Salt shakedown: How and why you should eat less sodium

Sodium, an essential component of salt, plays many vital roles in the body. This mineral helps regulate blood volume, transmit nerve impulses, and contract muscle fibers, among other things. But we only need about 500 milligrams (mg) of sodium a day to survive — and the average American consumes nearly seven times that much.

Health experts have been urging Americans to cut back on sodium for years. More than two decades ago, the landmark Dietary Approaches to Stop Hypertension (DASH)–Sodium trial provided strong evidence that reducing sodium in the diet can lower blood pressure. Also, too much sodium can have other detrimental effects (see "How excess sodium can harm your health").

Many studies reinforce the benefits of cutting back on salt, including a recent one that looked at cardiovascular biomarkers (substances that reflect heart health) in stored blood samples from the original DASH trial. Researchers found that the diet progressively lowered biomarkers for heart injury and heart strain over the course of the three-month study. Another study, which followed almost 177,000 people for nearly 12 years, found that people who reported that they rarely or never added salt to their food had a lower risk of heart disease than those who usually salted their food.

"I definitely tell my patients with high blood pressure to pay attention to how much salt they eat, and I hand out copies of the DASH diet," says Dr. Katherine Sakmar, an internist at Harvard-affiliated Massachusetts General Hospital. The DASH diet emphasizes whole grains, fruits, vegetables, and low-fat dairy products as well as fish, poultry, beans, nuts, and healthy oils. (For more information, including recipes, see the National Heart, Lund, and Blood Institute's DASH Eating Plan page.) Following this diet will help you reach a daily sodium goal of less than 2,300 mg per day, which is the amount recommended by the Dietary Guidelines for Americans.

Check product labels

More than 70% of the sodium in the average American diet comes from packaged, prepared, and restaurant foods. That's why checking food labels is an important first step for curbing your salt intake, says Dr. Sakmar, who makes a habit of checking labels herself. "If I recommend healthy lifestyle changes to my patients, I believe I should do them too," she says. Look at the Nutrition Facts panel for the sodium content, and make sure to check the serving size. Product package sizes have changed in recent years, which means the number of servings in a package may have changed as well, she says.

Many people don't realize that bread and related products such as bagels, rolls, buns, pita bread, naan, and tortillas are often a major source of sodium in their diets, mainly because people eat these foods frequently. Processed meats such as cold cuts (also known as deli meat or lunch meat) are also big contributors. "My patients, many of whom are of Italian heritage, are surprised when I tell them that a typical Italian sub sandwich often has more than 1,000 milligrams of sodium," says Dr. Sakmar. Even some uncooked meats and poultry have added salt, she notes.

Salt or sodium appears in the ingredient list of many popular seasoning blends, and some also contain the flavor enhancer monosodium glutamate, or MSG, another sodium source. Instead, look for salt-free herb and spice blends, and seek out low-sodium or reduced-sodium versions of any condiments, sauces, or dressings you use frequently.

 Image: © EdNurg/Getty Images