Plain language summary
DASH (Dietary Approaches to Stop Hypertension) diet is recommended for reducing blood pressure (BP) and the risk of cardiovascular disease (CVD). The DASH diet emphasises the intake of fruits, vegetables, and low-fat dairy, includes a variety of protein sources and it is low in red and processed meats and sugar-sweetened beverages. The aim of this study was to identify metabolites associated with differences in systolic blood pressure (SBP) or diastolic blood pressure (DBP) in response to the diet interventions. This study used data from 2 randomised controlled feeding trials (DASH trial and DASH-Sodium trial). Results show the identification of 42 unique metabolites (9 serum and 33 urine) which were significantly associated with changes in SBP or DBP DASH diet versus control diet interventions. Furthermore, pathway overrepresentation analysis revealed metabolite pathways that were relevant for the association between DASH diet and BP. Authors conclude that their findings provide insights on formulating intervention strategies to reduce BP.
Abstract
BACKGROUND The DASH (Dietary Approaches to Stop Hypertension) diets reduced blood pressure (BP) in the DASH and DASH-Sodium trials, but the underlying mechanisms are unclear. We identified metabolites associated with systolic BP or diastolic BP (DBP) changes induced by dietary interventions (DASH versus control arms) in 2 randomized controlled feeding studies-the DASH and DASH-Sodium trials. METHODS Metabolomic profiling was conducted in serum and urine samples collected at the end of diet interventions: DASH (n=219) and DASH-Sodium (n=395). Using multivariable linear regression models, associations were examined between metabolites and change in systolic BP and DBP. Tested for interactions between diet interventions and metabolites were the following comparisons: (1) DASH versus control diets in the DASH trial (serum), (2) DASH high-sodium versus control high-sodium diets in the DASH-Sodium trial (urine), and (3) DASH low-sodium versus control high-sodium diets in the DASH-Sodium trial (urine). RESULTS Sixty-five significant interactions were identified (DASH trial [serum], 12; DASH high sodium [urine], 35; DASH low sodium [urine], 18) between metabolites and systolic BP or DBP. In the DASH trial, serum tryptophan betaine was associated with reductions in DBP in participants consuming the DASH diets but not control diets (P interaction, 0.023). In the DASH-Sodium trial, urine levels of N-methylglutamate and proline derivatives (eg, stachydrine, 3-hydroxystachydrine, N-methylproline, and N-methylhydroxyproline) were associated with reductions in systolic BP or DBP in participants consuming the DASH diets but not control diets (P interaction, <0.05 for all tests). CONCLUSIONS We identified metabolites that were associated with BP lowering in response to dietary interventions. REGISTRATION URL: https://www. CLINICALTRIALS gov/ct2/show/NCT03403166; Unique identifier: NCT03403166 (DASH trial). URL: https://www. CLINICALTRIALS gov/ct2/show/NCT00000608; Unique identifier: NCT00000608 (DASH-Sodium trial).
Methodological quality
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