It has been estimated that 30–40 percent of all cancers can be prevented by lifestyle and dietary measures alone. Obesity, nutrient sparse foods such as concentrated sugars and refined flour products that contribute to impaired glucose metabolism (which leads to diabetes), low fiber intake, consumption of red meat, and imbalance of omega 3 and omega 6 fats all contribute to excess cancer risk. Intake of flax seed, especially its lignan fraction, and abundant portions of fruits and vegetables will lower cancer risk. Allium and cruciferous vegetables are especially beneficial, with broccoli sprouts being the densest source of sulforophane.
Protective elements in a cancer prevention diet include selenium, folic acid, vitamin B-12, vitamin D, chlorophyll, and antioxidants such as the carotenoids (a-carotene, ß-carotene, lycopene, lutein, cryptoxanthin). Ascorbic acid has limited benefits orally, but could be very beneficial intravenously. Supplementary use of oral digestive enzymes and probiotics also has merit as anticancer dietary measures. When a diet is compiled according to the guidelines here it is likely that there would be at least a 60–70 percent decrease in breast, colorectal, and prostate cancers, and even a 40–50 percent decrease in lung cancer, along with similar reductions in cancers at other sites. Such a diet would be conducive to preventing cancer and would favor recovery from cancer as well.
Obesity has reached epidemic proportions in the United States. Sixty-four percent of the adult population is overweight or obese . About 1 in 50 are now severely obese (BMI > 40 kg/m2) [3]. Mokdad et al found that poor diet and physical inactivity was the second leading cause of death (400,000 per year in the USA), and would likely overtake tobacco as the leading cause of death.
It was estimated in a recent study, from a prospective cancer prevention cohort, that overweight and obesity accounted for 14 percent of all cancer deaths in men and 20 percent of those in women . Significant positive associations were found between obesity and higher death rates for the following cancers: esophagus, colon and rectum, liver, gallbladder, pancreas, kidney, stomach (in men), prostate, breast, uterus, cervix, and ovary . The authors estimated that over 90,000 cancer deaths per year could be avoided if the adult population all maintained a normal weight (BMI < 25.0) [5]. Clearly, obesity is a major risk factor for cancer.
Refined sugar is a high energy, low nutrient food – junk food. “Unrefined” sugar (honey, evaporated cane juice, etc) is also very concentrated and is likely to contribute to the same problems as refined sugar. Refined wheat flour products are lacking the wheat germ and bran, so they have 78 percent less fiber, an average of 74 percent less of the B vitamins and vitamin E, and 69 percent less of the minerals (USDA Food database, data not shown). Concentrated sugars and refined flour products make up a large portion of the carbohydrate intake in the average American diet. One way to measure the impact of these foods on the body is through the glycemic index.
One of the most important messages of modern nutrition research is that a diet rich in fruits and vegetables protects against cancer. (The greatest message is that this same diet protects against almost all other diseases, too, including cardiovascular disease and diabetes.) There are many mechanisms by which fruits and vegetables are protective, and an enormous body of research supports the recommendation for people to eat more fruits and vegetables.
Nutrition Journal 2004, 3:19doi:10.1186/1475-2891-3-19
The electronic version of this article is the complete one and can be found online at: http://www.nutritionj.com/content/3/1/19
