Add a little sodium and a little chloride together with some electrostatic forces and you get that ubiquitous mineral, salt. It is used in pretty much every way, shape or form possible, from food to transportation to fire extinguishers to manufacturing, the list goes on and on. As a dietary staple, a little salt (in moderation) can go a long way to enhancing flavor. The problem is Americans don't really do moderation. So, the Institute of Medicine urged the Food and Drug Administration to start regulating the amount of sodium in foods, since simply telling us to eat less salt hasn't had much impact, according to USN&WR.
Ok, but why? Besides knowing that it has something to do with blood pressure, many aren't sure why Chef's chocolate salty balls aren't high on the list of recommended foods on the USDA's Food Pyramid.
Salt is part of the process that regulates fluid in your body. Sodium is one of the four cationic electrolytes (positively charged ions that float around hoping to find a negatively charged partner) in your body, along with potassium, magnesium and calcium. Chloride is anionic electrolyte, or a negatively charged ion looking for a positively charged friend, like sodium. The electrolytes help keep your body fluids in check - not too much water, not too little, not too many ions floating around, etc.
They are also important because all of the cells in our body use them as gatekeepers, allowing things in and out of the cell. Pretend you are a muscle cell, just hanging out resting. Suddenly sodium ions from the outside start crowding in to your cell through a channel! All this positivity, you can't handle it! Things need to be balanced. So, you take a bunch of negatively charged ions like potassium or chloride and shove them out of your cell to restore the positive/negative balance. This movement of positive and negative starts a cascade that can open other channels in the cell to let things in/out, or to communicate with other cells (like neurons), or to contract (like you, the muscle cell).
If you have too little or too much salt in your diet, this exchange of goods across cell membranes won't work like it's supposed to, and you could end up with cramps, dehydration, neurological problems, renal failure, even death.
Where this affects your blood pressure is through fluid regulation. This is a very simplified explanation, but hopefully it suffices so you can understand why we don't want a bazillion milligrams of sodium in our food. The idea of balance isn't just about positive and negative charges, it's also about the content of the fluid inside and outside your cells. Your body is all about being stable and doesn't like to shake things up much. So, say you eat a lot of salt. After various filtration processes occur, you'll have quite a bit of sodium in your blood. As your blood passes by tissues, the cells in those tissues get all bent out of shape because there's a lot more sodium in the blood than there is in the cell. We don't like that. So, again through various filtration processes (i.e. kidneys), your cells pump out water to try and equalize the amount of sodium inside and outside the cell. So now your cells are happy because everything is equal inside and out. Normally the kidneys recognize that there's extra fluid and squeeze it out and you increase urine production until your blood volume gets back to normal. But with chronic high sodium intake, the kidneys start to lose their ability to regulate so well. The other problem is that your blood vessels are only so big and can only handle so much fluid. Now that you have all this extra fluid in you, your heart is going to have to work harder to pump out the extra volume. This puts extra pressure on your blood vessels, which weakens their walls, and also puts extra pressure on your heart muscles, which thicken yet get weaker over time. These results can lead to stroke, heart attack, renal failure, and all sorts of other not-so-fun diseases that will land you in the hospital.
To go full circle, we've been told for a long time that we should watch our salt intake. But, it's not really working. So, the Institute of Medicine told FDA that it should set mandatory standards for safe levels of sodium, using their existing authority to regulate salt as a food additive. IOM says the average American takes in more than 3,400 milligrams of sodium (equivalent to 8.5 grams or about 1.5 teaspoons of salt) a day, which is way more than the maximum intake level of 2,300 milligrams or about 1 teaspoon established under the 2005 Dietary Guidelines for Americans. And a level of 1,500 milligrams per day is termed ''adequate" by the Institute of Medicine, says WebMD. IOM also wants the food industry to voluntarily cut back on salt amounts in food (usually used as a preservative).
Here's a list of what the food industry has already done/said they'd do regarding salt levels in food. FDA doesn't have to do what IOM says, but did say that it would review the report and see what it can do to work with industries to regulate the sodium content. So maybe those friendships are safe after all, as it doesn't sound like we'll have sodium-free mandates rolling out any time soon.