单选题
In recent years, there has been a steady assault on salt from the doctors: Salt is bad for you — regardless of your health. Politicians also got on board. " There is a direct relationship" , US Conqressman Neal Smith noted, "between the amount of sodium a person consumes and heart disease, circulatory disorders, stroke and even early death". Frightening, if true! But many doctors and medical researchers are now beginning to feel the salt scare has gone too far. " All this hue and cry about eating salt is unnecessary," Dr. Dustan insists. "For most of us it probably doesn't make much difference how much salt we eat. " Dustan's most recent short-term study of 150 people showed that those with normal blood pressure underwent no change at all when placed on an extremely low-salt diet, or later when salt was reintroduced. Of the hypertensive subjects, however, half of those on the low-salt diet did experience a drop in blood pressure, which returned to its previous level when salt was reintroduced. "An adequate to somewhat excessive salt intake has probably saved many more lives than it has cost in the general population", notes Dr. John H. Laragh. "So a recommendation that the whole population should avoid salt makes no sense. " Medical experts agree that everyone should practice reasonable "moderation" in salt consumption. For an average person, a moderate amount might run from four to ten grams a day, or roughly 1/2 to 1/ 3 of a teaspoon. The equivalent of one to two grawrs of this salt allowance would come from the natural sodium in food. The rest would be added in processing, preparation or at the table. Those with kidney, liver or heart problems may have to limit dietary salt, if their doctor advises. But even the very vocal " low salt " exponent, Dr. Arthur Hull Hayes, Jr. admits that " we do not know whether increased sodium consumption causes hypertension". In fact, there is increasing scientific evidence that other factors may be involved: deficiencies in calcium, potassium, perhaps magnesium; obesity(much more dangerous than sodium); generic predisposition; stress. "It is not your enemy," says Dr. Laragh, "Salt is the No. 1 natural component of all human tissue, and the idea that you don't need it is wrong. Unless your doctor has proven that you have a salt-related health problem, there is no reason to give it up. "
单选题
According to some doctors and politicians, the amount of salt consumed