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Broccoli Sprouts for Autism? What You Need to Know

Autism Speaks’ Paul Wang answers your questions about new findings suggesting that a sulforaphane supplement can ease autism symptoms in some individuals

Yesterday, a new scientific report described how sulforaphane, a chemical derived from broccoli sprouts, helped ease autism symptoms in nearly half of the 29 individuals enrolled in a small 18-week trial. We’ve asked developmental pediatrician Paul Wang, Autism Speaks senior vice president for medical research, to address reader questions sparked by the findings.

Today, a lot of parents are talking about adding broccoli sprouts to their kid’s salads and sandwiches. Can this help? Hurt?

The amount of sulforaphane that was administered in the study is many times higher than you can reasonably get through food. Even sulforaphane-rich foods like brussels sprouts, broccoli and broccoli sprouts don’t have enough of the chemical to get you close. So eating these vegetables can’t be expected to improve autism symptoms. Within reason though, eating sulforaphane-rich vegetables is safe and healthy.

What about taking sulforaphane supplements or giving them to a child with autism? Are they safe?

I would caution against starting sulforaphane supplements at this time. First and foremost, this was a very small trial – much too small to assure safety. There was actually a potentially worrisome side effect in the study: Two of the 29 boys and men taking sulforaphane had seizures during the study. Both had a history of seizures in the past, so this could have been a coincidence. However, none of those taking the placebo, or dummy treatment, had seizures during the study.

The study also showed a small increase in liver enzymes in study participants who received sulforaphane. None of these individuals showed any symptoms related to this side effect. However, it poses the possibility that sulforaphane may produce liver inflammation.

It’s important to remember that anything powerful enough to exert biological effects – even beneficial effects – also has the potential to produce unwanted side effects. Just because sulforaphane is found in vegetables doesn’t mean it’s safe. There are many chemicals found in nature that can be toxic. This is particularly true when these chemicals are concentrated into a supplement. Much more study is needed to understand sulforaphane’s actions in the body – for good or bad.

Also, though sulforaphane supplements have been on the market for some time, nutritional supplements don’t go through the kind of rigorous safety testing required for pharmaceutical medicines. So we don’t have good safety data on these products.  

No doubt, some people will decide to take sulforaphane supplements based on this study’s findings, regardless of potential safety concerns. How can they select a reputable brand? What would be a safe and reasonable dose?

The brand of supplement used in the study was a patented, pharmaceutical-grade product not available for purchase over the counter. So there’s no way of using the study’s results to gauge the effectiveness or safe doses of the many related health-food products with lesser quality-control during manufacturing.

In the study, the researchers used doses ranging from 50 to 150 µmol daily, depending on the participant’s weight. Their weights ranged from around 120 to 220 pounds.

So if an individual or parent decides to try these supplements – despite safety concerns – I would urge them to work closely with a physician to monitor possible reactions. This monitoring needs to include, but not be limited to, seizures. For example, blood work should probably be done to monitor liver enzyme levels.

How do the findings of this new study relate to the observation, by many parents, that their children’s autism symptoms improve when they have fevers?

The researchers offer the theory that both sulforaphane treatment and fever trigger a biological reaction called the heat-shock response. The idea is that this eases autism symptoms in some individuals by somehow easing stress and inflammation inside the body’s cells – including brain cells. It’s an intriguing theory, and one that I’d like to see further investigated. 

Editor's note: The authors of this study disclose that their institution has a licensing agreement with Brassica Protection Products, which makes a sulforaphane supplement. As part of this agreement, Johns Hopkins is entitled to royalty on the sale of products described in the study. The university also owns Brassica Protection Products stock. The university declares that it is managing these arrangements in accordance with its conflict of interest policies. Read more here


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The Autism Speaks blog features opinions from people throughout the autism community. Each blog represents the point of view of the author and does not necessarily reflect Autism Speaks' beliefs or point of view.