Salt and Longevity
Salt and Longevity
How important is salt? According to the Roman historian Pliny the Elder, as stated in his Natural History, “in Rome…the soldier’s pay was originally salt and the word salary derives from it…”. That the word salary still stands today indicates a historical understanding of the importance of salt to health and life.
What is Salt?
Salt is an electrolyte and, like all electrolytes, serves the function of transmitting electrical signals throughout the central nervous system, muscles, the brain, and other organs. The sodium ion (liberated after the body breaks apart the chlorine bond found in sodium chloride) is the body’s main positively charged electrolyte, and is involved in controlling fluids in the body, and regulating blood pressure and cellular pressure. The body regulates salt to a degree, by causing us to crave it when we need it, and by excreting it through our urine when we have too much. (As a related aside, salt and fat cravings, especially for chips, can be an indication of adrenal malfunction.)
Is it possible to ingest too little salt? These days you would think not but, just as the government rallies to mandate lower salt intake, we find that, yet again, they are bringing up the rear guard. The range of sodium-related regulations that are being implemented are mostly based on the idea that sodium leads to hypertension, which is in turn then linked to stroke and heart disease.
The Dangers of Insufficient Salt
Yet, surprisingly, one controlled study involving about 3,000 people, done in the 1990s, actually showed the opposite conclusion. In this case, the patients who consumed the most sodium were less likely to have a heart attack. The 25% of males consuming the lowest amount of sodium had more than 4 times as many heart attacks, compared to the 25% of patients who consumed the most sodium (for some reason women did not show any statistically significant relationship). (Study)
Another study, from 2017, followed more than 2,600 men and women for 16 years and found that consuming less sodium wasn’t associated with lower blood pressure. According to Lynn L. Moore, DSc, associate professor of medicine at Boston University School of Medicine, “we saw no evidence that a diet lower in sodium had any long-term beneficial effects on blood pressure. Our findings add to growing evidence that current recommendations for sodium intake may be misguided.” (Source)
Furthermore, a study published in the American Journal of Cardiology (2009) showed heart disease patients to be at even higher risk of an event when following a low sodium regimen. Those consuming normal levels of sodium were less likely to be re-hospitalized and less likely to die. (Source)
Recommended amounts of sodium from Health Canada are as follows: 1500 mg for ages 9 to 50; 1300 mg for ages 51 to 70; 1200 mg for those over 70. The current U.S. FDA guidelines for salt intake is that one should take no more than 2 grams daily, down to 1500 mg for those at risk for heart disease or hypertension.
In a recent study out of Europe, the study author, Dr. Jan Staessen, stated that their findings “certainly do not support the current recommendation to lower salt intake in the general population.” This study looked at a total of 3,700 people previously followed in two different studies. They broke the total into three groups based on highest, lowest and average salt intake. No one in the study had heart disease at the beginning and two thirds had normal blood pressure, and they were followed for about 8 years.
These findings, published in JAMA in 2011 (Study) came to a surprising conclusion: those with the lowest salt intake had the highest rate of death from heart disease, and those who ate the most salt had the lowest rate. One measure of blood pressure, the systolic, increased along with salt intake, but the change was statistically insignificant. This study only included white Europeans so the results may not apply to other ethnicities. Other exceptions found are based on how sodium interacts with cultural diets, and environmental and genetic factors.
For example, African Americans seem to be salt-sensitive, while Kuna natives from Panama appear to be salt insensitive. The Kuna traditionally had a low sodium diet and had normal blood pressure. Decades later their salt consumption was similar to North Americans, yet they continued to have normal blood pressure, if they remained on their Islands and ate their traditional diet. However, those who migrated to the mainland and ate a modern diet then developed the same amount of high blood pressure and heart disease as North Americans.
So clearly there are other factors at work. Another example of this is the discovery that some of the studies which found sodium intake to be protective against heart disease, when analyzed closely, showed that those who were overweight did not do better when they increased their salt intake. In fact, in this circumstance, the obese experienced more death from cardiovascular disease.
The long and short of it appears to be that “elderly subjects, African Americans, and obese patients, are more sensitive to the blood pressure-lowering effects of a decreased salt intake”. (Source)
Other Factors Affecting Salt Needs
One of these “other factors” now appears to be that the issue is not just about how much sodium you consume, but how that relates to the amount of potassium that you consume. An American study (Archives of Internal Medicine) surveyed over 12,000 people whom they followed for about 14 years. They found that a high sodium intake was linked to a higher mortality rate, but a higher potassium intake was associated with lower mortality, and those who had a higher sodium-to-potassium ratio had more risk of heart disease. (Source)
This study was commissioned because of an awareness that most of the US population consumes more sodium, and less potassium, daily than is recommended by health experts.
Now, those who eat a mostly plant-based diet will naturally get more potassium and less sodium than those who eat a lot of meat. This is because meat is one of the highest sources of sodium in the diet (outside of adding salt to food). Thus, I am always reminding vegetarians to be careful not to avoid salt too much, as they can actually become salt deficient. Which as the European study indicated, can be as bad for your health as too much salt.
Of course, the worst source of excess sodium in the diet is the eating of processed and “junk” foods, which are overly high in salt.
Now, on the other hand, as we observed above, too much salt is usually only a problem if our potassium gets too low. And, since those on a Paleo or Keto diet (and low-carb and SIBO diets) often avoid high potassium foods (avocado, tropical fruits, bananas, potatoes, tomatoes), they are at a special risk of running into this sodium/potassium imbalance.
