单选题

Iron Deficiencies

Sports medicine experts have observed for years that endurance athletes, particularly females, frequently have iron deficiencies. Now a new study by a team of Purdue University researchers suggests that even moderate exercise may lead to reduced iron in the blood of women.
"We found that women who were normally inactive and then started a program of moderate exercise showed evidence of iron loss," says Roseanne M. Lyle, associate professor at Purdue. Her study of 62 formerly inactive women who began exercising three times a week for six months was published in the journal Medicine & Science in Sports & Exercise. "Women who consumed additional meat or took iron supplements were able to bounce back," she notes. "But the new exercisers who followed their normal diet showed a significant decrease in iron levels."
Iron deficiency is very common among women in general, affecting one in four female teenagers and one in five women aged 18 to 45, respectively. But the ratio is even greater among active women, affecting up to 80 percent of female endurance athletes. This means, Lyle says, that "too many women ignore the amount of iron they take in".
Women of childbearing age are at greatest risk, since their monthly bleeding is a major source of iron loss. Plus, many health-conscious women increase their risk by rejecting red meat, which contains the most easily absorbed form of iron. And because women often restrict their diet in an effort to control weight, they may not consume enough iron-rich food, and are liable to experience a deficiency.
"The average woman takes in only two thirds of the recommended daily allowance for iron," notes another expert. "For a woman who already has a poor iron status, any additional iron loss from exercise may be enough to tip her over the edge into a more serious deficiency," notes the expert. Exercise can result in iron loss through a variety of mechanisms. Some iron is lost in sweat, and, for unknown reasons, intense endurance exercise is sometimes associated with bleeding of the digestive system.
The best sources of iron, and the only sources of the form of iron most readily absorbed by the body, are meat, chicken, and fish. Good sources of other forms of iron include dates, beans, and some leafy green vegetables.

单选题 According to experts, who will possibly have iron deficiencies?

A. Sprinters.
B. Marathoners.
C. Weight-lifters.
D. High jump athletes.

单选题 Who will show evidence of iron loss?

A. Active women.
B. Inactive women.
C. Women who do a program of moderate exercise regularly.
D. Women who are inactive and start to do moderate exercise.

单选题 Who will have a significant decrease in iron levels?

A. All the women.
B. All the inactive women.
C. Women who start to do moderate exercise and follow their normal diet.
D. Women who start to do moderate exercise and consume additional meat or take iron supplements.

单选题 Which group of women will possibly have iron loss?

A. 80 percent of active women.
B. 80 percent of female endurance athletes.
C. One in four women aged 18 to 45.
D. One in five female teenagers.

单选题 Who will have the least risk of having iron loss?

A. Women who reject red meat.
B. Women of childbearing age.
C. Women who take dates and beans often.
D. Women who control their weight by taking less meat and vegetables.