PHYTOSTEROLS IN HUMAN NUTRITION

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。植物甾醇是一种类似胆固醇的分子，存在于所有植物食品中，其中植物油中的含量最高。它们只能被微量吸收，但会抑制肠道胆固醇的吸收，包括循环的内源性胆汁胆固醇，这是消除胆固醇的关键步骤。正常饮食摄入量约为167-437毫克/天。由于在水和脂肪中的溶解度有限，在喂养研究中测量生物学效应的尝试受到了阻碍。植物甾醇与长链脂肪酸的酯化使脂肪的溶解度提高了10倍，并允许每天在人造黄油等脂肪食品中摄入几克。每天2g的剂量可以使低密度脂蛋白胆固醇降低10%，Delta(5)-甾醇和5α-还原的甾醇(斯坦醇)几乎没有区别。植物甾醇在与卵磷脂乳化后也可以分散在水中，当添加到非功能性食品中时，可以减少胆固醇的吸收。与这些补充剂研究相比，人们对天然饮食中低植物类固醇水平的影响知之甚少。然而，在不含类固醇的试验餐中，只需150毫克的剂量就可以测量到胆固醇吸收的减少，这表明天然食物植物类固醇可能在临床上很重要。目前的文献表明，添加到饮食中的植物甾醇是安全的，而且测得的吸收和血浆水平非常低。增加各种食物中植物甾醇的总消耗量可能是降低人群胆固醇水平和预防冠心病的重要途径。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Phytosterols are cholesterol-like molecules found in all plant foods, with the highest concentrations occurring in vegetable oils. They are absorbed only in trace amounts but inhibit the absorption of intestinal cholesterol including recirculating endogenous biliary cholesterol, a key step in cholesterol elimination. Natural dietary intake varies from about 167-437 mg/day. Attempts to measure biological effects in feeding studies have been impeded by limited solubility in both water and fat. Esterification of phytosterols with long-chain fatty acids increases fat solubility by 10-fold and allows delivery of several grams daily in fatty foods such as margarine. A dose of 2 g/day as the ester reduces low density lipoprotein cholesterol by 10%, and little difference is observed between Delta(5)-sterols and 5alpha-reduced sterols (stanols). Phytosterols can also be dispersed in water after emulsification with lecithin and reduce cholesterol absorption when added to nonf at f oods. In contrast to these supplementation studies, much less is known about the effect of low phytosterol levels in the natural diet. However, reduction of cholesterol absorption can be measured at a dose of only 150 mg during otherwise sterol-free test meals, suggesting that natural food phytosterols may be clinically important. Current literature suggests that phytosterols are safe when added to the diet, and measured absorption and plasma levels are very small. Increasing the aggregate amount of phytosterols consumed in a variety of foods may be an important way of reducing population cholesterol levels and preventing coronary heart disease.