What You Think About Salt Is Wrong

My team is always on the clock.

The most recent example came this weekend when my researcher talked to her family about salt. Her family members expressed concern over the "high sodium content" of the microwavable dinners that the 93-year-old matriarch enjoys. They fretted over the fact she was getting too much salt in her diet.

Here's the thing... Not enough salt is just as dangerous as too much.

And with Heart Health Month coming to a close today, we wanted to revisit our stance on salt...

Why do we need salt?

Salt contains sodium, an important element that creates a balance in the blood and fluids of our bodies. When we take in other nutrients, sodium helps transport them into our cells. Plus, sodium is critical in nerve signaling.

How do our bodies regulate salt?

The balance between water and sodium is vital to keep your body functioning. Your kidneys do most of the work with a sort of master "on/off" switch.

If you have too much salt and not enough water, your body starts pulling water out of other parts of your body. This puts pressure on your kidneys and strains your blood vessels.

If you don't have enough salt, your kidneys produce an enzyme called renin. Renin tells your body to get into sodium-conservation mode. One of the effects of this is that your blood vessels constrict, raising blood pressure.

Wait, so not enough salt raises my blood pressure?

Yes... in the short term. But chronic high blood pressure takes a long time to develop. And it depends on more than just salt intake. A 2013 study out of the University of Virginia found that 15% of people who followed low-salt diets actually saw their blood pressure increase within seven days, rather than decrease.

Even the study used by the American Heart Association to back the recommendation for cutting salt showed how little it works. For people with high blood pressure (140/90 or higher), their readings only dropped three to five points, to about 135/87. For people in the group with normal blood pressure (lower than 120/80), cutting salt only lowered their blood pressure one to two points, or to just 118/79. Essentially meaningless.

So can I eat all the salt I want?

Salt and its harmful effects show up statistically on what is called a U-shaped curve, also called the "Goldilocks" curve. In other words, too much is bad and too little is bad.

You want to hit the sweet spot. But the amount that's "too much" isn't as clear as the "experts" would have you believe.

For example, a study published in 2015 in the Journal of the American Medical Association: Internal Medicine found that modest amounts of salt in your diet aren't harmful. Researchers found that, after a decade, participants who consumed the highest level of the "recommended" salt intake (2,300 mg of sodium) were no more likely to experience heart disease, stroke, heart attack, or heart failure than those who ate less salt.

The study found that death rates were lowest in people getting between 1,500 mg and 2,300 mg of salt per day, at 30.7%. The death rate was 33.8% in people consuming less than 1,500 mg and 35.2% in people consuming more than 2,300 mg.

But a 2014 study published in the New England Journal of Medicine found that people consuming less than 3,000 mg (30% higher than the "recommended" amount) of salt had a 27% increased risk of having a heart attack or stroke and dying from a cardiovascular event.

Why is not having enough salt dangerous?

Some people cut down way too much on their salt intake, which leads to even worse health problems, including hyponatremia.

Hyponatremia, which is a condition caused by abnormally-low levels of salt in the blood, causes everything from muscle cramps to confusion and nausea. It can affect the nerves and the ability to walk. And it's one of the leading causes of falls in the elderly.

If you take a diuretic, the most common first-line drug for lowering blood pressure, you could be at greater risk. These medications take salt out of your body and thus remove water along with it. Combining them with low-salt diets can reduce your salt level too much. If you're on a low-salt diet already and add a diuretic, be sure to talk to your doctor about how to prevent hyponatremia. A simple blood test can help measure the level of salt in your system.

Is there anyone who should watch his or her salt intake?

Not everyone responds to salt the same way. Extra salt in moderation is fine for most people. But there are exceptions.

First, you should have healthy kidneys. If you have any kidney diseases or a common illness that affects your kidneys (such as diabetes), you should avoid going crazy on a salt binge.

Second, there's a genetic factor that most of these government regulations fail to acknowledge. Some folks are genetically "salt-sensitive." That means their genetic makeup makes them more likely to be affected by higher salt intake than others.

The study we mentioned above from the University of Virginia also reported that about 25% of Americans are salt-sensitive.

How do I know how much salt I'm eating?

Salt doesn't just come from what you sprinkle onto food yourself. Many prepackaged foods contain salt. Just take a look...

Make sure to get your other "salts," too. Magnesium and potassium are nutrients critical to helping your body maintain that sodium-water balance we mentioned earlier. In fact, low magnesium and potassium levels in Americans' diets are probably a major component of high-blood-pressure problems.

Here at Health & Wealth Bulletin, we want to empower you to make informed decisions about your health. Don't shy away from salt – just make sure you drink plenty of water to keep your fluid-to-salt ratio balanced. Also be sure to get enough potassium and magnesium by eating plenty of fruits, vegetables, nuts, and beans. Three foods that pack in potassium and magnesium all at once are fish, avocados, and bananas.

What We're Reading...

• A study from last summer backing the idea of a correct level of salt. 

• Something different: We've recommended this diet tip for years...

Here's to our health, wealth, and a great retirement,

Dr. David Eifrig and the Health & Wealth Bulletin Research Team
February 28, 2019