Greer McGuinness decided when her son Keegan was diagnosed with autism at 19 months old that she needed to go back to college and pursue a master’s degree in health sciences to better help him.

As she researched natural remedies for autism for her capstone project, McGuinness stumbled onto sulforaphane—a plant compound found in cruciferous vegetables, frequently extracted from broccoli seeds and sprouts. The research compelled her to dive in and publish a review. Meanwhile, her experience using it for Keegan produced fascinating changes.

“You could tell he felt better. He became more clear with his speech. He started processing things a little better and clearer. You might not get long sentences, but we could conversate back and forth,” McGuinness told The Epoch Times.

A dietitian by trade, she now recommends sulforaphane as part of a treatment protocol for children with autism spectrum disorder (ASD). Even before research elevated sulforaphane as a treatment for autism, many families who have children with autism have used the compound. It’s found on must-do lists among organizations, doctors, and parents in autism circles. Experts say almost everyone with autism could likely benefit from it if they use the right form in the best way.

The experience challenged McGuinness’s understanding of autism as a genetic disorder. The compound can protect the body from inflammation, DNA damage, and oxidative stress—factors linked to autism—through mechanisms tied to improved immune system regulation and detoxification.

“Sulforaphane checks all the boxes. It’s really rare to find a supplement that has as many abilities as sulforaphane,” Dr. Armen Nikogosian, a physician who specializes in functional and integrative medicine for autism and other complex conditions, told The Epoch Times.

Buzz in Autism Circles

Supplement companies have been grinding broccoli sprouts and seeds into capsules and heavily marketing them with bold claims for autism well before science established benefits. This was largely based on sulforaphane’s documented immune system benefits in cancer studies and cognitive dysfunction improvements in studies of neurodegenerative diseases like Alzheimer’s.

Lofty promises are common in the supplement world. Nikogosian said often, when research catches up to claims, the results don’t match expectations, and fame fizzles. That wasn’t the case with sulforaphane.

“Most of the claims were actually supported by evidence. We started really taking it seriously,” he said. “Essentially the case has to be made why I shouldn’t have the kids on it, rather than why I should.”

The evidence stems from a 2014 PNAS study conducted by pediatric neurologist Dr. Andrew Zimmerman and others. They compared 29 boys with autism taking a pure sulforaphane supplement of broccoli sprouts to 15 boys with autism taking a placebo. In 18 weeks, the group taking sulforaphane experienced improvements in behavior, social interaction, and verbal communication.

Four weeks after they stopped taking the supplement, scores in all three areas returned to baseline levels.

“The differences were really dramatic,” Zimmerman told The Epoch Times. “This was very successful, and it was the most successful of any of the clinical trials we’ve done.”

Reports From the Study

A follow-up case series offered additional insight into the study, including at least one boy who stopped taking sulforaphane after the trial but seemed to experience lasting results.

“He really turned into the most relaxed and fantastic child (on sulforaphane). Definitely something great. Helped him a lot. His friends, family, and members at his home all noticed a wonderful change,” a parent reported to the authors.

Another participant experienced rapid improvements in behavior and communication. Before taking sulforaphane, he had no language skills, made constant noises, had tics—involuntary rapid movements or sounds—and appeared to have no control over his body and behavior. He’d taken 18 different medications that had little effect on his symptoms.

Two of his medications—risperidone and aripiprazole—are commonly given to children with autism to control behavior. Side effects were intolerable for him, including sleeping difficulties, constipation, and increasing tics.

However, the boy’s mother reported that within days of being part of the study, she knew he was taking sulforaphane and not a placebo.

“I want to scream from the rooftops and tell people to give the kids broccoli sprouts [extract] because literally, it changed my life,” his mother said. “Now we can go to the movies, restaurants, plays, we went on vacation with another family, we go to church, we just went to a concert, things we could never do before are now possible.”

Connection to the Fever Effect

Zimmerman noted that sulforaphane offers something unique in autism treatment. Medications used for autism attempt to tamp down unwanted behaviors and mood, while sulforaphane works on improving synaptic function largely by inducing what’s called a heat-shock response.

Heat-shock response is a protective mechanism that guards cells from damage. It’s also activated when you have a fever by stimulating heat shock proteins and cellular stress responses that improve nerve or synaptic function and connectivity. It also increases the expression of gene that’s normally reduced in ASD.

