Metabolomic Insights on Potassium Excretion, Blood Pressure, and Glucose Homeostasis: The African-PREDICT Study

Abstract

Background: Low-potassium intake is associated with a higher risk of type 2 diabetes and hypertension. Both conditions occur more frequently in Black populations, who also consume less potassium-rich foods. Objectives: Using metabolomics to identify dysregulated metabolic pathways associated with low-potassium excretion may procure more accurate entry points for nutritional prevention and intervention for type 2 diabetes and hypertension. Methods: A total of 440 White and 350 Black adults from the African-PREDICT study (aged 20-30 y) were included. Twenty-four-hour blood pressure (BP) was measured. Potassium, sodium, and fasting glucose concentrations were analyzed in 24-h urine and plasma samples. Liquid chromatography-tandem mass spectrometry-based metabolomics included the analyses of amino acids and acylcarnitines in spot urine samples. Results: Black participants had lower urinary potassium concentrations than Whites (36.6 compared with 51.1 mmol/d; P < 0.001). In White but not Black adults, urinary potassium correlated positively with 2-aminoadipic acid (2-AAA) (r ¼ 0.176), C3-[propionyl]carnitine (r ¼ 0.137), C4-[butyryl]carnitine (r ¼ 0.169) and C5-[isovaleryl]carnitine (r ¼ 0.167) in unadjusted and 2-AAA (r ¼ 0.158) and MC4-carnitine (r ¼ 0.160) in adjusted analyses (all P < 0.05 and q < 0.05). Elevated C0-, C3-, and C5-carnitine in turn were positively associated with systolic BP (Black and White groups), diastolic BP (Black group), and glucose (White group) (all P < 0.05). Conclusions: Racial differences are an important consideration when investigating nutrient-metabolite relationships and the role thereof in cardiovascular disease. Only in White adults did urinary potassium associate with 2-AAA and short-chain acylcarnitines. These metabolites were positively related to BP and fasting plasma glucose concentrations. In White adults, the metabolomic profiles related to potassium excretion may contribute to BP regulation and glucose homeostasis.