Showing papers in "Nutrition and Cancer in 1988"

Colorectal cancer and the consumption of foods: A case‐control study in Belgium

Abstract: A case-control study on 453 cases with colon cancer, 365 with rectal cancer, and 2,851 population controls was carried out in two Belgian provinces known to differ in certain dietary habits, particularly with regard to the use of butter. All raw vegetables had a clear protective effect for both colon and rectal cancer; bread was also protective for colon cancer. Starchy foods and foods rich in oligosaccharides (sugar) caused an increased risk for both colon and rectal cancer. No other foods were found to have a systematic effect in both sexes and in both provinces, either in one direction or in the other, except for maize, soybean, and sunflower oils, which were clearly protective in all cases. Among the foods contributing to the intake of fats, there was no effect either for butter, margarine, or fatty meats; the only clear-cut protective effect was that of the oils having a high polyunsaturated-to-saturated ratio. These findings are consistent with our previous findings on the role nutrients play in the relationship with colon and rectal cancers.

Dietary habits and lung cancer risk among Chinese females in Hong Kong who never smoked.

Abstract: This describes a retrospective study in which 88 lung cancer patients and 137 district‐matched controls were interviewed concerning the effects of diet on lung cancer risk among Hong Kong Chinese women who never smoked tobacco. Those in the lowest fertile of consuming fresh fruit or fresh fish had statistically significant adjusted relative risks (RRs) of 2.4 and 2.8, respectively. The protective effects of diet, i.e., higher consumption of leafy green vegetables, carrots, tofu, fresh fruit, and fresh fish, were confined mostly to those with adenocarcinoma or large cell tumors. Only fresh fruit was found to positively, and smoked meats to negatively, affect the risk of squamous or small cell tumors. Foods high in vitamin C, retinol, and calcium seemed to exert larger effects. Subjects from larger households were shown to be more frequent consumers of fresh vegetables, fruit, and fish. Because the lifetime weighted household size could be used as a surrogate index of past dietary quality, when it ...

Prevention of experimental oral cancer by extracts of Spirulina‐Dunaliella algae

Abstract: An extract of Spirulina-Dunaliella algae was shown to prevent tumor development in hamster buccal pouch when a 0.1% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil was applied topically three times weekly for 28 weeks. The algae extract was delivered by mouth in continued dosages of 140 micrograms in 0.4 ml mineral oil three times per week. After 28 weeks, the animals given vehicle and untreated controls all presented gross tumors of the right buccal pouch. Animals fed canthaxanthin presented a notably and statistically significant reduction in tumor number and size compared with controls. Animals fed beta-carotene demonstrated a smaller but statistically significant reduction in tumor number and size. The algae animals presented a complete absence of gross tumors. However, microscopic sections of the buccal pouch in the algae group showed localized areas of dysplasia and early carcinoma-in-situ undergoing destruction.

Calcium and colon cancer: a review.

Abstract: The role of dietary calcium as a protective factor in the etiology of colon cancer is reviewed by examining data from ecological and analytical epidemiological studies. Biological evidence that explains the mechanisms whereby calcium intake could alter risk of developing colon cancer is also presented. The data reviewed here in general support the hypothesis that dietary calcium is linked to colon cancer in a protective manner, and that it may be one component in the etiology of colon cancer which alters an individual's risk of developing the disease.

The safety of β-carotene

Abstract: Epidemiological studies have associated low dietary and/or plasma level of carotenoids with higher incidences of certain cancers. This evidence has led the National Cancer Institute to initiate more than a dozen prospective clinical trials in which supplements of beta-carotene alone, or in combination with other micronutrients, are being taken. In these trials, the beta-carotene supplements are given in the range of 15-50 mg/day. The safety of this level of intake is well documented. beta-Carotene has been successfully used to treat inherited photosensitivity diseases for more than 15 years at dosages of 180 mg/day or more, without any adverse effects other than hypercarotenemia. Toxicity studies in animals have shown that beta-carotene is not carcinogenic, mutagenic, embryotoxic, or teratogenic and does not cause hypervitaminosis A. In the few isolated reports of carotenoid-related toxicity, the findings are associated with very large intakes of foods containing beta-carotene, among other constituents, and have not been substantiated in individuals who have taken high doses of beta-carotene for several years.

