Autism & Nutrition

By Dr. Becca Kurzweil

My name is Rebecca Kurzweil and I am a child and adolescent psychiatrist here at the Children's Institute. I've been working with children on the autism spectrum and their families since the beginning of my career. And throughout my training, I've had a lot of questions from families about whether specific diet plans or supplements can have a positive impact on behavioral symptoms that sometimes present in children with autism. So today I've prepared a presentation to hopefully shed some light on this very complex topic.

So autism spectrum disorder is a neurodevelopmental condition that presents in many different ways. It can be diagnosed very young when kids are toddlers and more and more frequently we are seeing it diagnosed in teens or even young adults.

When a child is being evaluated for autism, usually families have noticed differences in social communication, repetitive behaviors, restricted interests, or differences in sensory processing. As the name suggests, this is a spectrum and can present in many different ways depending on the child. There's no specific medicine to treat autism. But as a psychiatrist, my role is to prescribe medications for symptoms that arise or are comorbid. And what I mean when I say comorbid is that several diagnoses are very commonly seen along with autism spectrum disorder. Frequently, this is ADHD, but it can also present with anxiety, aggression, self-injurious behavior, or depression. We have lots of different types of medications and different therapies that we can use to try and make sure that these children are having full and comfortable lives.

So nutrition is a topic that we hear about a lot. It's all over social media, and I'm sure that we have all seen supplements branded toward parents of children with autism that claim to do all these miraculous and amazing things. And I'll be the first to say, or probably not the first, that nutrition absolutely matters. Nutrition is important for everyone. Brain development and function is dependent on getting enough nutrients. Diet and nutrition can impact behavior, mood, sleep, and daily energy. Good nutrition supports growth, how the immune system functions, cognitive performance during the school day, and importantly for our conversation today, also emotional regulation. It is very common for children with autism to have feeding challenges.

Some findings suggest that up to 75% of kids diagnosed with autism will have some type of feeding difficulty. Research also shows that kids with autism are at risk for being an unhealthy weight, and sometimes this can lead to a nutritional deficiency, meaning that the body isn't getting enough of a specific nutrient that it needs to stay healthy.

So why is this important specifically for autism?

Nutrition is a common issue in kids diagnosed with autism, as we discussed, and most commonly this results from parents reporting selective eating. This is often related to food texture, taste, smell, temperature, and our over-reliance on safe foods. And of course, this does tend to be processed foods that usually don't have a lot of nutritional value, like French fries from a specific fast food restaurant or frozen pizza. Kids feel safe with these foods because they always taste and look the same. Like we talked about, French fries from that specific restaurant always look and taste the same, usually served at the same temperature, and the kids know the process of what it is to get them. Unlike a piece of fruit, which can have a different taste or texture depending on which piece you bite into or even what season you bought it in.

Many times, this is obviously due to sensory processing or even maybe behavioral concerns, so you want only a certain texture of food. Usually, I hear kids say that they don't want anything mushy. Kids with autism often also have heightened oral and sensory processing. This could change how intense flavors taste. So maybe we can't notice it, but kids with autism can really pick up on minute changes in taste and texture.

And they can tell apart the things that wouldn't really bother someone who isn't on the spectrum.

Sometimes it also just has to do with a preference for repetitiveness and rituals, needing meals to be at the same time, wanting foods to be in the same package, or fear of trying a new food that they've never had before. There are cases where there's problems with things like oral functioning skills, like chewing a food or having a safe swallow, and that could impact their nutrition as well.

And sometimes, a little bit more rarely, there are digestive issues like GERD, which is acid reflux, or celiac disease, which is gluten intolerance. It's important to note here that research shows that kids with autism do report more gastrointestinal issues like constipation, diarrhea, bloating, and stomach pain. And there are a lot of things that can contribute to this, like the medical problems that we talked about just a second ago, like celiac disease or acid reflux.

Other factors that may lead to more stomach issues include low fiber intake. So that means not eating enough fruits, vegetables, or whole grains. Also, not drinking enough water, and having a very restricted diet with few safe foods, or even just differences in the gut microbiome, which we're going to get into a little bit later in this talk.

Some kids ultimately get diagnosed with something called ARFID, which is avoidant restrictive food intake disorder. This is newer to the DSM-5, which is the big book, I guess, for lack of a better term, that we use to go through all of our psychiatric diagnoses and make diagnostic decisions.

ARFID can lead to weight loss, failure to grow, nutritional deficiency, dependence on supplements or even tube feedings, and it has a marked interference with psychosocial functioning. So now I want to talk about some really common nutrient deficiencies that we see in autism.

