These findings were presented at the American Association for Cancer Research’s 2012 Annual Meeting in Chicago. The research team, led by Dr Xiao Ou Shu, Professor of Medicine at Vanderbilt University in Nashville, Tennessee, collaborated with scientists at the Shanghai Centers for Disease Control and Prevention to examine the role of cruciferous vegetables in breast cancer survival.
Using data from the Shanghai Breast Cancer Survival Study, which monitored 4,886 Chinese breast cancer survivors from 2002 to 2006, the researchers found that survivors who ate increased amounts of cruciferous vegetables within the first 36 months after their diagnosis had higher survival rate as compared with other breast cancer survivors.
“Breast cancer survivors can follow the general nutritional guidelines of eating vegetables daily and may consider increasing intake of cruciferous vegetables, such as greens, cabbage, cauliflower and broccoli, as part of a healthy diet,” said Sarah J Nechuta, MPH, PhD, a postdoctoral research fellow at Vanderbilt University.
The researchers analysed dietary information of the breast cancer survivors in three measures: at 6 months, 18 months and 36 months post-diagnosis. After adjusting for demographics, clinical characteristics and lifestyle factors, they found that increased intake of cruciferous vegetables was associated with reduced risk of dying of breast cancer, a decreased risk of mortality overall, and lower cancer recurrence in a dose-response pattern.
“Across increasing quartiles of cruciferous vegetable consumption, risk for total mortality decreased by 27% to 62%, risk for breast cancer-specific mortality decreased by 22% to 62%, and risk for recurrence decreased by 21% to 35%,” the researchers noted.
The cruciferous advantage
Members of the cabbage family, cruciferous vegetables are well-known for their abundance of conventional nutrients such as fibre, vitamin C, vitamin A carotenoids, and folic acid, as well as other vitamins and minerals. But phytonutrients may be their most physiologically beneficial components. These chemical compounds are suggested to protect against cancer by reducing oxidative stress, or inhibiting the growth of certain types of cancer cells.
“Cruciferous vegetables contain high amounts of glucosinolates, which are hydrolysed to bioactive compounds such as isothiocyanates (ITCs) and indoles,” Dr Nechuta told NutraIngredients.
“These bioactive compounds have many anti-cancer properties that may influence cancer development, progression and survival. For example, ITCs and indole-3-carbinol have been shown to reduce tumor proliferation in human breast cancer cells.”
Dr Nechuta added that the type and amount of cruciferous vegetables one must consume to produce a level of bioactive compounds that might yield anticancer effects is still unknown.
“Future studies with direct measurements of bioactive compounds and host factors that influence the effects of these biological compounds are needed to better understand the association of cruciferous vegetable intake with breast cancer outcomes,” she said.
American Association for Cancer Research
'Cruciferous Vegetable Consumption Linked to Improved Breast Cancer Survival Rates'
Authors: Xiao Ou Shu, Sarah J. Nechuta,Wei Lu, Hui Cai, Ying Zheng, Ping-Ping Bao, Wei Zheng, Xiao Ou Shu