The problem of profound mismeasurement and the power of epidemiological studies of diet and cancer.

Abstract: Ecological associations of fat intake with breast cancer incidence have not, in general, been corroborated by individual‐based epidemiological studies. Profound mismeasurement, which, in these studies, probably typifies measures of dietary exposures in general and of fat in particular may, in part, explain this lack of agreement. To demonstrate the way in which error masks effects, we studied the impact of extreme mismeasurement in analysis of strong or moderate underlying associations using computer‐simulated, case‐control studies (300 cases, 300 controls). Severe error causes the mean and median odds ratios to be biased toward unity, tests for trend and upper category odds ratios to be often not significant, and lower category odds ratios frequently to exceed higher exposure ones. Important risk relationships can be concealed, despite careful design and analysis if there is substantial mismeasurement of exposure.

Response to a diet low in total fat in women with postmenopausal breast cancer: a pilot study.

Abstract: A feasibility study was instituted to determine if women with postmenopausal breast cancer would follow a low‐fat diet (20% of kcal) for at least four months. Nineteen women, whose baseline food intake was 1,504 ± 420 kcal with 56 ± 16 g of fat, reported a decrease in fat intake to 21 ± 6 g after two months of dietary intervention. Serum concentrations of cholesterol, HDL cholesterol, and estradiol were significantly reduced by the fifth month on the diet. We conclude that self‐selected patients can adhere to a low‐fat diet, and that serum cholesterol may serve as an indicator of dietary compliance.

Regression of experimental oral carcinomas by local injection of β‐carotene and canthaxanthin

Abstract: Regression of 7,12-dimethylbenz[a]anthracene (DMBA)-induced epidermoid carcinomas of hamster buccal pouch was accomplished by local injections of beta-carotene and canthaxanthin. One-hundred male hamsters (2-3 months old) were divided into five groups of 20 animals. All animals had the right buccal pouches painted three times weekly for 14 weeks with a 0.5% solution of DMBA in mineral oil, at which time all animals exhibited gross tumors of variable size and number. Group 1 animals were then injected locally into the right buccal pouch twice weekly for 4 weeks with 250 micrograms-carotene in 0.1 ml minimal essential medium (MEM) per injection. Group 2 animals were similarly injected with 250 micrograms canthaxanthin in 0.1 ml MEM. Group 3 animals were similarly injected with 250 micrograms 13-cis-retinoic acid in 0.1 ml MEM. Group 4 animals were injected only with MEM; Group 5 animals were untreated controls. Animals were killed in a carbon dioxide chamber, and buccal pouches were photographed. Tumors were counted and measured. Tumor burden in each group was compared, and statistical significance between groups was recorded. beta-Carotene was more effective than canthaxanthin in tumor regression. 13-cis-Retinoic acid had no effect in this system.

Salt and gastrointestinal cancer.

Abstract: This study reports on the taste for salt among patients with gastric, colon, or rectal cancers and among population controls, within the scope of an investigation on those cancers in two Belgian provinces. Among people who systematically added salt to their food, the relative risks observed were as follows: 1.78 for gastric cancer, 1.53 for colon cancer, and 1.74 for rectal cancer. Even though all three were statistically significant, these increases are moderate and may be due to interaction with other, as yet unknown causal factors.

Cytotoxicity of extracts of spices to cultured cells

Abstract: The cytotoxicity of the extracts from eight different spices used in the Indian diet was determined using Dalton's lymphoma ascites tumor cells and human lymphocytes in vitro and Chinese Hamster Ovary cells and Vero cells in tissue culture. Alcoholic extracts of the spices were found to be more cytotoxic to these cells than their aqueous extracts. Alcoholic extracts of several spices inhibited cell growth at concentrations of 0.2-1 mg/ml in vitro and 0.12-0.3 mg/ml in tissue culture. Ginger, pippali (native to India; also called dried catkins), pepper, and garlic showed the highest activity followed by asafetida, mustard, and horse-gram (native to India). These extracts also inhibited the thymidine uptake into DNA.

