Sodium is essential to life. Sodium is so important, in fact, that humans have a specific sensor on the tongue that can detect salt. Thousands of years ago, when the diet of humans was potassium-rich and sodium-poor, this sensor for salt was a crucial survival tool. Nature, in its infinite wisdom, devised a way to help humans (as well as animals) seek out salty foods so that they could be assured of receiving adequate sodium from their diets. This is important because sodium—often found in the form of sodium chloride or salt—plays countless roles in the body.
To begin with, sodium is crucial for maintaining the health of every cell in the human system. It permeates the fluid between cells (often called the extracellular fluid) and potassium exists mainly on the inside of the cells (in the intracellular fluid). These two minerals need to be in a constant dynamic balance so nutrients and waste can move across cell membranes. If either of these minerals is deficient or in excess, cell permeability becomes compromised and the health of all of the cells suffers.
Besides being a component of extracellular fluid that bathes every living cell, sodium is important in two other “salty oceans” in the body—our blood and our lymphatic fluid. It is also necessary for the production of hydrochloric acid, the digestive enzyme secreted by the stomach in order to digest protein. Along with potassium, sodium is required for the proper functioning of our nerves and the contraction of our muscles. (The heart, as you may know, is our hardest-working muscle.) Finally, sodium is necessary to maintain several kinds of equilibrium—fluid balance, electrolyte balance, and pH (acid/alkaline) balance—which are all of the utmost importance to the body.
With the many crucial roles sodium plays, it’s clear that if we had no sodium, we would cease to exist. Obtaining adequate, easily absorbable sodium from foods then is important for maintaining health, but obtaining too much of the wrong kinds of sodium is harmful.
Like fat, sodium is often misunderstood. Sodium and fat are nutrients we need for health, but not all forms of them are healthy.
Most of us already know that excessive salt consumption contributes to the development of high blood pressure, but recent research shows that it is also associated with strokes, calcium deficiency and osteoporosis, fluid retention, weight gain, stomach ulcers, and stomach cancer. However, reducing sodium too much can be just as harmful as consuming large amounts of it. Too little can cause spasms, poor heart rhythms, an increase the risk of heart attack in hypertensive patients, and even sudden death. Understanding the role sodium plays in the body and the difference between “good” and “bad” sources of sodium will help you get the salt out of your diet while you still meet your sodium needs.
How much salt?
Just how much salt do we consume? According to The Sodium Counter (Pocket Books, 1993), the average American’s salt intake is two to three teaspoons per day. This may not sound like a lot, but it provides 4,000 to 6,000 milligrams of sodium a day—which can be more than double the U.S. Food and Drug Administration’s maximum recommended daily quantity of 2,400 milligrams.
No other mammal eats this much salt and no other mammal has the health problems we do. High blood pressure, for example, was never even seen in animals until researchers found they could induce it either by surgery or by introducing large amounts of salt into animal’s diets.
We unknowingly absorb excessive salt not only from the food we consume, but also from an unsuspected source: the salt-softened water in which we bathe. Because the American Heart Association now warns that salt-softened water can cause an elevated sodium level, many health-conscious Americans no longer drink salt-softened water. Few realize, however, that we receive a lot of unwanted sodium every time we take a shower or a bath or wash clothes in softened water. Sodium is very efficiently absorbed through the skin and topically ingested salt has become a common culprit of excess sodium.
Part two of this column will appear in the next issue (May/June 2003) of Herbs for Health.
Ann Louise Gittleman, Ph.D., C.N.S., is one of the foremost nutritionists in the United States. She is the author of The Fat Flush Plan (McGraw Hill, 2001), Eat Fat, Lose Weight (Keats, 1999), and Why Am I Always So Tired? (Harper San Francisco, 1999).