Rationale and Design of a Parallel Randomized Trial of a DASH-Enhanced Portfolio Diet With or Without Ultra-Processed Plant Proteins for Blood Pressure and Other Cardiometabolic Risk Factors in Adults With Hypertension and Obesity: The Substitution of High With Low Ultra-Processed Soy Protein Foods in a Guideline-Based Diet Intervention on Cardiometabolic Health Trial.
Houshialsadat Z, Viscardi G, et al. • Journal of the American Heart Association • 2026
The SWITCH trial is a planned 12-week, 3-arm, open-label, parallel randomized superiority-noninferiority trial in 300 adults with hypertension and obesity that will test whether a DASH-enhanced Portfolio diet lowers blood pressure versus standard of care and whether a high-UPF soy protein version is noninferior to a low-UPF version.
Key Findings
Methods
The paper describes the rationale and design of the SWITCH trial, which will address two questions: whether a DASH-enhanced Portfolio diet meaningfully reduces blood pressure versus standard of care, and whether a high-UPF soy protein version is noninferior to a low-UPF version.
The trial is a parallel, randomized, 3-arm, open-label, superiority-noninferiority design.
The arms are a high-UPF soy protein-containing DASH-enhanced Portfolio diet, a low-UPF soy protein-containing DASH-enhanced Portfolio diet, and standard of care.
The comparison with standard of care tests superiority; the high-UPF versus low-UPF comparison tests noninferiority for blood pressure reduction.
The trial is registered at ClinicalTrials.gov, identifier NCT06907862.
Methods
The trial will enroll 300 adults with hypertension and obesity, including 50% with type 2 diabetes, and will run for 12 weeks.
Participants will be randomized to one of three arms.
The intervention duration is 12 weeks.
Including 50% with type 2 diabetes is intended to cover a high-risk cardiometabolic population.
Methods
The primary outcome is systolic blood pressure, and the key secondary outcomes are non-HDL cholesterol and body weight.
Other outcomes include additional cardiometabolic risk factors.
The primary outcome corresponds to the DASH diet's main target, and non-HDL cholesterol corresponds to the Portfolio diet's LDL-cholesterol-lowering target.
Background
The trial is motivated by the idea that combining key elements of the DASH and Portfolio dietary patterns may enhance cardiovascular disease risk reduction.
Guidelines recommend the DASH diet for blood pressure and the Portfolio diet for LDL cholesterol.
Cardiovascular disease remains the leading cause of death and hospitalization globally.
Background
Many soy-based products, a key Portfolio diet component, are classified as ultra-processed foods (UPFs), creating uncertainty about their role in guideline-based dietary patterns.
The trial directly tests substituting high-UPF with low-UPF soy protein foods within the diet.
The authors describe these soy foods as nutrient-dense.
Findings are intended to inform dietary strategies for cardiometabolic risk reduction.
What This Means
This paper is a trial protocol, not a results report. It explains how researchers plan to test a combined eating pattern that blends the DASH diet (designed to lower blood pressure) with the Portfolio diet (designed to lower LDL cholesterol). No results are available yet.
The study will enroll 300 adults with high blood pressure and obesity, half of whom also have type 2 diabetes. For 12 weeks, participants will be assigned to one of three groups: the combined diet with more ultra-processed soy foods, the combined diet with less ultra-processed soy foods, or usual standard-of-care advice. The main measure is systolic blood pressure, with cholesterol (non-HDL) and body weight as key secondary measures.
The study matters because many soy foods that fit healthy-diet guidance are technically classified as ultra-processed, which raises questions about whether they belong in dietary advice. This research suggests it will provide evidence on whether such soy foods work as well as less processed ones for blood pressure, and whether the combined diet outperforms standard care. This could help shape future dietary recommendations for people at high cardiovascular risk.
Houshialsadat Z, Viscardi G, Rossi A, Ayoub-Charette S, El Chaar D, McKay B, et al.. (2026). Rationale and Design of a Parallel Randomized Trial of a DASH-Enhanced Portfolio Diet With or Without Ultra-Processed Plant Proteins for Blood Pressure and Other Cardiometabolic Risk Factors in Adults With Hypertension and Obesity: The Substitution of High With Low Ultra-Processed Soy Protein Foods in a Guideline-Based Diet Intervention on Cardiometabolic Health Trial.. Journal of the American Heart Association. https://doi.org/10.1161/JAHA.126.049902