US sodium intake higher than dietary guidelines recommend

More than 88% of the US population’s daily sodium intake exceeds guideline recommendations of less than 2,300 mg, according to recent data published by the CDC.

The US Department of Health and Human Services’ and US Department of Agricultures’ Dietary Guidelines for Americans, 2010, recommend that all Americans aged 2 years and older should limit their daily sodium intake to less than 2,300 mg. Subpopulations who would benefit from further reducing sodium intake to 1,500 mg daily include people aged 51 years and older, non-Hispanic blacks, and those with hypertension, diabetes or chronic kidney disease.

Using data from NHANES 2005-2008 (n=18,823), CDC researchers found that although nearly 48% of the US population aged 2 years and older meet the criteria to limit their sodium intake to 1,500 mg, the usual sodium intake for 98.6% was more than 1,500 mg. Nearly just as many people consume up to 2,300 mg per day, the data show (see Table below). The proportion of the population with a 1,500-mg daily recommendation was higher among adults (57.1%) than children (16.2%). In particular, all non-Hispanic blacks, 44% of non-Hispanic whites and 24% of Mexican-Americans aged older than 2 years were advised to limit their sodium intake to 1,500 mg daily.

The assessment of dietary sodium intake was published in the Oct. 21 Morbidity and Mortality Weekly Report.

Varying reports, recommendations

Other reports have released similar findings. In December 2010, the US Department of Agriculture’s Center for Nutrition Policy and Promotion released dietary guidelines revealing that sodium intake in the US was higher than it should be, around 3,400 mg per day. The American Heart Association responded with evidence of high sodium intake in January 2011 through an examination of results from several trials.

The Center for Nutrition Policy and Promotion reports that adequate sodium intake for those aged 9 to 50 years is 1,500 mg per day, but that amount does not apply for ages 1 to 3 years (1,000 mg per day); 4 to 8 years (1,200 mg per day); 51 to 70 years (1,300 mg per day); and 71 years and older (1,200 mg per day) due to lower calorie requirements.

“According to the Institute of Medicine, a usual sodium intake of 1,500 mg daily is adequate for most adults, allowing for sweat loss among moderately active persons or those exposed to high temperatures after living in a moderate temperature environment,” Catherine M. Loria, MD, MS, FAHA, nutritional epidemiologist and program director in the Division of Cardiovascular Sciences at NHLBI, and colleagues wrote in an editorial note published in the MMWR report. “The 1,500 mg level does not apply to highly active persons or to workers exposed to high temperatures because of increased loss of sodium via sweat. However, the proportion of US adults who are competitive athletes, firefighters, or foundry workers is estimated to be less than 0.2%.”

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Fight against high sodium intake

Shortly after the MMWR report was released, the AHA issued an advisory on the conclusions. According to Gordon Tomaselli, MD, president of the AHA, the report is “too conservative in its suggestion that only 47.6% of American adults fit into the population group that should be consuming no more than 1,500 mg a day of sodium.”

Clyde Yancy, MD, former AHA president, said a prior 2009 report from the CDC on the same topic suggested that approximately 70% of American adults should be included in the 1,500 mg per day sodium restriction. “The data which drove us to this new target of 1,500 mg of sodium per day cannot be minimized and, conversely, the benefits of significant sodium reduction globally and especially in those at risk cannot be overstated.”

The AHA report emphasized that its experts will continue to advocate that the daily sodium intake for all American adults should be limited to 1,500 mg. According to association estimates, if most Americans achieved a daily sodium intake of 1,500 mg per day or less, an estimated $24 billion in health care costs may be saved per year.

Strategies to meet recommendations

The CDC researchers concluded that new population-based strategies and increased public health and private efforts will be needed to meet the recommendations in the Dietary Guidelines.

The Dietary Guidelines list four methods for Americans to reduce sodium consumption:

• Reading the Nutrition Facts label for sodium content information.
• Buying low-sodium foods.
• Consuming fresh foods and fewer processed foods that are high in sodium.
• Eating home-prepared foods with little or no salt, and ordering foods with lower sodium at restaurants.

Along with the Center for Nutrition Policy and Promotion’s suggestions, the AHA set into motion its own goal to improve CV health of all Americans by 20% while continuing to reduce deaths from CVD and stroke by 20% by 2020. – by Casey Murphy

For more information:

• Appel LJ. Circulation. 2011;123:1138-1143.
• Davis CA. Dietary Guidelines for Americans, 2010. USDA Center for Nutrition Policy and Promotion. www.cnpp.usda.gov/Publications/DietaryGuidelines/2010/PolicyDoc/PolicyDoc.pdf. Published December 2010.
• Loria CM. MMWR. 2011;60:1413-1417.

Disclosure: The CDC researchers report no relevant financial disclosures. The AHA receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations are available at www.heart.org/corporatefunding.

Joseph Alpert

The debate about how much sodium to take in the diet has been going on for decades. Some hypertension experts believe that a low-sodium diet is very important in the control of BP; others ‘pooh-pooh’ these recommendations. Certainly, in patients with HF, low sodium intake is important. In the control of hypertension, as stated above, there are advocates and opponents. I am generally middle of the road in this regard, telling patients to eat nothing for which they can see the salt, for example, salted peanuts and pretzels, and to keep to a minimum on canned and preserved foods, for example, corned beef, which have a lot of salt added. I also recommend that they not sprinkle salt on their food. The average American definitely eats too much salt, but the best level of intake has been controversial for years.

– Joseph Alpert, MD

Cardiology Today Editorial Board member

Disclosure: Dr. Alpert reports no relevant disclosures.