Maximising the Bioavailability and Activity of Broccoli Phytochemicals Using a Broccoli Soup Enriched for Myrosinase by Addition of Mustard Seeds

Epidemiological and experimental studies have indicated that the consumption of diets rich in cruciferous vegetables such as broccoli has a range of beneficial effects on human health. These effects are usually attributed to naturally-occurring glucosinolates and their breakdown products, isothiocyanates, in cruciferous vegetables. One of these compounds, sulforaphane, the hydrolysis product of glucoraphanin, the main glucosinolate in broccoli has been reported to have bactericidal activity against H. pylori and other human pathogens. The investigators have recently shown that adding mustard seeds, which contain a more resilient form of this enzyme, to processed broccoli actually increased the formation of sulforaphane and minimised production of another biologically-inactive form. Experimental studies by the investigators have shown that sulforaphane can inhibit growth of a number of enteric pathogens including salmonella and E. coli which exert their effects in the small intestine. Currently the bioavailability, stability and bioactivity of sulforaphane in the small intestine of a human following consumption of broccoli is not known.

To assess the effect of broccoli phytochemicals in vivo 20 participants who have previously had an ileostomy (removal of colon, > 1.5 years post operative) will be fed 200 ml of broccoli soup/control in a randomised double blind crossover design and collect the ileal fluid before (0 hr) and after (4 hr) the feeding. The ileal fluid collected from participants will have undergone in vivo digestion, allowing analysis of the chemical composition and bioactivity of the ileal fluid. The hypothesis to be tested is that consumption of cooked broccoli plus myrosinase from mustard seeds will result in high levels of sulforaphane in ileostomy fluid, sufficient to suppress growth of enteric pathogens. This study will be used to assess whether previous observations on the in vitro antibacterial activity of broccoli are relevant in vivo.