This can be iron, which is found in foods like beef, dark poultry meats like chicken thighs, seafood like tuna, lentils and beans, and of course dark leafy greens like kale and spinach. Iron is important for growth, brain development, and cognition. Not getting enough iron can lead to something called anemia, which results in fatigue and low energy. Often kids will fall off their growth curve and it can affect cognitive function as well as daily functioning and emotional regulation. It can also cause pica. This is eating non-food items. The one we hear about the most with iron is chewing on ice.

Now, calcium is found in milk, yogurt, cheese, and again, everybody's favorite food, kale and spinach, and deficiencies in calcium can lead to weak bones, and rarely, if it's very severe, a medical condition called rickets.

The stores of calcium that we make in our youth are important as we age. So not getting enough calcium in your childhood can cause negative long-term effects and bone problems later in life.

Vitamin D goes right along with calcium. And the reason I bring that up is a lot of our dairy products are fortified with vitamin D. This is also very important for bone health, muscle function, immune support, and mood regulation.

We get it from sunlight as skin produces it when it's exposed to the sun's rays. Fatty fish like salmon, egg yolks, and fortified dairy products are also sources. Protein, we hear a lot about this nowadays.
Sources include lean meats, seafood, dairy, and legumes. Not getting enough can lead to a lot of problems like stunted growth, weakened immune system, muscle loss, and malnutrition.

Vitamin C is found in fruits like strawberries, kiwis, red bell peppers, and of course dark leafy greens. And it's important for general development, like healing of skin as well as connective tissue and the immune system. Vitamin A is very important for vision health. These are found in egg yolks, dairy, and orange and yellow vegetables like carrots and sweet potatoes and kale. And last but not least, I want to talk about omega-3s. These are an essential fat that are important for heart health and brain function, especially in our population that we're talking about today because they support mood regulation as well as anti-inflammatory effects. Good sources are salmon, chia seeds, walnuts, and hemp seeds.

Now, as I mentioned, I've been working with kids in this population for the majority of my career, and I know that this can all sound really daunting for our picky eaters. I'm hoping that we could share some tips and tricks in the question and answer session later in the presentation, and I also want to help alleviate some stress for families. This is not meant to make anybody feel intimidated. It is okay if your child is not eating a ton of kale.

Now I want to talk about special diets.

We hear a lot about this and we're going to go through some of these in detail, but I will say before you start any diet, it is so important that you talk to your psychiatrist or your pediatrician. Diets and nutritional plans have been used to treat various medical conditions since the beginning of medicine. Google whatever diagnosis you or a loved one have and there will be a diet somewhere on there that claims to cure or at least drastically improve that condition. There have been many studies that look at specific diets for treating the symptoms of autism and reports basically come back with mixed results and lack the rigorous controls needed for good scientific data. So you'll see a pattern here as we go through this.

A lot of families end up trying a specific diet based on the feedback that they have received from other families, either in Facebook groups or just in their community or in the school. And they'll say that, oh, my kid tried the gluten-free diet and had all these great results. You should try it too. And there's absolutely nothing wrong with that. Every kid is different. And I'm not going to pretend that we understand every single thing going on with the connection between what we're eating and symptoms of autism. However, it is very important that you talk to one of your care providers before starting any sort of restricted diet. Okay, let's get into it. The most common one and the one with the most data behind it, in the sense that it's had the most studies, is the gluten-free diet.

This got super trendy about 10 years ago for everybody. And more recently, I've been seeing it come up for families with children with autism.

This is the removal of wheat, rye, and barley products. Researchers have proposed that some reasons for possible benefit with this diet involve the gut-brain connection. And we'll talk about this more a little bit later. But for somebody with autism who is having gastrointestinal symptoms, maybe gluten is worsening that discomfort and could be influencing behavior. None of us feel good or act like ourselves when we don't feel well and if we're having gastrointestinal symptoms.

Some trials and parent surveys suggest that there were some improvements with communication and social interaction. Another study showed some improvements in nonverbal IQ and autism symptoms compared to controls.

However, larger reviews show that the evidence is insufficient as a primary treatment, and many other studies showed no improvement at all. Clear benefit really only existed when a child had a very clear and medically diagnosed condition, such as celiac disease or gluten intolerance.

The ketogenic diet is a very low-carbohydrate, high-fat eating pattern, and it actually changes the metabolism and the microbiomes in your gut. This is not an easy diet to follow and requires strict medical supervision with either a doctor or a nutritionist. This is well known as a treatment for certain seizure disorders, but evidence is really limited for autism. There are more anecdotal reports from families that this has been helpful, along with other diets like the Paleolithic eating style. However, again, this is extremely restrictive, and I recommend that you work really closely with a provider before embarking on this journey with your family.

