The Japanese salt diet

Another diet that I just recently heard of is the Japanese (sometimes called salt) diet. This diet tells you to cut off your daily salt intake almost to none (because high salt intake is associated with cardiovascular diseases, high blood pressure and obesity). In my opinion nothing that is extreme can't be good. Of course you mustn't eat too much salt (more than 5g per day) but you most certainly can't cut it off entirely. Your dietary salt is basically NaCl (sodiumchloride). Well sodium is very important element in human body. Firstly it is Na that determines your blood osmolarity. Osmolarity is defined as a number of osmoles of solute per liter of solution (Na atoms in your blood). Blood osmolarity is important for regulating your cell's water economy, your blood pressure etc. Also Na plays a very important part in electrochemical gradients thorough your cell membrane (important for nerve signal transmission and diffusion of different molecules thorough cell membranes). Another thing to remember is that Na is absolutely necessary for absorption of nutrients in the GI. Without Na the absorption of carbohydrates and proteins would be practically impossible (this means you could eat, but your body would starve). Now if you would cut off your dietary salt entirely, this mean that your blood osmolarity starts to drop fast. This means a fall in your blood pressure and your heart rate would increase. You would develop serious digestion disorders, the hydrolysates of digested food couldn't absorb through the GI wall. This would result in diarrhea, nausea. Also hyponatremia (low sodium levels) will cause serious muscle and nerve pains (as sodium is important in keeping membrane potential and signal transmission, important in muscle and nerve functioning). You would also develop edemas in different parts of your body. You see, sodium and water are strongly connected. If you would reduce blood Na levels, blood water levels would also decrease. Na "binds" water, if you understand what I mean. So in a case of hyponatremia (this is your blood has low sodium levels), the water from your blood diffuses to different cells. As I said above, sodium determines your blood osmolarity. So you have low sodium, low blood osmolarity. The cells in your various tissues would now have higher osmolarity than blood, the water want's to even those out and diffuses massively to cells, causing edemas (mainly in your limbs). My recommendation to you - don't go extreme!