Hughes J S, Ganthavorn C, Wilson-Sanders S
Food and Nutrition Science Program, Health, Physical Education, Exercise Science and Nutrition, Northern Arizona University, Flagstaff, AZ 86011-5095, USA.
J Nutr. 1997 Dec;127(12):2328-33. doi: 10.1093/jn/127.12.2328.
Epidemiological studies show a low incidence of colon cancer in many Latin American countries where the consumption of dry beans (e.g., pinto) is high. The purpose of this study was to use rats as an animal model to obtain experimental data on the inhibition of colon carcinogenesis by dry beans. Fifty-three 5-wk-old weanling male F344 rats were randomly assigned by weight to the following groups: control (11 rats), casein diet (21 rats), and bean diet (21 rats). Animals fed the casein and bean diets were treated with the carcinogen azoxymethane (AOM) once weekly for 2 wk. Rats in the control group also consumed the casein diet but were not exposed to AOM. All diets were isocaloric. The protein concentration of the diets was adjusted to 18 g/100 g with casein, and the fat concentration was adjusted to 5 g/100 g with corn oil. Rats fed the bean diet had significantly fewer colon adenocarcinomas (P < 0.05) than rats fed the casein diet (5 vs. 22 tumors), and significantly fewer rats fed the bean diet (P < 0.05) had colonic tumors than did casein-fed rats (24 vs. 50%). Tumor multiplicity was also significantly lower for the bean-fed rats, and significantly fewer (P < 0.05) tumors per tumor-bearing rat were observed in bean-fed rats than in casein-fed rats (1.0 +/- 0.0 vs. 2.5 +/- 0.6). This study demonstrates that dry beans contain anticarcinogenic compounds capable of inhibiting AOM-induced colon cancer in rats. However, the specific anticarcinogenic components within dry beans have not been identified, and it is unclear whether dietary fiber, phytochemicals or other components within dry beans are primarily responsible for the anticarcinogenic properties of beans.
流行病学研究表明，在许多干豆（如斑豆）消费量高的拉丁美洲国家，结肠癌的发病率较低。本研究的目的是使用大鼠作为动物模型，获取关于干豆抑制结肠癌发生的实验数据。将53只5周龄的断奶雄性F344大鼠按体重随机分为以下几组：对照组（11只大鼠）、酪蛋白饮食组（21只大鼠）和豆类饮食组（21只大鼠）。给食用酪蛋白和豆类饮食的动物每周注射一次致癌剂偶氮甲烷（AOM），持续2周。对照组的大鼠也食用酪蛋白饮食，但未接触AOM。所有饮食的热量均相同。用酪蛋白将饮食中的蛋白质浓度调整至18 g/100 g，用玉米油将脂肪浓度调整至5 g/100 g。食用豆类饮食的大鼠结肠腺癌的数量显著少于食用酪蛋白饮食的大鼠（P < 0.05）（分别为5个和22个肿瘤），且食用豆类饮食的大鼠发生结肠肿瘤的比例显著低于食用酪蛋白饮食的大鼠（P < 0.05）（分别为24%和50%）。豆类喂养大鼠的肿瘤多发性也显著较低，且与酪蛋白喂养大鼠相比，豆类喂养大鼠中每只肿瘤大鼠的肿瘤数量显著更少（P < 0.05）（分别为1.0±0.0和2.5±0.6）。本研究表明，干豆含有能够抑制大鼠AOM诱导的结肠癌的抗癌化合物。然而，干豆中的具体抗癌成分尚未确定，且尚不清楚干豆中的膳食纤维、植物化学物质或其他成分是否是豆类抗癌特性的主要原因。
