Alabaster O, Tang Z, Shivapurkar N
Institute for Disease Prevention, George Washington University Medical Center, Washington, DC 20037, USA.
Food Chem Toxicol. 1997 May;35(5):517-22. doi: 10.1016/s0278-6915(97)00014-8.
As variation in both type of fibre and its physical properties can influence physiological effects, the effects of different dietary levels (1, 4, 8%, w/w) of unprocessed wheat bran (WB) were compared with those of two of its processed commercial formulations used in breakfast cereals, on the formation of aberrant crypt foci (ACF) and colon tumours in Fischer 344 rats following azoxymethane (AOM) administration. All diets were high in fat (20 g/100 g) and low in calcium (0.2%, w/w). The rats were fed the experimental diets for 2 wk before receiving two sc injections of AOM (15 mg/kg body weight/wk). 8 wk following the first injection of AOM, five rats per group were killed and the formation of ACF was measured. 23 wk following the first injection of AOM, 12 rats per group were killed and the colon tumour incidence in different dietary groups was measured. The results showed that increasing the dietary concentration of fibre from 1 to 8% (w/w), using all the wheat bran formulations, significantly reduced the number of ACF per rat. None of the diets showed any significant effect on the normal growth of rats. No statistically significant differences were observed between the protective properties of WB and the two commercial formulations under investigation in terms of the reduction of the number of ACF, or in terms of the reduction of the colon adenocarcinoma incidence. The results suggest that wheat bran and its two commercial formulations can offer protection against colon cancer even when they are consumed with a high-fat/low-calcium diet. The addition of any of these formulations of wheat bran fibre is likely to be equally effective in the prevention of colon cancer in human populations that habitually consume high-fat/low-fibre Western-style diets.
由于纤维类型及其物理性质的变化都会影响生理效应，因此比较了未加工麦麸（WB）不同膳食水平（1%、4%、8%，w/w）与早餐谷物中使用的两种加工商业配方对给予偶氮甲烷（AOM）后的Fischer 344大鼠异常隐窝灶（ACF）形成和结肠肿瘤的影响。所有饮食脂肪含量高（20 g/100 g）且钙含量低（0.2%，w/w）。大鼠在接受两次皮下注射AOM（15 mg/kg体重/周）之前，先喂食实验性饮食2周。在首次注射AOM后8周，每组处死5只大鼠并测量ACF的形成情况。在首次注射AOM后23周，每组处死12只大鼠并测量不同饮食组的结肠肿瘤发生率。结果表明，使用所有麦麸配方，将纤维的膳食浓度从1%提高到8%（w/w），可显著减少每只大鼠的ACF数量。没有一种饮食对大鼠的正常生长有任何显著影响。在减少ACF数量或降低结肠腺癌发生率方面，未观察到WB与所研究的两种商业配方的保护特性之间存在统计学显著差异。结果表明，即使与高脂肪/低钙饮食一起食用，麦麸及其两种商业配方也能提供对结肠癌的保护。在习惯性食用高脂肪/低纤维西式饮食的人群中，添加任何一种这些麦麸纤维配方在预防结肠癌方面可能同样有效。
