CVM Professor Participates On National Committee Evaluating Sodium, Potassium Intake Values

The New Report Introduces A New Category For Sodium Based On Chronic Disease Risk Reduction

 

Dr. ChiuWeihsueh Chiu, a professor in the Texas A&M College of Veterinary Medicine & Biomedical Sciences’ (CVM) Department of Veterinary Integrative Biosciences (VIBS), was part of a National Academies of Sciences, Engineering, and Medicine committee that reviewed current evidence and updated intake recommendations known as the Dietary Reference Intakes (DRIs) for sodium and potassium that were established in 2005.

The committee’s new report, Dietary Reference Intakes for Sodium and Potassium, revises the Adequate Intakes (AIs), which are the best estimate of intakes assumed to be adequate in apparently healthy individuals.

The report reaffirms the sodium AI for individuals ages 14-50, decreases the sodium AIs for children age 1-13, increases the sodium AIs for adults ages 51 and older, and decreases the potassium AIs for individuals age 1 and older.

The report also uses guidance from a 2017 National Academies report to introduce the first DRI specific to chronic disease risk reduction, in this case for sodium. In particular, they recommended that adults who currently consume more than 2,300 miligrams per day of sodium lower their intake levels so as to reduce their risks of cardiovascular disease.

“We were tasked with looking at the world’s literature on sodium and potassium; we actually expanded upon the analysis provided by the 2018 Agency for Healthcare Research and Quality systematic review and, particularly, the heterogeneity of the studies,” Chiu said. “For example, different studies may say different things or seem like they have different results, so we did a more thorough exploration of why different studies might be giving different results.

“Some of the very important differences in these studies included the different amounts of sodium reduction—some studies only reduced sodium a little bit in their study and some of them reduced them a lot,” he said. “So, you’re going to get different results just because of that—it’s not because one is wrong and one is right.”

Sodium and potassium are interrelated, essential nutrients that play vital functional roles in the body, including being important for nerve signal transmission, muscle contraction, and fluid balance.

Both nutrients have been linked to risk of chronic disease, particularly cardiovascular disease, the report says. Possible associations between sodium intake with other adverse health outcomes have also been suggested.

“There has been some controversy about sodium, in particular. You often see contrasting editorials in the media—also known as the ‘salt wars’—between those who advocate that the public reduce sodium and those who say there is no problem,” Chiu said. “That is why we used rigorous systematic review methods to evaluate the available data.”

The physiological essentiality of sodium and potassium, in conjunction with their relationships to adverse health effects including chronic disease risk, called for a new approach to establishing DRIs.

“Diet-related chronic disease is a major driver of health care costs across the United States and globally,” said Patrick J. Stover, vice chancellor and dean for agriculture and life sciences at Texas A&M University and director of Texas A&M AgriLife Research. “The latest intake recommendations from the National Academies—and the first dietary guidelines for the new category of reduced chronic disease risk—are a transformative step toward the linkage between nutrition and long-term health.”

Chiu said the best ways to decrease sodium levels are to avoid prepared and processed food and to salt food to taste after cooking it instead of while cooking it.

“The reason for that is that table salt, you put it right on top so you taste it; the amount of salt you need to put on to taste it is less,” Chiu said. “Whereas for processed foods, when you cook with salt, you only taste what’s on the surface; you end up eating a lot more than you actually taste.”

The committee’s findings also included:

Sodium

The updated sodium AIs are 110 mg daily for infants 0-6 months; 370 mg daily for infants 7-12 months; 800 mg daily for children ages 1-3; 1,000 mg daily for ages 4-8; 1,200 mg daily for ages 9-13; and 1,500 mg daily for ages 14 and older. There remains limited evidence on sodium intakes below 1,500 mg per day for adults, which prevented the committee that conducted the study from considering further reductions in the sodium AI.

There is sufficient evidence to characterize the relationship between sodium intake and risk of chronic disease. Therefore, the committee established a Chronic Disease Risk Reduction Intake (CDRR) for sodium using evidence of the beneficial effect of reducing sodium intake on cardiovascular disease risk, hypertension risk, systolic blood pressure, and diastolic blood pressure.

Reductions in intakes that exceed the sodium CDRR are expected to reduce chronic disease risk within the apparently healthy population.

For individuals ages 14 and older, the CDRR recommendation is to reduce sodium intakes if above 2,300 mg per day. The committee also established a sodium CDRR for children ages 1-13.

The effect of sodium intake on blood pressure that was used to inform the sodium tolerable upper intake level (UL) established in the 2005 DRI report is part of the evidence base that informed the CDRR.

Most U.S. and Canadian populations consume sodium above both the AI and CDRR values. There is no concern of sodium inadequacy in the population, the report says. Reducing sodium intake has a greater effect on adults with hypertension than on adults with normal blood pressure, but the benefits of reducing sodium intake toward the sodium CDRR apply to both groups.

Potassium

The updated potassium AIs are 400 mg daily for infants 0-6 months; 860 mg daily for infants 7-12 months; 2,000 mg daily for children ages 1-3; and 2,300 mg daily for ages 4-8.  The potassium AIs for other age groups range from 2,300 to 3,400 mg per day, based on sex and life-stage groups. The potassium AIs in this report are lower than those established in 2005. This difference is due, in part, to the expansion of the DRI model in which consideration of chronic disease risk reduction was separate from consideration of adequacy.

This report reaffirms that there is insufficient evidence to establish a potassium UL for apparently healthy individuals. The absence of a potassium UL does not mean that there is no risk from excessive supplemental potassium intake, either overall or for segments of the population. Caution against high intake through supplemental potassium is warranted for certain population groups, particularly those with or at high risk for compromised kidney function.

Despite moderately strong evidence that potassium supplementation reduces blood pressure, particularly among adults with hypertension, a potassium CDRR cannot be established because of unexplained inconsistencies in the body of evidence, a lack of intake-response relationship, and limited evidence for relationships between potassium intake and chronic disease risk. The lack of a potassium CDRR does not necessarily mean a lack of an effect of potassium intake on chronic disease risk, the report says, but rather a lack of evidence to characterize the effect.

The committee identified a number of research needs that would help inform future potassium and sodium DRIs, such as additional research on the interrelationship between potassium and sodium intakes. In addition, with the vast majority of U.S. and Canadian populations consuming sodium at levels above the CDRRs, opportunities exist to find solutions to reduce population sodium intakes.

The study—undertaken by the Committee to Review the Dietary References Intakes for Sodium and Potassium—was sponsored by Health Canada, U.S. National Institutes of Health, Public Health Agency of Canada, U.S. Centers for Disease Control and Prevention, U.S. Department of Agriculture, and U.S. Food and Drug Administration. The National Academies are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln. For more information, visit nationalacademies.org

The report is available for download at www.nationalacademies.org/DRIsodiumpotassium.

 

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