There’s a big salt controversy raging these days in the pages of medical journals and in the media. In one corner: a string of studies that seem to suggest more sodium is OK and going low-salt might be bad. In the other: heart experts, including the American Heart Association (AHA), who maintain too much salt raises blood pressure and reducing salt intake can help prevent heart attacks and strokes.

Who’s right? Before you grab your salt shaker and sprinkle with abandon, know these six facts about how sodium affects your health and where it’s hiding in your diet.

1. You need a little every day. Sodium is crucial for maintaining healthy blood sugar, fluid levels in your bloodstream and for the healthy functioning of muscles and nerves, according to the National Institutes of Health. But it takes just a smidge — 180 to 500 milligrams (mg) per day, about than the amount in a quarter-teaspoon of salt — to hit that basic quota, according to the Centers for Disease Control and Prevention (CDC).

2. Most of us get way too much. The average American consumes 3,400 mg of sodium daily from food, drinks and, in small amounts, from some medications. That’s nearly 50 percent more than what the CDC recommends as the upper limit for most Americans. And it’s more than twice the daily limit recommended by the American Heart Association. 

3. Many adults have salt sensitivity. About 25 percent of adults with normal blood pressure and 40 to 50 percent of those with high blood pressure have salt sensitivity, studies show. If you’re salt sensitive, your body hangs onto more sodium than it should, increasing fluid levels in your bloodstream. That puts more pressure on your blood vessels, leading to high blood pressure and a higher risk for heart attacks, strokes, heart failure and even death, University of Alabama at Birmingham experts note. The Institute of Medicine estimates that reining in sodium excesses “could prevent more than 100,000 deaths annually.”

4. “Low salt is bad for you” studies have lots of critics. It’s true that several big studies found possible problems when people get less than 1,500 mg of sodium a day. But some of the research estimates sodium intake based on measurements of sodium exiting the body in urine — a method experts say is inaccurate. Other research used vague info on what study participants ate. More important, most of us don’t have to worry about getting too little sodium. We’re already getting too much.

5. Stick to these salt guidelines. The US Department of Agriculture (USDA) says to aim for less than 2,300 mg a day (about the amount in one teaspoon of salt). If you are over 50, African-American, or have high blood pressure, diabetes or chronic kidney disease, shoot for 1,500 mg (the amount in a little less than three-quarters of a teaspoon of salt). That means about half of all Americans should be getting less than 1,500 mg a day. 

6. Read labels and eat fresh. Fact is, 75 percent of the sodium in the American diet comes from processed foods, fast food joints and restaurants. Food makers add it to improve flavor and texture and to extend shelf life. Common “salt bombs” include pizza, soy sauce, frozen dinners and canned soups, but even a turkey-and-cheese sandwich on whole wheat bread could pack up to 1,500 mg of sodium.

Cut your sodium intake by checking the Nutrition Facts label of packaged foods. Labels that say “sodium free” or “salt free” cannot have more than 5 mg per serving, and a “low sodium” claim means 140 mg or less per serving. But the AHA warns “no salt added” or “unsalted” doesn’t mean a food is sodium free.

Lastly, choose more fresh, unprocessed foods. Fruit, vegetables, whole grains, dried beans and unsalted nuts are naturally low in sodium or sodium-free. So are most fresh meats (though some cuts of chicken and turkey may contain salty brine). Low-fat and fat-free dairy products are low in sodium. The bonus: These foods also provide potassium, calcium and magnesium — minerals that work with sodium to keep blood pressure healthy.

Sari Harrar is an award-winning health, medicine and science journalist whose work appears in Dr. Oz The Good Life magazine, Good Housekeeping, O--Oprah Magazine, Organic Gardening and other publications.