Now, the whole foods and Mediterranean-style diet really focuses on eating unprocessed foods, fruits and vegetables, lean proteins, and healthy fats.

With some caveats, this is really how we should all be eating. And there's really limited evidence specifically for autism. But I usually recommend that families start with this approach because we should all be eating less sugar and less processed food, although it is very difficult, especially for our picky eaters.

So the reason I talk about this one is that a whole foods or Mediterranean-style diet is really in contrast to the standard American diet that we hear so much about. The reason that this is an issue is that it's really rich in added sugars and highly processed foods. I'm going to include this in this conversation because that's been in the media and the news a lot as well.

These foods have been shown to increase irritability or cause energy swings in children and adults. These behavior changes and effects will, of course, vary by child. But there are studies showing that these foods can be problematic. For example, some studies have shown that higher intake of ultra-processed foods in early childhood was linked to more behavioral and emotional difficulties by age five, like hyperactivity or even anxiety. And there have been more studies linking ADHD than autism for this specific pattern that I'm talking about.

So this really all stems back to the gut microbiome and why it's important specifically for children with autism.

We now know that the bacteria in our gut affect our metabolic and neurobehavioral traits, meaning that the bacteria in our gut can really affect our mood, how we act under stress, how we sleep, and other situations. So I want to talk about the gut-brain axis. This is the communication network between the digestive system and the brain. It involves the nervous system, the immune system, hormones, and gut bacteria. The gut microbes produce substances that can affect brain function both positively and negatively.

I'm sure most of you have seen ads or commercials for probiotics that help with this and give you more good bacteria. Nutritional status depends on our dietary choices, and imbalanced diets have a negative effect on that gut microbiome. People with autism have been found to have differences in their gut microbiome compared to controls. Mainly what we're seeing is lower diversity of the good bacteria and higher levels of inflammatory species. Some of this may be genetic. And some of it is more likely due to restricted diet patterns and not getting the variety of nutrition you need to support a healthy gut microbiome.

Some studies with taking a probiotic did show improvement in digestion, irritability, and social behavior. And I'm sure you're sensing a pattern here, but data remains very inconclusive. The key to a healthy gut microbiome is variety. Eat a little bit of everything, but the best foods to improve it are high-fiber vegetables, fermented foods like yogurt, kefir, or sauerkraut, legumes and beans, and whole grains.
I do want to take some time to talk about supplements. This can be a tricky topic. More often than not, I will have families come in with a specific supplement asking, one, is it safe? Two, will it help? And the answer is often, I don't know. They are not usually FDA regulated.

A lot of different supplements, like we talked about, are marketed to families and people with autism as cures.

But because they're not FDA regulated, there is not a 100% guarantee of what amounts and what you're even getting. So I really want to take some time to go through the supplements that, due to having some data behind them, could theoretically be helpful for autism or may or may not be worth your time. I'm going to talk about the ones that I am comfortable recommending and signing off on. But again, please reach out to your provider before starting any supplements.

So omega-3 fatty acids are kind of my favorite. As discussed before, these are essential fats found in fish oil, and kids sometimes do not have enough of this in their diet, especially picky eaters and kids with autism. These are involved in brain development, and some small studies showed improvement with hyperactivity, attention, and irritability when supplements were added into the diet. Results are mixed, but the reason I feel comfortable kind of signing off on this one is that it's really unlikely to cause harm. They make different ones now that don't taste like fish or cause what one kid called a fish burp when he was taking them. So there's a lot of different things out on the market now that might be worth trying for your family.

Now, multivitamins. The data on multivitamins are interesting. For picky eaters, I do feel that they are probably worth it. If your kid is not a picky eater, the data shows that in all likelihood, you're just urinating out the excess vitamins that you're taking in. There's no data for changes in behavior, but they can be helpful for picky eaters. Just make sure that you're checking with your provider about what vitamin you're giving.

Vitamin D, there is actually some data here that it could cause some behavioral improvements, but we of course need larger trials to confirm that. Nutritional trials and trials in children are really tricky and they're kind of few and far between when it comes to good control, so that's why you keep hearing me say we don't know and we don't have enough data. You could absolutely ask your doctor to order lab work to confirm if your child is deficient in vitamin D, and this can help steer us in what dosage might be good to give. Again, there are gummies now and better-tasting ones. It's not like a giant tablet or anything like that.

