Effect of L. Plantarum Probiotic Supplementation on Broccoli Sulforaphane Bioavailability: Randomised Double-blind Placebo-controlled Crossover Study

Overview

Broccoli has the precursor of an active compound (sulforaphane) that has shown a wide range of health promoting benefits. Sulforaphane formation depends on the conversion of glucoraphanin (precursor) by myrosinase enzyme. Thus, the bioavailability of sulforaphane is affected by myrosinase activity. Some bacteria, such as L. plantarum (probiotic), have shown they can also convert glucoraphanin to sulforaphane in vitro. This study investigates the effect of short-term L. plantarum supplementation on broccoli sulforaphane bioavailability in humans using a randomised double-blind placebo-controlled crossover trial.

Brassicas (i.e. broccoli, kale, cabbage) are a group of edible plants that contain a phytochemical called glucoraphanin that upon enzymatic hydrolysis forms the bioactive form sulforaphane. Sulforaphane has shown consistent in vitro and in vivo (animals) anti-cancer activity. The enzyme responsible for this conversion is called myrosinase; however, the enzymatic activity of myrosinase can be affected by several biological factors (e.g. plant variety, growth conditions, etc...) and food processing (e.g. cooking, drying, etc...). Broccoli is one of the richest sources of glucoraphanin, but its myrosinase activity can be easily lost during cooking: 10 minutes at 70 °C reduces the enzyme activity by 95%. This means broccoli prepared this way will contain little to no biologically active sulforaphane. Therefore, is important to find strategies to increase the bioavailability of sulforaphane in broccoli and other brassicas for human consumption. Certain bacteria have shown myrosinase-like activity and were able to convert glucoraphanin to sulforaphane in vitro, one of these bacteria is Lactiplantibacillus plantarum. This bacterium is present in the human gut, however, there is a large biological variability in the prevalence of this bacteria between individuals. Several human studies have demonstrated that chronic (\>1 week) consumption of probiotic supplements containing L. plantarum was able to increase the presence of this bacterium in human gut participants. Thus, the investigators aim to test if supplementing participants with L. plantarum will increase the bioavailability of sulforaphane, compared to placebo.