Seal C J, Mathers J C
Human Nutrition Research Centre, Department of Biological and Nutritional Sciences, University of Newcastle, Newcastle upon Tyne, NE1 7RU, UK.
Br J Nutr. 2001 Mar;85(3):317-24. doi: 10.1079/bjn2000250.
The present study investigated the digestion and cholesterol-lowering effects of the water-soluble NSP guar gum (GG) and sodium alginate (SA) in laboratory animals. Groups of five male Wistar strain rats were fed semi-purified cholesterol-free diets containing 0, 50 or 100 g NSP source/kg for 21 d which comprised a 14-d adaptation period followed by a 7-d balance period. Weight gain over the balance period and food conversion ratio decreased linearly with increasing NSP intake ( and respectively). DM digestibility decreased with increasing NSP intake and this effect was greater for SA-containing diets compared with GG-containing diets At the lower inclusion rate, 0.9-1.0 of the additional NSP was digested, but this value fell to 0.8 for both NSP sources at the 100 g/kg inclusion rate, implying that the capacity for near complete digestion of the test NSP had been exceeded. Intestinal tissue mass was increased in response to inclusion of both NSP sources. Caecal digesta pH decreased linearly with additional GG, but increased slightly with consumption of SA. Total caecal short-chain fatty acid concentrations (micromol/g caecal contents) increased markedly with 50 g GG/kg but did not increase further with 100 g GG/kg, and were slightly lower than control values in rats consuming SA. Plasma cholesterol concentration fell linearly with increasing NSP in the diet and the effect was similar for both GG and SA. Total output of faecal bile acids rose in rats fed 50 g GG/kg and 50 g SA/kg (59 micromol/7 d v. 24 micromol/7 d for control rats) with no further increase at the higher inclusion rate. These results show that SA has a strong hypocholesterolaemic effect in rats which is similar to that of GG, and that this effect is most likely to be mediated through an interruption in the entero-hepatic circulation of bile acids and not through increased hepatic supply of propionate from fermentation of the NSP in the large bowel.
本研究调查了水溶性非淀粉多糖瓜尔胶（GG）和海藻酸钠（SA）在实验动物体内的消化及降胆固醇作用。将五组雄性Wistar品系大鼠分别喂食含0、50或100 g非淀粉多糖源/kg的半纯化无胆固醇日粮，为期21天，其中包括14天的适应期和随后7天的平衡期。平衡期内体重增加和食物转化率随非淀粉多糖摄入量增加呈线性下降（分别为 和 ）。干物质消化率随非淀粉多糖摄入量增加而降低，且含SA日粮的这种影响比含GG日粮更大。在较低添加率时，额外添加的非淀粉多糖有0.9 - 1.0被消化，但在100 g/kg添加率时，两种非淀粉多糖源的该值均降至0.8，这意味着测试非淀粉多糖几乎完全消化的能力已被超过。两种非淀粉多糖源添加后肠道组织质量均增加。盲肠食糜pH值随GG添加呈线性下降，但随SA摄入略有升高。盲肠短链脂肪酸总浓度（微摩尔/克盲肠内容物）在添加50 g GG/kg时显著增加，但在添加100 g GG/kg时未进一步增加，且略低于摄入SA的大鼠的对照值。血浆胆固醇浓度随日粮中非淀粉多糖增加呈线性下降，GG和SA的效果相似。喂食50 g GG/kg和50 g SA/kg的大鼠粪便胆汁酸总排出量增加（对照大鼠为24微摩尔/7天，喂食GG和SA的大鼠为59微摩尔/7天），在较高添加率时未进一步增加。这些结果表明，SA在大鼠体内具有与GG相似的强大降胆固醇作用，且这种作用最可能是通过胆汁酸肝肠循环中断介导的，而非通过大肠中NSP发酵增加肝脏丙酸供应来实现。
