Nearly all of us have been told that we should be on a low sodium diet at least once for various reasons ranging from hypertension to prevention. So is it really important and why?
Well first, lets distinguish between salt and “sodium”. Salt is NaCl and is the form of sodium that is utilized by the body, available from the ocean and to salt your food, and vital for every bodily function imaginable (if for no other reason than your nerves, which control everything, can’t work without it). Sodium includes salt, as well as tons of other chemical combinations available for dietary consumption. Many of these combinations, such as MSG (monosodium glutamate, an excitory neurotoxin linked with obesity, excessive food consumption, food “addiction”, headaches, etc.. and in virtually all processed and restaurant food), are extremely rich sources of sodium that poorly convert to NaCl and have a high affinity for water (as all sodium does). Unfortunately, these forms of sodium are harder to excrete than salt as well. So in short, non salt forms of sodium are hard to excrete, difficult to utilize metabolically, and have a very high affinity for water which will increase blood pressure (and cause numerous other issues). “Non salt” forms of dietary sodium make up approximately 80% of dietary sodium intake due to processed food and are in nearly 100% of all sauces and condiments.
Now what does the research say? Well, at first glance it says that high dietary sodium increases blood pressure and the risk of heart disease….but then at further glance it says that low dietary sodium increase the risk for heart disease and all cause mortality (especially in women). So why is the information so conflicting, is there a magic ideal range and if so, how do I know what it is for me? The first thing to note is that the majority of the studies showing an increase in risk are actually looking specifically at salt (NaCl), which is what most people eliminate from their diets when going on a low sodium diet. Why? Because “I know there is sodium in salt”, and it is easier to eliminate that than read the box (yes, I said it, most of us are too lazy to read the box). The opposite is what should happen..eliminate processed food and keep cooking with salt and salting your food. So why the increased risk in women? In my experience (and this is just a theory), women are more compliant to a low sodium diet. Men are more likely to say they are…but not actually be compliant (though they typically do pretty well with compliance to low carb diets). I do not believe that this is completely intentional (maybe partially) but more likely that we just aren’t paying attention all of the time. It is easier too look at a food and it be apparent that it has carbs in it, this is not so with sodium content.
So why is low salt intake bad? The simple answer is that you need salt to regulate metabolic processes. Digging in too the research shows that low salt diets are linked with a higher risk of mortality (death), lower cardiac output (important for fitness), muscle cramping during and after exercise (a further reduction in exercise capacity), higher risk of cardiovascular disease, and some studies even show a rise in peripheral blood pressure. ??? As it turns out, low salt diets create an increase in superoxide production, a decrease in Nitric Oxide (NO) production (regulates several metabolic systems and vasodilation, which regulates blood pressure and peripheral blood supply), causes the heart to switch from fat to glucose metabolism, and results in much higher insulin levels.
What is the effect of too much dietary salt? If you are drinking the appropriate amount of water (half of your body weight in ounces per day) your kidneys will regulate salt levels quit well and it is a mute point.
My advice, based on the evidence, is to eliminate processed food (just another reason to do so), continue to cook with salt and salt your food, and drink plenty of water. For those that just crave salty foods, try salting a cumber, boiled egg, or tomato rather than chips or pretzels. You may find that you consume a lot less and appease the craving much faster.
(Note: more and more evidence is emerging that artificial sweeteners and MSG are associated with weight gain, obesity and an increase in cravings. Why? My theory is that these forms of sweet and salty foods do not satisfy biological needs effectively and therefor result in you craving more of the particular food. There is a growing body of evidence that supports this through the explanation of various complex chemical pathways, though there is still quite bit that is not answered. But the simple version is that your body asked for X and you gave it Y, which is like X but not as good, so it asks for more.)