like kefir, sauerkraut, probiotic-enriched yogurt, and other fermented products, as well as in dietary supplements.

Research suggests that there is a relationship between the gut microbiome (the community of microorganisms living in your digestive tract) and symptoms associated with autism spectrum disorder (such as anxiety, social interaction differences, sleep disturbances, self-injury, destructive behaviors, aggression, etc.). This connection is often referred to as the brain-gut axis.

Interestingly, some research also shows that the digestive tracts of autistic individuals are less diverse in bacteria compared to neurotypical individuals. 

A small study in autistic children showed that probiotic supplementation improved gastrointestinal symptoms and behaviors.

More small studies in autistic children who took probiotic supplements had a better ratio of gut bacteria, improved GI symptoms, and less hyperactivity, impulsivity, and improvement in disruptive and rule-breaking behaviors.

Probiotics have been shown to improve the gut microbiome, which may offer benefits for autistic individuals. Overall, while the potential is promising, there are limitations to these studies and further research is necessary to understand the full impact of probiotic supplementation on ASD.

There is little risk associated with taking a probiotic supplement. If an autistic child or adult struggles with GI issues, constipation or diarrhea, or has been on multiple rounds of antibiotics, they may want to consider taking a probiotic supplement. As always, consult with a doctor or dietitian before making these changes. 

Foods that contain probiotics - vitamins for autism

Factors to Consider Before Supplementing with Vitamins for Autism:

1. Individual Needs: Each person’s nutritional needs are unique. Factors such as age, gender, diet, and overall health status can all influence what supplements may be beneficial to an individual.It’s important to work with a healthcare provider to identify specific deficiencies and tailor supplementation accordingly.

2. Dosage: Determining the correct dosage of supplements is essential. Your healthcare provider can help establish the right amount for your individual needs. It’s important to follow recommended dosages, as excessive amounts of certain nutrients can be harmful. 

3. Dietary Sources: Whenever possible, aim to obtain nutrients from whole foods. A balanced diet that includes a variety of fruits, vegetables, proteins, and whole grains is essential for overall health. While supplements can be helpful, they should not be a substitute for a healthy diet.

4. Limited Research: While some studies suggest that certain supplements MAY benefit individuals with ASD, the research is still evolving and there is a long way to go before we can draw firm conclusions. Further studies are needed to fully understand the effects of supplementation. It’s important to approach supplementation with caution and to discuss any concerns with a healthcare provider.

An infographic listing the factors to consider before supplementing with vitamins for autism


Focusing on a balanced diet and lifestyle is essential for supporting the health and development of all people, including autistic individuals. Vitamins and supplements may offer some additional benefits to individuals with autism, and can be included as part of a holistic approach to health and well-being with the support of a registered dietitian

However, it is important to note that vitamins cannot “cure” autism. We embrace a neuro-affirming approach and do not seek to “fix” symptoms. Instead, our goal is to share vitamins supported by research that may offer health benefits. Supplementation may be a useful tool for managing certain aspects of ASD, but it should be approached carefully and tailored to individual needs.

Before starting any new supplement regimen, it’s important to consult with a healthcare provider to ensure that the supplement is appropriate for your individual needs.

If you like this article, be sure to check out some of our other blogs by clicking the links below!

Laura Ugwuoke is wearing a dark brown and navy striped sweater and standing in front of a beige wall

About Laura

Meet Laura Ugwuoke, a wellness advocate with a deep-rooted passion for promoting a healthy lifestyle. Armed with a BSc in Nutrition from UBC and actively working towards a degree in Dietetics and Nutrition, Laura possesses a wealth of knowledge to guide individuals on their path to wellness. Embracing the belief that wellness should be inclusive and available to all, Laura is committed to breaking down barriers and making healthy choices accessible.  Beyond the world of nutrition, you’ll often find Laura unwinding and enjoying the latest binge-worthy series on Netflix, finding joy in a well-deserved moment of relaxation.

About Jackie

Jackie is a Registered Dietitian whose mission is to empower and support the neurodivergent and physically disabled communities through nutrition. Jackie runs a virtual private practice and blog which has simple recipes and health information tailored to these communities. She loves cooking, exercising, traveling, journaling, and spending time with family and friends.

Check out her full bio here →

A headshot of Gabi Abreu

About Gabi

Gabi Abreu, BSc, is a Nutrition & Dietetics graduate from Toronto Metropolitan University and the Blog & Social Media Manager at Jackie Silver Nutrition. She is also the founder of the Working Woman’s Health Collection. WWHC was created with the purpose of inspiring women to achieve a healthy relationship with food, while taking into consideration the busy lifestyles that we live today. Beyond her professional pursuits, she loves experimenting with new recipes, trying new workout classes, and indulging her love for adventure through travel!

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