A comparison of dietary fish oil and corn oil in experimental colorectal carcinogenesis

Abstract: Rats fed either fish oil (n = 16) or corn oil (n = 16) in calorically and nutritionally balanced diets were injected with 1,2-dimethylhydrazine, which is a colorectal specific carcinogen; differential colorectal tumor induction was then measured. In addition, plasma peroxide concentrations were measured in rats in each dietary group as well as in a group receiving a low-fat diet, either with or without prior carcinogen treatment (n = 3 for each of the 6 groups). Tumor incidence did not differ between groups fed corn oil and fish oil. Tumor yield in the left colon was significantly lower in rats fed fish oil (p = 0.0499). Total colorectal tumors induced were also fewer in the rats fed fish oil (p = 0.065). Plasma peroxide concentrations were difficult to interpret because of the wide variation within groups. The data on tumor yield in the left colon support the hypothesis that a diet rich in n-3 fatty acids, which are found in fish oil, may be less supportive of colorectal tumor development than a diet rich in n-6 fatty acids, which is found in corn oil. However, the mechanism by which fish oil decreases tumor induction is still unknown.

Enhancement of BOP-induced pancreatic carcinogenesis in selenium-fed Syrian golden hamsters under specific dietary conditions.

Abstract: We measured the effects of dietary selenium (Se) on pancreatic cancer induced in Syrian golden hamsters by N-nitrosobis(2-oxopropyl)amine (BOP). The animals were fed six experimental diets that contained different combinations of the following: 0.1, 2.5, or 5.0 ppm Se from sodium selenite or 2.5 ppm Se from D,L-selenomethionine in either a low (6.0%)- or high (24.4%)-fat diet. Se treatment was begun four weeks before BOP treatment, and the high-fat diet was fed from one week after the last BOP treatment. No evidence for inhibition of pancreatic cancer by Se was observed; in fact, with some experimental conditions, high-Se diets increased the pancreatic carcinoma yield. However, the dietary conditions needed for enhancement differed between the sexes. The male hamsters that received the high-fat diet containing 2.5 ppm Se had more carcinomas than did males given the 0.1 ppm Se level. Carcinoma yields in females did not differ between these diets. Females that received 2.5 ppm Se from D,L-selenomethionine had a greater pancreatic carcinoma yield that did those given 0.1 ppm Se diet. However, carcinoma yields did not differ in males fed these diets. Acinar cell nodule yields were generally reduced in hamsters given the high-Se diets, especially when Se levels in the high-fat diets were compared. Prefeeding 0.1 or 2.5 ppm Se did not influence the elution constants of pancreatic DNA from ductal cells, indicating no effect of Se on the repair of BOP-induced, single-strand breaks in DNA from these cells. Measurements in acinar cells suggested a more rapid repair of single-strand breaks in hamsters prefed 2.5 ppm Se than in those prefed 0.1 ppm Se.

The relative validity of a retrospective estimate of food consumption based on a current dietary history and a food frequency list

Abstract: The relative validity of information and food consumption in the distant past was assessed by combining a dietary history (referring to the recent past) with a food frequency list (monitoring major changes over the past 12–14 years). This approach was evaluated in a study of two groups of apparently healthy elderly people (mean age 80 years) who had participated in a food consumption study 12–14 years before the start of the present study. One group consisted of 18 harbor employees who retired subsequent to the initial assessment of food intake. On the average, each member of this group had reduced his food consumption by about 1,000 kcal. The other group consisted of 46 elderly men and women who had retired before their food consumption was measured initially. This group had not markedly changed their food intake. The results showed that both groups overestimated changes in their food intake and that the systematic overestimation and random error were similar for both groups. If the men in both ...

Mortality among German vegetarians: first results after five years of follow-up.

Abstract: A prospective study of vegetarians recruited from all regions of the Federal Republic of Germany, including West Berlin, was started in 1978 after a preparatory phase of two years in which the cohort was established. The mortality of the 1,904 study participants was evaluated after a follow‐up of five years, comparing observed deaths with expected rates based on the national mortality statistics. Of the 858 men and 1,046 women, 89% had followed their diet for at least five years at study entry, the majority of them as strict vegetarians (1,163). By the end of 1983, only 82 persons had died, whereas 219 deaths were expected. In both sexes, the mortality was lowest from cardiovascular diseases [standardized mortality ratio (SMR)for ischemic heart disease about 20] and from cancer (SMR 58 for men, 54 for women). Deaths from diseases of the respiratory and digestive system were also reduced. For individual cancer sites the observed numbers were extremely small, but the risk of dying from lung cancer ...

