Dietary sodium restriction has multiple beneficial effects on cardiovascular health. The underlying mechanisms are not fully understood, and the roles of metabolomics have been rarely studied. We aimed to test the hypothesis that the reduction in
dietary sodium intake would induce changes in metabolomic profiling among black hypertensives, and the changes would be associated with reduced blood pressure (BP) and improved skin capillary density. A total of 64 untreated black hypertensives were included from a randomized, double-blind, placebo-controlled cross-over trial of
sodium reduction. The participants were given either 9 slow
sodium tablets (10 mmol
sodium per
tablet) or placebo
tablets daily for 6 weeks, they then crossed over to receive the other
tablets for another 6 weeks, while on reduced
sodium diet aiming at achieving daily
sodium intake around 2.0 g. Untargeted metabolomic profiling was performed in paired serum samples, which were collected at the end of each period, so were BP and capillary density. Mixed-effects models were used. There were 34 metabolites identified with raw P's<0.05. Among those, 2 metabolites including β-hydroxyisovalerate and
methionine sulfone were significantly increased with
sodium reduction (false discovery rate =0.006 and 0.099, respectively). Increased β-hydroxyisovalerate was associated with reduced office systolic BP and ambulatory daytime systolic BP, whereas increased
methionine sulfone was associated with reduced 24-hour diastolic BP, ambulatory nighttime diastolic BP, and increased skin capillary density. Our results suggest that
dietary sodium reduction increases the circulating levels of β-hydroxyisovalerate and
methionine sulfone. Further studies are warranted. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT00152074.