Salt is an essential nutrient for our health, yet health authorities often urge us to reduce our intake over blood pressure concerns.
There is perhaps a misconception that we should all reduce salt intake as much as possible.
But did you know that too little salt can also cause problems?
This article takes an in-depth look at sodium deficiency, salt, and its potential benefits and drawbacks.
What is the Difference Between Salt and Sodium?
First of all, people use the words salt and sodium almost interchangeably.
Is salt the same thing as sodium? Not quite.
Salt is a naturally occurring mineral with a crystal-like appearance, and it contains two elements; sodium (Na) and chlorine (Cl).
These two elements occur at a ratio of approximately 40% sodium to 60% chlorine (1).
As a result, the chemical name for salt is sodium chloride (NaCl), and it is essential not only for humans but for all animal life (2).
There are also many different kinds of salt we can buy.
Some of the more popular options include crystalline salts such as Himalayan pink salt, Fleur de sel, and sea salt. There is also common table salt, which has the appearance of a fine white powder.
Salt has been part of the human diet for thousands of years. Over the years, it has been vital for preserving food – especially before the advent of refrigeration.
Salt’s excellent preservation and moisture-controlling properties are the reason we can find it in a vast variety of foods.
Some of the most popular foods which contain large amounts of salt are bacon, sauerkraut, cheese, and kimchi.
Sodium is one of the two electrolyte minerals contained within salt. Along with chlorine, it plays a critical role in a range of biological processes.
The Benefits of Salt
Despite the persistent fear-mongering over salt, sodium is a mineral that is necessary for every cell in our body.
Quite literally, if sodium in our body falls too low (hyponatremia), then we may slip into a coma (3).
Here are some functions of sodium in the body;
- Blood pressure regulation: the joint action of sodium and potassium control the water volume of every cell. Therefore, they also contribute to blood pressure (4).
- Optimal muscular and nerve function: In conjunction with other electrolytes, sodium helps the nerves send electrical signals telling the muscles to contract (5).
- Maintains an optimal electrolyte balance in the body: Sodium is one of the minerals necessary for a proper electrolyte balance in the body (6).
- Supports a healthy metabolism: Iodine is critical for our thyroid health, so the intake of iodized salt can be very beneficial (7, 8)
- Improves blood sugar control: One thing many people don’t know about salt is that a sufficient amount increases insulin sensitivity. Likewise, very low salt intakes can lead to sodium deficiency and insulin resistance (9, 10).
- Helps maintain stomach PH: Consuming a low salt diet may result in insufficient secretion of hydrochloric acid (11).
Salt and Blood Pressure Regulation
Sodium determines the volume of fluid in our cells, and thus plays an important role in regulating blood pressure.
Despite claims that too much salt causes high blood pressure, it is not quite so simple.
In fact, a recent study utilizing a 16-year follow-up period found that participants consuming less than 2,500 milligrams (about 6g salt) of sodium each day had higher blood pressure on average than those consuming higher amounts (12).
Interestingly, this figure is very close to the ‘maximum’ salt intake of 2,300mg recommended by the dietary guidelines (13).
However, other studies show a long-term “high” intake of salt may lead to excessive levels of sodium in the blood, which can raise blood pressure (14).
The big question is: how much is too much and is that amount the same for every individual?
Furthermore, studies show only a “weak relationship” between high blood pressure and salt in the general population. Only some people exhibit large changes in blood pressure in response to salt, which is known as “salt sensitivity” (15).
In other words, we need salt, and it’s good for us, but there’s a delicate balance between sufficient and too much salt.
Salt Intake by Country
Here are the twenty countries with the highest salt consumption (16);
|Rank||Country||Salt Consumption (g per day)|
The first thing that stands out here is that these nations are predominantly Asian.
This makes sense because Asian cooking tends to use the most seasoning in the world.
Given we always hear too much salt raises blood pressure, surely these countries will have the highest blood pressure rates.
But is that the case?
Highest Blood Pressure by Country
According to the World Health Organization (WHO), the twenty countries having the highest rate of individuals with raised blood pressure are (17);
|Rank||Country||Raised Blood Pressure %|
|9||The Czech Republic||34.4|
|12||Bosnia and Herzegovina||34.0|
|14||Republic of Moldova||33.6|
|19||Republic of Macedonia||32.7|
Notably, you may notice that not one of the countries with the highest salt intake is in the top twenty.
Additionally, the countries with the highest prevalence of raised blood pressure are predominantly Eastern European.
So, what do the blood pressure rates look like for the nations with the highest salt intake?
Raised Blood Pressure Rates For the Nations Consuming the Most Salt
|Country||Salt Per Day (g)||Raised BP %|
As you can see in this table, the rate of high blood pressure doesn’t correspond to the salt intake.
Notably, the four Eastern Asian countries—China, Japan, Korea and Singapore—show a much lower rate of high blood pressure.
