In another boon for broccoli, researchers have found that eating the green vegetable may improve outcomes after a breast cancer diagnosis. A new study points to the positive role that all cruciferous veggies -- like cauliflower, brussels sprouts, kale and cabbage -- can play in improving survival and recurrence rates associated with breast cancer.
In the study, presented Tuesday at the American Association for Cancer Research's annual meeting, researchers looked at data from more than 4,800 breast cancer survivors in China who had been diagnosed with breast cancer between 2002 and 2006. The women's cancers ranged from stage 1 to stage 4.
Overall, researchers with the Vanderbilt Epidemiology Center and Shanghai Centers for Disease Control and Prevention found that higher consumption of cruciferous vegetables in the years following diagnosis was tied to better outcomes. Women who ate the most reduced by 62 percent their risk of both overall mortality and breast cancer-specific mortality, as compared to women who consumed the least. Those who consumed the most vegetables also reduced by 35 percent the risk of their breast cancer coming back. Researchers compared relative quantities of the vegetables in women's diets and have not determined at what quantities the beneficial effects are derived.
"Cruciferous vegetables, such as cauliflower, cabbage, bok choy, turnips and broccoli, contain high amounts of glucosinolates, which are hydrolyzed to bioactive compounds including isothiocyanates (ITCs) and indoles," said Sarah Nechuta, a research fellow in Vanderbilt University's epidemiology center and a researcher on the new study, who explained that she and her fellow researchers attempted to control for other factors that might influence women's outcomes, including demographics, exercise and additional dietary behaviors.
"These bioactive compounds have many anti-cancer properties that may influence cancer development, progression and survival," Nechuta added.
This is not the first time that the cabbage family has been tied to decreased breast cancer risk.
A 2008 study in The American Journal of Clinical Nutrition, which also focused on Chinese women, linked consumption of cabbage and white turnips to lower breast cancer risk.
"An association has also been established with colon cancer and prostate cancer," explained Emily Ho, an associate professor in nutrition and exercise sciences at Oregon State University. "There is pretty strong evidence from studies that compounds found in cruciferous vegetables may have cancer-fighting properties."
The new study is, however, among the first to look at the role that cruciferous vegetables can play after a cancer diagnosis.
But Ho cautioned that many questions about the connection between vegetables and cancer risk remain.
"There are still a lot of unanswered questions about what, exactly, is in [cruciferous vegetables] that is protective," she said. Researchers do not understand exactly what the underlying mechanisms are and what impact these vegetables may have at the tissue level, she said. Furthermore, research has not yet made it clear whether supplements could have the same potential effect as vegetables themselves seem to have.
Nechuta also cautioned that it should not necessarily be assumed that similar results would be achieved in the United States, where the types of cruciferous vegetables women eat may be different than those in China.
"Commonly consumed cruciferous vegetables in China include turnips, Chinese cabbage [or] bok coy and greens, while broccoli and brussels sprouts are the more commonly consumed cruciferous vegetables in the United States and other Western countries," Nechuta said in a statement. In an email to The Huffington Post, she said that future studies with direct measurements of various bioactive compounds are needed in order to understand the possible link between cruciferous vegetables and breast cancer intake.
In the meantime, Ho said people would do well to follow fruit and vegetable consumption guidelines. The American Cancer Society, for example, recommends that individuals consume at least two and a half cups of fruits and vegetables per day to lower cancer risk, pointing out that those foods with the most color -- which are dark green, red, yellow and orange -- provide the most nutrients.
"If you try and include cruciferous vegetables as some of those servings," Ho said. "It probably won't hurt and it certainly might help."