Furthermore, “consuming a lot of sodium can cause an imbalance in your potassium levels because the two minerals work together to maintain a normal balance of fluids in the cells. Too much sodium causes potassium to be eliminated from the body through urination, which can lead to low levels of the mineral.” (Source)
At this juncture, I’d like to make people aware that attempting to correct a lack of potassium in the diet with supplements is a lost cause in Canada. Here, our protectorate, Health Canada, has limited the amount of potassium allowed in a pill to 99 mg. Since, according to the National Institute of Health the daily requirement of potassium is 4,700 mg for adults and children 4 years and older, well, you do the math. Twenty pills would barely meet half of one’s daily requirement.
Probably the most viable way to increase potassium intake, for those unwilling to eat the above mentioned high potassium foods, is to use a potassium salt (“salt substitute”), which provides about 400 mg of elemental potassium per 1/4 teaspoon. (Or use “Low-Sodium” V8, which provides about 850 mg of potassium per cup.)
One other factor overlooked by sodium researchers is the possibility that table salt may one of the only appreciable sources of iodine in the modern diet. Iodine deficiency is already common and the extra radiation in the environment is going to worsen that condition. Since seaweed is the only serious source of iodine in the diet, and is seldom consumed by Westerners, deficiency is widespread, though seldom acknowledged by Western medicine. A quick google-search of “iodine deficiency and heart disease” indicated that this is a valid theory, as this excerpt illustrates.
“In recent years, public health bodies have aggressively promoted sodium restriction as a means of reducing hypertension and the risk of cardiovascular disease. These inducements have led to a general decline in iodine intake in many developed countries. This paper reviews evidence suggesting that iodine deficiency can have deleterious effects on the cardiovascular system, and correspondingly, that a higher iodine intake may benefit cardiovascular function.” (Source)
(See also my previous blogs on Iodine)
A Natural Perspective on Salt
Now, let’s have a look at salt from the natural foods perspective. The first thing to be aware of is that when Pliny the Elder was writing, salt was a far different substance from modern commercial salt.
I raised my family on the supposedly healthy sea salt from the health food store, but I now realize that it was not much better than regular table salt, except for lacking in synthetic iodine, anti-caking and flow agents. The problem was that, in those days, commercial sea salt was treated much like table salt, with all the other minerals being removed, leaving a product that is 98% sodium. However, if we simply dehydrate sea water we get a substance very close to human blood in its mineral profile. This is the type of salt that was used in Pliny’s day, and throughout history, until the age of industrial food production.
Fortunately, this type of natural salt is now commonly available again in health food stores, and even in some grocery stores. Such salts include Celtic (the first natural salt on the market), Himalayan (pink), and a variety of salts from all over the world from the Arctic to New Zealand (this particular salt, sold by “Earth’s Choice”, being the best tasting salt I have ever had), and even from here on Vancouver Island. These new naturally harvested and dried salts are becoming more popular in gourmet cooking, and so are increasing in options and availability.
Himalayan salt stands as unique in the salts because it is ancient and thus predates modern times and the industrial age. Other salts are derived from the oceans of today, which are more or less polluted, depending on where harvesting occurs. That being said, Himalayan salt is fossilized and the other salts are not which makes them both easier to digest and more flavorful. As well, a smart salt producer makes a point of harvesting sea water from remote areas, well away from industrial pollution (something established by Celtic salt which is harvested from the protected Isle of Noirmoutier, Brittany, France).
These true salts, naturally processed without the minerals stripped out, average about 35% sodium with the remaining being composed of magnesium, potassium and a wide array of trace minerals. This can be observed in the nutritional panel on the side of the product where, if the serving size is 1,000 mg (1 gram) the amount of sodium is listed at between 350 and 400 mg (indicating 35 to 40%). Such products are balanced in their mineral profile and are a healthful addition to the diet.
According to those who practice Macrobiotics, salt can be an irritant to the digestive system if the crystals are swallowed whole. Therefore, it is recommended that salt be added to the cooking process or in some manner dissolved into the food. This would not be an issue if people chewed food to liquid, but given our tendency in the West to gulp n’ go, salt added at the table is very often not properly dissolved.
This approach to salt is the opposite of how we should approach pepper. Black pepper is damaged by cooking and is most healthful when added, freshly ground, at the table.
Studies have found a correlation between pre-ground pepper and increased prostate cancer, as well as a reduction in prostate cancer risk for those who use fresh ground pepper (remember: third world cash crops are best purchased in organic form due to excessive pesticide use). This difference between fresh and pre-ground probably occurs because peppercorns are high in oils, and being pre-ground gives these oils a chance to go rancid, unlike with the fresh ground version. But, worse than that, black pepper is prone to being contaminated with mold byproducts (mycotoxins), whether fresh or pre-ground, so one should not be liberal in its use. Especially since organic certification is no protection against mold contamination.
As usual, there are pros and cons to this subject, and we need to look at our whole diet and lifestyle when deciding how much salt we need. But, certainly we need sodium (and iodine), and, unless your diet is high in animal protein, you probably should be generous in your use of salt, letting your taste buds and cravings help you determine how much to ingest. And, again, if you take in a lot of salt don’t let your potassium intake drop too low.