A few weekends ago during a family Sunday Roast I asked my sister to “pass me the salt shaker”. I got a variety of disapproving looks from around the table. My mother muttered under her breath “you are going to get high blood pressure” and my brother chimed in “yeah and you will have a heart attack before you are 30”.

It is hardly surprising that my family, like most of the general population, view salt with such disdain. We have long been indoctrinated, as a society, that salt is bad. The media bombards us with reports that we are eating increasing amounts of salt and that we should all eat a low salt diet as it will lower blood pressure, reduce cardiovascular disease, decrease stress levels and improve your general health. In short, we are told on a daily basis that salt should be avoided. But have we ever asked ourselves where this idea comes from? What is it based on? Is it even true? Do we need salt?

We do need salt. Without salt (sodium chloride) in our diets we would die. Sodium plays a vital role in maintaining the body’s salt-to-water ratio, in cardiovascular function, nutrient transportation, our metabolism, blood regulation and the nervous system.

Salt (sodium) is an electrolyte, which means when dissolved in water, it possesses an electric charge. These electrolytes allow neurons to send instructions between other neurons and cells, making these electrolytes vital to nerve impulse transmission, cardiac function and mechanical movement.

Chloride ions that come from salt (sodium chloride) are secreted in the gastric juices as HCL (hydrochloric acid). HCL is vital to your health; it sterilizes your food and also triggers the release of enzymes, such as pepsin, which will help you to digest your food.

Low sodium sparks a chain of reactions in our bodies designed to sustain osmotic balance and blood pressure. If sodium intake drops too low, then our metabolism goes into what is known as “sodium sparing mode”. Some studies actually suggest this “sodium sparing mode” can occur when consuming as little as 1.5 teaspoons a day. Low sodium causes an increase in renin and aldosterone which if remain chronically elevated can cause a whole host of inflammatory responses in the body such as insulin resistance, cardiovascular disease and metabolic syndrome.

 

So when did the scaremongering begin?

The “salt is bad for you campaign” started in 1979 when the US government conducted a report on health promotion and disease prevention and stated that  “salt is a clear cause of high blood pressure.” This report was based on a study carried out in the 50s where rats were fed the human equivalent of 500 grams of salt. Perhaps a little excessive?!

In 1984 the US government spent a further $1.3 million dollars on another study, probably worrying that individuals might one day question why rats were fed the human equivalent of 500 grams of salt a day. This study was called the InterSalt study, however, there were a variety of flaws in this study.

The study concluded, “societies with higher sodium intakes had higher blood pressure” and thus provided further evidence we should all eat a low sodium diet. This statement was based on the analysis of 52 populations, four of which populations consumed low amounts of salt and had low blood pressure. What the study failed to mention is that firstly the data from these four populations would normally be excluded from the analysis, as they were “outliers”. Secondly, two of the four populations were rainforest dwellers that were genetically predisposed to low blood pressure. These populations have a complete absence of the D/D genotype. Also if one looks at the general health of these populations with low sodium intake and low blood pressure they had low life expectancies, were short in statue and never actually acclimatized to a low sodium diet so had high levels of renin in their blood. The study actually also demonstrated that in Chicago where the lowest salt intake was reported, hypertension rates were sky high. And in China in the Tiajin Province, where the highest levels of salt were consumed and there were almost zero cases of hypertension.

In 1999 another study was conducted, called the NHAMES salt study (National Health and Nutrition Examination Survey). This study, again much like the previous studies, concluded salt is the devil. It stated that individuals consuming the highest amount of salt were 32% more likely to have strokes, 44% more likely to have heart attacks and had much higher mortality rates. This study however, was not based on urine or blood analysis. It was based on asking individuals “how much salt did you eat today?”. So perhaps not the most accurate of sodium reading. “Do you know how much salt exactly you have eaten today to the nearest millimole?”

Unfortunately, the US government has accepted these claims like Holy Scriptures and has set the upper limit of salt to 1,500 mg, which is slightly more than half a teaspoon for young adults.

Some modern salt studies contradict the claims made by the previous studies mentioned. Interestingly, Michael Alderman who was previously the President of the American society of Hypertension once stated “the more salt you eat the less likely you are to die.” Michael Alderman has also conducted a study over a four-year period testing the urine of individuals with mild hypertension. He discovered that individuals with the lowest amount of sodium in their urine had more heart attacks and other cardiovascular complications. A recent study conducted by Harvard University demonstrated that when healthy individuals are placed on a very low-salt diet (one fifth of a teaspoon a day), they developed insulin resistance within 7 days.

If there were such a profound relationship between salt and blood pressure then has anyone ever questioned why saline drips in hospitals provide patients with up to 4.5 teaspoons of salt each day? These same patients have their blood pressure checked every 4-5 hours but mysteriously their blood pressure does not increase.

There is no black and white, clear-cut answer to how much salt an individual should consume. It should be based on the individual and depends on a number of factors such as your age, health, genetics, physical activity, climate and some individuals are more sensitive to salt than others. Active individuals can lose 800mg or more of sodium per litre of sweat. There is a small subset of the global population that are estimated to have one of the 16 discovered genetic defects which means either your kidneys excrete salt very rapid so they have a greater need for salt, or alternatively, their kidneys conserve salt so less salt is needed in the diet.  

You can make good choices when it comes to consuming salt. Salt has become a very refined, over-processed product. Nowadays bleaching agent and anti-caking agents such as sodium silicoaluminate are added to salt. Celtic Sea Salt and Pink Himalayan salt are rid of any nasty chemicals and are also full of an array of other trace minerals.

Base your salt intake on your individual needs, not on myth-information or media speculation. It is true that some overweight individuals with high blood pressure might benefit from a low-sodium diet but the general population does not. When eating a low salt diet one must look at the sum of the net health outcomes as a low salt diet might decrease your blood pressure but might also increase other risk factors in your body such as insulin resistance and increased aldosterone. If you are a fit, healthy individuals do not forget the health benefits of salt and do not be afraid to say, “Pass me the salt shaker.”