BY JULIE S MATTHEWS, MSc

At just four years old, Matthew had very limited language. His frequent frustration and anxiety often led to intense tantrums.

Night after night, his sleep disruptions woke his older sister and kept his parents up for hours, leaving the whole family stressed and exhausted.

His mother, Terri, was almost at the end of her rope, but she and her husband were determined to do everything they could to help Matthew find relief and rest.

Then Terri learned about families in similar situations who had seen improvements through dietary interventions—and realized that modifying Matthew’s diet was something within their reach. She also began working with an integrative physician who ran lab tests and recommended targeted food eliminations and nutritional supplements tailored to Matthew’s specific needs.

After transitioning to a gluten-free, casein-free, soy-free (GFCFSF) diet, Matthew experienced significant improvements in behavior, mood, and sleep. His care team also educated the whole family on how to read ingredient labels—highlighting common symptom-triggers such as monosodium glutamate (MSG), emulsifiers, artificial sweeteners, and other industrial food additives.

Terri shared with me, “Matthew’s symptoms of autism began to fade. It was incredible to see better cognition, more language, better sleep, fewer tantrums, and increased eye contact just from changing his diet.

The less inflammation he had, the fewer meltdowns, food cravings, and negative behaviors we saw. Even his therapists and teachers started noticing a difference—and they began to appreciate just how powerful food, and supplements can be in shaping mood and behavior.”

Terri has since become one of my closest friends, and I’ve had the privilege of witnessing many of Matthew’s milestones firsthand. Today, at twenty years old, Matthew no longer meets the diagnostic criteria for autism.

He graduated from high school, became an Eagle Scout, and is now attending college. He’s also an aspiring author—and just recently, he was awarded “Student of the Year” in writing and literacy.

While not every child will experience such a dramatic transformation, Matthew’s story is a powerful example of what’s possible.

Over the past two decades, I’ve worked with hundreds of children and adults with autism spectrum disorder (ASD) using personalized diet & nutrition strategies.

I’ve seen children gain speech, hold their first conversation with a parent, connect more deeply with their siblings, improve sleep, reduce pain, and experience greater emotional calm.

This work—helping individuals on the spectrum live healthier, more fulfilling lives—is not only my profession, it’s my passion.

Whole-Body Treatment Approach

Diagnosing physicians often recommend speech and behavioral therapy. While these are valuable supportive therapies, they do not address the underlying medical conditions that often drive symptoms—nor do they target the common co-occurring issues in Autism, such as seizures, inflammation, gastrointestinal problems, or immune dysfunction.

One reason for this misunderstanding is that many doctors and parents still view ASD as solely a psychiatric—or brain-based—disorder. However, to truly support individuals with autism, we must recognize it as a whole-body disorder.

Yes, the brain is affected—but it doesn’t operate in isolation. It is part of an interconnected system, and what happens in the body influences what happens in the brain. For example, the brain’s nutritional status is dependent on the nutrient levels in the rest of the body. If the body is depleted, the brain is likely to be as well.

Martha Herbert, MD, a prominent pediatric neurologist and professor at Harvard Medical School, has long advocated viewing autism as a whole-body disorder that affects the brain.

She explains that rather than thinking of ASD as originating in the brain, it is more accurate to view it as a condition involving multiple systems of the body that, in turn, impact the brain’s function and development.

For this reason, the treatment approach must be comprehensive—addressing not only cognitive and behavioral development but also nutritional, immune, and gastrointestinal factors that may be underlying or exacerbating symptoms.

Let’s review a few key factors that should be considered as part of the whole body treatment approach:

Food Reactions & Nutrient Deficiencies

• Certain foods can directly trigger or aggravate autism symptoms. For instance, artificial sweeteners, colors, and flavors have been linked to increased hyperactivity—a common concern in children with ASD. Eliminating these additives is an essential first step in any dietary intervention.

