Govers M J, Van der Meet R
Department of Nutrition, Netherlands Institute for Dairy Research, Ede.
Gut. 1993 Mar;34(3):365-70. doi: 10.1136/gut.34.3.365.
Luminal free fatty acids and bile acids may damage the colonic epithelium and stimulate proliferation, which may increase the risk of colon cancer. It has been suggested that only soluble calcium ions (Ca2+) precipitate fatty acids and bile acids, thus reducing their lytic activity. Consequently, precipitation of luminal Ca2+ by dietary phosphate should inhibit these effects. To evaluate the proposed antagonistic effects of dietary calcium and phosphate, we studied the intestinal interactions between calcium, phosphate, fatty acids, and bile acids in rats fed purified diets that differed only in the concentrations of calcium and phosphate. Increased dietary calcium drastically decreased the solubility of fatty acids in the ileum, colon, and faeces, as well as the solubility of bile acids in the colon and faeces. Although dietary calcium strongly increased the total faecal fatty acid concentration and hardly affected the total faecal bile acid concentration, the fatty acid and bile acid concentrations in faecal water were drastically decreased by dietary calcium. Consequently, the lytic activity of faecal water was decreased. Dietary phosphate did not interfere with these intestinal effects of calcium. These results indicate that dietary phosphate does not inhibit the protective effects of dietary calcium on luminal solubility and the lytic activity of fatty and bile acids.
肠腔内的游离脂肪酸和胆汁酸可能会损害结肠上皮并刺激其增殖，这可能会增加患结肠癌的风险。有人提出，只有可溶性钙离子（Ca2+）能沉淀脂肪酸和胆汁酸，从而降低它们的溶解活性。因此，膳食磷酸盐使肠腔内Ca2+沉淀应能抑制这些作用。为了评估膳食钙和磷酸盐的这种拮抗作用，我们研究了喂食仅钙和磷酸盐浓度不同的纯化日粮的大鼠中钙、磷酸盐、脂肪酸和胆汁酸之间的肠道相互作用。增加膳食钙显著降低了脂肪酸在回肠、结肠和粪便中的溶解度，以及胆汁酸在结肠和粪便中的溶解度。虽然膳食钙强烈增加了粪便中总脂肪酸浓度，且几乎不影响粪便中总胆汁酸浓度，但膳食钙使粪便水中的脂肪酸和胆汁酸浓度大幅降低。因此，粪便水的溶解活性降低。膳食磷酸盐并未干扰钙的这些肠道效应。这些结果表明，膳食磷酸盐不会抑制膳食钙对肠腔内溶解度以及脂肪酸和胆汁酸溶解活性的保护作用。
