A high protein moderate carbohydrate diet fed at discrete meals reduces early progression of N-methyl-N-nitrosourea-induced breast tumorigenesis in rats

Abstract

Breast cancer is the most prevalent cancer in American women. Dietary factors are thought to have a strong influence on breast cancer incidence. This study utilized a meal-feeding protocol with female Sprague-Dawley rats to evaluate effects of two ratios of carbohydrate:protein on promotion and early progression of breast tissue carcinomas. Mammary tumors were induced by N-methyl-N-nitrosourea (MNU) at 52 d of age. Post-induction, animals were assigned to consume either a low protein high carbohydrate diet (LPHC; 15% and 60% of energy, respectively) or a high protein moderate carbohydrate diet (HPMC; 35% and 40% of energy, respectively) for 10 wk. Animals were fed 3 meals/day to mimic human absorption and metabolism patterns. The rate of palpable tumor incidence was reduced in HPMC relative to LPHC (12.9 ± 1.4%/wk vs. 18.2 ± 1.3%/wk). At 3 wk, post-prandial serum insulin was larger in the LPHC relative to HPMC (+136.4 ± 33.1 pmol/L vs. +38.1 ± 23.4 pmol/L), while at 10 wk there was a trend for post-prandial IGF-I to be increased in HPMC (P = 0.055). There were no differences in tumor latency, tumor surface area, or cumulative tumor mass between diet groups. The present study provides evidence that reducing the dietary carbohydrate:protein ratio attenuates the development of mammary tumors. These findings are consistent with reduced post-prandial insulin release potentially diminishing the proliferative environment required for breast cancer tumors to progress.

Effects of a fixed-intensity of endurance training and pistacia atlantica supplementation on ATP-binding cassette G4 expression

“…Exercise training along with a high dose of Baneh extract may provide a similar circumstance as high fat or athrogenic with endurance exercise training could do which has been use as a tool in some researches [23-26]. It is believed that macrophage-to-feces reverse cholesterol transport (RCT) is reflecting completed RCT [27], but it has no much significant impact on whole RCT which is completed by liver and small intestine on RCT and HDL biogenesis [27]. In this regards, Meissner et al .…”

“…In this regards, Meissner et al . [27] showed that the voluntary exercise (10.2 ± 2.2 km, average speed: 1.78 ± 0.18 km/h) did not change plasma lipoprotein levels in vivo but changed the cholesterol efflux in running rats in vitro , and macrophage-to-feces RCT and the levels of ABCG5/ABCG8 gene expression remained unchanged. A high dose of Baneh extract was chosen because our GC-MS data analysis of Pistacia atlantica (Baneh) extract revealed that the percentage of trans isomer of oleic acid (elaidic acid) was higher than cis-isomer of oleic acid, similar to those reported elsewhere [28-30].…”

“…[36] reported that silymarin has a positive feedback on ABC Transporters. On the other hand, exercise training as a metabolic stressor, particularly at low to moderate intensities even with a high-fat diet can increase fat oxidation and thereby spare muscle glycogen [23-27]. The responses of some of the ABC subfamily members such as ABCA1, ABCG1, and ABCG5/ABCG8 to acute and chronic exercise training have been investigated [20,37-42].…”

Nutrition Support To Patients Undergoing Gastrointestinal Surgery

“…Once a cell became malignant, high insulin and IGF1 levels might accelerate proliferation and progression towards a more aggressive, glycolytic phenotype. In rats treated with the carcinogen N-methyl-Nnitrosourea, it has been shown that lowering the CHO content of the diet from 60 E% to 40 E% with a simultaneous increase in protein was sufficient to lower postprandial insulin levels as well as decrease the appearance rate of tumors from (18.2 ± 1.3)%/wk to (12.9 ± 1.4)%/wk (p < 0.05), however with no statistically significant effect on tumor latency and weight measured after 10 wk [143]. Similarly, a recent study reported that NOP mice, which normally have a 70 -80% chance of developing breast cancer over their lifetime due to genetic mutations, stayed tumor-free at 1 year of age when their calories from CHO were limited to 15%, while almost half of those on a 55% CHO diet developed tumors [131].…”

Breast tumors induced by N-methyl-N-nitrosourea are damaging to bone strength, structure, and mineralization in the absence of metastasis in rats

“…(9,14) This study was designed to test multiple hypotheses, including the influence of dietary protein level on MNU-induced tumor incidence and progression. (15) Accordingly, animals were randomly assigned to one of two modified AIN-93 semipurified diets (16) designed to be equal in all regards except for the ratio of protein to carbohydrate (using a substitution of casein for starch). Additional information on these diets may be found in the supplemental material.…”