Salt makes your body hold on to water. The human body requires a small amount of sodium to conduct nerve impulses, contract and relax muscles, and maintain the proper balance of water and minerals.
It is estimated that we need about 500 mg of sodium daily for these vital functions. If you eat too much salt, the extra water stored in your body raises your blood pressure. So, the more salt you eat, the higher your blood pressure. The higher your blood pressure, the greater the strain on your heart, arteries, kidneys and brain. This can lead to heart attacks, strokes, dementia and kidney disease.
Too much sodium in the blood is called hypernatremia. This acute condition can happen in older adults who are mentally and physically impaired who do not eat or drink enough, or who are sick with a high fever, vomiting, or infection that causes severe dehydration. Excessive sweating or diuretic medications that deplete the body of water are other causes. When sodium accumulates in the blood, water is transferred out of cells and into the blood to dilute it.
Too much salt can increase the amount of protein found in your urine. More protein in your urine is a "major risk factor" for kidney disease. Additionally, high-sodium diets can also increase the risk of kidney stones.