It’s largely a matter of information. Most don’t realize where the salt they eat comes from and how easy it is to lower intake with smarter shopping.
Making a convincing connection between lowering dietary sodium and lowering BP is not difficult. It’s been documented in study after study, particularly since 1990.
Getting patients to use less salt is another matter. Clinicians’ efforts “haven’t been very effective,” says Lisa Hark, PhD, RD (registered dietitian) who directs the nutrition education and prevention program at the University of Pennsylvania School of Medicine in Philadelphia. “We make recommendations, but it’s like a salmon swimming upstream because of the big food companies.” She’s referring to the fact that most of the sodium in the American diet is hidden in the foods we buy in grocery stores and restaurants.
The need to rein in sodium intake has taken on added urgency in light of a new study done at the Harvard Medical School, NIH, and several other centers. It followed up on 2,400 people who had participated in sodium-reduction trials 10-15 years ago. The researchers found that those who had cut their intake 25%-35% had a 30% lower risk of MI or stroke than those who didn’t change their diets (BMJ. 2007;334:885-895).
Sodium is an essential nutrient. It is a primary electrolyte that helps maintain the balance of fluids in the body. Only about 500 mg/day is necessary for that function, but nutrients don’t exist in isolation. Sodium occurs naturally in most foods, and a diet limited to just 500 mg would be too deficient in protein, fats, and vitamins to be healthy, experts say.
The U.S. Department of Agriculture (USDA) and the American Heart Association (AHA) recommend no more than 2,300 mg of sodium a day. That’s roughly equal to 1 teaspoon of table salt, which is about 40% sodium.
Hypertensives, blacks, and middle-aged or older adults should aim for 1,500 mg/day. People with heart failure should limit themselves to 2,000 mg/day.According to the American Dietetic Association (ADA), the average American consumes 3,200 mg/day. Most of it comes in prepared foods (Figure 1), not from the saltshaker. “It can be difficult to reduce sodium intake,” says Paul Whelton, MD, who chaired several clinical trials for hypertension prevention, including the Institute of Medicine’s Committee on Lifestyle and Prevention. “We live in a society where 80% of our salt comes from processed food. Our taste has become accustomed to very high levels of saltiness.”
Bob Earl, senior director of nutrition policy at the Grocery Manufacturers Association, says salt is added to processed foods “for flavor and for safety, as a preservative.”
High-sodium foods include canned goods; cured or processed meats, such as ham, bacon, or hot dogs; pancake, muffin, or cornbread mixes; flavored rice mixes; prepared sauces, gravies, or chili; and snack foods, such as pretzels and chips. For example, a single slice of deli bologna has 295 mg sodium, a 3-oz serving of canned ham has 837 mg, and a large dill pickle contains 1,731 mg.
Hidden sodium is everywhere
Sodium lurks in some unexpected places, like soft drinks, desserts, bread, and OTC remedies for headache and heartburn. FDA regulations require manufacturers to list sodium content on the labels of antacids that have ≥5 mg of sodium per dose.
“Hidden salt is very pervasive, especially in convenience products like canned tomatoes, canned tomato sauce, and ketchup,” says Bill Briwa, a chef-instructor with the Culinary Institute of America in Greystone, Calif. “You can go for low-sodium products, but recognize that even a low-sodium soy sauce is still going to have a lot of sodium.”
Experts agree on several basic recommendations clinicians can make to help patients cut back:
• Get rid of the saltshaker at the table, and use minimal salt when cooking.
• Make meals from scratch using fresh or frozen foods instead of canned or processed products.
• Read labels. Sodium content can vary widely in similar products. According to the USDA, 8 oz of reconstituted tomato soup has 340-1,040 mg sodium; a 4-oz serving of frozen plain pizza contains 450-1,200 mg.
• Avoid processed meats and other high-sodium foods.
“We have to move people away from processed, packaged, and prepared foods,” says Hark. “Clinicians have to ask the right questions. For example, do you use garlic salt or garlic powder? People don’t realize there’s a difference.” A teaspoon of garlic salt has 1,480 mg sodium; a teaspoon of garlic powder contains 1 mg. Adobo and Sazón are very popular seasonings among Hispanics, and they’re loaded with salt, Hark adds.
