Chemically, salt is sodium chloride; table salt is 40 percent sodium and 60 percent chloride. Your body has various mechanisms that work constantly to keep sodium and potassium in proper proportion. However, if you eat like most Americans, you probably consume more salt you need and you likely underconsume potassium. Too much salt can lead to high blood pressure, but potassium's job is to counterbalance sodium and dampen its effects.
The Body Electric
Sodium and potassium are two electrolytes -- particles that form when your body metabolizes them from your diet. They literally hold electric charges that allow them to determine where and how the fluids are distributed throughout your body. This is an important function because your cells must stay awash in fluid, both internally and externally, to work properly. Sodium and potassium are both positively charged, but the chloride in sodium is negatively charged. Electrolytes move in and out of cells, carrying nutrients and waste with them, and fluids follow their charge around. This makes electrolytes regulators of body fluids. Sodium and potassium both play a role in nerve impulses and muscle function, as well as in balancing other electrolytes. Keeping electrolytes maintained at their proper level is critical. Even the smallest deviation can result in serious and life-threatening health issues. In the case of potassium and sodium, the major concern in hypertension and heart disease.
Sodium Works
Most Americans consume sodium in the form of salt. Sodium helps control the movement of fluid across cell membranes. It has different function within cells than in the liquid environment outside cells. Your body contains channels that carry sodium from areas of high concentration to places where sodium is less concentrated. Your kidneys act as a filter for sodium. If you consume too much, your kidneys can't keep up and get rid of enough. As a consequence, your sodium levels build up, which can cause high blood pressure. With excessive consumption of salt common, high blood pressure is also common among Americans. According to 2010 information released by the Centers for Disease Control and Prevention, 33 percent of adults have the condition.
Potassium Power
Like sodium, your body needs potassium for normal cellular function. Having a diet deficient in potassium can lead to irregular heartbeats muscle weakness and glucose intolerance. Moreover, it can lead to salt sensitivity, a condition in which sodium's effect on blood pressure is intensified. Also like sodium, your kidneys excrete potassium, usually as part of the dynamic balancing act that is always taking place between fluids and electrolytes. Moreover, potassium ion channels disperse potassium wherever its concentration is low by tapping into areas where it's high.
The Connections
At certain levels, salt intake can affect your potassium levels, and the same is true in the reverse. According to the Institute of Medicine, intake of potassium can increase urinary sodium excretion. Sodium intake, however, has to be extremely high, about 6.9 g daily, to cause a net potassium loss. The CDC reports that the average American consumes about 3.4 g daily, which is still significantly higher than recommended amounts. In addition, sodium and potassium work interdependently through the sodium-potassium pump. This is a specific mechanism in which cells flush sodium out and take potassium in based on needs. Perhaps most significant to your health is potassium's anti-hypertensive effects. Potassium blunts the effects of sodium on both blood pressure and the formation of kidney stones. A diet that is low in potassium amplifies the effects of sodium, but you can change things by consuming more potassium or supplementing.
Balance is Key
Your body has sophisticated machinery to keep electrolytes in specific proportions. You can throw your sodium and potassium out of balance through an unhealthy diet. According to an article by group of University of California, San Francisco researchers published in 2006 in the "Journal of the American College of Nutrition," this is a common imbalance among Americans. While most consume too much salt, few get enough potassium, according to the Dietary Guidelines for Americans 2010. The Institute of Medicine states that most adults need a minimum of between 1.2 and 1.5 g of sodium daily, 1.8 to 2.3 g of chloride and 4.7 g of potassium.
References
- "Journal of the American College of Nutrition"; Relationship and Interaction between Sodium and Potassium; R. Curtis Morris et al.; 2006
- Columbia University Go Ask Alice!; What is the Main Purpose of Electrolytes?; February 23, 2001
- Winona State University Biology: Electrolyte Homeostasis
- National Academies Press; Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate; Institute of Medicine; 2005
- Merck Manuals Online Medical Library; Minerals and Electrolytes;
- Thomson Brooks/Cole: Sodium/Potassium Pump
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