Broccoli, Sulforaphane, and Immune Resilience

    Bacterial infections are becoming increasingly difficult to treat, largely due to the growing prevalence of antibiotic-resistant bacteria. This challenge has increased interest in complementary, non-antibiotic approaches that may help support the body’s ability to manage infections (1).

    One compound receiving particular attention is sulforaphane, a naturally occurring phytonutrient found in high concentrations in broccoli and other cruciferous vegetables. A systematic review of 28 scientific studies examined the effects of sulforaphane on bacterial infections across laboratory experiments, animal models, and human research settings (1).

    Across these studies, sulforaphane demonstrated multiple antibacterial actions. It inhibited the growth of a broad range of bacteria, including both Gram-positive and Gram-negative species. In addition, sulforaphane reduced key bacterial virulence behaviors, such as biofilm formation and toxin production, that contribute to treatment resistance and tissue damage (1).

    Importantly, sulforaphane did not act solely on bacteria. It also supported host immune defenses by enhancing bacterial clearance while reducing excessive inflammation and oxidative stress. This balance is critical, as inflammation is necessary for immune defense but can contribute to tissue injury when it becomes dysregulated. Several studies also reported protective effects against aspirin-induced small intestinal injury and reduced gastric inflammation associated with Helicobacter pylori infection (1).

    Beyond direct antibacterial effects, sulforaphane-rich foods such as broccoli may also influence systemic inflammation—an important determinant of immune resilience and infection outcomes. To explore this in a real-world dietary context, researchers evaluated the effects of whole broccoli consumption on inflammatory markers.

    In a 10-day crossover intervention, young male smokers consumed 250 g of broccoli per day. Circulating levels of carotenoids, folate, and inflammatory markers—including C-reactive protein (CRP) and several cytokines—were measured before and after the intervention (2).

     Although this study did not isolate sulforaphane itself, broccoli is a primary dietary source of sulforaphane and related phytonutrients, making it relevant for assessing food-based effects. Broccoli intake significantly increased plasma folate (+17%) and lutein (+39%). While most inflammatory cytokines did not change, plasma CRP decreased by 48% (post-hoc analysis, p < 0.05), independent of changes in folate or lutein. Baseline analyses also showed inverse correlations between lycopene and inflammatory markers, including TNF-α and IL-6sR.

    CRP, or C-reactive protein, is a substance produced by the liver that rises when there is inflammation in the body. It acts like a smoke alarm for inflammation—increasing during infection, injury, or chronic stress and falling as inflammation resolves. Because CRP provides a quick snapshot of overall inflammatory status, it is commonly measured in clinical practice, even in people who feel otherwise healthy.

    Persistently elevated CRP levels are associated with infections, smoking, excess body weight, poor diet quality, and a higher long-term risk of chronic diseases such as cardiovascular disease and diabetes. CRP itself does not cause disease, but sustained elevations signal ongoing inflammatory stress. For this reason, reductions in CRP—such as those observed with higher fruit and vegetable intake—are often interpreted as a sign of improved inflammatory balance and immune health.

Taken together, current evidence suggests that sulforaphane and sulforaphane-rich foods may offer a promising dietary support strategy for bacterial infections. While not a substitute for antibiotics when clinically indicated, their combined antibacterial, immune-modulating, and tissue-protective effects highlight the potential value of sulforaphane-rich vegetables as part of a broader dietary pattern that supports immune resilience (1,2).

References:

1.     Pötschke V, Bereswill S, Heimesaat MM. Antibacterial effects of sulforaphane - A phytonutrient derived from broccoli as promising candidate in the combat of bacterial infections. Eur J Microbiol Immunol (Bp). 2025 Jun 24;15(3):139-149. doi: 10.1556/1886.2025.00028. PMID: 40553560; PMCID: PMC12505145.

2.     Riso P, Vendrame S, Del Bo' C, Martini D, Martinetti A, Seregni E, Visioli F, Parolini M, Porrini M. Effect of 10-day broccoli consumption on inflammatory status of young healthy smokers. Int J Food Sci Nutr. 2014 Feb;65(1):106-11. doi: 10.3109/09637486.2013.830084. Epub 2013 Sep 2. PMID: 23992556.

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