Rachel Schemmel

Dietary fish oil inhibits human breast carcinoma growth: A function of increased lipid peroxidation

Female athymic nude mice were implanted subcutaneously with human breast carcinoma MDA-MB231. Seven to ten days later, the mice were divided into groups and fed a purified diet containing the following types of fat (% of diet):(i) 20% corn oil (CO); (ii) 15% CO:5% fish (menhaden) oil (FO); (iii) 10% CO:10% FO; (iv) 5% CO:15% FO; (v) 1% CO:19% FO; and (vi) 1% CO:19% FO plus antioxidants (α-tocopherol acetate, 2000 IU/kg diet and tertiary butyl-hydroquinone, 2% of the total fat). The linoleic acid levels (% of diet) of the groups were 12.0, 9.1, 6.2, 3.3, 0.9 and 0.9%, respectively. After 6–8 wk, the carcinomas were assessed for tumor volume (cm3) and assayed for thiobarbituric acid reactive substances (TBARS). Human breast carcinoma growth was suppressed in mice consuming FO diets without antioxidants as compared to mice fed CO; the greater the amount of dietary FO fed, the greater the carcinoma growth suppression (P<0.05). The addition of antioxidants to the FO diet significantly (P<0.05) reversed the FO-induced carcinoma growth suppression. Concentrations of TBARS in the human breast carcinomas were increased in all the FO (without antioxidants) fed mice, compared to mice fed CO; the level of increase in TBARS was directly related to the increase in the level of FO fed (P<0.05). The addition of antioxidants to the FO diet significantly (P<0.05) reduced the concentration of TBARS in the breast carcinomas. Thus, these results provide evidence that dietary FO can significantly suppress growth of human breast carcinoma MDA-MB231, even in the presence of substantial amounts of linoleic acid (3.3–9.1%). The inhibitory effect of FO on growth of these carcinomas was associated with an increased concentration of TBARS in the tumor tissue. In conclusion, dietary FO induced suppression of human breast carcinoma growth is a function, at least in part, of an accumulation of lipid peroxidation products in the tumor tissues.

What do college students eat? Food selection and meal pattern

Abstract Data are limited on food selections of young adults. This study was undertaken to examine the eating practices of college students relevant to improving nutrition and health education programs. Dietary records (n=1912) were used to determine the frequency of meals skipped and specific foods selected by male and female students in different seasons between Fall 1990 and Summer 1991. Twenty-two percent, 8%, and 5% of the students skipped breakfast, lunch, and dinner, respectively; 80% of the students snacked at least once a day. There were no significant differences in frequency of meals skipped and snacks consumed among seasons, or between men and women. Forty foods consumed most frequently for meals and snacks included various carbonated beverages but few vegetables and fruits. Skimmed milk, 2% milk and chicken or turkey were among the top 40 foods selected by both genders whereas whole milk and higher-fat meats were not. Men consumed more high calorie and high fat foods, more fast foods but fewer vegetables than women. These findings suggest that health promotion for young adults in college should address importance of eating vegetables and fruits with less frequent consumption of carbonated beverages and high fat combination dishes. The message for men may need to differ for women.

Blood pressure of rats as affected by diet and concentration of NaCl in drinking water.

Summary In the first experiment, weanling rats were fed a grain ration or one of three semipurified diets high in fat, sucrose, or cornstarch. Rats in each dietary group were divided into two subgroups, one of which drank distilled deionized water whereas the other group drank 2% NaCl solution. Blood pressure and sodium intake were individually measured for each rat at weekly intervals for a 10-week period. Rats receiving the salt solution had higher mean blood pressures (127-178 mmHg) than rats offered distilled water (108-127 mmHg). When drinking solutions were the same, more severe rises in blood pressure occurred in rats fed the semipurified diets than in those rats fed grain. In a second experiment, rats were fed one of the four diets used in the first experiment; however, they received a 1% NaCl drinking solution for 9 weeks followed by a 1.5% NaCl solution for an additional 9 weeks. At Week 18, pressures among these groups of rats ranged from 136-140 mmHg, regardless of diet.

Fat depot removal, food intake, body, fat, and fat depot weights in obese rats.

Summary Weanling Osborne Mendel male rats had one or both inguinal fat depots, or one or both testicular fat depots removed. Another group was subjected to an identical operation but the fat pads were not excised (sham operated). Postsurgically, the rats were fed a high fat diet with progressive obesity developing during the 32 weeks of the experiment. Mean food intakes, growth rates and percentage of body fat (36 to 41%) were similar for all groups of rats. The surgically removed fat depots did not regenerate. In the group with the inguinal fat depots removed there was a visible depression at the surgical site due to the absence of the fat pad. Abdominal fat depots shifted to compensate for the removed testicular depots with no disfiguration apparent in the live rat. At autopsy, fat depots such as interscapular, axillary, perirenal and retroperitoneal, omental and mesenteric, and xiphoid weighed the same in operated and sham-operated rats.