Dietary factors affecting the proliferation of epithelial cells in the mouse colon

Abstract: Corn oil (CO), given as a bolus to female C57BL/6J mice, caused a marked increase in cell proliferation in the colon; this was assessed with a two‐hour colchicine arrest for mitotic figures (MF) and with [3H]thymidine incorporation for labeled cells (LC) per crypt measured in histological preparations. In contrast, the same amount of fat given as a bolus in a high‐fat diet mixture failed to increase cell proliferation. To determine whether a particular component in the diet was responsible for this protective effect, mice were treated with boluses of CO (0.4 ml) mixed with cellulose (CL), starch (ST), sucrose (SU), casein (CS), vitamin mix (VM) or mineral mix (MM). The results indicated that cellulose, starch, and minerals reduced the proliferative activity caused by CO (MF/crypt CO = 1.30 ± 0.24; CO + CL = 0.55 ± 0.70, CO+ST = 0.91 ± 0.23, CO+MM = 0.63 ± 0.16), whereas sucrose, casein, and vitamin mix did not. To test the implications of these findings in chronic feeding studies, groups of anima...

The relationship between dietary fat, adipose tissue composition, and neoplasms of the breast.

Abstract: Dietary fat has been implicated in the development of carcinoma of the breast. Because of the difficulties in obtaining accurate dietary histories, we analyzed subcutaneous adipose fatty acids to compare the quality of fat intake in three groups of patients undergoing investigations for breast masses. These included carcinoma (n = 37, avg. age 54 yrs.), fibroadenoma (n = 27, age 31 yrs.), and other types (n = 21, age 50 yrs.). Subjects in the carcinoma group were heavier, although they were not obese. A one‐way analysis of variance of nine adipose fatty acids and their derived ratios fpolysaturates:saturates (P:S)J did not show any systematic differences in the three groups. The quality of dietary fat does not appear to be associated with the development of neoplasia of the breast in this population, which consumes a diet of a high P:S ratio.

Effects of excess vitamin A and canthaxanthin on salivary gland tumors.

Abstract: The effects of feeding semipurified diets supplemented with excess retinyl palmitate (20,000 and 100,000 IU/kg), β‐carotene (250 mg/kg), and canthaxanthin (250 mg/kg) on 7,12‐dimethylbenz[a]anthracene (DMBA)‐induced salivary gland tumors were studied in rats. None of the dietary supplements had a significant effect on tumor incidence. Tumor weights, however, tended to be lower in rats fed the dietary supplements compared with the controls. The incidence of tumor‐bearing rats with large tumors was significantly lower in rats fed canthaxanthin than in the control rats. At termination of the experiment, the levels of vitamin A were higher in plasma, liver, normal salivary glands, and the tumor of rats fed diets supplemented with the higher level of retinyl palmitate. Feeding the canthaxanthin‐supplemented diet had the opposite effect on tissue and plasma vitamin A levels. β‐Carotene supplementation was associated with higher vitamin A concentrations in the liver but not in plasma, salivary glands, o...

Cooking methods, carcinogens, and diet-cancer studies.

Abstract: A neglect of natural, preservative, and cooking‐induced carcinogens or mutagens in food, along with a neglect of dietary patterns during the first portion of a person's lifetime, may be responsible for the many conflicting epidemiological reports dealing with dietary factors and cancer. From animal and occupational studies, we know that the two most important factors in the study of cancer are the dose of carcinogen and allowance for a long latent period. Most of the recent nutrition and cancer studies have ignored both factors. Some bile acids or other endogenous factors may be influenced by diet and may act as cancer‐promoting agents, but promoting agents cannot be studied in the absence of knowledge about, or control of, the cancer‐initiating events with which they must interact.

The binding of blood-borne estrogens in normal vegetarian and omnivorous women and the risk of breast cancer.

