Dietary salt intake has been a hot topic for many decades. The consensus is that salt in the diet should be limited, mainly because it increases blood pressure, which is the most significant risk factor for heart disease. How much truth is there in this recommendation? We will find out today. 

When we say salt, we mean sodium chloride or just sodium. Luckily, salt is readily available today, but that was not always the case. During the hunter-gathering period, the leading food for us was meat, which has the highest concentration of salt of natural food. The intake of salt in paleolithic times is estimated to be about 1/2 to 1 gram or 500 to 1000 milligrams per day. More recently, in the agricultural period, human beings consumed the same amount of salt as their hunter-gathering ancestors did. (1) 

Salt intakes remained stable until about 5000 years ago when people realized it was a good food preservative. Its value skyrocketed, and worldwide trading networks flourished. The Latin word for salt is sal, and the root of the word salary shows just how valuable it was. You may have heard the phrase "being worth one's salt," which is another homage to the value of salt. The peak of salt ingestion came in the nineteenth century but declined after the advent of refrigeration. (2)

Physiological requirements for sodium are 500 milligrams or less per day in most healthy individuals. Healthy individuals can conserve salt in times of scarcity and eliminate excess when needed. The current Dietary Guidelines for Americans recommend that Americans consume less than 2.3 grams or 2,300 milligrams of sodium each day as part of a healthy eating pattern. Unfortunately, the average American consumes 3.4 grams or 3,400 milligrams of it daily. More than 70% of the sodium consumed is from processed and restaurant foods.. (3) The recommended dose and the actual amount consumed are both above the optimal level, but is it dangerous to consume that much?   

A 2015 review of the literature says yes. The authors' consensus is that excess dietary sodium can adversely affect target organs, including the blood vessels, heart, kidneys, and brain, even when it is not enough to elevate blood pressure. (4) Some groups are more resistant to the harmful effects of too much sodium, including those middle-age and younger, Caucasians, and people with healthy blood pressure. Salt sensitive groups include the aged, individuals with high blood pressure, African-Americans, chronic kidney disease patients, low birth weight babies, and women with a history with pre-eclampsia. (5)

Most of the studies examining the association between salt intake and heart health are observational cohort studies, which means they are of low quality, so we can't precisely hang our hats on their conclusions.  

The limitations of most observational studies are too numerous to get into, but one of their shortcomings are confounding factors. I want to address one of them today that I think is very important. Potassium intake in America is too low. Potassium ingestion takes place in the form of another kind of salt, potassium chloride. High potassium foods include bananas, oranges, cantaloupe, honeydew, apricots, and grapefruit. Many other fruits, vegetables, nuts, seeds, fish, and meats also contain potassium. It is essential to understand that sodium raises blood pressure, and potassium lowers it. (6)High blood pressure is the single most significant risk factor for heart disease, so studying sodium levels while neglecting potassium status in patients is a problem. 

A review paper from 2013 shows that dietary potassium and sodium ratios should be considered together for benefits to blood pressure reduction. The authors observed that higher potassium:sodium intakes have more substantial beneficial effects on blood pressure and the risk of subsequent cardiovascular disease than either sodium or potassium alone. (7) Current recommendations for potassium intakes lead to a ratio of about 1.8. Achieving this intake ratio is a challenge with current eating patterns (8). 

Before I get into recommendations, I want to talk about low sodium, known as hyponatremia. Hyponatremia is very dangerous. It is a medical emergency that carries a high mortality rate if not addressed acutely. Hyponatremia occurs in approximately 15–30% of hospitalized patients. Hyponatremia is also a common occurrence in heart failure, with about 20% in patients hospitalized for heart failure. Risk increases with age and medication status, with more than 50% of nursing home residents had at least one episode of hyponatremia over a 12-month study period. (9)

The causes of hyponatremia are numerous and include drug-induced episodes, age, gastrointestinal disease, skin losses due to burns and sweating, kidney disease, Addison's disease, drinking too much water, malnutrition, glucocorticoid deficiency, severe hypothyroidism, cancer, lung disease, and central nervous system disorders. (10) You may have heard reports of people dying after trying to drink large amounts of water for a dare and sudden death during sports practice on hot days. Both are usually due to hyponatremia. In the case of too much water, the sodium in the blood gets diluted. In sports, the combination of sweating out sodium, and drinking too much water dilutes the sodium in the blood.

Not that I recommend Gatorade, but drinking water fortified with minerals is an excellent idea on hot, sweaty days. In short, Too much sodium is way less dangerous than too little!

For most Americans, decreasing sodium is appropriate to avoid the chronic health problems induced by high sodium. Because of the risks associated with hyponatremia, you need to consult with your healthcare practitioner. The best way to lower sodium if it is too high is to limit processed foods. Conversely, increasing potassium is probably necessary if you fall into the category of the average American. Apps like My Fitness Pal are a great way to track your intake. 

On a personal note, my diet may be deficient in sodium and potassium, so I drink filtered water fortified with LMNT to ensure I get enough sodium and potassium. I am on the carnivore diet and don't get enough sodium and potassium sometimes. I also sauna and sweat during daily workouts. Zero and low-carb diets are diuretic in nature, meaning the kidneys excrete electrolytes at a higher rate, and it is essential to replace my electrolytes. LMNT is a sugar-free, scienced backed formulation that you can add to your water to ensure adequate sodium, potassium, and magnesium levels. It is available online. You can find it here. 

One final note. Diets high in processed carbs raise blood pressure and other health risks. I will post much more on the subject shortly, but suffice to say that most of the studies to date are on subjects consuming processed carbohydrates, which is a significant confounding factor. During the hunter-gathering period, meat, which is the highest in sodium among food sources, was the staple food for us. Even so, the intake of salt in paleolithic times was less than 1 gram or 1000 milligrams daily. As I stated earlier, healthy individuals will remain so on 500 milligrams or less per day. Nothing would suggest that paleolithic populations were unhealthy due to their low salt consumption. (11) Further evidence comes from Vilhjalmur Stefansson, who spent the better part of a decade amongst the Inuits of the north who rely almost solely on animal-based products and add no salt to their food. Stefansson himself ended up throwing away his salt supply as he found he did not require the added salt and lost his desire for its taste. They all had excellent health. He wrote several books on the subject. The Fat of The Land and My Life Among the Eskimos are two of them. Not By Bread Alone chronicles a 1928 scientific experiment, conducted by the Russell Sage Institute of Pathology at Bellevue Hospital in New York, in which Stefansson and his colleague Dr. Karsten Andersen ate a meat-only diet for one year. The two men stayed healthy and fared very well, leading him to claim that we should reexamine our notion of what foods constitute a healthy diet. (11)

Bottom Line

Adequate levels of potassium diminish the adverse effects of mildly excessive sodium, especially when on a diet that does not include processed carbohydrates. However, the effort to alter one's diet to include sufficient levels of potassium is challenging. Apps that track nutrients are a big help. If you are an average American with no underlying health issues, you may need to lower the sodium in your diet and increase your potassium level. With minimal effort, a diet devoid of processed food, rich in both plant and animal-based foods, should lead closer to optimized levels of both. If you eat three bags of potato chips per day, cutting them out of your diet will lower your sodium to a safer level without risking hyponatremia. Since low sodium can be life-threatening, you should consult with your healthcare practitioner before trying to reduce your sodium intake, unless it only involves giving up processed foods.