• Nutrient deficiencies are also common in individuals with autism, particularly in vitamin B12, vitamin B6, zinc, and vitamins A and D. It’s important to note, however, that these deficiencies aren’t always due to insufficient intake. For example, even if a child eats plenty of meat, they may still be low in protein or B12 if digestion and absorption is impaired.
  
  Consider working with a functional or integrative medicine practitioner to identify the underlying cause of poor nutrient absorption, which may include genetic variants, gut microbial imbalances, or chronic inflammation.

Gastrointestinal Issues & Microbiome

• The gastrointestinal (GI) tract, also known as the digestive system, is a key player in autism: up to seventy percent of children with autism have gastrointestinal symptoms.

• GI problems are significantly more prevalent in children with autism than their siblings without autism, and the severity of autism has been associated with gastrointestinal symptoms in multiple studies.

• Because the digestive system is responsible for breaking down food and absorbing essential nutrients, it plays a central role in nutrient metabolism.
  
  For instance, dietary proteins must be properly broken down into amino acids to be absorbed and used by the body. However, when digestion is impaired—and the intestinal lining becomes overly permeable (a condition known as “leaky gut” commonly seen in ASD)—partially digested protein fragments can enter the bloodstream in a form the body doesn’t recognize, leading to an immune response and inflammation.

• The gastrointestinal tract hosts a complex community of bacteria and other microbes that can influence brain function—either positively or negatively, depending on the balance of organisms present.
  
  Research has shown that children with autism have distinct differences in their gut microbiota compared to neurotypical children, including lower levels of Bifidobacterium and higher levels of Lactobacillus. What’s more, pathogens such as Clostridia and Candida in the gut can release toxins that can cause mood problems—and have been associated with increased autism symptom severity.

• In a groundbreaking study led by James B Adams, PhD, Director of the Autism/Asperger’s Research Program at Arizona State University, children with autism were found to have lower levels of short-chain fatty acids—beneficial compounds produced by gut bacteria that help maintain gut integrity. The study revealed a strong correlation between gastrointestinal symptoms and the severity of autism, highlighting the critical role of gut health in ASD.
  
  Building on this connection, two trailblazing studies have demonstrated just how powerful a healthy microbiome can be in supporting children with ASD. In one study, fecal microbiota from healthy donors was transferred to eighteen children with ASD via microbiota transfer therapy. While this may cause some of us to feel squeamish, the results were remarkable: the children experienced an eighty percent reduction in gastrointestinal symptoms, increased bacterial diversity, and significant improvements in autism-related behaviors.
  
  Two years later, a follow-up study was done, and researchers found that most of the participants’ GI improvements remained and that the ASD symptoms continued to improve significantly years after the therapy had ended.

• Maternal and early childhood exposure to broad-spectrum antibiotics can disrupt the gut microbiome and contribute to dysbiosis. Such disturbances have been linked to an increased risk of neurodevelopmental disorders, including ADHD and autism.

• Exposure to the herbicide glyphosate—a patented antibiotic—not only kills the good gut microbes including Lactobacillus, Bifidobacterium, and Bacillus, it doesn’t kill pathogenic bacteria such as Clostridia and Salmonella, instead allowing them to overgrow. Glyphosate disrupts the microbiome, particularly in children before puberty. Glyphosate may contribute to the development of autism because of Clostridia overgrowth.

Immune System Dysfunction & Inflammation

Inflammation is a normal and essential function of the immune system. It helps the body fight infections and heal injuries. Under healthy conditions, the body is able to turn inflammation on and off as needed. The issue arises when this response becomes chronic and unresolved. In fact, research consistently finds strong associations between chronic inflammation and ASD.

Chronic inflammation can be caused by a number of factors, such as:

• Chemicals in our cookware and food storage containers

• Food intolerances

• Mast cell activation (notably, mast cell activation may contribute to brain inflammation)

• Blood sugar imbalances

• Gut microbial imbalances

• Food additives

Impaired Detoxification

Children with ASD tend to have low levels of glutathione—the “master antioxidant” that plays an important role in detoxifying chemicals, heavy metals, and other toxins. A study of fifty-two boys with ASD found they had higher levels of lead and mercury than controls, along with lower glutathione activity and vitamin E levels—all of which are strongly linked to social and cognitive impairment.

