What is sodium?
Sodium is one of the most abundant minerals on the planet. The sodium atom is most comfortable when it gives up an electron. Thus, sodium in foods as well as in the body will have a positive charge (Na+). In light of the involvement of sodium in the electrical events of the body, we often refer to sodium, along with chloride and potassium, as electrolytes. Again, an electrolyte is a substance that when dissolved into a body of water will increase the speed of the electrical conduction of the water.
What foods and other substances contribute to our sodium intake?
The adult diet can include 3 to 7 g of sodium daily, which is a lot compared to other minerals. Oddly, the natural sodium content of most foods is very low. Typically, more than half of the sodium consumed is added to foods by food manufacturers for taste or preservation purposes. Some of the foods having higher sodium content are snack foods (e.g., chips), luncheon meats, gravies, cheeses, and pickles. Also, sodium is added in the kitchen during cooking and by “salting” foods at the table. The sodium occurring naturally in foods such as eggs, milk, meats, and vegetables may provide less than one-fourth of the total sodium people consume. Drinking water can also contribute to sodium intake along with certain medicines.
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Within the past few decades many people have become concerned about how sodium in their diet might impact their health. This has applied pressure upon food companies to reduce the sodium content of some of their products. In order for a product label to make certain sodium-related claims, it must meet the criteria
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How much sodium do we need daily?
The AI for sodium is 1.5 grams for younger adults and teens which includes pregnancy and lactation. Since sodium is a key component of sweat, people who sweat profusely such as athletes, may need a little more sodium which is easily provided in foods. The AI decreases to 1.3 for people over 51 and then 1.2 grams over the age of 70. It is important to remember that sodium is 40% of the weight of “salt”.
What does sodium do in the body?
Sodium is very well absorbed (about 95 percent) from the digestive tract. Therefore the primary means of regulating body sodium content is through urinary loss. Sodium is the predominant positively charged electrolyte dissolved in extracellular fluid. This, of course, includes the blood. Because of its abundance in the body, sodium is perfect for serving fundamental roles in the electrical activity of excitable cells such as muscle and neurons.
Sodium is also involved in regulating body water content as water is naturally attracted to sodium. Water will always move from one area to another in an effort to balance the total concentration of dissolved substances in both areas. This process is called osmosis and is a fundamental law of nature. Under certain circumstances the body will adjust the amount of sodium lost in the urine to decrease the amount of urinary water loss. This may occur as an adaptive measure during dehydration or a reduction in blood pressure such as after significant blood loss. Aldosterone is the principal hormone that governs the amount of sodium in urine.
Can sodium deficiency develop?
Unlike most essential nutrients whereby aberrations resulting from a diet deficiency can take weeks, months, or even years to develop, electrolyte imbalances can lead to alterations much more rapidly. A reduced level of sodium in the body would result in alterations in the activity of excitable tissue, which certainly includes the brain, nerves, and muscle. This can occur within a day or two.
Because of the abundance of sodium in the human diet the potential for a deficiency is somewhat low. However, certain situations may place some people at a greater risk. These include eating a very low sodium diet in conjunction with excessive sweating and/or chronic diarrhea. Still, even under these conditions deficiency is very rare. Excessive sweating makes us thirsty and beverages would probably include some sodium. Furthermore, since the sodium concentration in our sweat is lower than in our blood it would take the loss of a couple of pounds of body weight in the form of sweat before any distress would occur.
Can sodium be toxic?
Provided that the kidneys are operating efficiently humans can rapidly remove excessive diet-derived sodium from the body without concern. However, individuals eating a very salty diet should include more water in their diet. Since water is attracted to sodium, more water will be urinated along with the excessive sodium. For people experiencing significantly decreased kidney performance, sodium becomes more of a concern. Dialysis may be necessary to remove excessive sodium and other substances from their body fluid.
Ingesting salt tablets on a hot day used to be a common practice, especially for athletes. However, this practice is no longer recommended for several reasons. First, it can cause intestinal discomfort and possibly diarrhea. Second, it would add more sodium to the body than is lost in sweat. To correct the elevated sodium concentration in the blood, more urine would have to be produced. This would lead to more water loss from the body, which during athletic performance could be a problem.
