Terpstra A H M, Lapré J A, de Vries H T, Beynen A C
Department of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
Eur J Nutr. 2002 Feb;41(1):19-26. doi: 10.1007/s003940200002.
We found in preliminary studies with hamsters that citrus peels have a cholesterol lowering effect comparable to that of pectin extracted from these peels.
We wanted to examine whether the cholesterol lowering effect of the peels could be completely accounted for by the pectin in the peels.
We fed cholesterol enriched (0.1 %,w/w) semipurified diets containing 3% (w/w) of cellulose, lemon peels, lemon pectin, and the waste stream material of the lemon peels to hybrid F1B hamsters for a period of 8 weeks. The waste stream of the lemon peels is the left over after extraction of the lemon pectin.
Feeding the semipurified diets resulted in an increase of plasma cholesterol levels in all the dietary groups after 2 and 4 weeks on the diets. Cholesterol concentrations in the cellulose fed hamsters continued to increase after 4 weeks on the diet, whereas cholesterol levels in the other groups had reached a plateau. As a consequence, the plasma cholesterol levels in the hamsters fed the peels (5.59 +/- 0.74 mmol/L, mean +/- SD, n = 14), pectin (5.19 +/- 0.48 mmol/L), or waste stream (5.53 +/- 0.94 mmol/L) were lower than those in the hamsters fed cellulose (6.71 +/- 1.52 mmol/L) after 8 weeks on the diets. Differences in total plasma cholesterol were reflected in differences in both VLDL and LDL cholesterol concentration, but this effect was more distinct for the VLDL. There was no effect of the type of fiber on HDL cholesterol levels. Liver cholesterol concentrations paralleled. the concentrations of plasma cholesterol and the liver cholesterol concentrations in the hamsters fed the peels (3.57+/- 1.01 micromol/g liver, mean +/- SD, n = 14), pectin (4.86 +/- 1.42), and the waste stream (4.96 +/- 1.89) were lower than those in the cellulose group (7.19 +/- 2.32). The hamsters fed the peels, pectin, or waste stream tended to have a higher excretion of fecal bile acids and neutral sterols then the cellulose fed hamsters.
The results of this study suggest that lemon peels and the waste stream of the lemon peels are as effective in lowering plasma and liver cholesterol in hamsters as the pectin extracted from the peels and that also compounds other than pectin are probably responsible for the cholesterol lowering effect of the citrus peels.
我们在对仓鼠的初步研究中发现，柑橘皮具有与从这些果皮中提取的果胶相当的降胆固醇作用。
我们想研究果皮的降胆固醇作用是否完全由果皮中的果胶引起。
我们给杂种F1B仓鼠喂食富含胆固醇（0.1%，w/w）的半纯化日粮，日粮中含有3%（w/w）的纤维素、柠檬皮、柠檬果胶以及柠檬皮的废物流物质，持续8周。柠檬皮的废物流是提取柠檬果胶后剩余的部分。
喂食半纯化日粮2周和4周后，所有饮食组的血浆胆固醇水平均升高。喂食纤维素的仓鼠在饮食4周后胆固醇浓度继续上升，而其他组的胆固醇水平已达到平稳状态。因此，在饮食8周后，喂食果皮（5.59±0.74 mmol/L，均值±标准差，n = 14）、果胶（5.19±0.48 mmol/L）或废物流（5.53±0.94 mmol/L）的仓鼠的血浆胆固醇水平低于喂食纤维素的仓鼠（6.71±1.52 mmol/L）。血浆总胆固醇的差异反映在极低密度脂蛋白（VLDL）和低密度脂蛋白（LDL）胆固醇浓度的差异上，但这种影响在VLDL上更为明显。纤维类型对高密度脂蛋白（HDL）胆固醇水平没有影响。肝脏胆固醇浓度与之平行。喂食果皮（3.57±1.01微摩尔/克肝脏，均值±标准差，n = 14）、果胶（4.86±1.42）和废物流（4.96±1.89）的仓鼠的肝脏胆固醇浓度低于纤维素组（7.19±2.32）。喂食果皮、果胶或废物流的仓鼠粪便胆汁酸和中性固醇的排泄量往往高于喂食纤维素的仓鼠。
本研究结果表明，柠檬皮及其废物流在降低仓鼠血浆和肝脏胆固醇方面与从果皮中提取的果胶同样有效，并且除了果胶之外的其他化合物可能也对柑橘皮的降胆固醇作用负责。
