摘要:

AbstractAbout 35% (10–70%) of all cancers may be associated with nutritional causes (1). However, while natural or added substances in foods may be carcinogenic, nutritional deficiencies or excesses may promote carcinogenesis. We compared data from blacks and whites using dietary and nutritional status surveys in the United States to determine whether the poorer dietary patterns and nutritional status of American blacks may be associated with their higher incidence and mortality from certain cancers (compared with whites). Our review indicates that blacks eat more nitrate and animal foods and not enough fiber in relation to protein, fat, and carbohydrate. Blacks also have poorer nutritional status with respect to getting enough thiamine, riboflavin, vitamins A and C, and iron, to being obese (females), and to being underweight (males). This is in agreement with hypotheses regarding the interactions between diet and cancer (associations found in whites) and dose‐response relationships reported for some cancers for which blacks have a higher incidence and mortality than whites. More large‐scale prospective case‐control and cohort studies are needed in both blacks and whites to elucidate the contribution of specific dietary and nutritional factors to the risk of specific cancers in these population groups. However, such studies must be preceded by methodological research to obtain more valid measures of dietary and nutritional status.

ISSN:0163-5581    

DOI:10.1080/01635588909513997

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractOncogenic viruses are among the known or presumed initiating agents of human cancer. Although evidence suggests that DNA and RNA oncoviruses may be acquired through multiple routes, our attention focuses chiefly on the ingestion pathway. We have two reasons for this. One is the possibility that viral as well as nonviral oncogenic amino acid sequences might be acquired at the top of the food chain. The other is that the food chain‐infection hypothesis may reconcile several biological, ecological, and epidemiological phenomena. Transfection experiments suggest that the concept of infection may have to be broadened to embrace the cellular precursors of oncogenic viruses. Accumulating circumstantial evidence from viral oncology and molecular biology provides a basis for the belief that oncogenic viruses and their cellular precursors might be transmitted from animals to humans through the ingestion pathway. The possibility that such transmission may give rise to some human cancers must now be considered. The ingestion and genomic integration of food‐associated DNA sequences may directly account for the increased risk of human cancer associated with an elevated intake of animal fat and protein. This paper addresses the role of infective oncogenic agents as the initiators, rather than the promoters, of cancer.

ISSN:0163-5581    

DOI:10.1080/01635588909513998

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractThe limonoids, limonin and nomilin, are bitter principles found in common edible citrus fruits. Nomilin, when given three times (at 5 and 10 mg per animal) every two days, induced increased glutathione S‐transferase activity 2.48 and 3.44 times over the control, respectively, in the liver of female ICR/Ha mice. The increases of GST activity in the small intestinal mucosa were 3.00 and 4.17, respectively, over the control. Limonin, when given at the same dose levels, was not active in the liver. However, marginal activity was obtained in the small intestinal mucosa. Nomilin, which is the more active enzyme inducer, was found to inhibit benzo[a]pyrene (BP)‐induced neoplasia in the forestomach of ICR/Ha mice. The number of mice with tumors was reduced from 100 to 72%, and the number of tumors per mouse was significantly decreased as a result of nomilin treatment. Limonin, which is a weak enzyme inducer, was less potent as an inhibitor of BP‐induced neoplasia. These findings suggest limonoids as a class of regularly consumed natural products may be effective chemopreventive agents.

ISSN:0163-5581    

DOI:10.1080/01635588909513999

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractThe appetite‐stimulating (orexigenic) potential of the peripheral dopamine (DA) receptor antagonist domperidone was compared with that of the central DA antagonist pimozide in anorexic, tumor‐bearing rats. DA antagonists were administered via the intraperitoneal route on Days 7–15 after the subcutaneous implantation of the Walker 256 carcinosarcoma. The doses of domperidone injected were 0.05 and 0.1 mg/kg once daily and 0.1 mg/kg twice daily. The dose of pimozide given was 0.1 mg/kg daily. While all doses of DA antagonists caused an initial drop in body weight and food intake, the body weight of pimozide‐injected animals was not reduced significantly (in the early stages of drug treatment) as it was with the various doses of domperidone. There was significantly more food in the stomachs of domperidone‐and pimozide‐treated animals compared with those of the vehicle‐treated, tumor‐bearing animals at the time of sacrifice. These results indicate that short‐and long‐term satiety factors, in addition to gastric motility, should be considered when assessing the orexigenic potential of various drugs.

ISSN:0163-5581    

DOI:10.1080/01635588909514000

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractDiets low in carotenoids have been associated with greater risks of developing certain cancers. Diets high in fats, especially unsaturated fats, have also been associated with increased risks of developing cancer. This study was undertaken to evaluate the effect of fat type on theß‐carotene status in a rat model. Rats were fed diets containing 2 g/kgß‐carotene or placebo and either 10% lard or corn oil for 13–16 weeks. Plasma vitamin A was unaffected by the dietary regimes. Liver vitamin A levels were significantly increased in theß‐carotene groups and were greater in the lard‐fed animals. No detectable level of plasmaß‐carotene was found in the rats fed placebo diets. In animals given dietaryß‐carotene, plasmaß‐carotene levels were significantly reduced in the group fed corn oil compared to the group fed lard. Liverß‐carotene levels were higher in the groups fed corn oil. The results suggest that the type of dietary fat can significantly affect the circulating and tissue levels ofß‐carotene.

