For decades, health experts have been advising Americans to cut back on their daily sodium intake to help prevent high blood pressure, which can lead to heart attack, stroke, and kidney disease.

Yet our average daily sodium intake increased more than 4 percent—from 3,266 mg to 3,409 mg—over five years, according to a new study from the Centers for Disease Control and Prevention (CDC). That’s almost 50 percent more than the maximum recommended daily intake of 2,300 mg.

What's behind the big increase? The study zeroes in on favorite packaged and highly processed foods from supermarkets and restaurants.  

And these sobering numbers don't include what you're adding from the salt shaker. The study's authors estimate that when you include that figure, the true average amount of sodium consumed daily may rise to around 3,750 mg. 

The Biggest Sodium Sources

The researchers found that 70 percent of sodium intake came from just 25 foods, with nearly half of the sodium coming from 10 foods specifically: bread, pizza, sandwiches, cold cuts and cured meats, soups, burritos and tacos, savory snacks (such as chips, crackers, pretzels), chicken, cheese, and eggs and omelets.

Even just one serving of some foods, such as pizza, cold cuts, and cheese, is high in sodium. For example, 2 ounces (about two slices) of Boar’s Head Cap-Off Top Round Pastrami has 600 milligrams of sodium, and one slice of a large Domino’s cheese pizza has 620 milligrams. But other foods, such as bread, contribute a lot of sodium to the diet simply because people eat so much of them.

While the top 10 sources were the same for all age groups, the ranking of them varied depending on age. In kids ages 2 to 5, savory snacks (such as chips or crackers) supplied the most sodium. Pizza came in at number one for children and teenagers, ages 6 to 19, as well as for adults between the ages of 20 to 50. Bread was at the top of the list for people 51 and older.  

How to Cut Back

Even small reductions in sodium can have a big impact on health. For example, if everyone cut their intake by just 400 mg per day—the amount in less than ¼ teaspoon of table salt—it could prevent an estimated 32,000 heart attacks and 20,000 strokes per year, according to a 2010 study published in the New England Journal of Medicine. Here are some easy ways to consume less sodium.

Increase the whole foods in your diet. Even healthy foods can be full of sodium when they come in a package. Frozen vegetables with sauce, canned vegetables, and boxed rice and grain mixes are often high in sodium. For example, Green Giant Original Olive Oil & Sea Salt Mashed Cauliflower has 380 milligrams of sodium in ½ cup, while the brand’s Rice Cauliflower has just 10 mg per half cup. Canned soups, sauces, and frozen meals are other typical high-sodium foods.

Pump up the potassium. Getting enough of this mineral—which is found in fruits, vegetables, whole grains, nuts, beans, some fish, and dairy products—can blunt the effects of sodium on your blood pressure. Potassium and sodium work together to maintain fluid balance in your body, which has an effect on blood pressure and kidney function. When you’re eating more potassium, you excrete more sodium through urine, and potassium also helps blood vessel walls relax, according to the American Heart Association. 

Compare nutrition labels. Packaged foods can vary widely among brands in their sodium content. Take whole wheat bread, for instance. One slice of Pepperidge Farm’s has 105 mg, while one slice of Arnold’s has 160 mg. “Be sure to take serving sizes into consideration, too, to make sure that you’re comparing apples to apples,” says Maxine Siegel, a dietitian and head of the Consumer Reports food testing lab. “And if you will likely eat more than the serving size on the label, you'll want to multiply the sodium.” The Percent Daily Value column can be used as a quick check to see if a food is high or low in sodium: 5 percent is low and 20 percent or more is high.

Rinse some canned foods. Draining and rinsing canned chickpeas and other beans and vegetables such as green beans, corn, and carrots can remove up to 40 percent of the sodium.

Downsize sandwiches. “With the bread, cold cuts, cheese, and condiments, sandwiches easily can become a sodium bomb,” says Siegel. She suggests replacing mustard and mayo with avocado, roasted red peppers, or even a drizzle of olive oil to add moistness. Choose lower-sodium cold cuts and add just one or two slices. Or make your own chicken, turkey, or roast beef and use that for sandwiches. Consider eliminating the cheese.

Taste before you eat. “Even though packaged and processed foods are the biggest sodium villains, reducing the amount of salt you add at the table can put a dent in your daily intake,” says Siegel. “Many people automatically pick up the salt shaker and season their food before tasting it, when often the food is already salty enough.”

At restaurants, ask to hold the salt. While more sodium came from store-bought foods, the CDC report noted that 27 percent came from restaurant foods and that these foods contributed more sodium per calorie consumed. “The ingredients in a dish may already contain sodium, but chefs often add salt at many stages during cooking,” says Siegel. “Asking them not to can really make a difference in the final sodium count of the dish. She also suggests asking for dressing and sauces on the side (and using them sparingly) and splitting a main dish with a dining partner. “Restaurant portions are notoriously oversized. Share a meal and you’ll be cutting calories and fat along with the sodium.”  

Chuck Bell, programs director for Consumers Union, the policy and mobilization arm of Consumer Reports, says that although approximately half of Americans should be reducing sodium in their diet to less than 1,500 milligrams per day—either because they’re suffering from or are at high risk of cardiovascular problems, such as high blood pressure—it is challenging to hit those targets, despite voluntary reductions by some manufacturers and restaurants.

“We still have a very long way to go,” says Bell. “It is surprisingly hard to find low-sodium options for bread at many supermarkets and grocery stores, no matter how many loaves you examine.”

Consumers Union strongly supports the improvement of sodium labeling on menus at restaurants, says Bell: “We also applaud the Food and Drug Administration’s efforts to establish voluntary sodium reduction targets for processed foods and restaurant meals, which can help assure that consumers will have meaningful and actionable choices.”