Studies find that plant-based diets reduce the risk of cancer, the second leading cause of death in the United States, ranking just below cardiovascular disease. (See Chapter 7.)

Cancer is a group of conditions that result from the uncontrolled growth or division of abnormal cells that invade a part or parts of the body. Although scientists don’t fully understand how cancer develops, most agree that it is a multistep process. (INFOGRAPHIC 9.2)

Question 9.2

First, during the process of initiation, DNA inside a cell undergoes a mutation that alters the DNA sequence permanently. Any cells produced from the division of the mutated cell will also carry the mutation. Once a cell has been mutated, it is susceptible to the effects of promoters. During promotion, various factors (like inflammation or some chemicals) selectively promote these mutated cells to divide and proliferate more quickly than they should. Finally, in the process of progression, the mutated cells acquire additional mutations that allow the cancer cells to migrate to, and invade, other tissues (metastasis) where they can form new tumors that disrupt the function of body organs and tissues.

Although many cancers are influenced by genetic factors, cancer risk is also affected by environmental factors, including lifestyle choices—so in that sense, dietary choices can both increase and decrease risk. For example, eating a diet rich in vegetables, fruits, and legumes has been linked with a reduced risk of mouth, esophageal, stomach, and colon cancer. In contrast, alcohol consumption is associated with an increased risk of several types of cancer. (INFOGRAPHIC 9.3)

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Question 9.3