There isn’t a day that goes by that the Internet or the print media isn’t bombarding readers with a new diet that prevents cancer.
Every day, there are headlines that bombard readers with various diets that purportedly prevent cancer: “The Diet That Stops Cancer” and “Eating Your Way Out of Cancer.” But what do the hard data really say about lifestyle choices preventing cancer? Studies have shown that the combination of healthy eating, not smoking, and regular exercise can reduce the risk of heart disease by 80 percent and of stroke and some cancers by 70 percent.
Although no diet has received conclusive evidence of presenting cancer, there are lifestyle choices such as exercise that support conclusions that they can serve as deterrent of cancer. Even the American Cancer society recommends avoid being overweight and includes being physically active for at least 30 minutes every day. They also suggest eating a mostly plant-based diet; limiting red meats and avoiding processed meats; limiting alcoholic drinks (two glasses of wine a day for men and one glass for women); and to protect against cancer (Table 1). Other recommendations include avoid sugary drinks, limit consumption of processed foods and eat more vegetables, whole grains, and legumes such as beans. Limit salt intake to 1.5 grams per day and limit consumption of salty foods, chips, pretzles, smoked or cured meats like salami, baloney, and beef jerky.
Other Cancer Prevention Recommendations
To prevent breast cancer, the ACS recommends at least 150 minutes of moderate-intensity physical activity per week, alcohol intake of one or fewer drinks per day, and maintaining a body mass index (BMI) less than 25 kg/m2. In a study of 2905 women at high-risk for breast cancer, adherence to these three recommendations reduced the risk for breast cancer by 44%.
Perhaps this shouldn’t be all that surprising, given that BMI itself is a risk factor for cancer. Too much body fat triggers insulin resistance, raising levels of insulin and growth factors that promote cancer. Fat also increases estrogen production, which can fuel some cancers, and fat secretes enzymes that promote inflammation.
Numerous medical studies have concluded that avoiding adult weight gain confers protection against certain types of cancer, particularly among nonusers of hormone replacement therapy (HRT). The study found that for each 5-kg increase in adult weight gain, the relative risk was increased 11% for postmenopausal breast cancer among no or low HRT users; 39% and 9% for postmenopausal endometrial cancer among HRT nonusers and users, respectively; and 13% for postmenopausal ovarian cancer among no or low HRT users. For each 5-kg increase in men, the risk for colon cancer increased by 9%. The relative risk for kidney cancer comparing highest and lowest level of adult weight gain was 1.42.
In addition to lowering the risk of cancer, eating a diet that is high in fruits and vegetables is associated with a lower risk for all-causes of death and lower risk of dying of cardiovascular causes such as heart disease or stroke.
Bottom line on diet and exercise and cancer prevention: Weight gain, lack of exercise, and high alcohol intake are the key factors for leading a healthy lifestyle and decreasing the risk of cancer.