Japanese men and women with H. pylori infections who consumed 70 grams a day of fresh broccoli sprouts had lower levels of the bacteria after eight weeks than men and women consuming alfalfa sprouts, according to results published in Cancer Prevention Research.
H. pylori is the only bacteria that can survive in the acidic environment of the stomach and it is known to cause peptic ulcers and gastritis.
Infection with H. pylori also causes gastritis, and infected persons are said to have a two to six-fold increased risk of developing mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer compared with uninfected counterparts.
“Broccoli has recently entered the public awareness as a preventive dietary agent. This study supports the emerging evidence that broccoli sprouts may be able to prevent cancer in humans, not just in lab animals,” said researcher Jed Fahey, ScD, from the Johns Hopkins School of Medicine.
Dr Fahey is co-founder of Brassica Protection Products LLC (BPP), a company that produces broccoli sprouts under license by Johns Hopkins University, although he had no equity in the company.
Benefits of broccoli
The tissue of cruciferous vegetables, like broccoli, cauliflower, cabbage and Brussels sprouts, contain high levels of the active plant chemicals glucosinolates. These are metabolised by the body into isothiocyanates, which are known to be powerful anti-carcinogens. The main isothiocyanate from broccoli is sulphoraphane.
Broccoli sprouts have previously been shown to reduce blood pressure in rats with hypertension due to the presence of a compound called glucoraphanin (Grn+). Sprouts are the richest source of Grn+, containing up to 50 times more than mature broccoli.
Glucoraphanin, also known as sulforaphane glucosinolate (SGS), is the precursor of sulforaphane.
Fahey and his co-workers recruited 48 Japanese men and women (average age 54.5) infected with H pylori and randomly assigned them to eat 70 grams of fresh broccoli sprouts daily for eight weeks or an equivalent amount of alfalfa sprouts.
After eight weeks the researchers observed significantly lower of H pylori using breath, serum and stool for people in the broccoli sprouts group, while no changes were observed in the alfalfa sprouts group. These results suggested that the broccoli sprouts could reduce but not eradicate the bacteria in the stomach, said the researchers.
Commenting on the mechanism behind the effects, the researchers noted that previous studies have reported that sulforaphane may induce cytoprotective, antioxidant, and anti-inflammatory enzymes, while other studies have reported that H pylori and sodium chloride may combine to enhance inflammation of the mucus membrane of the stomach.
“Sulforaphane may be inhibiting this inflammation,” they said.
“The findings in this study strongly suggest that sulforaphane has promise both as an antibacterial agent directed against H. pylori and as a dietary preventive agent against the development of human gastric cancer,” concluded the researchers.
The other researchers were affiliated with Tokyo University of Science, University of Tsukuba, and Johns Hopkins University.
Source: Cancer Prevention ResearchApril 2009, Volume 2, Issue 4, Pages 353-360 "Dietary Sulforaphane-Rich Broccoli Sprouts Reduce Colonization and Attenuate Gastritis in Helicobacter pylori–Infected Mice and Humans"
Authors: A. Yanaka, J.W. Fahey, A. Fukumoto, M. Nakayama, S. Inoue, S. Zhang, M. Tauchi, H. Suzuki, I. Hyodo, M. Yamamoto