The human body contains about 65% of water. Some body parts have very high water content, for instance, muscles contain 75% water, while liver 70%, brain 79% and kidneys have 83% water content. The water present in the body has common salt dissolved in it. To maintain the required level of salt in the body, we eat salt. Now the question arises — why should we maintain a certain level of salt in our body? According to one scientific theory, all land animals including man, are the descendants of organisms that came from the sea. The body fluid of these creatures had a high content of seawater. Since they were born in the seas, they were not able to survive without salt water. When these creatures shifted to dry land, they retained seawater as their body fluid, as the organs of the body were accustomed to it. Once out of the sea they still needed salt, and as they could not get it from the sea, to make up the deficiency of salt, they started consuming salt. Carnivorous animals do not need extra salt, since their salt requirement is fulfilled by the amount of salt present in the meat they consume. This is true of human beings also. Non-vegetarians need only small quantities of salt. Eskimos who are mainly nonvegetarians take very little salt. Those who live on land need more salt. In the ancient Mexico, common salt was treated so precious that people used to worship it as God. The word ‘salary’ comes from the word salt because in Roman times ‘salarium’ or allowance of money for salt was given to officers and men in the Roman Army. Most of the salt in our body is stored in the skin. The excretions from our body deplete the amount of salt in our body. If we consume food without salt, the amount of salt in the blood reduces, in which case the salt stored in the skin gets used up. The excretion of salt from the body is mainly done by the kidneys and skin as sweat. Salt is essential for effective functioning of our body. Today, iodised salt is consumed to meet the iodine requirement in our body. Iodine deficiency causes ailments like goitre and congenital disease like cretinism. Some medical authorities opine that excess of salt intake increases the risk of high blood pressure and hence leads to heart attack.