Why can’t a high sodium diet be offset by the consumption of a lot of water?
In: Chemistry
your entire body works very hard to try to stay balanced, and the process is more complicated than simply throwing out the bad and keeping the good.
you can think of it as a puzzle where you want everything as even as possible, but you arent allowed to have any empty slots. if you want to throw out sodium you need to fill the spot the sodium is in with something else similar enough to fit there. if you want more calcium you need to try to throw out something in a calcium shaped spot.
while drinking water after ingesting too much sodium helps with short term symptoms such as dehydration or cramps, it usually does not supply the necessary pieces to fill in the sodium spots when sodium is thrown away. those still need to be taken from elsewhere.
so a large excess of sodium long term heavily taxes the body by causing a loss of other similar nutrients that cant be absorbed since there are no open spots for them, heavily taxes organs like the kidney that are trying to move sodium everyday when it doesnt have enough puzzle pieces to keep up with the consupmtion, and can eventually cause even further unbalances as other puzzle pieces have to be reshuffled to attempt to balance with the sodium.
p.s. the reason water retains with sodium is because your body is struggling to find pieces to trade out with the sodium and must keep it. the water is kept as well to prevent those immediate issues of sodium like dehydration and cramps etc. but doesnt fix the core issue.
***tldr having a very high amount of sodium is like playing a game of tetris with a ton of one piece and hardly any of the others. your body tries to adapt but eventually you end up with more and more pieces on the board that are sodium and no way to get rid of them. while water can help short term with sodium consumption it doesnt give your body the needed pieces to clear a board full of sodium, and instead fills the board up even more as a piece that glues itself to sodium.***
Sodium follows water, so as someone else stated above – they are hand in hand.
To your point though, the only way I know of that drinking water can lower sodium – no matter your salt intake – is when you are sick with something called SIADH. Which basically means your kidneys are producing too much of a hormone that makes you not pee enough, therefore causing too much water retention in your body and something called dilutional hyponatremia – low sodium due to dilution.
Homeostasis (your body’s always going for this – equilibrium) prevents this low sodium due to dilution from occurring. Only if something is wrong with your body’s balancing act (like SIADH) will what you are asking actually occur.
There are special proteins in the kidneys which transports sodium out of the body while taking potassium inside the body. The body cant just let water + sodium out without “paying” energy and in exchange of another molecule for the transfer.
Water and sodium like to move in pairs. So a high consumption of sodium is going to cause the body to retain a lot of water. Trying to offset high Na consumption by drinking more water just adds insult to injury in the way of even more water retention. Excess fluid volume/retention causes a whole host of problems – extra work for the kidneys, extra work for the heart, and damages the blood vessels due to increased blood pressure to name a few (and high blood pressure is the leading cause of stroke – definitely don’t want that! High blood pressure also contributes to kidney and heart failure). Extra work for the heart and kidneys also leads to long term damage in the ways of physiological compensation and physical/structural changes of some organs (that at first are efficient in handling the increased fluid volume, but overtime actually do much more harm than good) leading to exhaustion and poorer functioning – AKA heart and kidney failure. The healthy body initially will be able to compensate for the high Na/H2O intake, but eventually the long term effects of that poor diet choice are going to cause a lot of dysfunction and leave the consumer pretty unhappy.
Because water and sodium interact with other things in your body besides each other. One important interaction involving sodium is the sodium/potassium pump.
The ELI5 version is that you need to have a proper balance of potassium and sodium for energy production. Too much or too little of one screws up the ratio and then the chemical interactions can’t happen the way they should.
Aside from the water retention/hydration issues, Sodium ions perform important cellular functions. One example: [https://en.wikipedia.org/wiki/Na%2B/K%2B-ATPase](https://en.wikipedia.org/wiki/Na%2B/K%2B-ATPase) The consumption of excess sodium isn’t just flushed away immediately (the same way your body continues to absorb excess calories when you overeat). Do this regularly, for long enough, and you’ll create problems.
The consumption of water only helps one symptom of excess sodium intake, hydration level (as far as I know). This isn’t like neutralizing an acid by adding a base until you get back to a pH of 7.
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