Sulforaphane Treatment of Autism: Does It Really Work?

Introduction

Autism spectrum disorder (ASD) affects approximately 1 in 36 children in the United States, according to the latest CDC data [1]. As prevalence rates continue to rise, families and researchers alike are exploring complementary approaches to traditional behavioral and pharmaceutical interventions. Among these emerging options, sulforaphane—a compound found primarily in cruciferous vegetables like broccoli sprouts—has garnered significant attention. But beyond the headlines and anecdotal success stories, what does the scientific evidence actually tell us about sulforaphane's effectiveness for autism?

What is Sulforaphane?

Sulforaphane is a natural plant compound (specifically an isothiocyanate) with potent antioxidant and anti-inflammatory properties. It's produced when an enzyme called myrosinase interacts with a glucosinolate called glucoraphanin—a process that occurs when cruciferous vegetables like broccoli, Brussels sprouts, and cabbage are chopped, chewed, or otherwise damaged.

Broccoli sprouts contain particularly high concentrations of glucoraphanin, making them the most commonly studied source for sulforaphane in autism research. Young broccoli sprouts (3-4 days old) can contain up to 100 times more glucoraphanin than mature broccoli.

The Theoretical Basis: Why Might Sulforaphane Help?

The interest in sulforaphane for autism is rooted in several biological mechanisms that may address underlying features of ASD:

1. Oxidative Stress Reduction: Multiple studies have documented higher levels of oxidative stress markers in individuals with autism. As a potent activator of Nrf2 (a protein that regulates antioxidant responses), sulforaphane may help counter this imbalance.
2. Anti-inflammatory Effects: Neuroinflammation has been observed in post-mortem brain tissue of individuals with autism. Sulforaphane has demonstrated anti-inflammatory properties in multiple tissues, including the brain.
3. Heat Shock Response: About 35% of autism patients show improvement during fever, suggesting that heat shock proteins (produced during fever) might temporarily improve symptoms [2]. Sulforaphane activates heat shock proteins without requiring actual fever.
4. Mitochondrial Function: Approximately 5-10% of children with autism show signs of mitochondrial dysfunction, which sulforaphane may help improve.

The Clinical Evidence: What Do Studies Show?

The Landmark Johns Hopkins Study

The most significant clinical evidence comes from a 2014 randomized, double-blind, placebo-controlled study conducted at Johns Hopkins University Medical Center [3]. The study involved 29 young men (aged 13-27) with moderate to severe autism who received either sulforaphane extract or placebo for 18 weeks.

Key findings included:

• 46% of participants showed significant improvement in social interaction
• 42% showed improvement in aberrant behavior
• 54% showed improvement in communication
• Most improvements diminished after the treatment was discontinued

While promising, it's important to note the study's limitations: small sample size, limited demographic range (only males, mostly with severe autism), and relatively short duration.

Follow-up Studies

Subsequent smaller studies have shown mixed results:

• A 2017 study of 15 children and adults reported improvements in social responsiveness in approximately 60% of participants [4].
• A 2020 open-label study found significant improvements in social responsiveness scale scores in 17 out of 35 children with ASD.
• However, a 2019 placebo-controlled trial with 57 children with ASD found no significant differences between sulforaphane and placebo groups on most behavioral measures.

Safety and Side Effects

Overall, sulforaphane appears to be relatively safe. In clinical studies, reported side effects were mild and included:

• Insomnia
• Flatulence
• Changes in bowel habits
• Weight gain or loss

The long-term safety profile, however, has not been thoroughly established.

Practical Considerations

Forms of Supplementation

Sulforaphane is available in several forms:

1. Fresh broccoli sprouts: The most natural source, but with variable sulforaphane content
2. Stabilized sulforaphane supplements: Containing the actual compound
3. Glucoraphanin supplements with myrosinase: Requiring conversion in the body
4. Glucoraphanin-only supplements: Relying on gut bacteria for conversion (less reliable)

Dosage Uncertainties

A major challenge in sulforaphane treatment is determining appropriate dosages. The Johns Hopkins study used approximately 100-150 μmol of sulforaphane daily, which would require consuming about 40-60 grams of fresh broccoli sprouts—a quantity that may be difficult for many children with autism to consume due to sensory sensitivities and food selectivity.

Cost Considerations

High-quality sulforaphane supplements can be expensive, potentially costing $100-200 per month, and are typically not covered by insurance. Growing broccoli sprouts at home is more economical but requires consistent effort and may yield variable sulforaphane content.

Expert Perspectives

The medical community remains cautiously optimistic but divided. Dr. Andrew Zimmerman, a pediatric neurologist involved in the original Johns Hopkins study, suggests sulforaphane may be a promising complementary approach but emphasizes that it's not a replacement for evidence-based behavioral interventions.

The Autism Research Institute classifies sulforaphane as a "Level 2" treatment, meaning it has some research support but requires more investigation before stronger recommendations can be made.

Conclusion: The Current Verdict

Based on available evidence, sulforaphane shows promise as a complementary approach for some individuals with autism, but it's premature to declare it broadly effective. The research to date suggests:

• It may help some individuals, particularly males with more severe symptoms
• Effects appear to vary considerably between individuals
• More research is needed to determine optimal dosing, identify responsive subgroups, and evaluate long-term effects
• It should be considered a complementary approach, not a replacement for established interventions

For families considering this approach, consultation with healthcare providers familiar with both autism and nutritional interventions is essential. Additionally, expectations should be realistic—while some may see notable improvements, others may experience minimal or no benefit.

As research continues, we may develop a clearer understanding of which individuals are most likely to benefit and how sulforaphane might be optimally incorporated into comprehensive treatment plans.

References

[1] https://www.cdc.gov/mmwr/volumes/72/ss/ss7202a1.htm

[2] https://doi.org/10.1542/peds.2007-0540

[3] . https://www.pnas.org/content/111/43/15550

[4] https://doi.org/10.1177/2164957X17735826

[5] https://jneuroinflammation.biomedcentral.com/articles/10.1186/s12974-020-01766-9