Cruciferous vegetables like broccoli, cauliflower, and cabbage—as well as fruits like blueberries and apples—are powerful allies in boosting glutathione production and supporting detoxification.

Evidence-Based Approach to Managing Autism

The good news is that there are practical, nutrition-based strategies—well within a parent’s control—that can help break the cycle of chronic inflammation, impaired detoxification, and nutrient depletion. Through targeted dietary changes and supplementation, families can play a powerful role in helping children with autism feel better, function more optimally, and truly begin to thrive.

I had the opportunity to explore various nutritional strategies firsthand as a coauthor of a study entitled “Comprehensive Nutritional and Dietary Intervention for Autism Spectrum Disorder—A Randomized, Controlled, 12-Month Trial,” published in the peer-reviewed journal Nutrients in 2018. The lead researcher was Dr. Adams, the autism nutrition expert from Arizona State University.

Our study was a randomized controlled trial—a design considered the gold standard in nutrition research. A total of 117 individuals, aged three to fifty-eight years, were enrolled in the study. More than half of the participants had ASD and were randomly assigned to a treatment group or a control group. The remaining fifty participants were neurotypical, and their baseline results were used in comparison to the ASD group before and after treatment.

Our study measured the effects of six interventions added one at a time monthly:

1. Vitamin/mineral supplementation

2. Essential fatty acid supplementation

3. Epsom salt baths

4. Carnitine supplementation

5. Digestive enzyme supplementation

6. Healthy gluten-free, casein-free, soy-free (GFCFSF) diet

These common diet and nutrient strategies have all been previously studied and/or used by clinicians and families with beneficial results. Our study was one of the first for ASD that combined multiple nutrition interventions.

The participants were followed over the course of a year. We found that dietary changes combined with nutritional supplements are safe and can help address underlying factors in autism, improve debilitating symptoms, and improve health, learning, and behavior. We also found that the interventions helped no matter what the participants’ age.

The comprehensive diet and nutrition intervention provided significant benefits:

• Improved cognitive function: 6.7-point increase in nonverbal IQ, on average

• Improved developmental age: 4.5 times improvement, increased from four months in control group to eighteen months in treatment group, on average

• Decreased autism severity: twenty-eight percent decrease in Autism Treatment Evaluation Checklist (ATEC) score, compared to a six percent decrease in control group, on average

• Increased speech and language comprehension

• Reduced gastrointestinal symptoms

• Increased vitamin status

• Improved levels of carnitine, red blood cell minerals, and fatty acids

• Improvements in language, hyperactivity, anxiety, physical symptoms, and other markers based on the Parent Global Impressions (PGI) symptom rating scale

Several individual cases were so impressive they warrant mention here:

One seven-year-old boy had severe pica—a potentially very dangerous condition involving eating nonfood items. This boy had very low levels of vitamin B12, vitamin C, beta-carotene, and several more B vitamins. Within one week of starting the healthy GFCFSF diet, his pica was fully resolved and remained that way throughout the study.

A twenty-seven-year-old man struggled with kidney stones and a severe inability to urinate, which required catheterization daily, leading to urinary tract and bladder infections. Because his health care team couldn’t find a cause, it was assumed to be neurological. However, four days after eliminating dairy products on the healthy GFCFSF diet, he was able to urinate on his own.

On two separate occasions in the following months, he ingested dairy (ice cream and cheese) and was again unable to urinate for several days after each incident. With a strict dairy-free diet, he no longer needed catheterization, so he stopped getting infections and his quality of life improved significantly.

A nine-year-old girl with severe autism had very low energy levels and strength. She could not get up from the floor on her own, climb stairs, get into the family van, or walk more than a quarter mile. Because of this she used a wheelchair when out in public. Her lab tests revealed that—at the start of the study—her carnitine levels were very low.