Leucovorin is really interesting. If you Google autism cures, this will come up in your search engine very quickly. It has been shown to work for kids with confirmed cerebral folate deficiency. This is a metabolic condition that is found in some autistic people. And clinical trials have shown improvement in communication in very select cases. Again, evidence is limited, and this should only be used under medical supervision. This isn't a supplement that you go out and buy at the pharmacy. This requires blood work, specialized clinics, and there are more clinical trials going on. Hopefully, in the future, we learn more about this. But it's good to know that we are continuing to look at different deficiencies and how they can affect the symptoms that we're looking to target.
Probiotics, we talked about this a little bit. This can help improve the gut and the bacteria. There is some research that shows that this can be helpful. There are other studies that show that it does nothing. Check with your doctor, but in all likelihood, it won't cause any harm other than maybe some excess gastrointestinal issues if they aren't necessary for your child.

There is some data for NAC, which is N-acetylcysteine. This is an antioxidant supplement. Some clinical trials showed improvement in aggression and irritability compared to placebo, but the effects appeared to be moderate. And the other ones that I've been getting a lot of questions about are magnesium and B6.

This has gained popularity online for a lot of different issues. They're involved in neurotransmitter function, and I'm hearing a lot of anecdotal results from families that certain forms of magnesium have been really helpful for their child's sleep. So again, this is something that you could talk to your provider about. Most of us know the different types of magnesium and what would be better for GI health and what might be better for neurobehavioral concerns.

Another question that I want to talk about really specifically, because I got it from a parent, was: can a nutrient deficiency cause autism? Basically, if you were pregnant and perhaps you didn't have the best diet or you didn't take your prenatals or you didn't have good follow-up care, did not eating enough cause my child to have this neurodevelopmental condition? The answer is no.

There is no data that shows that any deficiency in any nutrient has a direct cause of autism. There is some data that low folate during pregnancy perhaps might be linked to a higher rate of autism, but we don't know. That is one reason why folate is in prenatal vitamins for neural development. But I want to take that off of everybody's plate. In all likelihood, it was genetics. It was environmental causes. The answer is we don't know. It's complicated. We might not ever know. But there was nothing anybody did specifically in regard to diet that caused this.

So what can families do?

For severe and restrictive eating patterns, talk to your doctor about options. This includes occupational therapy, which can help with sensory issues and processing or even just helping your child get food in their mouth.

If you're worried about swallowing issues or palate issues, talk to your providers. These are things that we can absolutely work with children on.

I absolutely think a gastroenterology workup can be really helpful for kids who are experiencing bloating, diarrhea, constipation, or excess flatulence. All of this could be linked to a GI cause, and they might have some answers and solutions. Talk to your doctors about good multivitamins or any supplements that you might be interested in. And remember, it could take up to 20 times or more for a child to accept new foods. Start with early exploration, like touching it, making a big mess, smelling it. Try to make it fun. Try to make it casual with low pressure. However, we absolutely have occupational therapy for this if you need some guidance on how to approach this.

The standard advice that you'll also see is when you are serving a new food, serve it along with a food that you know they'll eat. Allow children to have some control. What shapes do they want it cut in? Do they want the crust on it? And of course, aim for family-centered meals where everyone is eating together. The TV is off. The books aren't at the table. There's no toys. Again, I have a three-and-a-half-year-old, so I understand that a lot of this is easier said than done. So take it all with a grain of salt and figure out what works for your family. The other big things that people and professionals recommend are to limit snacks so that you can increase hunger cues during mealtimes. And of course, we all know this one: limit sugar-sweetened beverages that contain empty calories. This could really lead to kids feeling overly full.

So what are the takeaways?

There's no strong evidence that supplements or a special diet as a standalone treatment will improve core autism symptoms. However, nutritional adequacy is very, very important for all of us.

Perhaps omega-3 supplementation or vitamin D supplementation could be helpful in some cases if a child is not getting enough of these nutrients through their diet. Try to limit extra sugar. Try to limit processed foods. Instead of banning or taking away an entire food group, if it's something your family is used to, add on. For example, you can absolutely have four or five Oreos for dessert, but try to eat them with a fruit that is safe or a more nutritious snack like yogurt or a piece of cheese to create that balance, but also lessen the pressure on yourself and on your child.

Get help. Reach out to your providers. There's so many services that I didn't even know existed until I started working at Children's Institute and saw the amazing work that the different therapists here are doing.

And remember, I think this was an Oscar Wilde quote, everything in moderation, even moderation. Eat a little bit of everything. There is no shame in going to Chick-fil-A with your family once or twice a week if it's something that you enjoy and it's part of your routine and something your family looks forward to. A couple of mistakes here and there are not going to throw anybody's nutritional status off track. Nobody has to be perfect. And in fact, that variety, even the bad stuff every once in a while, is probably good for your gut microbiome. Enjoy your life, enjoy your time with your children, and always remember that we have help and options here.