Govers M J, Termont D S, Lapré J A, Kleibeuker J H, Vonk R J, Van der Meer R
Department of Nutrition, Netherlands Institute for Dairy Research, the Netherlands.
Cancer Res. 1996 Jul 15;56(14):3270-5.
Dietary calcium may reduce the risk of colon cancer, probably by precipitating cytotoxic surfactants, such as secondary bile acids, in the colonic lumen. We previously showed that milk mineral, an important source of calcium, decreases metabolic risk factors and colonic proliferation in rats. We now report the effects of the habitual intake of milk calcium on metabolic risk factors in healthy subjects. A double-blind, cross-over metabolic study was performed in 13 healthy males. Placebo milk products (calcium, 3 mM) were compared with regular milk products (calcium, 30 mm). In each 1-week period, the habitual diet was recorded, and urine and feces were collected for 1 and 3 days, respectively. Milk calcium significantly increased fecal pH and fecal excretion of phosphate (132%), total fat (139%), free fatty acids (195%), and bile acids (141%), indicating intestinal complexation. In fecal water, the concentrations of long-chain fatty acids, secondary bile acids (deoxycholic and lithocholic acid), neutral sterols, and phospholipids were about halved (P <0.05). Consistent with these changes in soluble hydrophobic surfactants, calcium decreased the cytotoxicity of fecal water from 68 +/- 9 to 28 +/- 12% (P < 0.005). Calcium in milk products precipitates luminal cytotoxic surfactants and thus inhibits colonic cytotoxicity. Therefore, habitual dietary calcium may contribute to a nutritional modulation of colon cancer risk.
膳食钙可能会降低患结肠癌的风险，这可能是通过在结肠腔内沉淀细胞毒性表面活性剂，如次级胆汁酸来实现的。我们之前表明，牛奶矿物质作为钙的重要来源，可降低大鼠的代谢风险因素和结肠增殖。我们现在报告习惯性摄入牛奶钙对健康受试者代谢风险因素的影响。对13名健康男性进行了一项双盲交叉代谢研究。将安慰剂奶制品（钙含量3毫摩尔）与常规奶制品（钙含量30毫摩尔）进行比较。在每个为期1周的时间段内，记录习惯性饮食情况，并分别收集1天的尿液和3天的粪便。牛奶钙显著提高了粪便pH值以及磷酸盐（132%）、总脂肪（139%）、游离脂肪酸（195%）和胆汁酸（141%）的粪便排泄量，表明发生了肠道络合作用。在粪便水中，长链脂肪酸、次级胆汁酸（脱氧胆酸和石胆酸）、中性固醇和磷脂的浓度约减半（P<0.05）。与这些可溶性疏水表面活性剂的变化一致，钙将粪便水的细胞毒性从68±9%降低至28±12%（P<0.005）。奶制品中的钙沉淀肠腔细胞毒性表面活性剂，从而抑制结肠细胞毒性。因此，习惯性膳食钙可能有助于对结肠癌风险进行营养调节。