Caritine is a nutrient that helps with mitochondrial function to support energy levels. Her diet up until that point included no red meat or pork, which are the main sources of carnitine.

Four months into the study—after starting carnitine supplements—her endurance and strength significantly improved. And by one year from the start of the study, she could get up and climb independently and walk up to two miles at a time, and she no longer required her wheelchair. At the end of the study, when her energy had returned, her carnitine levels tested above average.

It’s interesting to note that not all children respond to carnitine; however, this supplement was life-changing for her—a testament to the importance of personalizing nutrition!

Nutritional Supplement Support

While good food choices are an important way to improve your child’s nutrient intake, a child with autism often needs additional help through nutritional supplementation.

Vitamins, minerals, and other nutrients are a useful tool for picky eaters who may be hesitant about trying new, healthier foods right away. And for those who have genetic variants or chemical imbalances that affect their nutrient absorption, supplementation can provide nutrients in amounts greater than they can get with food.

With that in mind, let’s take a closer look at three of my go-to supplements I recommend as a starting point for families: a high-quality multivitamin/mineral formula, an essential fatty acid blend, and digestive enzymes. These three were among the six core interventions used in the clinical study I coauthored and referenced above.

Of note, the multivitamin/mineral formula and essential fatty acids were ranked by parents as the most effective supplements for their child. Digestive enzymes, also part of the study protocol, have shown significant benefits for digestive health in both the research and my own clinical practice.

Multivitamin/ Mineral Formulas

Supplementing with a high-quality multivitamin/mineral formula has been shown in multiple studies to support individuals with autism by improving nutrient status and reducing core symptoms.

Research has also demonstrated its benefits for children with ADHD, where it can significantly improve behavioral outcomes. In our randomized controlled trial, the multivitamin/mineral supplement was reported by caregivers to improve speech and language in up to thirty-nine percent of participants with ASD.

It also led to improvements in a range of symptoms—including anxiety, emotional regulation, irritability, attention, play, social interaction, and cognition in twenty-three percent or more of participants.

Not all multivitamin/mineral supplements are created equal, and many children’s formulations often contain added sugars, artificial colors, and synthetic flavors. Some may even include common allergens like gluten, soy, or dairy.

Multivitamin/mineral supplements formulated for children with autism in mind and professional supplement brands are good places to start looking.

A Note on Copper and Iron

Two nutrients you may not find in a multivitamin/mineral supplement designed for children with autism are copper and iron—and for good reasons:

• Research has shown that individuals with autism often have elevated copper levels and low zinc levels. This imbalance—particularly a high copper-to-zinc ratio—has been linked to increased autism severity. Because zinc and copper compete for absorption in the body, supplementing with copper in someone already zinc-deficient can further deplete zinc while raising copper to potentially toxic levels.

• Excess copper can negatively affect liver and neurological function, and has been associated with symptoms such as aggression, poor concentration, and heightened sensitivity to clothing textures or tight-fitting clothes.

• Iron is often found to be above the reference range in forty-two percent of children with autism. Excess iron in the brain has been observed in neurological and neurodegenerative conditions, and some researchers suspect that excess dietary iron may be responsible for increases in autism and food allergies.

That said, copper and iron are essential minerals, and some individuals may need supplementation based on their unique needs—particularly vegetarians/vegans, menstruating females, and those who consume meat minimally.

Since iron deficiency can negatively affect cognitive function, it’s important to work with a qualified healthcare provider to assess nutrient status and determine whether supplementation is appropriate.

Starting Multivitamin/Minerals

Once you have chosen a multivitamin/mineral supplement, start low and slow with a fraction of the targeted dose (by taking less or pouring out some of the powder in the capsule, if applicable). I recommend starting with about twenty-five percent of the targeted daily total, once a day. Then, when you know that amount is tolerated, increase that dose to twice per day.

After that, continue twice per day and increase the amount every few days until 100 percent of the recommended amount has been reached. Typically, it takes a couple of weeks to reach the full amount.

