Le Marchand L. Hankin JH. Wilkens LR. Kolonel LN. Englyst HN. Lyu LC. Institution
Etiology Program, University of Hawaii Cancer Research Center, Honolulu, USA.
Dietary fiber and colorectal cancer risk. Source
Epidemiology. 8(6):658-65, 1997 Nov.
We conducted a population-based case-control study among different ethnic groups in Hawaii to evaluate the role of various types and components of fiber, as well as micronutrients and foods of plant origin, on the risk of colorectal cancer. We administered personal interviews to 698 male and 494 female Japanese, Caucasian, Filipino, Hawaiian, and Chinese cases diagnosed during 1987-1991 with adenocarcinoma of the colon or rectum and to 1,192 population controls matched to cases by age, sex, and ethnicity. We used conditional logistic regression to estimate odds ratios, adjusted for caloric intake and other covariates. We found a strong, dose-dependent, inverse association in both sexes with fiber intake measured as crude fiber, dietary fiber, or nonstarch polysaccharides. We found inverse associations of similar magnitude for the soluble and insoluble fiber fractions and for cellulose and noncellulosic polysaccharides. This protective effect of fiber was limited to fiber from vegetable sources, with an odds ratio of 0.6 (95% confidence interval = 0.4-0.9) and 0.5 (95% confidence interval = 0.3-0.7) for the highest compared with the lowest quartile of intake for men and women, respectively. We found associations of the same magnitude for soluble and insoluble vegetable fiber, but no clear association with fiber from fruits or cereals. This pattern was consistent between sexes, across segments of the large bowel (right colon, left colon, and rectum), and among most ethnic groups. The effect of vegetable fiber may be independent of the effects of other phytochemicals, since the effect estimates remained unchanged after further adjustment for other nutrients. Intakes of carotenoids, light green vegetables, yellow-orange vegetables, broccoli, corn, carrots, bananas, garlic, and legumes (including soy products) were inversely associated with risk, even after adjustment for vegetable fiber. The data support a protective role of fiber from vegetables against colorectal cancer, which appears independent of its water solubility property and of the effects of other phytochemicals. The data also indicate that certain vegetables and fruits may be protective against this disease through mechanisms other than their fiber content.
Sankaranarayanan R. Varghese C. Duffy SW. Padmakumary G. Day NE. Nair MK.
Regional Cancer Centre, Trivandrum, Kerala, S. India. Title
A case-control study of diet and lung cancer in Kerala, south India.
International Journal of Cancer. 58(5):644-9, 1994 Sep 1. Abstract
A total of 281 male lung-cancer patients were identified from the hospital cancer registry in the Regional Cancer Centre in Trivandrum. The controls were selected from the visitors and patients' bystanders in the hospital. The recruitment of cases and controls started in 1990, and the present study used the cases registered in the first year. The questionnaire administered to cases and controls collected information on tobacco smoking and alcohol habits. Dietary data were collected using a food frequency questionnaire and were analyzed by multiple logistic regression producing odds ratio estimates of the relative risk and deviance chi-squared tests of significance. Analysis was done on the computer package, EGRET. All models included age, education, religion and smoking to adjust for the effect of confounding. Green vegetables and bananas were found to have a protective association with lung cancer. The odds ratio associated with the highest quartile of vegetable consumption compared with the lowest was 0.32 (95% confidence interval 0.13, 0.78). Forward stepwise regression analysis indicated pumpkins and onions as the most consistently significant protective factors. Animal protein foods and dairy products were found to have a predisposing effect on lung cancer in this study. The expected influence of smoking on lung cancer (a considerable increase in risk among smokers) provided evidence of the reliability of the data. In conclusion the results from this study show that diet has a role in lung cancer aetiology, although the association is weak compared to the effects of smoking.
Zheng T. Boyle P. Willett WC. Hu H. Dan J. Evstifeeva TV. Niu S. MacMahon B.
Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy.
A case-control study of oral cancer in Beijing, People's Republic of China. Associations with nutrient intakes, foods and food groups. Source
European Journal of Cancer. Part B, Oral Oncology. 29B(1):45-55, 1993 Jan.
A case-control study of oral cancer was conducted in Beijing, People's Republic of China to examine the association between dietary nutrient intake and risk of oral cancer, both in terms of estimated intake of nutrients and micro-nutrients, and in terms of specific foods and food groups. The study was hospital-based and controls were hospital in-patients matched for age and sex with the cases. The response rate for cases and controls was 100% and 404 case/control pairs were interviewed. The results suggest that increased protein and fat intake are related to a decreased risk of oral cancer. Carbohydrate intake, however, showed a moderate increased risk for oral cancer. Total carotene intake and carotene intake from fruits and vegetables are inversely associated with risk of oral cancer. A similar pattern was observed for dietary vitamin C intake. Dietary fibre derived from fruits and vegetables showed a strong negative association with oral cancer risk, but fibre derived from other sources did not exhibit any protective effect. At the level of foods and food groups, increased consumption of fresh meat, chicken and liver was significantly associated with a reduction in oral cancer risk: the tests for trend were all statistically significant at the P < 0.01 level. Consumption of common carp, hairtail, shrimp and lobster were also associated with decreased risk. Risk was found to increase with increasing consumption of millet and corn bread (P < 0.01) but to decrease with increasing consumption of rice (P < 0.01). Increased consumption of grapes, bananas, oranges, tangerines, peaches and pears were associated with reduced risk.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Biomathematics, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Dietary, total body, and intracellular potassium-to-sodium ratios and their influence on cancer. [Review] [9 refs] Source
Cancer Detection & Prevention. 14(5):563-5, 1990. Abstract
One of the greatest changes in the human diet, a change that has occurred only within the past few thousand years, is the immense increase in the intake of sodium (Na) caused by use of table salt in the preparation and preservation of food. At the same time, man's intake of potassium (K) has decreased. The result is that from Paleolithic times to modern times the dietary K/Na ratio has been reduced by a factor of about 20. Based on a comparison of modern people in civilized areas with the primitive Yanomamo Indians in South America (who do not eat salt but who do grow and eat potassium-rich cooking bananas), this factor may even be on the order of 100 to 200. Humans, who initially had to adapt to retain sodium from a sodium-poor diet and to excrete potassium from a potassium-rich diet, have not yet evolutionarily adapted to today's high-sodium, low-potassium diet. This failure has caused increased rates of a number of diseases in civilized man, among them cancer. The influence of the K/Na ratio on cancer development--first discovered by epidemiologic studies--has been confirmed by various means, such as dietary studies, gerontological studies, studies of relationships between hyper- and hypokalemic diseases and cancer, and review of the cellular changes of this ratio induced by carcinogenic and anticarcinogenic agents. Recently, animal experiments have also confirmed the results. The recommended dietary K/Na ratio should be well above 1, preferably 5 or higher, and the cellular K/Na ratio should be above 10. [References: 9]