Salt and blood pressure relationship

The most familiar sodium compound is salt. Table salt is actually sodium chloride (40 percent sodium and 60 percent chloride). And sodium is not only found in salt shaker but also in foods and products that have been made with salt or one of its cousins, such as monosodium glutamate (MSG) and sodium bicarbonate (baking soda).

Sodium chloride is an ionic compound with a melting point of 800° C. Within a piece of salt, the ions are arranged in a structure called a crystal lattice, in which each sodium ion is surrounded by six chlorine ions and each chlorine ions is surrounded by six sodium ions. When salt is dissolved in water the ions are pulled apart and can move around.

Sodium is an essential mineral. Its main role is to help maintain the right balance of fluids in human body. It also helps transmit nerve impulses that influence contraction and relaxation of the muscles.

If the kidney can’t eliminate enough salt in urine, sodium starts to accumulate in blood. Sodium naturally attracts and holds water, which increases the total volume of the blood. This, in turn, makes the heart work harder to pump blood through the body, which increases the blood pressure.

Salt and blood pressure relationship

Sodium consumption

Sodium is a mineral that occurs naturally in food. Sodium is required by the human, as it part of all of the extra cellular fluid of the body: including regulating blood pressure; transmitting nerve impulses; and helping muscles, including heart muscle.

It is also necessary for the production of hydrochloric acid in the stomach, thereby supporting digesting function.

About 50 percent of the body’s sodium is in fluids and the remaining is found within the bones.

Since table salt is used by essentially all people, there is little likelihood for deficiencies except in the disease involving prolonged vomiting or diarrhea.

Table salt is actually the common name for sodium chloride. It’s 40 percent sodium and 60 percent chloride.

Sodium also appears in food as sodium bicarbonate (baking soda) and sodium benzoate (a preservative).

The consumption of salt and other sodium sources should be limited. Sodium has been shown to lead to hypertension (high blood pressure) and it is recommended to keep daily consumption level between 110 and 3300 mg.

The average in the typical American diet is closer to 6000 mg. The majority of sodium in the United States diet is from sodium added during food processing and by restaurant and other food service such as cafeterias and catering services.
Sodium consumption

The importance of sodium

SODIUM compounds were known and used extensively during ancient times, but the element was not isolated until 1807 when an English chemist used a process called electrolysis to extract pure metal from sodium hydroxide. Although sodium was long believed to be a dietary essential, final proof was not obtained until 1918 when Osborne and Mendel conducted experiments on lab animals.

Although we hear much today about the adversities of salt, the body does require small amounts. Sodium is the chief cation (positively charged ion) in extracellular fluid and, acting with potassium, maintains proper body fluid balance. 

Sodium and potassium also work together to regulate muscle contractions and nerve stimulation. Sodium helps keep calcium and other minerals soluble in the blood and is necessary for the production of hydrochloric acid in the stomach. Acting with chlorine, sodium assists in keeping blood lymph healthy. It also purges carbon dioxide from the body.

Those on salt-restricted diets are advised to avoid all products containing salt. Studies are now indicating that if an adequate intake of water each day (8-10 glasses minimum) is maintained and caffeine drinks are eliminated, some dietary sodium becomes a benefit rather than a health risk. 

A chloride deficiency can occur when there is a loss of sodium caused by excessive sweating, chronic diarrhea, vomiting, and with some kidney disorders. These losses may result in metabolic alkalosis and disorders of the body's pH which can lead to coma and death. Therefore, maintaining an adequate sodium level is vital. 

However, it is estimated that the average consumption of sodium is more than twenty times the amount needed by the metabolism. Most fast foods and processed foods are oversalted. This interferes with the utilization of nutrients. The oversalting is done supposedly to improve flavor, but also to cause the kind of thirst that is a boon to the soft drink industry.

There is no official RDA, but the National Academy of Sciences estimates that a safe daily intake would be 500 mg. for most adults, but slightly higher amounts for pregnant or lactating women. 

Some other sources have suggested the RDA should be 2000-3500 mg. per day, but this seems excessive for the average need unless there is profuse sweating during prolonged exercise. It is also suggested that a single gram of sodium chloride for each kg. of water drunk is sufficient. More than 13 grams of sodium chloride daily can produce toxic effects.
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