A vitamin and mineral supplement is best taken with food. In a typical diet, nutrients are naturally consumed as part of a meal, and taking supplements alongside food can help mimic this process. Eating with supplements also helps reduce the risk of nausea, which some people may experience when taking them on an empty stomach.

Essential Fatty Acids

Essential fatty acids—especially omega-3 supplements like cod liver oil—are another key supplement I recommend for most patients. I typically suggest introducing them after a multivitamin/mineral formula has been successfully added to the routine. Most western diets are low in omega-3s, and this is true of children with ASD as well, since many do not eat fish.

Meta-analyses examining ASD and other neurological conditions have found omega-3 supplementation to be particularly beneficial for individuals with autism. Reported improvements include reduced hyperactivity, lethargy, and irritability, along with decreased stereotypical behaviors (such as rigidity and repetition) and enhanced social awareness and communication.

These studies also noted positive effects in related conditions, including ADHD, depression, and schizophrenia.

Additional research supports these findings. A study published in Alternative Therapies in Health and Medicine found that combining omega-3s with vitamin E improved speech, eye contact, and behavior in adolescents with ASD.

In a broader review of nutraceuticals for autism, parents rated omega-3s highly, with many parents reporting improvements in overall autism severity. The most notable gains were in areas of brain function—particularly cognition, attention, and language.

GLA (gamma-linolenic acid), a type of omega-6 fatty acid, can help enhance the brain’s ability to utilize omega-3s more effectively. In our Nutrients study, the essential fatty acid supplement we used included both fish oil (a source of omega-3s) and GLA.

Several studies on ADHD have shown that a combination of EPA and DHA (omega-3s) with GLA is more effective than omega-3s alone—reducing inattentiveness and hyperactivity, while also improving reading skills, cognition, working memory, and impulsive behavior.

Digestive Enzymes

Digestive enzymes can be especially helpful for children who need extra support with digestion—which includes many children on the autism spectrum. I typically recommend introducing enzymes after starting the first two foundational supplements (a multivitamin/mineral and essential fatty acids).

Digestive enzymes assist the body in breaking down food more efficiently, which can help reduce gastrointestinal symptoms, enhance nutrient absorption, and break down problematic protein fragments that may contribute to food sensitivities.

Digestive enzymes include lipase to break down fats, protease to break down proteins, and amylase to break down carbohydrates. I recommend choosing formulas that also contain DPP-IV—an enzyme that supports the breakdown of problematic opioid compounds derived from wheat and dairy.

In a randomized double-blind trial in children with ASD, researchers found statistically significant improvements in gastrointestinal symptoms, autism symptoms, emotional response, and behavior following supplementation with digestive enzymes. And in the nutraceuticals rating survey, digestive enzymes were highly rated with very few adverse effects, and forty percent who found digestive enzymes beneficial had improvement in constipation and eighteen percent in diarrhea.

Starting Digestive Enzymes

Digestive enzymes should be dosed according to the size of the meal, not the size of the person. Because they work to break down the food being consumed, they should always be taken with meals.

As with any new supplement, it’s best to start low and go slow—begin with a fraction of the recommended dose at one meal, and gradually increase over the course of a week or so, based on tolerance and response.

Recipes For Even The Pickiest Eaters

Nutritional supplements can offer powerful support, but the ultimate goal is to nourish the body through real, whole foods.

You may be thinking, “How am I going to get my picky eater to eat that?”

First, remember you are not alone. Picky eating is very common in children with autism.

How common?

One study found seventy percent of children with autism had atypical eating patterns, compared to thirteen percent of children with other disorders and less than five percent of neurotypical children.

In that study, ninety-two percent of children with autism preferred food like grain products and/or chicken (usually chicken nuggets).

Does this sound familiar? I bet it might.

When you’re already facing so many daily challenges, it’s understandable to wonder, “Why not just let them eat what they like if it keeps the peace?”

