mmm…salt. Good to the last blood pressure raising drop. No, salt isn’t evil. It’s necessary for maintaining the zen-like balance of our bodies, but perhaps it’s time to give our nutritional knowledge a total makeover.
Spend enough time playing high stakes mahjong with health enthusiasts outside of the local smoothie shop and it won’t be long before “salt” is thrown around like a four letter word when things get a little heated (and salt is 4 letters…how perfect is that?). How did salt, the Ying to pepper’s Yang, land itself on America’s most wanted list? I blame its devious ability to raise blood pressure. It is the sodium component of salt that is responsible for influencing the absorption of water by our bodies. Table salt, or sodium chloride (NaCl) is the main source of sodium in our diets. So for many of us, lowering our sodium levels is pretty much synonymous with cutting back on salt.
Aldosterone and Friends
Alright people let’s talk seriously about urine for a second and try not to go “eewww he’s talking about pee”(well you can if you want to). Urine is what you get when blood plasma has been scrupulously filtered by the kidneys so that whatever the body isn’t using right then and there (salts, nitrogenous waste, elf magic) doesn’t get reabsorbed back into the circulation. So urine is actually just ultra filtered plasma…and that’s not so sketchy is it? The chemistry of our bodies is largely regulated by how our kidneys produce urine…salty like the dead sea one day…watered down like cheap beer the next.
Our always handy adrenal cortex produces the hormone aldosterone in response to physiological cues (not voodoo as I previously suspected). Aldosterone’s main magic trick is to increase the overall blood volume. Guess how..by increasing the reabsorption of sodium by the teeny tiny functional units of the kidney (nephrons). Water kind of plays follow the leader with sodium. So if sodium goes out then water comes back in.
So that means….
The body can manipulate the concentration of water in the blood by manipulating the levels of sodium. The kidneys are able to retain sodium which in turn allows water to flow back into circulation. Since water makes up more than 50% of the total volume of blood, sodium’s ability to lead water alters the blood volume through the vessels, and the increase in blood volume increases the amount of pressure that the blood flow exerts on vessel walls. Too much salt in the diet overloads your kidney’s capacity to deal (technical term). The body has a nifty early warning system for when your salt/water mojo is out of whack – thirst. It’s not just for Gatorade commercials.
SHAZAAAM!!!! Ok that’s enough physio for now. You can let the kids back in the room..scary monsters are gone.
There is a hefty percentage of Americans that exceed the maximum daily recommendation of sodium (less than 2400 mg) in the first half of the day. Fast foods and processed foods are largely to blame whereby the products that we consume have already been seasoned, often with a great deal more salt than we would have added ourselves (have you blamed your cheeseburger for anything today? Please take a moment and do that). In fact, canned soups are a notorious source of sodium in most household kitchen cabinets. “Naughty chicken noodle soup! Go in the corner and think about what you’ve done.”
So buy more fresh ingredients. Prepare more of your own meals. Stay hydrated, stay classy, and never stop learning my friends.