Protein-Distinct Macronutrient-Equivalent Diet 1 (PRODMED1)

Effect of a Pulse-based USDA-diet on Gut Microbial Metabolites and Biomarkers of Healthspan: A 18-week Randomized Controlled Crossover Feeding Study in Older Adults

Plant-based diets are naturally low in Methionine (Met), and also low in precursor molecules (e.g L-carnitine, choline, betaine, etc.) producing microbiota-mediated proatherogenic TMAO. Among plant proteins, pulses are rich in micronutrients, and dietary fibers, making them ideal for microbiome-stimulating, nutrient-dense, healthful dietary patterns. However, daily pulse intake remains low at 8% in America despite recommendations by DGA, a resource to guide health promotion across communities. A significant body of preclinical data, waiting to be translated to humans, suggests that dietary Met restriction can trigger beneficial metabolic and anti-inflammatory adaptations leading to improved chronic health and longevity. The central hypothesis is that a pulse-protein-based healthy diet can be simultaneously equivalent to omnivorous diets in protein content and yet naturally lower in Met and TMAO to improve glycemic control, body composition, and immunometabolic flexibility to reduce the risk of chronic diseases and improve healthspan. The goal is to systematically elucidate for the first time the effects of a lacto-vegetarian feeding pattern with pulses as the primary protein source on a comprehensive panel of ~500 traditional and next-generation biomarkers of health, and assess the role of the gut microbiota in mediating such effects. We also aim to interrogate the potential concern about the lower bioavailability of non-heme iron from pulses.

Study Overview

• Status: Active, not recruiting
• Conditions: Healthy Lifestyle
• Intervention / Treatment: Other: Meat based; Other: Pulse based

• Study Type: Interventional
• Enrollment (Actual): 76
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • South Dakota
    • Brookings, South Dakota, United States, 57007
      • South Dakota State University, Wagner Hall 416

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 61 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Generally good health status based on routine physical in the past 12 months, current healthy status
• Normal HbA1C, not underweight
• Age 60 years or more, all races, both sexes and all education level
• Do not have any special dietary requirements and willing to consume vegetarian diet
• Willingness to comply with the study protocol, including on-site meal consumption and sample/data collection.

Exclusion Criteria:

• Probiotic, long-term antibiotic, and tobacco/drug/alcohol use
• Not on any special diet within 3 months of recruitment
• Impaired kidney functions
• Active history of cancer, diabetes, heart, liver, and kidney diseases
• Major gastrointestinal disorders in the past 3 months
• History of heart attacks or stroke
• Unable to meet in-person visit requirements for dining, picking up meals, and tests
• Any mental health condition that would affect the ability to provide written informed consent.
• If they had not had a routine health checkup during the 12 months prior to recruitment.
• If they were unwilling to abstain from taking certain nutritional supplements, alcohol, or non-study foods during the study period.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Meat based; Animal protein-based dietary intervention	Other: Meat based; Omnivorous diet following dietary guidelines
Experimental: Pulse based; Pulse-protein-based dietary intervention	Other: Pulse based; Lacto-ovo-vegetarian pulse-based diet following dietary guidelines

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concentration of TMAO in blood	Using LC/MS based method method	16 weeks
Fasting blood glucose concentration in blood	Using Glucometer	16 weeks
Ferritin	Microplate assay	16 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concentration of sulfur containing amino acids in blood	LC/MS based method	16 weeks
Digestible indispensable amino acid score using different amino acid concentrations	Using standard equation	16 weeks
Concentration of IGF-1 in blood	Using Microplate assay kit	16 weeks
Concentration of IGF-BP3 in blood	Using Microplate assay kit	16 weeks
Concentration of Fasting insulin in blood	Using Microplate assay kit	16 weeks
Peak heights of several complex lipids panel using metabolomics technique	LC/MS based assay	16 weeks
Concentration Short-chain fatty acid panel in stool	using LC/MS based assay	16 weeks
Peak heights of several Biogenic amines panel using metabolomics technique	using LC/MS based assay	16 weeks
Gut microbiota composition and diversity	16S rRNA gene sequencing	16 weeks
Body weight in kilograms	Measurement	16 weeks
Fat and lean mass in kg using DXA for body composition measures	DEXA scan	16 weeks
Muscle strength using Isokinetic muscle testing	Biodex ergometer	16 weeks
Grip force per kg mass	using Dynamometer	16 weeks
Blood pressure in mm Hg	Upper arm cuff	16 weeks
Concentration of CRP in blood	Microplate assay	16 weeks
Balance assessment using balance	Mechanography	16 weeks

Collaborators and Investigators

• Sponsor: South Dakota State University
• Investigators: Principal Investigator: Moul Dey, Ph.D., South Dakota State University

Study record dates

Study Major Dates

• Study Start (Actual): November 15, 2022
• Primary Completion (Actual): December 20, 2023
• Study Completion (Estimated): December 1, 2025

Study Registration Dates

• First Submitted: October 7, 2022
• First Submitted That Met QC Criteria: October 11, 2022
• First Posted (Actual): October 13, 2022

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 14, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: IRB-2209011-EXP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No