But here’s the concern: picky eating often leads to limited food variety and poor nutritional intake—which can have serious consequences, especially without the support of targeted supplementation.

One review analyzed case reports of seventy-six children with autism who developed serious nutrient deficiencies from “self-imposed dietary restrictions.” The most common deficiencies were vitamin C (almost seventy percent of the reports were about this), vitamin A, thiamine (vitamin B1), vitamin B12, and vitamin D.

One report detailed the case of a boy with autism who had only eaten French fries and potato chips from the ages of four through eight years old and developed, among other issues, severe vitamin A deficiency. This caused vision loss and night blindness. Sadly, even with vitamin A supplementation, the vision loss was irreversible.

Another paper described a fourteen-year-old boy who showed up at the emergency room with a swollen left leg and a fast heart rate. He had anxiety and refused to walk. Doctors discovered his diet was limited to chicken nuggets, macaroni and cheese, chocolate milk, junk food, soda, and water—no veggies or fruits (other than the occasional banana).

He was diagnosed with anemia and scurvy. This severe deficiency in vitamin C required intense interventions and caused him emotional distress. Fortunately, he was able to reverse it.

It should be noted that most of the children referenced in the review had a body weight within normal range. So, we can’t rely on a child being underweight as a sign of nutritional deficiency.

The good news is, picky eating patterns and overall health in ASD can be improved.

Remember Matthew, the young man with autism whose story I told in the introduction?

As a young boy with very little language who became an aspiring author, Matthew wanted to tell you in his own words how therapeutic nutrition changed his life.

When it comes to nutrition, I believe that it plays a critical role in not only recovering from autism but improving life in general. It was easy being addicted to crap food; the flavors and the sugars were—and still are—certainly enticing, but it was short-term thinking.

I don’t remember when I went on a diet; those memories are like puzzle pieces now lost to time. But nowadays when I eat a certain food, healthy or unhealthy, there are consequences. My mood can shift erratically. My mental health could take a dive. When I eat healthy foods—protein mostly—I feel stronger and more capable.

When you eat well, you’ll feel well. That’s my experience with dieting. If my mom hadn’t found out about the diet connection, my family and I would still be eating the standard American diet. I owe my mom a lot, and I think that I will never pay off that debt in my lifetime. However, I know I can try to reach out to others and persuade them to live the healthy lifestyle as I have. It’s not easy, but nothing worth doing is easy.

I couldn’t have said it better myself. Focusing on diet and nutrition is worth it. You won’t regret it. Take one step and one meal at a time. Start where you can and keep nourishing hope. Here are three simple recipes to get you started!

• Chicken Apple Sausage

• Coconut Pancakes

• Dairy-Free Low Sugar Fudge

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Julie Matthews is a Certified Nutrition Consultant and published researcher who received her master’s degree in medical nutrition, with distinction, from Arizona State University.

She has specialized in children’s nutrition and complex neurological conditions, most notably autism spectrum disorder, for over twenty years. Julie sits on the Nutritional/Medical Advisory Board of the Autism Nutrition Research Center and helps children, families, and clinicians from 146 countries with her online resources, nutrition programs, and professional training courses.

Julie has educated parents and health professionals on how to use personalized nutrition and therapeutic diets to help children thrive at conferences in more than sixty-five cities over three continents including Medical Academy of Pediatric & Special Needs (MAPS), Integrative Medicine for Mental Health (IMMH), and American Academy of Anti-Aging Medicine (A4M).

She has been featured in newspapers and blogs, and on podcasts, radio, and television including CBS. She has co-authored peer-reviewed research studies demonstrating the efficacy of nutrition and therapeutic diet intervention for ASD.

When she is not studying the latest nutrition research, supporting families, or experimenting with new recipes in her kitchen, she can be found camping with her daughter, hugging redwood trees, and gardening.

Well Being Journal adapted the above excerpt from The Personalized Autism Nutrition Plan by Julie S Matthews, MSc. Copyright © 2025 by Julie S Matthews and reprinted with permission from BenBella Books.