The worry about salt is that it may 【B1】 high blood pressure. Chemically, salt 【B2】 of sodium and chloride ions, both of 【B3】 are common in the human 【B4】 and are important for many physiological and biochemical 【B5】 We not only need salt, we are salt; but too 【B6】 may still be bad for us. Although the idea of a 【B7】 between salt and high blood pressure 【B8】 back to 2000 BC, there is still no scientific 【B9】 as to whether this is so or not. One reason for this 【B10】 to agree is that individual salt intake 【B11】 enormously from day to day, and so reliable measures of intake are hard to come 【B12】 . Those who believe that salt does 【B13】 to high blood pressure point to the high 【B14】 of high blood pressure in countries that eat a very 【B15】 diet. In Japan, for instance, where salted fish is an important part of the diet, high blood pressure and 【B16】 complications are common, 【B17】 among some Amazonian and African tribes, which have a low intake of salt, they are almost 【B18】 . But 【B19】 there is this neat relation between salt intake and the incidence of high blood pressure between countries, it doesn’’t seem to apply 【B20】 those countries themselves. Studies, for instance, of couples who have a similar salt intake don’’t show any consistency in how often they develop high blood pressure.