In one of the first studies of the relationship between diet and leukemia, researchers found a strong correlation between total caloric intake and both lymphoid and total leukemia incidence, especially among males. “The findings from this rigorous analysis of international data strengthen and expand the hypothesis based on previous simple correlation analyses and animal experiments that an underlying biological relationship exists between diet, particularly energy intake, and international variations in the incidence of certain types of human leukemia.”
Source: S. D. Hursting et al., “Diet and Human Leukemia: An Analysis of International Data,” Preventive Medicine 22:409-22, 1993.
In a review of 200 studies that examined the relationship between fruit and vegetable intake and cancer at selected sites, researchers found that consumption of these foods offered a significantly protective effect in 128 of 156 dietary studies in which results were expressed in terms of relative risk. For lung cancer, these foods were protective in 24 of 25 studies after control for smoking in most instances. Fruit was protective for tumors of the esophagus, oral cavity, and larynx in 28 of 29 studies. Vegetables and fruit were protective in 26 of 30 studies for the pancreas and stomach, as well as in colorectal and bladder cancers (23 of 38 studies). For malignancies of the cervix, ovary, and endometrium, a significant protective effect was shown in 11 of 13 studies. In breast cancer, a protective effect was found to be strong and consistent in meta-analysis. Overall, the relative risk of cancer was about twice as high for those eating few fruits and vegetables compared to those who ate plenty of these foods.
“In 1854, John Snow stopped a cholera epidemic simply by taking the handle off the pump. The research presented above suggests that consumption of fruits and vegetables may be a handle that, if manipulated by public policy, clinical advice, and public education, could have a substantial impact on a wide range of cancers,” the researchers concluded.
Source: Gladys Block et al., “Fruits, Vegetables, and Cancer Prevention: A Review of the Epidemiological Evidence,” Nutrition and Cancer 18:1-29, 1992.
In a case-control study in Hawaii, researchers reported a decreased risk for bladder cancer among women who consumed vegetables and fruits high in vitamin C, such as broccoli, cabbage, and oranges, and among men who consumed dark green vegetables such as watercress, broccoli, and spinach.
Source: A.M.Y. Nomura et al., “Dietary Factors in Cancer of the Lower Urinary Tract,” International Journal of Cancer 48:199205.
The high rate of stomach cancer in Japan caused some Japanese scientists to speculate that a diet high in soy sauce might be a factor. However, researchers at the University of Wisconsin observed just the opposite. In laboratory tests, mice given fermented soy sauce experienced 26 percent less cancer than mice on the regular diet. Also soy-supplemented mice averaged about one-quarter the number of tumors per mouse as the control group. Soy sauce “exhibited a pronounced anticarcinogenic effect,” the researchers concluded.
Source: J. Raloff, “A Soy Sauce Surprise,” Science News, 139:357, 1991.
Scientists at Johns Hopkins University School of Medicine reported that they had identified the ingredient in broccoli that worked as a powerful anticancer compound in laboratory experiments. The chemical, sulforaphane, boosts the production of an important enzyme known to neutralize carcinogens before they trigger tumor growth. In addition to broccoli, sulforaphane is found in bok choy, ginger, scallions, and other vegetables.
Source: Paul Talalay, Proceedings of the National Academy of Sciences, March 16, 1992.
In studies of men employed by the Western Electric Company in Chicago, researchers reported that men who ingested 500 milligrams or more of dietary cholesterol a day faced almost twice the risk of lung cancer as those who ate less than that amount. Eggs were cited as the chief cause.
Source: R. B. Shekelle et al., “Dietary Cholesterol and Incidence of Lung Cancer,” American Journal of Epidemiology 134:48084, 1992.
An Indian cancer researcher concluded that thorough chewing lowered the risk of cancer. “The proper chewing of meals ensuring that mucous-rich saliva mixed with the food seemed to be protective factors.” Cancer also appeared to be more prevalent in South India where white rice and considerably more fat, oil, and spices are used in cooking than in Northern India where whole-grain chapatis and thick dal made with lentils are the staple.
Source: S. L. Malhotra, “Dietary Factors in a Study of Cancer Colon from Cancer Registry, with Special Reference to the Role of Saliva, Milk and Fermented Milk Products, and Vegetable Fibre,” Medical Hypotheses 3:122-26, 1977.
Japanese cancer researchers found that people who regularly ate tofu were at less risk for stomach cancer than those who did not.
Source: T. Hirayama, “Epidemiology of Stomach Cancer,” in T. Murakami (ed.), Early Gastric Cancer. Gann Monograph on Cancer Research, 11 (Tokyo: University of Tokyo Press, pp. 3-19), 1971.
Japan’s National Cancer Center reported that people who eat miso soup daily are 33 percent less likely to contract stomach cancer and 19 percent less likely to contract cancer at other sites than those who never eat miso soup. The thirteen-year study, involving about 265,000 men and women over forty, also found that those who never ate miso soup had a 43 percent higher death rate from coronary heart disease than those who consumed miso soup daily. Those who abstained from miso also had 29 percent more fatal strokes, three and a half times more deaths resulting from high blood pressure, and higher mortality from all other causes.
Source: T. Hirayama, “Relationship of Soybean Paste Soup Intake to Gastric Cancer Risk,” Nutrition and Cancer 3:223-33, 1981.
Japanese scientists reported that several varieties of kombu and mojaban, common sea vegetables eaten in Asia and traditionally used as a decoction for cancer in Chinese herbal medicine, were effective in the treatment of tumors in laboratory experiments. In three of four samples tested, inhibition rates in mice with implanted sarcomas ranged from 89 to 95 percent. The researchers reported that “the tumor underwent complete regression in more than half of the mice of each treated group. ” Similar experiments on mice with leukemia showed promising results.
Source: I. Yamamoto et al., “Antitumor Effect of Seaweeds,” Japanese Journal of Experimental Medicine 44:543-46, 1974.