Is salt bad for you?
The answer isn’t as simple as you might think
Do you need to put down the salt shaker? That depends…
Salt has been a hot topic in the nutrition world for years now, and with good reason. Salt is an important electrolyte and a great culinary flavour enhancer. However it has gained most of its notoriety from its well-established link to cardiovascular disease. At one point there was even a bill proposed to ban the use of salt in New York restaurants (it never passed, but this bill requiring restaurants to label high salt menu items did). As with most things in nutrition, the answer to the question ‘Is salt bad for me?’ isn’t black and white- it varies depending on the individual risk factors each of us might have and the dose of salt in question.
How does salt work in our bodies?
Sodium is an essential nutrient- meaning we need it to function. It has many roles in the body, including regulating fluid levels and maintaining nervous system and muscle function. Too little sodium and we may experiencing low blood pressure, fainting, muscle spasms, confusion and possible seizures. Too much sodium and we may experience high blood pressure and resulting cardiovascular complications (1).
How does sodium cause high blood pressure you may ask? When we consume too much sodium (over 2.3g per day according to Health Canada), this excess sodium enters our blood stream. In order for your body to maintain homeostasis, more water enters into the blood to dilute the sodium. This causes the volume of fluid in your arteries and veins to increase, and can result in high blood pressure. Studies have shown that excessive sodium consumption (>5g/day) is associated with hypertension and further cardiovascular complications (1).
On the flip side, too little sodium leads to low blood pressure by the same mechanism. Sodium draws water into your blood vessels; a lack of sodium can lead to low blood volume and resulting low blood pressure. This can cause symptoms like weakness and fainting. In a 2014 meta-analysis study analyzing the link between sodium intake and heart disease, it was found that very high and very low sodium consumption were both associated with poor patient prognosis (2). While the mechanism linking high salt intake and heart disease is pretty clear, the link between extremely low sodium intake and heart disease is more complex and multi-factorial.
Where do we get salt from?
Salt is found naturally in many foods, such as vegetables and fresh meats. The amounts of salt found in unprocessed foods is fairly insignificant; for example 55-80mg per 3 ounce serving of meat or 35mg per 100g of vegetables. So where does most of our sodium intake come from? The answer is processed foods.
As mentioned earlier in this article, salt is a potent flavour enhancer, and can also act as a preservative. For these reasons, salt is used in higher levels in packaged, dried, preserved, and restaurant foods. For comparison to the sodium levels in fresh food listed above, a 6” cold cut combo from Subway contains 870mg of sodium (that’s 58% of Health Canada’s recommended intake of 1500mg). As more women have entered the workforce these convenience foods have become a bigger part of our diets, thereby increasing our population’s overall sodium intake.
Salt sensitivity
Studies have shown that there are some individuals (salt-sensitive) who experience significant changes in blood pressure in response to changes in their dietary sodium intake, and other individuals (salt-resistant) who do not. This is likely a result of genetic and metabolic differences. The research shows that salt-sensitive folks have a higher risk for cardiovascular disease compared to salt-resistant people (1).
How should I optimize my salt intake?
The first step in determining how much salt you should be consuming is to determine your risk level. Book an appointment with your naturopathic or family doctor in order to have your cardiovascular risk assessed. A detailed health history (including diet, exercise, stress levels and smoking status), simple physical exams and lab work can be used to evaluate your cardiovascular health and provide you with the most accurate recommendations for you.
Sources
Grillo, Salvi, Coruzzi, Salvi, Parati. Sodium Intake and Hypertension. Nutrients. 2019 Aug 21;11(9):1970.
Graudal, N.; Jurgens, G.; Baslund, B.; Alderman, M.H. Compared with usual sodium intake, low- and excessive-sodium diets are associated with increased mortality: A meta-analysis. Am. J. Hypertens. 2014, 27,1129–1137.