Consuming 3,000 mg of salt daily did not adversely affect blood pressure (BP) in adolescent girls, but consuming at least 2,400 mg of potassium daily may help combat increases in BP during adolescence, according to data published in JAMA Pediatrics.
“The scientific community has historically believed that most people in the United States consume excessive dietary sodium, resulting in an elevated risk of hypertension and cardiovascular disease,” the researchers wrote, noting that current guidelines recommend limiting sodium intake to less than 2,300 mg daily for healthy people aged 2 to 50 years.
Even so, data on the health effects of sodium intake are conflicting. Further, the relationship between sodium intake and BP in children and adolescents is largely unexamined in prospective studies, according to background information in the study.
For this study, the researchers sought to assess the effects of dietary sodium, potassium and the potassium to sodium ratio on BP in adolescents by evaluating data from the National Heart, Lung, and Blood Institute’s Growth and Health Study. The prospective cohort study followed 2,185 black and white girls, aged 9 to 10 years at baseline, for 10 years.
According to study results, higher sodium intakes, defined as 3,000 mg to less than 4,000 mg daily and 4,000 mg or more daily, did not appear to adversely affect BP in adolescence. Moreover, in longitudinal mixed models, girls consuming at least 3,500 mg of sodium daily generally had lower diastolic BPs than those consuming less than 2,500 mg of sodium daily (P=.18).
In contrast, higher potassium intakes were inversely associated with change in BP throughout adolescence (P<.001 for systolic and diastolic BP). Overall, girls who consumed the most potassium, defined as at least 2,400 mg daily, had lower late-adolescent systolic and diastolic BP than those who consumed less (P=.02 for systolic and P=.05 for diastolic BP), according to the data.
Potassium to sodium ratio was also inversely associated with systolic BP (P=.04), but the effect was generally weaker than potassium alone.
Girls who consumed the most sodium, defined as at least 4,000 mg daily, were mostly black, had lower socioeconomic status families and watched more television than those consuming less sodium (P<.001 for all). Girls who consumed the most potassium, defined as at least 2,400 mg daily, were mostly white, more active, had lower BMIs and watched less television (P<.001 for all), the researchers reported.
Data also showed that participants with the highest sodium and potassium intakes consumed the most calories as well as the most dairy, fruits and vegetables, and fiber (P<.001 for all). Higher sodium intake was linked with increased fat intake and higher potassium intake with increased protein intake.
“This prospective study showed that black and white adolescent girls who consumed more dietary potassium had lower BPs in later adolescence. In contrast, the data indicated no overall effect of sodium intake on BP, and, thus do not support the call for a global reduction in sodium intake among children and adolescents,” the researchers wrote.
“This study emphasizes the need to develop methods for estimating salt sensitivity to be used in future studies of high-risk populations and points to the potential health risks associated with the existing low dietary potassium intakes among U.S. children and adolescents.”