Some children with autism have been observed experiencing symptom reversal when they have a fever—called the fever effect—thus leading researchers to test sulforaphane on children with autism.

McGuinness saw the fever effect firsthand with Keegan. During a fever, he stopped flapping his arms. He could speak in full sentences. His language was clearer. He was calmer.

“When he had a fever, it was almost like his brain could work better. That was essentially what sulforaphane can do,” she said.

New Understanding of Autism

McGuinness explained in her paper how toxins can potentially trigger autism. Brain tissue is damaged by free radicals—unstable atoms that harm cells—leading to oxidative stress and mitochondrial dysfunction. Mitochondria are a component in cells responsible for making energy. If they don’t work properly, cells can become damaged.

Too many free radicals—from exposure to chemicals, pesticides, nanoparticles, and metals—can cause mitochondrial dysfunction. People with autism have higher levels of metals and lower levels of glutathione, an antioxidant that protects the mitochondria. This suggests something could be driving the condition from the inside—genetics—and from the outside—exposure to toxins.

McGuinness pointed out that ASD is also associated with lower levels of essential sulfur-containing compounds, which help the body regulate oxidative stress, glutathione, and mitochondrial function.

Pinpointing a single cause of autism is likely a fruitless endeavor, according to Zimmerman. In a presentation he gave last year, he noted a myriad of causes responsible for autism and a number of biochemical abnormalities in autistic children, including a higher ratio of oxidized molecules compared to glutathione molecules. That means someone with autism doesn’t have a high capacity to sweep away the free radicals.

Falling Back

Another frustration with autism is how common it is for children to develop normally and then regress.

McGuinness questions whether regression can result from specific or combined environmental toxins that trigger symptoms. Her son was developing normally but then lost vocabulary and eye contact.

“We have this new version of what we’re calling autism that might not be autism. We call it autism, but could it be mold or lead or another environmental toxin?” McGuinness said, pointing to broad acceptance that lead can lower IQ.

“That’s just lead. That’s just one thing. We have to look at the whole gamut.”

She mentioned a popular saying that when you’ve met one person with autism, you’ve met one person with autism. Meaning, there’s no template to root cause, symptom expression, treatment, or or recovery.

No One Size Fits All

Likewise, there’s no guarantee sulforaphane will work for everyone, and it doesn’t.

Zimmerman said about 5 percent to 10 percent of patients had problems with sulforaphane during clinical trials and noted that, like medicine, it’s not perfect for everyone. These included increased aggressions, abdominal pain, increased gas, irritability, and more, though numbers were similar to the placebo group.

One study in 2023 found no clinical improvements in behavior when giving sulforaphane to 28 children with autism between ages 3 and 7 who were followed for 36 weeks.

Autism researcher Luke Curtis commented on the study, noting that more research on nutrition and plant chemicals is needed to treat autistic patients effectively.

“Since many autistic patients consume very low levels of fruits and vegetables, and since many phytonutrients may be helpful, treatment with single phytonutrients may not yield statistically significant improvements.”

Considering Dietary Options

Sulforaphane underscores how food holds potential as medicine—a topic that motivates a great deal of autism research and parental curiosity.

Exploring the link between diet and behavior motivated Jennifer Giustra-Kozek when her autistic son was getting ready to start kindergarten. She had an unshakable feeling that it wouldn’t be long before she would be pressured to consider medication for him.

“I saw firsthand young kids being put on antipsychotic medications. Kids as young as 3 and 4 years old were being put on medications for bad behavior,” Giustra-Kozek, a psychotherapist, told The Epoch Times.

“I just didn’t want my own children to go down that road and get stuck in the cycle of the western medication route.”

Realizing they had nothing to lose, the family opted to try food instead of drugs to address Evan’s symptoms, which included poor communication, inattentiveness, and arm flapping. One major turning point for symptom relief was starting him on sulforaphane.

Giustra-Kozek decided to write a pamphlet to share with parents of her struggling patients who asked for referrals, as well as with fellow psychotherapists who often send patients into the medical model where they often begin pharmaceuticals.

She wanted to be able to let them know that there was help beyond medication. The pamphlet turned into a book called “Healing without Hurting: Treating ADHD, Apraxia and Autism Spectrum Disorders Naturally and Effectively without Harmful Medications.”

Boosting Vitamin D

Sulforaphane has another benefit. Nikogosian said he’s observed that it improves patients’ vitamin D levels. Vitamin D, which isn’t really a vitamin but a hormone, can be boosted by foods like oily fish and egg yolks, and sun exposure.

