For decades, the Centers for Disease Control and Prevention (CDC) and other health agencies have advised us to consume less sodium. Too much salt in our bodies causes high blood pressure and puts us at risk for heart disease, kidney disease, and other conditions. On average, Americans eat 3,400 mg of salt each day. The CDC wants us to be at less than 2,300 mg of sodium per day. And no more than 1,500 mg of sodium per day if you are any of the following: 51 years of age or older; African American; have high blood pressure; diabetes; or chronic kidney disease. That’s close to 50 percent of us advised to cut our sodium intake by half or more. Despite years of recommendations to reduce salt in our diet, the typical average consumption of 3,400 mg has not budged.
Into this atmosphere comes a report from the Institute of Medicine (IOM).
The CDC asked the IOM, a non-profit organization that is part of the National Academies, to review the latest research on dietary sodium intake and health outcomes. The study came to some surprising conclusions. Surprising because the IOM’s meta-study of research published during the past eight years failed to find evidence to support the CDC’s salt consumption guidelines. The report does suggest that sodium intakes over 5,000 mg per day are harmful but—unlike the CDC’s recommendation for all of us to lower sodium levels—the IOM report does not find evidence for a targeted amount of sodium intake. It also found that the evidence on direct health outcomes does not support at-risk populations (diabetics, African Americans, those over age 51) lowering their sodium intakes to 1,500 mg per day. In addition, the analysis found that, for certain people, like those who have experienced heart failure, ultra-low sodium diets (under 1,500 mg per day) could even be harmful.
Yes, sodium has an impact on blood pressure, the report notes, but the hypothesis that reducing sodium to lower blood pressure and impact human health does not seem to be supported by the studies the IOM analyzed.
According to an editorial in the American Journal of Hypertension, despite the fact that the CDC commissioned the IOM report, “the CDC and the New York Department of Health appear to remain committed to efforts to have all Americans consume <2,300mg/day, and for nearly 50 percent, <1,500mg/day.” The editorial notes that the CDC has indicated that the IOM report will not “deter them from vigorously pursuing efforts to reduce the sodium intake of all Americans. They give no indication that reconsideration [of sodium guidelines] is required.”
What is Salt?
That said, sodium is not what you would call a health food. Certain populations need more of it (athletes who sweat a lot out during workouts, for example), but most of us get more than we need. But what is sodium and how does it work?
Sodium is a little less than one-half of the chemical formulation (NaCl) of table salt (the other part being chloride). It is an essential part of the human body’s fluid balance. It helps muscles contract and nerves fire.
But if we get more sodium than we need, the body will start to hold onto water to maintain its sodium-to-water ratio. One of the ways people develop high blood pressure (hypertension) is that this extra water in the body increases the blood volume and increases blood pressure. According to the USDA’s “Dietary Guidelines for Americans 2010,” there is a direct relationship between salt intake and blood pressure—the more salt you eat, the higher your blood pressure. High blood pressure puts us at risk for kidney disease, stroke, and heart disease.
Most Salt is in Packaged Foods
Surprisingly, most of the salt that we eat does not come from the shaker on our dining room table. Instead, it lurks in packaged foods and restaurant meals. Consider this: a recipe for Winter Tomato Soup in Women’s Health magazine has 96 mg of sodium per serving. A serving of Campbell’s Condensed Tomato Soup has 480 mg of sodium. A 10-piece order of McDonald’s Mighty Wings has 2,900 mg of sodium. What are the top sources of sodium in the American diet? According to the CDC, breads and rolls; processed meats; and pizza. Another reason to make meals at home using fresh ingredients—more control over how much sodium in in your diet.
And speaking of fresh ingredients, eating plenty of fruits and vegetables help lower blood pressure as well. This is because fresh produce is high in potassium, which balances sodium in the body. Consumption of lots of fruits and veggies is a cornerstone of the DASH—Dietary Approaches to Stop Hypertension—diet. The DASH diet also greatly limits salt and emphasizes whole grains, fresh fruits, and veggies, and plant-based protein like nuts and legumes.
The CDC has not yet indicated whether or not it will revise its recommended sodium levels based on the IOM’s report.
In the meantime, what’s the bottom line for sodium intake? Same as it ever was:
Prepare as many meals at home as is feasible for your lifestyle
Incorporate plenty of fresh fruits and vegetables into your diet
Read labels on packaged foods and choose lower-sodium varieties when available.
If you have high blood pressure, kidney disease, or heart disease, follow the advice of your physician.
Always consult your doctor or a health care professional before making significant diet and lifestyle changes.
Miriam Wolf is a Portland-based wellness coach, writer, and editor.