Sulforaphane in Broccoli Sprouts May Improve Blood Sugar Levels among individuals with prediabetes: Study

A study from the University of Gothenburg found that sulforaphane, a chemical compound in broccoli sprouts, can help improve blood sugar levels in individuals with prediabetes. The effects were more pronounced in certain individuals, suggesting potential targeted benefits in preventing type 2 diabetes.

This has been shown in a study conducted at the University of Gothenburg. The broccoli compound had a more significant effect on blood sugar levels in certain people.

Researchers at the University of Gothenburg have previously identified sulforaphane as an antidiabetic agent in type 2 diabetes. A patient study conducted in 2017 demonstrated significantly lower blood sugar in people with diabetes after they took large doses of sulforaphane extracted from broccoli sprouts.

In this new study, published in Nature Microbiology, Professor Anders Rosengren and colleagues have instead looked at prediabetes. This condition is a precursor to type 2 diabetes, with slowly rising blood sugar levels due to impaired insulin production.

The study encompassed 89 people with elevated fasting blood sugar, an indicator of prediabetes. Other criteria included the participants being overweight or obese and 35–75 years old.

The participants were randomly assigned sulforaphane or a placebo for twelve weeks. Neither the participants nor the researchers knew who was assigned which. A total of 74 participants completed all stages of the study.

Fasting blood sugar fell

The results show that participants taking the sulforaphane compound had a higher average reduction in fasting blood sugar than those taking the placebo. The difference between the two groups in the study was considerable.

An even greater difference was seen when analyzing clinical subgroups. The group with the greatest improvement after taking sulforaphane had early signs of mild age-related diabetes, a relatively low BMI in the context of the study, low insulin resistance, low incidence of fatty liver disease, and low insulin secretion.

The third stage, conducted in collaboration with Professor Fredrik Bäckhed at the University of Gothenburg, involved the study of gut bacteria, with the discovery of a gut bacterium able to interact with sulforaphane that could be linked to further improved efficacy of the broccoli compound.

In terms of numbers, the differences in fasting blood sugar were 0.2 millimoles per liter between all participants taking sulforaphane compared to the placebo group, followed by 0.4 in the concerned clinical subgroup, and 0.7 in those who were both in the clinical subgroup and had the gut bacterium.

Possible precision treatment

The prevalence of prediabetes in Sweden is estimated to be up to ten percent, with no clear treatment structure currently in place. While the condition often remains undetected, early detection increases the chances of not developing type 2 diabetes. Anders Rosengren emphasizes the importance of early and individualized interventions to prevent the disease.

"The treatment of prediabetes is currently lacking in many respects, but these new findings open the way for possible precision treatment using sulforaphane extracted from broccoli as a functional food. However, lifestyle factors remain the foundation of any treatment for prediabetes, including exercise, healthy eating, and weight loss," he says."The results of the study also offer a general model of how pathophysiology and gut flora interact with and influence treatment responses. A model that could have broader implications," Anders Rosengren ends.

Reference:

Dwibedi, C., Axelsson, A.S., Abrahamsson, B. et al. Effect of broccoli sprout extract and baseline gut microbiota on fasting blood glucose in prediabetes: a randomized, placebo-controlled trial. Nat Microbiol (2025). https://doi.org/10.1038/s41564-025-01932-w