2014年4月托福考试模拟试卷及答案(第四套)_第21页

　　The history of clinical nutrition, or the study of the relationship between health

　　and how the body takes in and utilizes food substances, can be divided into four

　　distinct eras: the first began in the nineteenth century and extended into the early

　　Line twentieth century when it was recognized for the first time that food contained

　　(5) constituents that were essential for human function and that different foods provided

　　different amounts of these essential agents. Near the end of this era, research studies

　　demonstrated that rapid weight loss was associated with nitrogen imbalance and

　　could only be rectified by providing adequate dietary protein associated with certain

　　foods.

　　(10) The second era was initiated in the early decades of the twentieth century and

　　might be called "the vitamin period." Vitamins came to be recognized in foods, and

　　deficiency syndromes were described. As vitamins became recognized as essential

　　food constituents necessary for health, it became tempting to suggest that every

　　disease and condition for which there had been no previous effective treatment might

　　(15) be responsive to vitamin therapy. At that point in time, medical schools started to

　　become more interested in having their curricula integrate nutritional concepts into

　　the basic sciences. Much of the focus of this education was on the recognition of

　　vitamin deficiency symptoms. Herein lay the beginning of what ultimately turned from

　　ignorance to denial of the value of nutritional therapies in medicine. Reckless

　　(20) claims were made for effects of vitamins that went far beyond what could actually

　　be achieved from the use of them.

　　In the third era of nutritional history in the early 1950's to mid 1960's, vitamin

　　therapy began to fall into disrepute. Concomitant with this, nutrition education in

　　medical schools also became less popular. It was just a decade before this that many

　　(25) drug companies had found their vitamin sales skyrocketing and were quick to supply

　　practicing physicians with generous samples of vitamins and literature extolling the

　　virtue of supplementation for a variety of health-related conditions. Expectations

　　as to the success of vitamins in disease control were exaggerated. As is known in

　　retrospect, vitamin and mineral therapies are much less effective when applied to

　　(30) health-crisis conditions than when applied to long-term problems of undernutrition

　　that lead to chronic health problems.

　　The paragraph following the passage most probably discusses

　　(A) the fourth era of nutrition history

　　(B) problems associated with undernutrition

　　(C) how drug companies became successful

　　(D) why nutrition education lost its appeal