Effect of Supplementary Dietary Protein (21g Per Day) on Lean Mass and Strength in Sedentary, Adult Vegetarians (MungBean)

It is possible that the lower protein intake in vegetarians and vegans may relate to a decrease in grip strength. Furthermore, there is limited research examining the effects of plant-based protein intake on strength and LBM independent of an exercise training component. The present study was designed to examine relationships between strength, protein intake, and LBM in underactive vegetarian and vegan adults, as well as the impact of protein supplementation (18 g mung bean protein daily) on these indices.

Study Overview

• Status: Completed
• Conditions: Muscle Weakness
• Intervention / Treatment: Dietary supplement: mung bean protein; Other: control biscuit

Detailed Description

The American Dietetic Association states that based off of evidence, it is possible for a vegetarian to obtain the recommended amount of nutrients with a properly planned diet. By mixing various sources of plant proteins throughout the day, a person can obtain all the amino acids needed for growth and tissue maintenance and repair. Yet, many vegetarians struggle to eat a substantial diet, especially when it comes to protein. This is because plant protein has protein bioavailability that is 10-30% lower than animal protein. As a result, current research suggests that there needs to be a separate protein dietary reference intake (DRI) for vegetarians and it needs to be larger than the protein DRI for omnivores. Whenever considering protein bioavailability, the quality must be assessed by analyzing the digestibility, chemical integrity, and freedom from interference in metabolism of the amino acid. This is a major concern because inadequate protein intake can affect bone health and alter muscle mass. Importantly, research has shown as a result of inadequate protein intake, vegetarians tend to have less lean body mass and less muscle strength than omnivores. Currently, all research available on this topic included strength training as a variable for increasing lean muscle mass, and no research has been reported that analyzed the impact of increased dietary protein on lean body mass without a training component. This parallel arm study will examine the effect of supplemental plant protein on strength and lean body mass in adult, non-athletic vegetarians in the Phoenix area.

• Study Type: Interventional
• Enrollment (Actual): 37
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Phoenix, Arizona, United States, 85004
      • Arizona State University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• vegetarian or vegan for at least one year
• healthy by self-report

Exclusion Criteria:

• supplement use such as protein powder or creatine
• previous diagnosis of heart disease, cancer, stroke, diabetes, autoimmune disorders, or thyroid condition
• competition in any athletic event in the past year
• moderate to strenuous exercise exceeding 150 minutes per week
• pregnant or planning to become pregnant.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: mung bean; daily oral administration of protein supplement	Dietary supplement: mung bean protein; Participants were instructed to consume the test foods in the morning hours and to keep a record of the days the foods were consumed on a study calendar which was returned to investigators at the final visit and used to track protocol adherence.
Placebo Comparator: biscuit; daily oral administration of control supplement	Other: control biscuit; Participants were instructed to consume the test foods in the morning hours and to keep a record of the days the foods were consumed on a study calendar which was returned to investigators at the final visit and used to track protocol adherence.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
grip strength	Dominant handgrip strength was measured in triplicate in a seated position with the elbow flexed to 90 degrees and a neutral wrist position in triplicate using a handheld dynamometer	change in strength from baseline to week 8
leg strength	Lower body strength was measured in the dominant leg using a multi-joint system dynamometer. Isokinetic knee flexion and extension were measured from a seated position at a resistance of 90°/sec.	change in strength from baseline to week 8

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
lean body mass	LBM was measured via dual energy X-ray absorptiometry (DEXA) and was conducted by a trained X-ray technician.	change in LBM from baseline to week 8

Collaborators and Investigators

• Sponsor: Arizona State University
• Collaborators: Christopher Wharton; Eric Bartholomae; April Incollingo; Maricarmen Vizcaino

Study record dates

Study Major Dates

• Study Start (Actual): September 3, 2018
• Primary Completion (Actual): January 12, 2019
• Study Completion (Actual): January 12, 2019

Study Registration Dates

• First Submitted: August 29, 2019
• First Submitted That Met QC Criteria: September 3, 2019
• First Posted (Actual): September 4, 2019

Study Record Updates

• Last Update Posted (Actual): September 4, 2019
• Last Update Submitted That Met QC Criteria: September 3, 2019
• Last Verified: September 1, 2019

More Information

Terms related to this study

• Keywords: strength; vegetarian; vegan; protein; plant-based
• Additional Relevant MeSH Terms: Pathologic Processes; Nervous System Diseases; Neurologic Manifestations; Musculoskeletal Diseases; Muscular Diseases; Neuromuscular Manifestations; Muscle Weakness
• Other Study ID Numbers: MungBean00005383

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No