2014年英语四级阅读练习及答案(17)_大学英语阅读

2014年英语四级阅读练习及答案(17)

　　Hair. Healthy, shining hair is second only to vibrant skin for making one look younger. Yet many people unwittingly mistreat their hair by eating an unbalanced diet.

　　When a 33-year-old employee at a Texas corporation decided to lose weight quickly, she went on a fad diet, high in fiber and bulk, but low in protein. Over three months, she lost a lot of weight. She also lost a good deal of her hair.

　　Dermatologist David Alkek, a clinical professor at the University of Texas Southwest Medical Center at Dallas, sees too many cases like this woman s. When diets don t contain enough amino acids, the building blocks of protein, there s dramatic increase in hair loss as the body breaks down its own protein.

　　Hair and skin cells are constantly reproducing and are, therefore, very sensitive to nutritional deficiencies, explains Dr. Alkek. Foods high in amino acids include meats, eggs, milk, grains and legumes. Just remember that the body cannot store protein. So foods high in protein must be ingested daily. Under Alkek s care, the woman began eating nutritionally balanced meals, and her hair was restored in about eight months.

　　Immune system. Vitamins E and C and beta carotene, known as antioxidants , are considered powerful disease-fighters, capable of slowing down or preventing a number of ailments typically associated with aging.

　　A growing body of evidence suggests that aging and decline in immune function may result in part from accumulated damage to cells caused by certain toxic compounds called free radicals . Antioxidants seem to counteract or impair the ability of these substances to attack healthy cells, thus avoiding at least some of the damage. Foods containing these nutrients are being linkedby science rather than mythto the control and prevention of heart disease and cancer, stroke, cataracts and to the body s ability to ward off infectious diseases.