Imagine eating everything delicious you want -with none of the fat. That wou

游客2024-06-08  11

问题     Imagine eating everything delicious you want -with none of the fat. That would be great, wouldn’t it?
    New "fake fat" products appeared on stone shelves in the United States recently, but not everyone is happy about it. Makers of the products, which contain a compound called olestra, say food manufacturers can now eliminate fat from certain foods. Critics, however, say the new compound can rob the body of essential vitamins and nutrients (营养物) and can also cause unpleasant side effects in some people. So it’s up to consumers to decide whether the new fat-free products taste good enough to keep eating.
    Chemists discovered olestra in the late 1960s, when they were searching for a fat that could be digested by infants more easily. Instead of finding the desired fat, the researchers created a fat that can’t be digested at all.
    Normally, special chemicals in the intestines (肠) "grab" molecules of regular fat and break them down so they can be used by the body. A molecule of regular fat is made up of three molecules of substances called fatty acids.
    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.
    OIestra, 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 it’s that ability to slide unchanged through the intestines that makes olestea 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 olestras can prevent vitamins A, D, E and K from being absorbed. It can also prevent the absorption of carotenoids (类胡萝卜素), 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. [br] we learn from the passage that olestra is a substance that ______.

选项 A、contains plenty of nutrients
B、renders foods calorie -free while retaining their vitamins
C、makes foods easily digestible
D、makes foods fat -free while keeping them delicious

答案 D

解析 从第一、二段的内容可知olestra是一种使食物不含脂肪而又保持其美味的物质。A、 B、C三个选项的内容可依据原文字予以排除。第二段倒数第2句指出:批评家们认为这种新的化合物会阻止人体吸收基本的维生素。由此可见,A、B项意思与原文不符;C项内容与第三段意思相悖。
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