Salt is an essential mineral, which the body needs for fluid balance, the proper functioning of muscles and the nervous system, and even the absorption of certain nutrients. (1) Salt has been held in high esteem  throughout history; healing qualities were frequently attributed to it. (2) Craving salt helped humanity figure out how to mine it or process it through distilling  sea water.  

Despite the importance of salt, health organizations mainly press the adverse effects of salt intake. It’s easy enough to overindulge in salt in our modern environment, but many believe that reducing salt intake is not always beneficial, and can even be harmful.  

What’s the composition of salt? 

The two main compounds of salt are sodium and chloride. They are minerals belonging to the larger class of electrolytes, which are necessary to get water to its proper place within the body. Besides that, they regulate blood pressure and pH-values , and they are essential for proper digestion and the production of gastric acid. (3,4) 

Though natural foods contain some, the main source is added salt, which, despite being composed primarily of sodium chloride, contains other minerals, such as iodine and other trace elements. The greyish or pink colour of less processed salt types is due to such other minerals. 

Despite the rising popularity of gourmet sea salts and salts sourced from various mountain ranges, the main component is still sodium chloride, and there’s no evidence that they would be significantly healthier than standard table salt.  

How much salt is necessary? 

There’s been a fair amount of controversy and debate in the past decades regarding the recommended daily intake of salt. The official recommendation is 5-6 g salt per day maximum for adults, an amount that’s surpassed by the majority. (5, 6) 

The majority of daily salt intake come from food made with processed wheat, processed meat and various dairy products, so people whose diet heavily features these types  of foods may be overeating salt while not getting enough potassium, magnesium and other important minerals. (7) 

Those who cook their own meals can safely season with salt, it’s unlikely that they would go overboard. The officially recommended, often incredibly low daily dose of salt has barely been tested, and several studies found it to have negative effects. (8) 

People performing intense physical activities need more salt, while people with high blood pressure are advised to decrease their salt intake. (9,10) 

The health effects of salt 

High blood pressure 

Health organisations have been promoting lower salt intake as they believe it to be largely responsible for high blood pressure, which is one of the main causes of cardiovascular diseases. Thanks to this, a large portion of the population came to regard salt as a harmful ingredient on a par with smoking, but in the case of   salt it’s less straightforward .  

Several studies didn’t find any correlation between salt intake and high blood pressure in healthy people. A metaanalysis summarizing the outcome of 133 clinical trials found that salt intake had no effect on those whose blood pressure did not exceed 131/78 and lowering their salt intake had little to no effect. On the other hand, lowering the salt intake of participants with high blood pressure resulted in reduced blood pressure. (11) 

An older metaanalysis reported similar findings: lowering the salt intake of participants who had no high blood pressure only resulted in minimal change, but in participants with high blood pressure, the effects were significant. (12) 

In conclusion, it’s mainly people with high blood pressure who are advised to lower salt intake. Reducing outstandingly high daily intake of salt (9-12 g) to 6 g a day can have a preventative effect. 

Cardiovascular diseases  

Salt intake is controversial when it comes to cardiovascular diseases as well. Results of several studies question the official recommendation of the extremely low dose of 3.7-5 g of salt per day, and many of them found that too low salt intake is actually harmful.  

A review study published in 2020 found that the general public’s salt intake is not high enough to increase the risk of cardiovascular diseases. It’s only extremely high doses, from 12.5 g of salt per day, which is proven to be harmful. Based on this, no strong argument can be made for the beneficial effects of universally lowering salt intake. (13) 

Some studies point to a higher risk of heart diseases. Several examinations demonstrated a U or J-shaped curve, wherein low salt intake was a risk factor alongside high salt intake. (14,15,16) 

In a study conducted in China the risk of cardiovascular diseases were significantly lowered by switching 25% of table salt to salt containing partly potassium-chloride. (17) China’s daily salt intake is the highest in the world (over 10 g per day), whereas potassium intake is generally low all around the globe. Higher potassium intake has nearly always been found to be beneficial, therefore it’s possible that the root of the beneficial changes was not lower salt, but higher potassium intake. (18,19) 

An observational study contradicts the officially recommended daily intake as well. It compared salt intake with life expectancy. (20) The result was that higher salt intake is inversely proportional with premature mortality, in other words, people who eat more salt tend to live longer. Of course, correlations such as this must not be regarded as strong evidence, but it challenges the notion that salt would be one of the highest risk factors shortening our lives.  

It can cause real harm

High salt intake, especially in the case of food preserved with salt can increase the risk of gastric cancer, and can stimulate the increase of h. pylori bacteria, which is likewise a risk factor. (21,22) 

In summary 

Salt, like other essential micronutrients, is necessary for health, but it’s important to consume the optimal amount. To prevent excessive salt intake and its side effects, avoid processed food and eat organic food high in potassium and magnesium. It’s not necessary to minimize salt intake if one doesn’t have problems with their blood pressure and follows a healthy diet. 

Fun fact 

More than three times as much salt is used to salt the roads to prevent frosting as people eat in the United States. While salting roads can be an effective way to reduce the number of accidents, such massive doses of salt significantly harm the environment. (23)