人体只需要半克盐，食品中足够了

鸡蛋，牛奶，牛肉，菠菜，鱼虾里都含有自然盐分。只要均衡饮食，根本不需要额外加盐。

Worried that you’re not getting enough sodium? It’s not likely. There’s no reliable evidence that eating less than 1,500 mg per day of sodium is a risk for the general population. 
The body needs only a small amount of sodium (less than 500 milligrams per day) to function properly. That’s a mere smidgen — the amount in less than ¼ teaspoon. Very few people come close to eating less than that amount. Plus, healthy kidneys are great at retaining the sodium that your body needs. 

How much sodium should I eat per day? | American Heart Association