The fatty acids are absorbed by the intestines and bring with them the essential vitamins A, D, E, and K. When fat molecules are present in the intestines with any of those vitamins, the vitamins attach to the molecules and are carried into the bloodstream.
Olestra, which is made from six to eight molecules of fatty acids, is too large for the intestines to absorb. It just slides through the intestines without being broken down. Manufacturers say its that ability to slide unchanged through the intestines that makes olestra so valuable as a fat substitute. It provides consumers with the taste of regular fat without any bad effects on the body. But critics say olestra can prevent vitamins A, D, E, and K from being absorbed. It can also prevent the absorption of carotenoids , compounds that may reduce the risk of cancer, heart disease, etc.
Manufacturers are adding vitamins A, D, E, and K as well as carotenoids to their products now. Even so, some nutritionists are still concerned that people might eat unlimited amounts of food made with the fat substitute without worrying about how many calories they are consuming.
简短回答题评分原则及标准
1. 评分原则
简答题要求考生在读懂文章的基础上,用正确简洁的语言回答问题。在评分时应同时考虑内容和语言。每题满分为2分,最低为0分。
2. 给分标准
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