Some sodium is stored in the bones and is available if needed. Sodium can be lost with excessive sweating and with vomiting or diarrhea. When this happens, we naturally crave water and salt. Should we then consume only water, we may experience "water intoxication," wherein water goes into the cells and causes swelling, which may lead to symptoms such as headaches, weakness, loss of appetite, or poor memory. More commonly, though, we first crave salt and then become thirsty for water to dilute or, rather, balance the osmotic effects of sodium, and help it to be eliminated. This is all carefully regulated by our masterful kidneys and adrenal glands.

Sources: Almost all foods contain some sodium, particularly as sodium chloride. It is found in high amounts in all seafood, in beef, and in poultry, and some sodium is in many vegetables, including celery, beets, carrots, and artichokes. Kelp and other sea vegetables are fairly high in sodium.

No wholesome natural food has a high salt content. It is only the Westernized diet of processed foods that has significant salt content, and many people consume these foods as their primary "diet." In many respects the standard American diet is sad! Breads, crackers, chips, cheeses, especially the processed types, some peanut butter, and salt-cured foods such as olives and pickles may constitute a good percentage of a typical unhealthy diet. Lunch meats and processed or cured meats such as bacon, bologna, corned beef, and hot dogs are particularly high in salt and other preservatives such as nitrates and nitrites. Luckily, most people can clear excess sodium chloride from their bodies, but it creates additional work for the kidneys. After many years, the kidneys may weaken from this chronic stress and be unable to clear the salt as well, which may lead to more problems including high blood pressure.

Sodium can also come from nonsalt sources, such as baking soda (sodium bicarbonate), monosodium glutamate (MSG), sodium propionate, or any other ingredient listed on a package as soda or sodium "something." Soy sauce, or tamari, has high amounts of sodium as well, but the sodium is less concentrated than in crystal salt. "Softened" water also has extra sodium added to replace the naturally occurring magnesium and calcium that are removed. This is done because the more soluble sodium can wash clothes better and "bubble" and "soap" more for daily cleaning and bathing, but when this water is used as a drink, it adds to the already excessive sodium levels.

Functions: Along with potassium, sodium helps to regulate the fluid balance of the body, both within and outside the cells. Through the kidneys, by buffering the blood with a balance of all the positive or negative ions present, these two minerals help control the acid-base balance as well. The high blood levels of sodium contribute to the osmolarity (concentration of solutes in solution) and thereby regulate the fluid volume of the body and blood. The shifting of sodium and potassium across the cell membranes helps to create an electrical potential (charge) that enables muscles to contract and nerve impulses to be conducted. Sodium is also important to hydrochloric acid production in the stomach and is used during the transport of amino acids from the gut into the blood.

Since sodium is needed to maintain blood fluid volume, excessive sodium can lead to increased blood volume and elevated blood pressure, especially when the kidneys do not clear it efficiently. It is easier to prevent hypertension with low salt intake than to treat it by lowering salt in the diet. Hypertension is more frequent in people who have a high salt intake, especially in people with low levels of potassium in their diets. Fresh fruits and vegetables are high in potassium and low in sodium, and research shows that increased potassium can balance out some of the effects high sodium intake has on blood pressure. Elderly people and the black population are more prone than others to elevated blood pressure. In cultures that consume low-sodium diets, there is very little, if any, hypertension.