High blood pressure is a risk factor for stroke and heart disease. Normal blood pressure is 120/80 mmHg. The top number, the systolic pressure, is the pressure when your heart is pumping blood out to your body. If systolic pressure is above 120, your heart is working extra hard to deliver oxygen to the rest of your body. If you consume too much salt, in excess of water, you tend to battle hypertension.
Moving Salt and Water Throughout Your Body
The human body is 50 to 60 percent water. Your body is comprised of cells surrounded by salt water. Sodium, half of the chemical name for salt, is the primary electrolyte, an electrically charged particle, which crosses cell walls to moderate blood pressure. Water moves into cells following the movement of sodium in an attempt to maintain a particular salt concentration inside and outside each cell.
Maintaining Hydration and Blood Pressure
Osmolarity is a measure of concentration of particles, in this case, salt, in a liquid, in this case, water. If your blood pressure is normal, your body's osmolarity is approximately 300 osmoles per liter. If the salt you ingest exceeds what your body needs, essentially, the solution becomes too thick, and blood pressure rises. If the salt concentration drops, water is conserved and blood pressure decreases. A complex series of hormonal signals triggers the kidneys to respond to changes in osmolarity, essentially, either by forming urine to excrete water, by making you thirsty to drink water, or by keeping your body's water volume fairly constant.
Recommended Daily Salt Intake
The US Department of Agriculture recommends most adult ingest approximately 1.5 g of sodium per day. Athletes and individuals who sweat profusely during the day need more sodium, but no numerical value has been recommended for this variable population. Adults older than 70 require only 1.3 g of sodium per day. The recommended daily intake for chloride, the negatively charged particular that combines with sodium to form salt, is higher than that for sodium, 2.3 g per day.
American Salt Intake
Most Americans grossly exceed the RDI for salt, consuming approximately 8.5 g of sodium per day. The primary sources of sodium in the American diet stem from processed and restaurant foods. The majority of excess salt is in the food itself; only about 5 percent comes from using a saltshaker. Therefore, if you were trying to reduce your salt intake, it would be best to cook at home, and if you desire a saltier flavor, use the saltshaker after the food has been cooked, or use spices in the cooking to substitute for the lacking salty flavor.
Hypertension and Other Diseases
Regulating your salt intake is imperative for maintaining normal blood pressure. Untreated hypertension has multiple ill effects. Diabetics, both type I and II, already battle excess of a particle in the blood, sugar, in the form of blood glucose. High blood sugar damages blood vessels independently of hypertension caused by excessive salt intake. Glaucoma, too much pressure in the eye, is also exacerbated by excessive salt intake. Pharmaceutical treatments for hypertension include diuretics, which reduce water retention, and sympathetic nervous system inhibitors, drugs that block your body's ability to raise blood pressure in response to salt intake.
