2 Answers

Vegetables and fruits are very powerful when it comes to fighting off cancer. These foods are naturally filled with antioxidants and ton of vitamins and minerals that your body needs to maintain a strong immune system and prevent the formation and growth of cancer cells. Many fruits and vegetables have components that are extremely powerful against cancer.

The more vegetables and fruits you can consume on a daily basis, the more protected you will be from cancer. Juicing is an easy way to get in lots of fresh produce without stuffing yourself. The CDC also recommends regular exercise as a way to control your weight, which also reduces your chances of developing cancer!

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UNfortunately, there is no sure-fire way to prevent cancer.  Staying away from tobacco, including "secondhand smoke" is  the most you can hope for in THAT arena.  Drinking "clean" water, eating organic vs. chem food, heavy on certain foods and light/avoid others can be helpful. 
Keep your weight within healthy limits, and stay physically active shouldn't hurt, either.
You probably KNOW the drills; google "cancer preventive lifestyle" and see what you get. :D