ISSN:0163-5581    

DOI:10.1080/01635588909514001

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractThere is experimental evidence that fish oils protect against mammary carcinogens in animals. However, there has been little investigation of the possible relevance of this finding to breast cancer in humans. We compared breast cancer incidence and mortality rates with estimates of the consumption of fish and other foods and nutrients in the countries for which reliable data are available. The results showed an inverse association between percent calories from fish and breast cancer rates that was consistent with a protective effect. This analysis confirmed the finding of others that dietary fat is strongly associated with international variation in breast cancer rates. It also showed that of the dietary components considered, percent calories from fish was the factor most strongly correlated with breast cancer rates after statistical adjustment for dietary fat intake. This result is therefore in accord with animal experimental data and suggests that the omega‐3 fatty acids contained in certain fish may protect against breast cancer.

ISSN:0163-5581    

DOI:10.1080/01635588909514002

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractThis paper reports the differences in the fecal excretion of cholesterol and its degradation products in high‐and low‐responding rhesus monkeys fed diets with and without extra cholesterol. The high‐responding monkeys had a great increase in plasma cholesterol concentration when fed a high‐cholesterol diet, whereas the low‐responders had a small increase when fed the same diet. The results show that low‐responding monkeys, when fed high‐cholesterol diets, excrete nearly two to three times the amount of cholesterol and its bacterial degradation products in the feces than the high‐responding monkeys. We suggest that these two select groups of monkeys may be useful models for the study of the role cholesterol and its bacterial degradation products play in colon cancer.

ISSN:0163-5581    

DOI:10.1080/01635588909514003

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractThe effects of DL‐α‐tocoperol and DL‐α‐tocopherol succinate on neuroblastoma NIE 115 cells were studied. Tocopherol had no growth‐arresting properties, whereas its succinate ester derivative inhibited growth at concentrations≥20μM. The succinate derivative was taken up somewhat more readily than free tocopherol; however, for any equal uptake of both forms of vitamin E, only the succinate derivative could affect growth. Tocopherol succinate was taken up without marked conversion to tocopherol. Following uptake, plasma membrane and organelle fractions contained most of the vitamin E derivatives; however, the paniculate and membrane fractions were about twice as enriched in the succinate derivative as in free tocopherol. On the other hand, a proportionally higher amount of unconjugated vitamin E was recovered in the cytosol fraction. Fluorescence polarization studies indicated no differences in the overall fluidity of the plasma membranes treated or not treated with either form of vitamin E. The data point to the functionality of the free carboxyl group of the succinate derivative as a basis for the difference in potency of the two forms of vitamin E.

ISSN:0163-5581    

DOI:10.1080/01635588909514004

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractThis study was conducted during the preparation of a case‐control study on patients with adenomatous polyps or cancer of the large bowel. It was done to compare two dietary history methods for assessing individual current dietary intakes. Subjects were interviewed concerning their food consumption by meal in one of the questionnaires and by broad food groups in the other questionnaire. Two groups of 20 volunteers, comparable according to sex and age, were interviewed by a dietitian who used one of the questionnaires. Data on diets obtained with the questionnaire were compared with those of a 14‐day dietary record. The subjects were informed of the importance of the validation procedure. Whatever the type of questionnaire, mean daily intakes of nutrients and foods were rather similar for the questionnaires and for the 14‐day records. Thus, there were more significant correlations between the questionnaire by meal and the record than between the questionnaire by food group and the record. When using tertiles, it appears that the questionnaire by meal was better at classifying individuals with regard to their food intake than the questionnaire by food groups. Although extrapolating these results to a patient population is not straightforward, it seemed likely that interviewing patients on diet without using a pattern of meals would prove even less reliable than for healthy subjects. The questionnaire by meal was preferred to the questionnaire by food groups for the ongoing case‐control study. Further studies are needed to know whether these results could be extrapolated to studies on past diet and to non‐Latin populations.

ISSN:0163-5581    

DOI:10.1080/01635588909514005

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor

摘要:

AbstractThe relationship between selected dietary factors and the risk of bladder cancer was investigated in a case‐control study conducted in northern Italy. The study included 163 cases and 181 controls who were hospitalized for acute, nonneoplastic or urinary tract diseases. The frequency of consumption of green vegetables and carrots was lower in the cases; thus, the estimated relative risks for the upper vs. the lower tertiles were 0.6 for green vegetables and 0.5 for carrots. Significant inverse trends in risk emerged with estimated carotenoid (as well as retinoid) intake. The apparent protection conveyed by vitamin A was stronger in current smokers. The risk of bladder cancer was not related to scores of fat and measures of alcohol consumption; the risk was elevated in coffee drinkers (although there was no tendency to rise with higher consumption), but it was reduced in tea drinkers. These findings were not explainable in terms of selection, information, or confounding bias. Thus, a/though available information is too uncertain for any precise definition of specific (micro)nutrients related to bladder cancer risk, the confirmation that several aspects of a less‐affluent diet adversely affect the risk is still of interest in terms of a better understanding of bladder carcinogenesis.

ISSN:0163-5581    

DOI:10.1080/01635588909514006

出版商:Taylor&Francis Group    

年代:1989

数据来源: Taylor