Salt Deficiency Could Be Life-Threatening. Here Are the Lesser-Known Dangers

The detrimental effects of high salt intake on the heart are undeniable, but surprisingly, consuming too little salt can also increase heart disease risk.

Illustration by The Epoch Times, Shutterstock

We are constantly warned of the dangers of eating too much salt. Some people, however, face a greater danger from eating too little salt—even as they try to eat less of it.

The Importance of Salt

Salt has been used since ancient times for food preservation and seasoning. Ancient people often obtained salt by boiling spring water rich in minerals. In fact, some of the world’s oldest known salt mines can be traced back to around 6000 B.C.

The term “salary” originates from the Latin word “salarium,” which referred to the allowance given to Roman soldiers to purchase salt, reflecting the importance of salt in daily life. Throughout human history, certain wars and the rise and fall of cities have been closely linked to salt.

However, when it comes to salt, our immediate thoughts are often, “I shouldn’t consume too much,” “It causes high blood pressure,” or “It is bad for my heart.” In reality, salt is indispensable for our life functions.

The scientific name for table salt is sodium chloride, the primary sodium source in the diet.

“Sodium is really what we need to maintain our life functions,” Cindy Chan Phillips, a registered dietitian, told The Epoch Times. “Sodium is one of the electrolytes. Without that, we will die.”

As an essential nutrient in the human body, sodium regulates the balance of fluids and electrolytes, keeping blood pressure within a healthy range. Ms. Phillips described sodium as a sponge that can absorb and carry water. “Where sodium goes, water goes,” she said.

Sodium is also responsible for the transmission of signals in muscle and nerve cells. “Without the adequate level of sodium, our nerve cells will fail to fire,” Ms. Phillips said.

Sodium also allows our muscles to contract when we need them to contract and relax when we need them to relax. “Our heart and our lungs are also muscles, too. For a heart to pulse, it also needs to know when to contract and relax by itself,” she said.

The chloride ions in table salt are essential components of stomach acid. In other words, the secretion of digestive fluids also requires salt.

The scientific name for salt is sodium chloride. Both sodium (Na) and chloride (Cl) are critical for life functions. Illustration by The Epoch Times, Shutterstock

The mean sodium content in an adult male is 92 grams, half of which (46 grams) is found in the extracellular fluid (including plasma and blood). Approximately 11 grams is located in the intracellular fluid, and the remaining 35 grams is found in the skeleton.

Who Is Prone to Salt Deficiency?

“To say salt deficiency is rare is simply not looking at the data or looking at the people suffering around us,” James DiNicolantonio, a cardiovascular research scientist and doctor of pharmacy at Saint Luke’s Mid America Heart Institute in Kansas City, Missouri, and author of “The Salt Fix,” told The Epoch Times.

For many years, Mr. DiNicolantonio has studied the impact of salt on the human body. Since 2013, he has published 15 research papers on salt in academic journals. He said that the misconception that people do not lack salt is due to few people undergoing proper salt deficiency testing. Low sodium levels in the blood are the most common electrolyte abnormality among hospitalized patients. He also stated that in the United States, millions of people are diagnosed with hyponatremia every year. Additionally, millions are hospitalized because of hypovolemia, “many times due to lack of salt.”

Hyponatremia occurs when the sodium level in the blood is abnormally low. It is a common electrolyte abnormality among both outpatient and hospitalized patients. Low salt intake is considered one possible cause of hyponatremia; according to an earlier study, low salt intake and high water intake led to the hospitalization of 5,259 people in England between 2006 and 2007.

Hypovolemia refers to a decrease in extracellular fluid volume when the loss of salt and liquid exceeds intake. Salt plays a crucial role in maintaining adequate blood volume, ensuring that our tissues are filled with oxygen-carrying blood and nutrients.

Researchers at the Johns Hopkins University School of Medicine conducted a study in which they measured plasma specific gravity in more than 300 individuals, including young adults, retirees, and older patients sent to the emergency room. Among the older emergency room patients, nearly 40 percent had probable or confirmed hypovolemia. Even among young adults and older individuals who did not report any abnormalities, 5 percent and 8 percent had hypovolemia, respectively.

Salt rocks inside the Khewra Salt Mine, the world's second-largest salt mine, and Khewra Salt Mine interiors. Bay_Media/Shutterstock

Hypovolemia may also be related to insufficient water intake. “Older people are prone to volume depletion, as they have blunted thirst mechanisms and, therefore, may not realize they are getting insufficient salt and water,” Dr. Jason Fung, a nephrologist specializing in Type 2 diabetes, told The Epoch Times. He also mentioned that dementia could affect the diet and drinking habits of older people, leading to inadequate blood volume.