It’s worth noting that these four countries mainly consume salt from fermented foods and salty broths. Would these foods have a different effect compared to unhealthy processed foods loaded with salt?
Perhaps salt consumption isn’t the issue and the foods that contain the salt are?
Studies on High Salt Intake
Cardiovascular Disease and Stroke
High blood pressure is the biggest risk factor for cardiovascular disease and stroke (18).
Some studies show that reducing our salt consumption lowers blood pressure.
Two meta-analyses agree, with one claiming that salt restriction “significantly reduces” blood pressure. In contrast, the other states that the drop in both systolic and diastolic blood pressure “is only minimal“. (19, 20).
As mentioned earlier, there is also a study from April 2017 that followed participants for 16 years and found that those consuming the least salt had the highest blood pressure (12).
In other words, there doesn’t appear to be any conclusive consensus.
A wealth of epidemiological studies links high salt diets to stomach cancer.
- A 2012 meta-analysis of pre-existing studies found that dietary salt has a direct association with the risk of gastric cancer, “with the risk progressively increasing across consumption levels” (21).
- However, several Japanese observational studies find a positive link between the sodium excretion rate and stomach cancer incidence, but dietary salt intake alone had no association (22, 23, 24).
- Animal studies using mice and rats show that salt intake alone doesn’t have a significant effect on increasing carcinogenesis. However, when combined with carcinogens (such as H. Pylori – a stomach bacteria), there was a significant increase in tumors (25, 26, 27, 28).
- In contrast, some studies show that high salt intake is a risk for stomach cancer regardless of possible confounders (29, 30, 31).
Although the studies do suggest an overall positive association between excessive salt and stomach cancer, the studies are very mixed.
Sadly, none of these studies control for quality of diet.
For example, most of the salt people are eating comes from ultra-processed food, which represents 57.9% of the American diet. Of course, this food is also very high in calories, refined carbohydrates, and vegetable oils (32).
A pretty big potential confounder.
Potential Harms of Low Sodium and Sodium Deficiency
Despite the potential dangers of very high salt intake, that does not mean we should unnecessarily restrict salt.
Different levels of salt have both benefits and risks, but we shouldn’t underestimate the importance of salt in our diet.
Here are some of the dangers of low salt levels and sodium deficiency;
Sodium Deficiency and Heart Health
- In 232 patients suffering from congestive heart failure (CHF), a study compared low sodium and “normal” sodium diets. Over a 180 day follow-up period, 12.71% of the “normal sodium” group were readmitted due to worsening CHF or died. In contrast, there was a 39.47% readmission or mortality rate in the ‘low sodium’ patents (33).
- Some studies show that those with a lower sodium intake have a higher rate of death from cardiovascular disease. Other studies indicate that both a very high and very low sodium intake increases mortality (34, 35).
- A low sodium diet decreases blood pressure by only 1% in healthy people and 3.5% in hypertensive patients. However, this diet also results in a 7% increase in triglycerides and has been shown to damage the arteries and induce atherosclerosis in mice – despite a lower blood pressure (36, 37).
- A review of the existing literature finds there is “no conclusive evidence that a low sodium diet reduces cardiovascular events.” Conversely, there is also solid evidence that “low sodium diets lead to a worse CVD prognosis in patients with heart failure or type 2 diabetes” (38).
Type 2 Diabetes
- Despite guidelines to reduce salt intake, lower sodium consumption is associated with an increase in all-cause and cardiovascular deaths in diabetics (39).
- A growing amount of research shows that low salt diets—and sodium deficiency in particular—increase insulin resistance. In a randomized controlled trial, modest salt restriction over five days decreased insulin sensitivity by 15% (40, 41, 42).
Sodium deficiency may also cause any of the following symptoms (43);
- Muscle weakness
- Poor appetite
How Much Salt Do I Need?
As with many things in the nutrition world, there is no uniform perfect amount of salt for every individual.
In truth, the optimal sodium intake per day will differ from person to person and depends on various lifestyle factors like activity level and current health.
As mentioned previously, the recommended salt intake is “a maximum of” 2,300mg sodium per day (about 6 grams salt).
This is probably the right advice for anyone with salt sensitivity, as high salt intake can greatly raise blood pressure in some individuals.
But overall, the studies on salt are mixed, and signs of harm from both excessive salt and sodium deficiency exist.
Cardiovascular researcher Dr. James DiNicolantonio of “The Salt Fix” fame puts the ideal amount of salt somewhere between 8 and 10 grams per day.
Additionally, the Japanese are one of the healthiest nations in the world.
The fact that their high salt intake is predominantly from soups and fermented foods rather than processed food probably isn’t a coincidence.
There is a large Cochrane review of the present evidence on salt. This study looks at the effects of more than 185 low salt intervention studies and you can find it here.
For more information on the potential harms of sodium deficiency, ‘The Salt Fix’ book by Dr. DiNicolantonio may also be worth a look.
If you want to read more about the book, then it’s available here.