Randomized Crossover Trial Evaluating Detoxification of Tobacco Carcinogens by Broccoli Seed and Sprout Extract in Current Smokers.
Level 2 - randomized trial
Individual randomized crossover trial
PubMed 35565256 · doi:10.3390/cancers14092129
What was done
Forty-nine healthy adult smokers (median consumption of 20 cigarettes per day; 53% female) participated in a randomized crossover trial evaluating the detoxification effects of a broccoli seed and sprout extract (Avmacol). Participants received two-week regimens of low-dose (148 µmol glucoraphanin daily) and higher-dose (296 µmol glucoraphanin daily) extract separated by a two-week washout period, randomized to low-then-high or high-then-low sequences. The primary endpoint was benzene detoxification measured by urinary excretion of S-phenylmercapturic acid (SPMA); secondary endpoints included bioavailability, urinary metabolites of acrolein and crotonaldehyde, GST genotype interaction, and safety.
What was found
Mean glucoraphanin bioavailability was 11% for the low-dose and 10% for the higher-dose extract. The higher-dose extract significantly increased the urinary excretion of mercapturic acids derived from benzene (p = 0.04), acrolein (p < 0.01), and crotonaldehyde (p = 0.02). These increases occurred independent of glutathione S-transferase (GST) genotype. Retention and compliance were high resulting in early study completion.
Why it matters
This trial shows that oral glucoraphanin from broccoli extract enhances the excretion and clearance of volatile tobacco carcinogens and toxicants in active smokers, supporting its role as a potential chemopreventive agent via phase II enzyme induction.
Limits
The sample size was small (n = 49) and intervention durations were short (two weeks per arm). The study used surrogate urinary biomarkers of excretion rather than long-term clinical or oncologic endpoints, lacked a non-exposed placebo arm, and absolute effect sizes or metabolite concentrations were not reported in the abstract.
Cited by
- supports Sulforaphane increases excretion of acrolein by activating the Nrf2 pathway and downstream phase II detoxification enzymes.