Matt Brundage publications

Salt, Sodium, and Hypertension

Salt: a world historySalt is a compound consisting of the elements sodium (Na: about 40%) and chloride (Cl: about 60%). The essential function of sodium in the human body is to maintain the equilibrium of fluids, or more specifically, extracellular fluid. Water is drawn to sodium — when there is a deficiency in sodium in the body, there is usually a deficiency in water as well. Potassium, on the other hand, is responsible for intracellular water volume in the body. Our water concentrations depend mainly on the minerals sodium and potassium.

There needs to be a proper balance of sodium and water in the body. An overabundance of one creates desire for the other. When we sweat, we lose both salt and water — merely drinking water will leave us salt deficient. The best, and most obvious, way to replenish yourself is to drink salt-water, or more conveniently, sports drinks. Salt-water does quench your thirst better than regular fresh water.

Safe amounts of daily sodium intake range from 500 mg to 3300 mg per day. Currently, the average American adult currently consumes three times the recommended daily allowance of sodium (RDA is 2400 mg.). Sodium deficiency is rare, mostly because we eat so much of it. Symptoms include muscle cramps, nausea, vomiting, dizziness, and in extreme cases, shock or coma.

High blood pressure

One condition that most likely comes to mind when one hears sodium is high blood pressure (or hypertension). The term "blood pressure" is a bit of a misnomer. It doesn't denote the pressure of the blood — it measures the pressure blood exerts in its passage. Excess sodium in the blood requires excess water in the blood to balance it. And this excess water means that the heart is working overtime, pumping a greater volume of blood than normal. This increased volume of blood stretches the arteries and blood vessels, putting one at greater risk for strokes and heart failure. Excess sodium in the blood also puts strain on the kidneys, making them work overtime to remove the salt. Hypertensive people are at greater risk for kidney failure as well.

Blood pressure is one of those conditions that rely as much on the individual as on the diet or lifestyle of the individual. And what might seem to increase blood pressure in one person might not increase it in another. Some of my sources deem hypertensive people as salt-sensitive or sodium-sensitive because of how their bodies react to it. About ⅓ to ½ of all hypertensives can be considered salt-sensitive. With these people, hypertension is just a symptom of their "allergy" to salt. But in other hypertensives, changes in diet will have no effect on their blood pressure. Hypertension currently afflicts about one in six Americans. Reducing salt intake for some of these individuals may help alleviate this condition. Maintaining a healthy weight may also be beneficial to hypertensive people.

Maintaining a stable and healthy blood pressure

  • Stop using the salt shaker. Adults can reduce their sodium intake by 33% or more by not using their salt shakers.
  • Rely less on processed foods, which use loads of salt for processing and stability.
  • Maintain a healthy sodium/potassium intake ratio (1:1 or 2:3). This balance of sodium and potassium is essential for proper nerve impulses, conduction, and muscular contractions. When our bodies have an overabundance of sodium, potassium acts as a cleaning agent, and helps to flush our system of excess sodium. Great sources of potassium in food include bananas, potatoes, tomatoes, and oranges.
  • Get proper amounts of calcium, potassium and magnesium. Reports have indicated that people with low calcium intake are at greater risk of developing high blood pressure. Also, an increase in potassium in the diet has been shown to decrease blood pressure in people who were deficient. Another word on calcium: diets high in sodium can lead to calcium loss in urine. Bottom line: get your calcium!

Sources of high blood pressure

  • Obesity.
  • Lack of exercise.
  • High amounts of sodium, meats and cholesterol in the diet. Blacks also show a consistently higher preference for salty foods than whites and are thus more susceptible to developing unhealthy blood pressures.
  • Family history. (predisposition to being "salt-sensitive")
  • Low amounts of calcium and/or potassium in the diet.
  • Pregnancy and oral contraceptives. (Subsequently, women are more susceptible to developing high blood pressure than men.)
  • A smoking habit.

Monosodium glutamate (MSG)

Monosodium glutamate is made commercially from fermented sugar cane or soy beans and is essentially a salt of glutamic acid. MSG, in addition to enhancing the aromas of foods, has a salt-like flavor of its own. MSG has a number of health drawbacks for certain people. Yes, there is a term for this: Chinese Restaurant Syndrome. Headaches, dizziness, burning and even numbness can occur with some people after eating food containing high levels of MSG (1 to 3 grams). truthinlabeling.org is a site specifically devoted to MSG, the prevalence of it in common foods, and the food industry's reluctance to label food products as containing MSG.

Sodium trivia

Sodium is the most common inorganic substance in the human body… High levels of sodium consumption have been linked to coronary heart disease… The consumption of alcohol has been linked to craving salty foods. This may explain why salty peanuts go so well with beer… The craving of salty foods has been linked to digestive cancers (stomach, colon, pancreas)… Americans are eating 6 to 8 grams of sodium every day. Asians are eating 25+… An average 155 pound man has 130 grams of sodium in his body. A mere 3 grams a day will maintain that amount… Increases of sodium have been used to combat chronic fatigue syndrome…

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Works Cited and Consulted

Deatherage, F.E. Food for Life. Written by a biochemist, Food For Life explores the chemical makeup of just about everything. It also contains in-depth nutritional tables similar to the ones in the back of our textbook.

healthfinder.gov A simple layout and an overall pleasing-to-the-eye page.

Labuza, Theodore P & John W. Erdman Jr. Food Science and Nutritional Health: An Introduction. This title was probably used as a college textbook. Information on sodium is sparse, but succinct.

Nugent, Nancy, et al. Food and Nutrition. Lavishly illustrated.

saltinstitute.org My favorite salt site. I recommend it. Loads of information about salt, an extensive FAQ page, information on the salt industry, news, a search function and more.

Tisdale, Sallie. Lot's Wife — Salt and the Human Condition. Perfect — an entire 200-page book written expressly about salt. I recommend it.

Toussaint-Samat, Maguelonne. Small ImageHistory of Food. It reads like a TV documentary. If one is looking for the nutritional aspects of salt, this book is of little use; but it does provide a lengthy history of salt and a section on salt mining.

truthinlabeling.org MSG-central. Pertinent links in almost every paragraph, loads of information about MSG. The site itself is unattractive, but navigable.

Wardlaw, Gordon. Contemporary Nutrition: Issues and Insights. I have no shame. No really, this book is alright.

Weil, Andrew. Small ImageEating Better For Optimum Health. Includes a quick and enlightening summary of sodium.