However, he also noted that salt deficiency is not common in most parts of the world because salt is cheap and widely used, often added to food for flavor enhancement.

Ms. Phillips stated that while salt-deficient patients seeking consultation with her are rare, salt deficiency in the population cannot be dismissed. “In epidemiology, sometimes a low incidence could also be due to inadequate diagnosis,” she said.

Older adults living in care facilities or hospitals may have insufficient sodium levels in their blood due to medication use or certain health conditions such as heart disease, kidney disease, or cancer. Additionally, excessive vomiting, diarrhea, and sweating can result in a significant loss of salt from the body.

Mr. DiNicolantonio pointed out that excessive caffeine intake, high temperatures, sleep apnea, diuretic use, excessive consumption of plain water, low-carbohydrate diets, and fasting can all lead to salt loss. He also mentioned that individuals with hypothyroidism are prone to salt deficiency, as thyroid hormones play a role in regulating sodium reabsorption in the kidneys.

Salt Deficiency Can Damage the Heart and Increase Mortality

Despite some dietary guidelines that recommend limiting salt intake for the general population to a relatively low level (less than 1 teaspoon), numerous studies have shown that for non-hypertensive individuals and those without cardiovascular health issues, maintaining salt intake at 1 to 2 teaspoons per day is healthier. Salt intake that is too low may actually lead to an increased risk of cardiovascular events and mortality.

One teaspoon of salt is approximately 5 grams, of which 2.3 grams is sodium.

A study published in the European Heart Journal in 2020 examined sodium intake and life expectancy in 181 countries and found that sodium intake was positively correlated with life expectancy and inversely correlated with all-cause mortality. The study concluded that dietary sodium intake is not the culprit in shortening lifespan or a risk factor for premature death. However, it also emphasized that “these data are observational and should not be used as a base for nutritional interventions.”

The detrimental effects of high salt intake on the heart are undeniable, but surprisingly, consuming too little salt can also increase the risk of heart disease.

A prospective cohort study published in The Lancet in 2018 involving nearly 10,000 individuals from 18 countries over a median follow-up of eight years revealed that the risk of cardiovascular events significantly increased for participants in the highest tertile of sodium intake (more than 5 grams per day). However, the risk of cardiovascular events also increased considerably for participants in the lowest tertile of sodium intake (less than 4.5 grams per day).

A review published in Nutrients in 2021 suggested that the optimal sodium intake for the lowest risk of cardiovascular disease and mortality is between 3 grams and 5 grams per day. The researchers called it the “sweet spot.” Both higher and lower intake levels were associated with increased adverse health outcomes.

According to a study published in Nutrients, 3 grams to 5 grams of sodium per day is optimal. The Epoch Times

There is no perfect method to measure a person’s daily salt intake accurately. Some studies estimate it through dietary surveys, while others measure sodium in urine and use the indicator of daily sodium excretion.

The New England Journal of Medicine published a tracking study in 2014 involving more than 100,000 people from 17 countries. After a mean follow-up of 3.7 years, researchers found that sodium excretion and the risk of adverse cardiovascular events and death followed a “J-shaped” curve. They suggested that the ideal daily sodium intake is between 3 grams and 6 grams, a recommendation that Mr. DiNicolantonio also supports.

Other research suggests the ideal daily sodium intake is between 3 grams and 6 grams. The Epoch Times

One possible reason for there being a sweet spot is that low salt intake can stimulate the rise of hormone levels unfavorable to cardiovascular health, as well as an increase in total cholesterol and triglycerides. “Because for heart disease, blood pressure is only one of the risk factors for developing these health conditions. Higher levels of these hormones are also quite deleterious,” Dr. Fung said. “In fact, blocking these hormones forms the very basis of our modern treatment for atherosclerosis.

“It’s a trade-off in that you can lower blood pressure, perhaps a little bit, but you’re going to pay for that with an increase in these other hormones.” The result is that “you have lower blood pressure but higher risk of heart attack.”

He used Japan and the United States as examples: While salt intake in Japan is relatively high compared to the rest of the world and even higher than in the United States, the risk of heart disease among Japanese people is much lower than among Americans.

That said, researchers generally agree that consuming more than 2 teaspoons of salt daily has a negative health impact.

Common Signs of Salt Deficiency

Individuals with salt deficiency may experience various discomforts, but these symptoms are often attributed to other causes rather than insufficient salt.

