Over the past few days there have been several articles showing research that claims that eating more fruits and vegetables does not protect against cancer (see link). I would be interested to see the research that was conducted. Of course, if you eat more fruits and vegetables, it will not prevent cancer if you also smoke or drink excessive amounts of alcohol, or you don't take care of yourself in other ways.
There have been numerous studies that show cancer fighting properties in fruits and vegetables: the famous Linus Pauling studies using large doses of vitamin C to extend the lives of terminal cancer patients, Vitamin A in it's natural form (not the synthetic form), and Vitamin D and E, all have been shown to be cancer preventative, if not also useful in treating cancer.
I will accept that it would be foolish to think that you could prevent cancer by eating one or two more fruits or vegetables a day, the intake would have to be significantly more than the "Eat 5 a Day" campaign. But even healthy people produce cancer cells daily. A healthy immune system stops the cancer. So, if eating fruits and vegetables is important to staying healthy, then it also is important in preventing cancer.
I often question the purpose of studies like this. I can understand the desire to show that eating fruits and vegetables will not make up for an unhealthy lifestyle, but often when they release their findings, the message seems to be: well, there's no point in eating more fruits and vegetables. (Yikes!!!)
Nothing could be further from the truth. A constant supply of cancer fighting antioxidants is a great way to keep our immune system strong.
Our bodies are fighting cancer every day. We don't want to encourage the cancer to grow by eating poorly, or smoking, etc. But whatever we do, however we choose to live our lives, eating more fruits and vegetables is an important part in bringing our body into balance, reducing cancer-causing toxins, and strengthening the immune system. I consider this fighting cancer.
Maybe fruits and vegetables don't completely prevent cancer (we haven't found anything that does yet), but in my opinion, they are still an important part of the fight.