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

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.

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.

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.

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.