1. Fatigue, Muscle Weakness, and Cramps

This is a common sign in people with salt deficiency, similar to symptoms seen in chronic fatigue syndrome patients. Mr. DiNicolantonio pointed out that the lack of salt results in insufficient blood volume and circulation to organs such as the brain and muscles, leading to fatigue and muscle weakness. Additionally, salt deficiency also reduces tissue fluid, which can cause muscle nerve endings to deform or contract, triggering muscle cramps and pain.

Japanese researchers conducted a series of tests on 75 older people with low blood sodium levels and 2,907 with normal sodium levels. The tests included assessments for muscle mass index, grip strength, walking speed, and one-leg standing time. The results showed that even mild hyponatremia can lead to physical dysfunction, such as balance impairment and gait disturbances, making these people more prone to frequent falls.

2. Brief Dizziness When Getting Up

Some people experience dizziness when getting up from a squatting or sitting position, often unaware of the cause. This condition, known as orthostatic hypotension, may be caused by salt deficiency. Patients with this condition are frequently advised to increase their salt intake to alleviate symptoms. Additionally, Mr. DiNicolantonio noted that postural orthostatic tachycardia syndrome often requires higher salt intake for treatment.

In a small-scale study of patients with unexplained fainting, the daily administration of salt for eight weeks significantly improved and enhanced orthostatic tolerance in 70 percent of the patients. It is worth noting that those who responded positively to salt therapy had low sodium excretion in their urine before treatment, indicating salt deficiency.

3. Headaches, Forgetfulness, and Mental Confusion

Salt plays a crucial role in the transmission of signals between nerve cells. When the body lacks salt, neuronal function decreases. Additionally, salt deficiency can lead to reduced blood volume and insufficient blood flow to the brain, causing headaches and forgetfulness.

This becomes even more critical in the brains of patients with acute hyponatremia. Low salt levels in the blood can cause cerebral edema, leading to neurological symptoms such as seizures, impaired mental status, coma, and even death. Chronic hyponatremia patients also experience changes in the brain, but because it occurs gradually, they may be asymptomatic. However, they may experience gastrointestinal symptoms, loss of appetite, and subtle neurologic abnormalities.

4. Depression and Stress

Mr. DiNicolantonio highlighted that a lack of salt can activate the sympathetic nervous system, raising levels of adrenaline and noradrenaline. This, in turn, contributes to worsened sleep and increased stress.

In the study involving the older Japanese people mentioned earlier, mild hyponatremia was also found to be associated with depressive mood. Depression is linked to the substance glutamate, which may be reduced in brain cells due to hyponatremia.

Moreover, a lack of salt can result in the loss of sodium, calcium, and magnesium, while a magnesium deficiency can induce depression and anxiety. Researchers have found that since the skeleton is the primary reservoir for sodium, calcium and magnesium are depleted when sodium is drawn from the bones. It is worth noting that even with sufficient calcium and magnesium in the diet, a lack of sodium can still lead to deficiencies in these minerals. Notably, a deficiency in calcium and magnesium can increase the risk of osteoporosis.

Animal experiments have confirmed that a lack of salt can alter the behavior of mice, specifically by inducing anhedonia (a lack of pleasure), one of the main criteria for the diagnosis of major depressive disorder.

Apart from the aforementioned symptoms, some cases of indigestion and gastroesophageal reflux disease may also be linked to a deficiency of salt in the diet. This is because insufficient salt intake can affect stomach acid secretion, thereby interfering with food digestion and nutrient absorption.

Different types of salt. Brent Hofacker/Shutterstock

How the Body Regulates Salt Is ‘Very Smart’

A constant craving for food, especially sweets, could be a sign of insufficient salt in the body.

The body has intricate and strict automatic mechanisms to regulate salt levels. Put simply, when the body lacks salt, the brain detects this and sends signals to the body, leading to changes in related hormones. These changes then trigger an interest and need for salty foods. Conversely, when the body has an excess of salt, other hormones are secreted, promoting thirst and appetite and prompting one to drink more water.

“Your body is very smart at regulating your intake of essential minerals, especially the one as important as salt,” Mr. DiNicolantonio said. “If you consume too much salt in one meal, your body has an innate safety mechanism that causes you to crave less salt later in the day.”

An animal experiment demonstrated that rats, initially averse to saltwater, will immediately consume it avidly after being injected with hormones signaling the body’s need for salt.

“A lack of salt activates the dopamine reward center in the brain to cause us to seek out salt,” Mr. DiNicolantonio said. However, this can lead to excessive consumption of processed foods to obtain salt, inadvertently resulting in the intake of other addictive substances, such as sugar.

Next:

Part 2 - The Healthiest Kinds of Salt: These Contain More Nutrients and Less Sodium

Since salt is an essential ingredient, knowing which type is healthiest is important.