资料：Why is Salt Bad for You?

FRANK LE CLAIR, a 58-year-old provincial government employee living in Winnipeg, had no idea that his blood pressure was too high. While out of town last winter, he came down with a cold and a sore throat and decided to see a local doctor.

Apart from checking his cold symptoms, the doctor also gave him a general health-check. The doctor found that Frank’s blood pressure was higher than normal and advised him to see his regular physician as soon as he got home.

Le Clair’s physician referred him to the Winnipeg Health Sciences Centre, where dietitians told him that he might be able to control his blood pressure by changing his lifestyle rather than by taking drugs. People with high blood pressure have to control or eliminate four elements: smoking, drinking, food quantities and salt. Le Clair doesn’t smoke or drink, but there were some changes he could make in the other two categories.

The most conclusive evidence so far that a high-salt diet is bad for you is the “Intersalt” study, involving 10,000 people in 32 countries. It measured the relationship between urinary sodium excretion -- a direct measure of salt consumption -- and blood pressure. The study found that populations with the lowest sodium excretion also have the lowest blood pressures.

Recent studies have shown that “salt sensitivity” is a major factor in the relationship between a high-salt diet and hypertension. And hypertension is a risk factor for two of the biggest killers in this country: coronary heart disease and stroke. Frank Le Clair’s high blood pressure was discovered by chance. There are no warning symptoms -- high blood pressure is known as the silent killer.

A high-salt intake triggers a vicious cycle. Those who are used to a lot of salt in their food find they need increasing amounts to be able to continue to taste its flavour --- the more salt they eat, the more they want. It is also an aggravating factor in osteoporosis and is closely linked to stomach cancer. A high salt intake can be dangerous for people with conditions that are aggravated by fluid retention, such as hepatitis, liver or kidney problems.

Recent research studies have shown that ______.

• A.salt consumption leads to a stroke
• B.sodium excreted in urine is a measure of salt intake
• C.an increase in blood pressure causes an increase in salt consumption
• D.the higher the sodium in urine, the greater the chance of hypertension