Low levels of vitamin D have been linked to a number of diseases, including a poor immune system.

“For years, I would pour vitamin D into our kids, and I could barely move the needle,” Nikogosian said. “You put sulforaphane on board and you get to 60 ng/mL, 70, 80, no issue.”

Optimal vitamin D levels are between 30 and 60 ng/mL. Nikogosian said supplementing vitamin D and sulforaphane together works more potently on overall health.

There’s evidence that sulforaphane and vitamin D synergistically can induce autophagy, a natural process of cell turnover that removes cellular waste and debris by recycling it and strengthening the cells. Autophagy may be compromised in some people with autism.

More Potential Mechanisms

A Molecular Autism study illustrates how there could potentially be dozens of mechanisms at play that impact autism symptoms when taking sulforaphane. The study measured 694 urinary metabolites of 15 children who took sulforaphane for 12 weeks. Metabolites are molecules produced by our digestive process that perform bodily functions.

There were 77 significant changes in metabolites that corresponded with improved symptoms. Some of the findings were an increase in metabolites that:

• Process free radicals
• Are associated with improvements in five neurotransmitters, including mood-improving serotonin and immune-enhancing glutamine
• Linked to cortisol, illustrating that the body is making more of the stress- and immune-regulating hormone or potentially excreting more of it

There was also an increase in sphingomyelin metabolites, which are found in abnormal levels in other central nervous system disorders like depression, anxiety, Alzheimer’s disease, and amyotrophic lateral sclerosis (ALS).

Sourcing Sulforaphane

Zimmerman’s second sulforaphane trial in 2021 didn’t result in quite as impressive results as the first, which he said can be explained based on the supplement used. Rather than a form of pure sulforaphane, the team used glucoraphanin, a precursor to sulforaphane.

Glucoraphanin is more shelf stable—pure sulforaphane must be refrigerated—making it preferred by many doctors and families. The effect was small and non-statistically significant.

Supplements can also be problematic because many brands do not contain the amounts stated on the labels, Zimmerman added.

For pure versions, he recommends BROQ and BrocElite Plus. For glucoraphanin, he recommends Life Extension Optimized Broccoli and Cruciferous Blend and Thorne Crucera SGS. Nikogosian often works with Sulophraclear by Metagenics or Sulphorozone by Master Supplements, in addition to Avmacol, a glucoraphanin version used in research.

Some patients prefer to go straight to the plant. Parents of many subjects in Zimmerman’s first trial began growing their own broccoli sprouts. Sulforaphane levels are highest when the sprouts are about three days old, he said.

Dosing Sulforaphane

Children who are very sick need to work their way slowly up to a full dose, Nikogosian said. Usually, starting at 20 percent is sufficient, but in rare cases, he will reduce the starting dose down to 5 percent.

“Kids sometimes get worse initially because it does upregulate their detoxification. If they can’t process that, you can actually get a tough reaction,” he said. “Parents can have a knee-jerk reaction that it’s not for their kid. Not really—it’s actually doing what it’s supposed to do.”

Sulforaphane is generally safe, making it an easy supplement to explore. It’s not ideal for people sensitive to sulfur or allergic to broccoli.

Because children with autism often have trouble swallowing pills, parents can pour the capsule contents into applesauce or juice. If it’s added to something warm, however, it can denature the seeds and lower the potency.

Hope for the Future

While Zimmerman has recently retired, he plans to keep tabs on ongoing sulforaphane research. He hopes new studies will be conducted in younger children since evidence now shows the benefits from autism treatments are greatest in children who are diagnosed before age 2.

Still, he said it’s never too late to try something new, and parents are often eager to do so. He recalled the gratitude of parents in his first study who reported delight in simple pleasures like eye contact with their children and listening to them speak in full sentences.

Zimmerman loves to tell the story of Jase, a boy from his first trial who loved hats. One of his first full sentences after his trial on sulforaphane was, “I want more color hats.” His mother posted it on Facebook, and people from several states sent him hats.

In many cases, Zimmerman noted that children with autism often exceed the expectations of parents as well as doctors, who sometimes have little to offer families beyond medication.

His advice to families: “Don’t give up. Always look for the next possible thing. I don’t think we’ve really covered the waterfront yet. I think there’s a long way to go and not just on sulforaphane.”