Sodium is part of the extracellular fluid of many multicellular creatures, not least mankind. It is needed for instance in nerve conduction and to balance the acid levels in the body. It is necessary for the functioning of organs such as the liver, intestine and kidneys in their work of ridding the body of toxins However there is an optimum intake. Above this there are problems such as a rise in the blood pressure. Also an excess of salt in the diet will draw fluid out of the cells by the process of osmosis. On the other hand a lack of sodium will lead to too much water in the body the brains cells will actually be flooded.