Women who increase their consumption of fruits and vegetables probably reduce their risk of developing invasive bladder cancer, researchers from the University of Hawaii Cancer Center reported in The Journal of Nutrition1.
The authors explained that fruits and vegetables have been extensively studied for their possible effects on the risk of cancer, including bladder cancer. Fruits and vegetables contain several nutrients, phytochemicals, as well as antioxidants which potentially protect from cancer.
According to the National Cancer Institute2, there are approximately 72,570 new cancer bladder cases and 15,210 deaths caused by bladder cancer annually in the United States.
Song-Yi Park, PhD., and colleagues set out to determine what effect high fruit and vegetable intake might have on invasive bladder cancer risk.
The team carried out a prospective analysis involving 185,885 older adults who participated in the Multiethnic Cohort Study. The study was set up in 1993 to examine the relationship between dietary, lifestyle, genetic factors, and the risk of cancer.
The researchers gathered and analyzed data over a 12.5-year period. During that time 152 females and 429 males developed invasive bladder cancer.
High fruit and vegetable intake may help protect women from bladder cancer, but not men
After making adjustments for some variables which influence cancer risk, such as age, the scientists discovered that those with the lowest bladder cancer risk were women who ate the most fruits and vegetables.
Dr. Park and team found that:
- Women with the highest yellow-orange vegetable intake had a 52% lower risk of developing invasive bladder cancer compared to women with the lowest consumption.
- Women with the highest consumption of vitamins A, C, and E were the least likely to develop bladder cancer.
- Fruit and vegetable consumption appeared to have no effect on male bladder cancer risk.
"Our study supports the fruit and vegetable recommendation for cancer prevention. However, further investigation is needed to understand and explain why the reduced cancer risk with higher consumption of fruits and vegetables was confined to only women."
What is bladder cancer?
This type of cancer forms in the tissues of the bladder. The bladder is the organ that stores urine.
The majority of bladder cancers start in the cells that make up the inner lining of the bladder - transitional cell carcinomas.
Adenocarcinoma starts in the cells that make and release mucus and other fluids. Squamous cell carcinoma starts off in the thin, flat cells.
Adenocarcinoma and squamous cell carcinoma develop in cells in the inner lining of the bladder as a result of long-term irritation and inflammation.
According to the National Health Service (NHS)3, UK, about half of all bladder cancer cases among men are caused by smoking. The NHS adds that smoking is thought to be the cause of 20% to 30% of all female cases. However, an article published in JAMA in 2011 states that the risk for female smokers is comparable with that of men4.
Bladder cancer can develop at any age, but is much more common among older adults. If diagnosed at an early stage the disease is highly treatable.
Bladder cancer has a high recurrence rate. Hence, survivors should undergo regular follow-up checks.