Effects of Diet, Age, Strain and Anatomical Site on Fat Depot Triglyceride and Fatty Acid Content in Rats

Summary OM rats fed a high fat ration were heavier, fatter and had fat depots which weighed at least three times as much as those fed a low fat (grain) ration. S rats fed a high fat ration showed a slight increase in fat depot weights and no increase in body weight or fat when compared to rats of the same strain fed grain. For both strains of rats fed either diet for 4, 10 or 20 wk following weaning, there was a lower percentage of TG in the inguinal depot than in the epididymal or perirenal-retroperitoneal fat depots. There was a tendency for rats fed a high fat ration to have a higher percentage of TG in adipose tissues than rats fed grain, but the differences were not significant as long as age, anatomical site and strain were constant. Strain and age had no significant effect on the percentage of TG in fat depots. The fatty acid composition of the fat depots was effected by ration, but not by age, strain or anatomical site of the fat depot. The authors wish to thank Janet Grommet, Hisako Iiado and Ellen Rand for technical assistance.

Dieldrin Storage of Obese, Normal, and Semistarved Rats

Dieldrin tissue levels in obese and “normal” weight adult male Osborne Mendel rats that had been on weight maintenance or weight reduction diets were compared with levels immediately after dieldrin feeding. Normal weight animals exhibited higher tissue pesticide reductions while very little of the body burden of dieldrin was lost in obese rats. Neither group exhibited any elevation of dieldrin levels in the brain because of tissue mobilization.

Influence of dietary disaccharides on mouth microorganisms and experimental dental caries in rats

Osborne-Mendel rats were inoculated with Streptococcus mutans at weaning, divided into 5 groups and fed cariogenic diets containing 56 per cent sugar either as sucrose, maltose, lactose or combinations of sucrose/maltose and sucrose/lactose. The number of Strep. mutans on molar teeth of rats fed the diet high in maltose was much lower than for any other group of rats (p less than 0.01). Although Strep. mutans levels were low for rats fed maltose, the incidence of carious lesions was similar to rats fed sucrose when the textures of the two sugars were similar. Although maltose does not support plaque formation, it is a fermentable carbohydrate which can provide, if microorganisms are present, an environment conducive to dental decay. The incidence of carious lesions was highest among rats fed lactose.

Moderate exercise in young female S5B/P1 rats does not reduce body fat.

Weanling S5B/P1 female rats were divided into four groups as follows: high fat diet, exercised (FE); high fat diet, unexercised (FU); high carbohydrate diet, exercised (CE); and high carbohydrate diet, unexercised (CU). After 25 days of progressive training, exercised rats ran on a motor-driven treadmill for 30 days at 25 m/min per 1 h at 0 degree grade for 6 days a week. Rats were weighed weekly throughout the experiment and food intakes were recorded for the last 3 weeks of the experiment. After euthanasia at 15 weeks of age, three muscles, liver, heart, kidney, 3 fat depots, and tibia-fibula were dissected out and weighted. The carcass, including weighted organs and fat depots, was analyzed for body fat. Exercised rats, regardless of diet, weighed slightly but significantly more than unexercised rats. They also tended to eat more food and to have a higher quantity of fat-free body mass than unexercised rats. Percent body fat was similar for exercised and unexercised rats. The tibia weighed significantly more (p less than 0.05) in CU than in FU rats but the weight was similar in CE and FE rats. The density of the tibia was significantly higher (p less than 0.01) in exercised than in unexercised rats.

Voluntary running in male S5B/PlRas rats fed high fat or high carbohydrate diets

Nineteen week-old male S5B/P1Ras (S5B) rats were randomly assigned to one of 4 groups as follows: (a) activity wheel access (running)/high fat diet (RF); (b) no activity wheel access (non-running)/high fat diet (NRF); (c) activity wheel access (running)/high carbohydrate diet (RC); and (d) no activity wheel access (non-running)/high carbohydrate diet (NRC) for the seven weeks duration of the experiment. Throughout the 7 wk of the experiment, rats ran more during subsequent weeks than they did the previous week. RC rats ran more than RF rats as measured by the running slopes. All groups of rats lost weight at the initiation of the experiment but significantly more weight was lost by running rats than their nonrunning counterparts. The inguinal, epididymal and perirenal/retroperitoneal (P/R) fat depots weighed significantly less in the running than in the nonrunning groups. From among the 3 fat depots, the difference was greatest in the P/R depot. There were no diet or voluntary activity effects on plasma corticosterone concentrations except at week 2 when running rats had higher concentrations than nonrunning rats.

Anticariogenicity of dietary glycerol monolaurin in rats.

Compared to rats inoculated with Streptococcus mutans , non-inoculated rats did not have any buccal/lingual caries and S. mutans in the oral cavity. However, sulca