Inflammation and salt in young adults: the African-PREDICT study.

PURPOSE

Low-grade inflammation and a diet high in salt are both established risk factors for cardiovascular disease. High potassium (K) intake was found to counter increase in blood pressure due to high salt intake and may potentially also have protective anti-inflammatory effects. To better understand these interactions under normal physiological conditions, we investigated the relationships between 22 inflammatory mediators with 24-h urinary K in young healthy adults stratified by low, medium and high salt intake (salt tertiles). We stratified by ethnicity due to potential salt sensitivity in black populations.

METHODS

In 991 healthy black (N = 457) and white (N = 534) adults, aged 20-30 years, with complete data for 24-h urinary sodium and K, we analysed blood samples for 22 inflammatory mediators.

RESULTS

We found no differences in inflammatory mediators between low-, mid- and high-sodium tertiles in either the black or white groups. In multivariable-adjusted regression analyses in white adults, we found only in the lowest salt tertile that K associated negatively with pro-inflammatory mediators, namely interferon gamma, interleukin (IL) -7, IL-12, IL-17A, IL-23 and tumour necrosis factor alpha (all p ≤ 0.046). In the black population, we found no independent associations between K and any inflammatory mediator.

CONCLUSION

In healthy white adults, 24-h urinary K associated independently and negatively with specific pro-inflammatory mediators, but only in those with a daily salt intake less than 6.31 g, suggesting K to play a protective, anti-inflammatory role in a low-sodium environment. No similar associations were found in young healthy black adults.