The Whole Truth About Low-Salt Diets
Through the years, salt has become a staple for most people. We crave it on our french fries. Doctors tell us to use it in moderation. Do we need salt? How much is too much?
The History of Salt
In Poland, the Wieliczka Salt Mine satisfied people’s need for table salt from the 12th century up until 2007. The mine, considered the 14th oldest business in the world, spans 300 kilometers and contains an underground lake, a cathedral made of salt and countless salt sculptures.
Refrigerators have only existed for a matter of decades. Prior to this, food spoilage was a major problem, especially for meat. If an animal was slaughtered, the meat needed to last more than a few days. Food-borne illness ran rampant. People were often left to gamble between getting protein nourishment or getting sick.
Before knowledge of microbial infestation, it was discovered that meat covered in salt could be kept long-term without the risk of getting sick. A large animal could be slaughtered and cuts could be covered with salt and hung from the rafters for a later date. Meat could be barreled in salt brine and brought aboard ships for the long journeys to distant lands. We now know that bacteria making a play to infect the meat would crenate when exposed to the salt. The salt would draw out all of the fluid in the bacteria through its semi-permeable membrane wall, effectively killing it.
And we developed a liking for salt.
Today, salt shakers are present on most every eating table and we often find ourselves craving salty things.
The Physiology of Salt: How Salt Affects The Body
In some ways we are like the ocean - a teaming fluid-based system of organs and organisms of different sizes, kept in a salty balance. The chemical name for table salt is sodium chloride. Both sodium and chloride are essential in our body, tightly regulated both inside and outside of body’s cells.
Sodium is essential in several metabolic chemical pathways that regulate body energy.
Chloride is an important component of stomach acid among other things.
When levels are off, so are we. For instance, the condition of low sodium (hyponatremia) causes confusion, coma and can even lead to death. When people are dehydrated or need fluid volume, we give liquid replenishment intravenously (that bag hanging on a pole hooked via tubing to a vein). This fluid is saline, a balanced solution of sodium, chloride and water. Simply giving water this way could eventually kill a person.
Too much? Too little?
While salt is important, this doesn’t mean that we should use the shaker as much as possible! Typical diets already provide more than enough salt and it is known that excess salt raises blood pressure and that long-term elevations in blood pressure increases risk for heart disease and stroke.
Lately, there's been a lot of discussion around cutting salt intake for lowered blood pressure. The DASH study (Dietary Approaches to Stop Hypertension) did show that a prudent diet low in fat and salt and high in fruits and vegetables can lower blood pressure.
High blood pressure is generally considered over 140 mmHg systolic and 90 mmHg diastolic. When salt is isolated, the results amount to only a few mmHg of systolic blood pressure, about 3 mmHg. On the other hand, while that may not seem like a lot when a blood pressure is running 165/100 mmHg, studies also show that every mmHg lowered, lowers cardiovascular risk over time!
Should you start buying salt substitute?
Lowering salt is helpful - but not very helpful. I always encourage my patients to engage in healthier lifestyles, but educate them on the magnitude of reward for the effort. Conservative lifestyle success in lowering blood pressure usually comes from the combination of healthier eating (including lowering salt intake) and weight loss.
Salt is as ubiquitous in our lives as it is in the waters of the ocean. We need it… in moderation and balance. Once used to improve health through preservation of food, we have come to enjoy the taste of salt. If you like salt and you don’t have high blood pressure, don’t worry! While the lowering of salt in our diet yields modest results on blood pressure, it is worth considering in a plan to conservatively lower blood along with a healthy diet and weight loss.