Allium vegetables may protect against gastric cancer
MedWire News: People who eat large quantities of Allium vegetables have a reduced risk for gastric cancer, results of a meta-analysis indicate.
The study adds weight to previous research pointing to a chemopreventive effect of vegetables from the Allium genus, which includes onions, garlic, shallots, leeks, scallion, and chives.
Allium vegetables are used around the globe in cooking and traditional medicine, and have been shown to have antimicrobial, antithrombotic, antitumor, hypolipidemic, antiarthritic, and hypoglycemic effects.
Recent research has focused on the putative anticarcinogenic properties of these vegetables and their organosulfur constituents, which include allylsulfides and flavonoids - particularly quercetin, which is abundant in onion.
In the present study, a Chinese team performed a meta-analysis of studies assessing the impact of Allium vegetable intake on gastric cancer risk. A total of 19 case-control and two cohort studies were eligible for inclusion.
Analysis of pooled data on 543,220 study participants found that the risk for gastric cancer was 46% lower for people with the highest versus the lowest consumption of Allium vegetables (odds ratio [OR]=0.54).
Further analyses found that high intake of individual vegetables offered similar reductions in the risk for gastric cancer, and this was true for all vegetables from the Allium genus with the exception of onion leaf.
Finally, a dose-response analysis indicated that each additional 20-g daily consumption of Allium vegetables - equivalent to the weight of a single garlic bulb - was associated with a 9% relative reduction in the risk for gastric cancer.
Writing in the journal Gastroenterology, Xiao-Ting Wu (Sichuan University, Chengdu, China) and colleagues warn that their results should be interpreted with caution given the potential for residual confounding and exposure misclassification.
They conclude: "Further study is needed to confirm this finding and to explore which constituents in Allium vegetables play a significant role in gastric cancer prevention."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Joanna Lyford