But Americans’ craving for salt is hardly limited to the Latino community. “There’s a cultural problem,” Hark says. “Every cooking show on television uses salt, but I don’t believe you have to cook with it. It’s an acquired taste.”
Briwa agrees. Salt performs specific functions in food preparation, such as lowering the boiling point of water and drawing moisture from food, but the real issue is one of flavor. “Salt does draw bitterness out of eggplant, but if sodium is a concern, stop doing that,” he says. “Eggplant is far from unpalatable if it’s unsalted.” If patients feel they must prepare vegetables in heavily salted water, tell them to shock the cooked vegetables in a cold-water bath to rinse off most of the salt, he adds.
Many nutritionists recommend substituting acids, like lemon juice, or fresh herbs and spices for salt. But this advice will go only so far because, according to Briwa, salt enhances other flavors and will be missed. “You can add garlic or pepper flakes or lemon and still want salt,” he warns.
The best strategy is to retrain the palate to appreciate salt-free food, but admittedly, this is a process that can take several weeks and requires self-discipline. “The first week, you feel total deprivation,” Briwa says. “The second week, you won’t notice it missing as much. The third week, you’ll notice flavors that the salt had previously obscured.” Ironically, as the palate learns to appreciate different flavors, “food that tasted good before will seem too salty.”
Eating out is hazardous
Restaurant fare can be loaded with hidden sodium. “Don’t tell patients not to eat out because they will,” says Hark. “But you can warn them about the big offenders: Chinese food, especially soy sauce, and Italian food. The red tomato sauces and cheeses are very high in salt.” She suggests diluting soy sauce with water if a low-sodium version is not available.
Quick-serve sit-down restaurants (Chili’s, Outback Steakhouse, Pizza Hut, etc.) and fast-food restaurants like Burger King also use much more salt than a home cook would, says ADA spokesman Christine Gerbstadt, MD, RD. She maintains a private practice in Altoona, Pa., and advises her clients to check the nutritional information on restaurant Web sites. “I tell them to identify three or four entrees that are lower in sodium, so they can have some good choices when they sit down to order. If there’s a higher-sodium dish that they just must have, then I tell them choose it once a month.”
Tricking the taste buds
In some cases, patients who just can’t toss the saltshaker might want to try the imitation table salts available in grocery stores, including AlsoSalt, Nu-Salt, and NoSalt. All of them are based on potassium chloride. “These certainly can be used if you feel absolutely compelled to add something at the table, but a natural approach is better,” says Whelton. Moreover, the substitutes can cause hyperkalemia, and people with renal disease should avoid them.
Patients looking for a cohesive, overall approach to lowering sodium intake can benefit from the Dietary Approaches to Stop Hypertension (DASH) diet, which was developed in 1996 and has been shown to lower BP in just 14 days. “The DASH trials produced reduced [BP] numbers as effectively as medication,” says Hark.
DASH focuses on nine nutrients, including sodium and fats. It’s based on 8-10 servings of fruits and vegetables daily, plus whole grains and low-fat dairy products. These foods are naturally low in sodium. Nutritionists advise telling patients to adopt the diet gradually so the palate has time to adjust.
Although DASH differs from the 2005 USDA Dietary Guidelines for Americans—which proposes 8-11 servings of bread, cereal, rice, or pasta at the base of its pyramid—DASH is recommended by the USDA, the AHA, and the National Heart, Lung, and Blood Institute. Details are available online at www.dashdiet.org, where patients can order a book with 28 days’ worth of menus and other tips.
The site acknowledges that adherence may be difficult. “The average American gets two to three servings of fruits and vegetables combined each day, so following the DASH diet can involve making a concerted effort,” it notes.
Reliance on fresh ingredients also requires more time in the kitchen than many people may be willing to spend. But, says Whelton, the results are worth the work. “Sometimes we pay more attention to what we pump into our cars than what we pump into our bodies,” he says. “Our engines are much more important than a car’s.”