Salt was used long before recorded history began. One of the earliest known writings, the Chinese Png-tzao-kan-mu, mentioned more than 40 types of salt. This work was written over 4700 years ago. Even older settlements have been found around the world with various devices such as pottery used to evaporate water to leave the salt behind. It is speculated by some that major civilizations flourished in arid regions at the edge of vast deserts due to the physiological need for salt.
What Is Salt?
Salt, or sodium chloride, is a chemical compound. Salt occurs naturally in many areas of the world. Salt crystals are cubic in form—if you view salt through a magnifying glass, you will see small "squares" or cubes.
Salt is an essential nutrient—your body requires both sodium and chloride, and cannot manufacture these elements on its own. This is why there is a human gustatory receptor (taste bud) specifically for salt, forming one of the basic components of "taste". Salt is an electrolyte and has a slight charge. Salt preserves food by making it difficult for microorganisms to live—the salt draws water from the cells of microorganisms and dehydrates them.
In the body, salt helps to regulate blood volume and pressure. The relationship between salt and blood pressure was known as long as 4,000 years ago, when the Chinese emperor Huang Ti wrote of the connection between salt and a "hardened pulse." Many studies have shown that increasing or decreasing salt intake for salt-sensitive individuals can have a direct impact on blood pressure. Within the body, salt serves as part of the ion pump. Just as salt formed a hostile environment for microorganisms by dehydrating them, salt controls water balance in the human body. The sodium/potassium pump is a prime example of how electrolytes are critical to health (sodium and potassium are both electrolytes). Two potassium molecules are pulled into a cell, and three sodium molecules are pumped out. This is an endless cycle, with the net result that cells carry a slightly negative electrical charge.
For many years, controversy has existed with respect to the optimal amounts of salt in the diet. Unfortunately, many studies focused on the salt content of foods without taking into account other electrolytes. Biologically and physiologically, sodium intake alone does not regulate the sodium/potassium pump—potassium intake is important as well! More important than the amount of sodium in the diet is the ratio of sodium to potassium. While food labels are required to report sodium content, they are not required to report potassium content, which makes analyzing potassium intake extremely difficult.
Recent research suggests that this ratio is critical. While many studies have focused on high sodium content in the diet, it appears that problems with hypertension may be related more to an inappropriate ratio of sodium to potassium. Processed foods are extremely high in sodium. The major sources of potassium are fruits and vegetables. In recent years, the typical American diet has increased in the amount of processed foods and drastically decreased in the amount of whole, unprocessed foods such as fruit and vegetables. This means that sodium intake is potentially much higher than potassium intake.
What You Should Know About Salt
When monitoring sodium in the diet, it is important to consider two factors. The first factor already discussed is the ratio of sodium to potassium. In order to balance this ratio, it is important to eat whole, unprocessed foods and not to add excessive salt to meals. This will lower the amount of sodium in the diet. One should also increase the amount of fruit and vegetables consumed in order to increase potassium in the diet. The exact ratio is unknown, but research suggests that a 1:1 ratio is probably a good target. The typical American diet is more than a 5:1 ratio in favor of salt!
The second factor to consider is fluctuation of intake. Salt sensitivity is not sensitivity to salt in general. It is sensitivity to a drastic change of salt intake. If a person is taking 5 grams of sodium consistently, then suddenly goes on a low sodium diet, problems can occur with a radical shift in blood pressure. Similarly, someone on a "low sodium" diet who suddenly increases sodium intake may experience similar problems.
This is why many people who eat healthy throughout the week and then treat themselves to a "splurge" meal sometimes feel nauseous and can even experience elevated heart rate and blood pressure: it is the body's reaction to the sudden increase in salt intake.
The sodium/potassium pump affects fluid balance. The body monitors the amount of salt and potassium in the bloodstream, as the body has no mechanism for storing electrolytes. Sodium and potassium are typically filtered in the kidney. When a shortage of either exists, the body secretes hormones that drastically reduce excretion of electrolytes and fluids. This is why cutting out sodium too soon before a body building competition can actually cause the competitor to retain water—the body is reacting to the lowered intake by preserving fluids and electrolytes.
The lesson here is one of moderation. Salt is not the enemy, and by no means should it be eliminated from the diet. On the other hand, everyone should be aware of the role that sodium plays in a balanced nutrition program, to make sure that excessive salt is not being consumed. Balance salt intake with potassium intake. The preferred source of any vitamin, mineral, or other nutrient is always natural, unprocessed foods.
The Skinny On Salt
- Be more concerned with the ratio of salt to potassium than the actual amount of salt in the diet.
- Do not try to eliminate salt—it is essential and required by the body—instead, try to reduce excessive intake by focusing on whole, unprocessed foods and minimizing the amount of salt that you add to meals.
- Increase potassium intake by including 4-5 servings of fruit and/or vegetables in your daily menu.
- Focus on restoring electrolytes post-workout, preferably with a higher potassium-to-sodium ratio.
- Avoid frequent, high fluctuations in salt and/or potassium intake, as these may have an adverse effect on your blood pressure.