Only positives for reduced sodium intake

Congress is currently considering legislation to reauthorize child nutrition programs, including nutrition standards for school meals. The Senate Agriculture, Nutrition and Forestry Committee’s bill takes a measured, bipartisan approach, addressing children’s health needs with respect to sodium reduction while providing flexibility to school food programs that need more time to reduce sodium levels. 

Unfortunately, the House Education and the Workforce Committee’s discussion draft bill dismisses that reasoned approach and guts the sodium standard. Moreover, it presents a disingenuous picture about the science behind sodium reduction in children. The discussion draft cherry-picks which studies can be considered when setting sodium standards and ignores what expert scientists and medical professionals use when analyzing the evidence of nutrition science. That evidence — or what we call the preponderance of evidence — supports current nutrition standards that reduce sodium intake as a means to lower blood pressure and prevent its adverse health consequences.

{mosads}We ignore the facts at our own peril. Elevated blood pressure is one of the leading causes of preventable deaths in the U.S. and manifests itself as heart disease and stroke. While such conditions typically occur in adults, the problem of elevated blood pressure begins in childhood. Today, we seek to halt the epidemic of blood pressure-related cardiovascular disease by emphasizing prevention beginning very early in childhood — even at infancy.

It is well accepted in the prevention research community that strategies aimed at reducing blood pressure over a lifespan are likely to have a greater impact if started early in childhood, when eating habits are formed — and before early damage to the heart and blood vessels occur. One such intervention is sodium reduction. 

There is persuasive evidence in support of sodium reduction in children. Research indicates that elevated blood pressure in children is associated with early damage to the heart and blood vessels and that reduced sodium reduction levels lowers blood pressure in children. Thankfully, severe adverse health outcomes from elevated blood pressure rarely occur in children. But there is considerable evidence to support a relationship between higher levels of blood pressure in children and blood pressure-related cardiovascular disease morbidity and mortality in adults. 

First, numerous studies have strongly documented that elevated childhood blood pressure continues into adulthood. Second, elevated blood pressure levels in children are associated with early damage to blood vessels and other heart abnormalities, such as stiff arteries and thickened heart muscle. Importantly, evidence shows that elevated blood pressure in adolescents predicts atherosclerosis in the coronary arteries. Third, higher levels of systolic blood pressure in children, as early as age six, are associated with blood vessel abnormalities in middle-aged adults. 

The evidence is clear: lowering sodium intake in children lowers blood pressure. Indeed, the adverse effect of sodium on blood pressure begins at birth. In a randomized trial, infants fed a low-sodium formula achieved lower blood pressure during the first six months of life than infants fed a regular-sodium formula. And when these infants were restudied at 15 years of age, the group formerly on the low-sodium diet during infancy continued to have substantially lower blood pressure than the regular formula group. 

It is not just infants who can benefit from lower sodium levels in their diets. Persuasive evidence has documented that lowering sodium intake reduces blood pressure in adolescents. The two-year Exeter-Andover school project found that it was possible to significantly reduce sodium by controlling the amount used in food preparation for students eating school meals on a daily basis. The result was a significant reduction of blood pressure. An analysis that combined data from these two trials and 11 others reached the same conclusion: sodium reduction lowers blood pressure in infants and children.

In summary, the preponderance of evidence is sufficiently strong to recommend a lower sodium intake as an effective and well-accepted approach to reducing high blood pressure in infants and children. Current efforts to weaken nutrition standards for school meals or trying to redefine the science to fit a political agenda undermines an effective strategy that will improve the health of our children and our nation. We urge Congress to not follow such a reckless course.

Appel is director of the Welch Center for Prevention, Epidemiology, and Clinical Research and professor of medicine at Johns Hopkins.