A Randomized Controlled Trial of the Effect of Broccoli Sprouts on Antioxidant Gene Expression and Airway Inflammation in Asthmatics.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 27130714 · doi:10.1016/j.jaip.2016.03.012
What was done
Forty adults aged 18 to 50 years with asthma and allergic sensitization to an indoor allergen were enrolled in a double-blind, placebo-controlled randomized trial. Participants were assigned to consume either 100 g daily of whole broccoli sprouts (rich in sulforaphane) or 100 g daily of alfalfa sprouts (placebo) for 3 consecutive days. Outcomes assessed before and after intervention included fractional exhaled nitric oxide (FENO, the primary outcome), forced expiratory volume in 1 second, nasal epithelial and peripheral blood mononuclear cell (PBMC) antioxidant gene expression, inflammatory and oxidative stress biomarkers, symptoms, and serum sulforaphane levels.
What was found
Broccoli sprout ingestion did not reduce FENO compared to placebo (21 vs 22 parts per billion, P = .76), despite causing a marked increase in serum sulforaphane concentrations. Furthermore, broccoli sprout consumption did not induce cytoprotective antioxidant genes in nasal epithelial cells or PBMCs, reduce oxidative stress or inflammatory biomarkers, or improve lung function and symptoms.
Why it matters
Despite strong mechanistic rationale for sulforaphane inducing phase II antioxidant pathways, short-term dietary broccoli sprouts did not provide measurable clinical, physiological, or cellular anti-inflammatory benefit in allergic asthma.
Limits
The intervention duration was extremely short (3 days) and the sample size was small (n = 40). The cohort was restricted to adults with atopic asthma, limiting generalizability to other asthma phenotypes. The abstract does not provide exact numerical values or effect sizes for lung function, gene expression levels, or symptom scores.
Cited by
- contradicts Sulforaphane activates the NRF2 pathway, turning on phase II detoxification and promoting the expression of 200 antioxidant genes for up to 72 hours.