Salt does more than just make your food taste more delicious—it’s important for your body to function properly. Sodium, one of the key ingredients in table salt, regulates blood flow and pressure, and helps transmit messages between nerves and muscle fibers. Chloride, the other chemical in table salt, aids in digestion. Foods in your diet need to have enough salt replenish these nutrients to keep you healthy.
But too much salt can be bad for you. Processed foods are packed with the stuff; restaurants add more salt to their food to make it taste better. As a result, more Americans are eating high-sodium diets (sometimes without even knowing it), which has some pretty drastic effects on their health.
When you consume too much sodium in your diet, your body holds extra water. That’s because the kidneys, which filter out waste from the blood, maintain a special ratio of electrolytes, such as sodium to potassium, to water.
More salt in the diet means the kidneys keep more water in the system. That can have lots of undesirable effects, such as edema (swelling in places like the hands, arms, feet, ankles, and legs); more fluid in general means more blood coursing through veins and arteries. Over time, that causes them to stiffen, which could lead to high blood pressure.
You probably already know that salt can make you thirsty—that’s the body’s way of trying to correct that sodium-water ratio. Drinking lots of water can exacerbate issues of edema and blood pressure. But not drinking enough could force the body to draw water out of other cells, making you dehydrated.
People who consume high-sodium diets usually urinate more because of all the excess water. Every time you urinate, your body loses calcium, the mineral that, among other things, makes strong bones and teeth; urinate too often and the body could lose too much calcium, weakening bones and exacerbating osteoporosis.
Then there are the effects that no one quite understands. Some studies have found that excess salt brings on stomach ulcers, infections, and may even hasten stomach cancer. No one is quite sure why, but some researchers suspect that the sodium may disrupt the stomach’s mucus lining, according to Live Strong.
Salt can negatively impact your cognitive function, too, according to a 2010 study. That study was purely observational, so the researchers don’t hypothesize why that might be happening.
The evidence is clear: Too much salt can have serious long-term health implications. But lots of people eat diets in which the sodium intake far exceeds the daily-recommended value of 2,300 milligrams. In an effort to better inform the public, New York City decided earlier last fall that it would require restaurants to mark dishes on their menus that exceeded the daily-recommended sodium intake; the regulation goes into effect this week.
Hopefully, as a result, New Yorkers can be more aware of the salt they consume, adjust their diets accordingly, and be healthier as a result. As for everyone else: it probably wouldn't hurt to pay closer attention to your salt intake.
Update 2/10/2017: This story has been updated to reflect the fact that hypertension is synonymous with high blood pressure.