Abstract: Serial blood samples were taken at two‐hour intervals over a 24‐hour period from 25 premenopausal vegetarians (12 vegans and 13 ovolactovegetarians) and from 21 omnivorous controls. All members of the former group had been on a vegetarian diet for a minimum of three years. The mean proportion of estradiol unbound to blood proteins was similar in both vegetarians (1.26%) and meat eaters (1.16%). However, the amount bound to albumin was significantly raised in vegetarians (50.1% vs. 43.1%, p < 0.009), whereas that bound to sex hormone‐binding globulin (SHBG) was correspondingly lower (48.7% vs. 55.8%, p = 0.01). Mean levels of SHBG were similar in vegetarians (59.9 nmole/l) and omnivores (62.0 nmole/l), as was the total amount of free fatty acid (0.42 mmole/l for both). Within the vegetarian group, no differences were detected between vegans and ovolactovegetarians.

Antitumor activity of sodium linoleate

Abstract: To identify the components in a microsomal fraction from the small intestinal mucosa of mice that were responsible for preventing the proliferation of Ehrlich ascites tumor (EA T) cells, we subjected the fraction to thin‐layer and gas chromatography. Assays for cytotoxicity against EAT cells in vitro indicated that linoleic acid, which was present in the free fatty acid fraction at a surprisingly high concentration, was probably the major component responsible for the antitumor activity. In further assays, using the water‐soluble salt sodium linoleate, we found that sodium linoleate was more effective in vitro in killing human chronic lymphocytic leukemia lymphocytes than normal lymphocytes and mouse leukemic thymocytes than normal thymocytes. We also found that a single intraperitoneal injection of 1 mg of sodium linoleate into Swiss‐Webster mice one day after the mice were inoculated with EAT cells increased the median survival from 18 (in the controls) to 48 days (in the treated mice) and prev...

Effects of dietary fat on long‐term growth and mammary Tumorigenesis in female Sprague‐Dawley rats given a low dose of DMBA

Abstract: The effects of dietary fat on experimental mammary cancer have typically been observed in relatively young animals. However, in human populations, breast cancer incidence and mortality are highest in postmenopausal women. To develop an animal model that simulates the human situation more closely, female Sprague‐Dawley rats were given a relatively small dose (1.5 mg) of 7,12‐dimethylbenzfa]anthracene (DMBA) at SO days of age while on a semipurified diet containing 3% sunflower‐seed oil. One week later, half of the 70 rats were transferred to a diet containing 20% sunflower‐seed oil. Very few mammary lesions appeared until about 35 weeks after administration of DMBA, at which time palpable mammary nodules began to appear in many of the animals on the high‐fat diet. More than half of the animals in this group had developed nodules by Week 41, whereas the other half of the animals on the low‐fat diet developed nodules by Week 46. Rats on the high‐fat diet gradually became much more obese than those o...

Diet, serum, breast fluid growth hormone, and prolactin levels in normal premenopausal Finnish and American women.

Abstract: A food frequency questionnaire was used to estimate and compare the dietary fat and fiber consumption of 94 premenopausal women in Kuopio (rural Finland, where there is a relatively low risk of breast cancer) and 61 American women in New York (where there is a high risk of breast cancer). In keeping with previous reports concerning middle-aged men, both groups had high fat intakes, but the Finnish women had considerably higher fiber intakes (24 +/- 11 vs. 16 +/- 6 g). Serum and breast fluid growth hormone and prolactin levels were compared in 29 of these American women and 24 of the Finnish women. All were healthy and had regular menstrual cycles. Serum growth hormone levels, which were measured by radioimmunoassay, were higher in the Finnish women; all but three of their breast fluids contained detectable growth hormone, frequently at extremely high concentration. In contrast, only 2 of the 29 breast fluids from American women had detectable amounts of growth hormone. Of the Finnish samples, 10 were also measured by an immunoradiometric assay with high specificity for the 22,000-dalton growth hormone molecule; all but 3 had values less than 3.0 ng/ml. Serum and breast fluid prolactin concentrations, which were determined by radioimmunoassay, were no different in the two groups; both groups frequently had considerably higher levels in breast fluid compared with the corresponding serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Malignant neoplasms of the stomach and the quality of drinking water

Abstract: This paper evaluates the influence of the quality of drinking water on the incidence of malignant stomach cancer. Both the author's own data and the data collected from published papers are used in this evaluation. The conclusion is that the quality of drinking water can have some influence on the frequency of stomach cancer incidence, especially among the population of autochthons (who have been using such water for a long time). However, taking into consideration all papers quoted here, it seems that there are also various other factors which can influence the incidence of stomach cancer.

The induction of neoplastic lesions by aflatoxin-B1 in the Egyptian toad (Bufo regularis).

Abstract: The carcinogenic activity of aflatoxin‐B1, the metabolic product of the mold Aspergillus flavus (a commonly occurring contaminant of groundnuts and other foodstuffs), was tested using the Egyptian toad (Bufo regularis). Injecting the toads with aflatoxin‐B1 at a dose level of 0.01 mg/50 g body wt in 1 ml corn oil once a week for 15 weeks induced hepatocellular carcinomas in 19% of the experimental toads. Four toads developed tumors in the kidney due to metastases from the primary hepatocellular carcinomas.

The effects of a "low-risk" diet on tumor incidence in chemically induced colon cancer in rats.

Abstract: The relationship between various dietary constituents and colon cancer has been demonstrated by previous research We conducted a study to investigate the combined effects of several dietary constituents on intestinal tumor incidence in azoxymethane (AOM)-induced colon cancer in rats A nutritionally adequate, "low-risk" (LR) diet was formulated through nonextreme dietary manipulations of dietary fat, fiber, protein, vitamins A and E, and selenium Seventy-two female F344 weanling rats were given three weekly subcutaneous injections of either AOM or physiological saline solution, and were maintained on either the LR or a "high-risk" (HR) diet Food consumption and body weights were monitored on a weekly basis throughout the study Tumor incidence was determined 36 weeks following the first injection of AOM The incidence of adenocarcinomas in the LR diet group was 42% compared with 292% in the HR diet group There were no significant differences in the incidence of small intestinal tumors or in the incidence of benign polyps between the diet groups The results of the study indicated a significant protective effect of the various chemopreventive dietary factors when combined in an LR diet for colon cancer

Correspondence Between Perceptions of Change in Diet and 15‐year change in diet reports in the Tecumseh diet methodology study

Abstract: As part of an effort to assess the most reliable method of obtaining information about long‐term dietary intake, a study was conducted of the correspondence between perception of change in diet and measured change in reported diet from 1967 to 1982. Respondents were 1,201 men and women participants in the Tecumseh Food Frequency Study of 1967–1969 who were 45–64 years of age in 1982–1983, the time of the Diet Methodology Study. Perceptions of change were obtained by asking respondents directly if they thought they currently ate each of 12 food groups more often, less often, or as often as they did during the year of their earlier interview. Measured change was obtained by subtracting each respondent's baseline frequency for each of the 12 food groups from his or her current frequency. For 10 of the 12 food groups, correspondence was found between perception of change and measured change; fats and oils added at the table and meat were the exceptions. Significant linear relationships were found bet...

Leucocyte zinc in non-Hodgkin's lymphoma and Hodgkin's disease.

Abstract: Zinc status and the effect of zinc supplementation were assessed in groups of patients with non-Hodgkin's lymphoma and Hodgkin's disease; patients were either untreated or in remission. In the patients in remission, plasma zinc was normal; and whereas 30% of untreated patients had low plasma zinc, the group as a whole did not differ from normal. For mononuclear cell zinc, the range of values in the disease group was far wider than in controls, but there was no significant difference between the means of the groups. Granulocyte zinc was significantly lower in both the groups of patients in remission from non-Hodgkin's lymphoma and Hodgkin's disease compared with the control group. Significant increases were found in the plasma copper, ceruloplasmin, and the copper-to-zinc ratio in several of the patient groups. Plasma zinc increased by 23% with zinc supplementation (50 mg elemental Zn/day), but there was no effect on mononuclear cell or granulocyte zinc. Apart from granulocyte zinc, there is little evidence of zinc deficiency in non-Hodgkin's lymphoma or Hodgkin's disease. However, the presence of depleted granulocyte zinc levels could modify the immune function of this cell population.