Impacts of Lentils on Metabolism and Inflammation

November 19, 2023 updated by: Montana State University

Gut Microbiota Dependent and Independent Impacts of Dietary Pulses on Pre- and Postprandial Metabolism and Inflammation in Overweight/Obese Humans

The overall goal of this investigation is to determine gut microbiome dependent and independent impacts of pulse consumption on metabolic resilience and metabolic risk profiles for type 2 diabetes (T2D) and cardiovascular disease (CVD) risk. Specifically, pulse crop consumption has unrealized potential to fundamentally alter how the body responds to disease promoting metabolic stresses of postprandial triglyceride and inflammation responses. The specific objectives are to (1) Determine the impact of green lentil consumption on postprandial triglyceride (TG) and inflammation responses to a high-fat meal challenge. (2) Determine the extent to which the gut microbiome and changes in the gut microbiome induced by pulse consumption influence health impacts (3) Measure metabolomic profiles to elucidate underlying mechanisms linking pulse consumption to improved health. To achieve these objectives investigators will determine the effects of green lentil on high impact risk factors of large postprandial triglyceride excursions and inflammation, composition of and changes in the gut microbiomes, and both gut and serum metabolomes in overweight/obese (OW/OB) individuals with elevated risk. The 12-week intervention will consist of consumption of 4.6 or 0 cups of pulses per week across 7 pre-made meals (matched for macronutrient content (except fiber) provided to experimental and control groups. The following hypotheses will be tested in the proposed investigation:

H1: Lentil consumption lower postprandial TG and inflammation responses and improve overall metabolic health.

H2: Characteristics of the gut microbiome and changes in the gut microbiome induced by lentil consumption substantially influence health impacts of pulse consumption.

H3: Features of the fecal and serum metabolomes distinguishing lentil and control treatments correspond to metabolic pathways elucidating potential gut microbiome dependent and independent mechanisms linking pulse consumption to improved health.

Study Overview

Detailed Description

Investigators will utilize a parallel intervention of lentil versus macronutrient-matched (not including fiber) control treatment for 12 weeks in OW/OB adults with demonstrated risk for T2D and CVD. Experimental diets will be provided to participants in the form of pre-made midday meals to exploit the second meal effect and lower caloric intake at the evening meal. Pre- and post-intervention assessments will be made for the following variables: makeup of the gut microbiome (microbial species and relative abundance), gut metabolome, postprandial response of TG, inflammatory cytokines, and serum metabolome to a high-fat meal challenge (established inflammation stimulus), fasting serum glucose, lipid, insulin, inflammation markers and metabolome, blood pressure, and anthropometric measures including weight, body composition, waist circumference, and quantity of visceral adipose tissue. Physical activity, sedentary behavior, and habitual diet will be measured so that these variables can be used to aid in our characterization of participants and aid in analysis and interpretation of data.

Procedures:

Postprandial lipidemic and inflammation responses: High-fat meal challenges with 40 to 100 g of dietary fat are an established laboratory test to measure both postprandial triglyceridemic and inflammation responses. Investigators have used a 50 g dose of fat delivered in the form of butter on toast on > 50 individuals because this particular dose is effective at discriminating between low versus high TG and inflammation responders. In brief, participants will report to the laboratory after an overnight fast, an indwelling venous catheter will be placed in an antecubital vein, and blood samples will be collected before, and 1, 2, 3, 4, and 5 hours following ingestion of the high-fat meal. Samples will be analyzed in real time for TG (and full lipid panel plus glucose) using a clinical chemistry analyzer (Piccolo xpress), while serum samples will be aliquoted and stored at -80 C until analysis for inflammatory cytokines, metabolomics, and insulin. Investigators will measure inflammatory cytokines (TNF-α, IFN-y, interleukin (IL)-1β, IL-6 IL-17, IL-23, IL-10, and granulocyte macrophage colony stimulating factor (GM-CSF)) using high-sensitivity Luminex multiplexing technology (Bio-Rad Bio-Plex® 200 HTS) prepared by Millipore.

Dietary intervention: Using methods established for an ongoing CRT with lentils, investigators will prepare 7 meals per participant per week to deliver a dose of 4.6 or 0 cups of lentils per week for the experimental and control groups. Meals are matched for macronutrient content (except for fiber), and ground turkey or chicken replaces lentils in the control meals. Dietary intervention will be 12 weeks in length with a possible extension to 13 weeks if participants either 1) miss 3 or more meals in a row at any point during the intervention or 2) miss any meals at all in the last week of the intervention prior to their final visit. To keep the meal intervention period between 12 and 13 weeks, participants will be dropped from the study if meal adherence failures result in more than a one week intervention extension.

Participants will be instructed to consume food provided for their midday meal, and then to proactively reduce portion sizes and to not eat beyond fullness at the evening meal. This strategy exploits the satiety effect of pulses at the midday meal and the 'second meal effect' in which volitional consumption is reduced at the next meal, the evening meal. Each participant will be surveyed once weekly to determine whether they consumed the experimental meal that day, their perceptions of hunger, fullness, satiety, and satisfaction with that day's meal (at 4:00 pm), and their gastrointestinal comfort (level of bloating, flatulence, cramping, and comfort) throughout the day (at 8:00 pm). This methodology has been successfully implemented in our ongoing study to demonstrate that lentil meals are equally pleasing, produce greater satiety, and are well-tolerated.

Gut microbiome analysis: Bulk DNA will be extracted from fecal samples using the Powersoil® DNA Isolation Kit (Mo Bio Laboratories Inc.). DNA will be shipped overnight to the University of Michigan, Center for Microbial Systems, for Illumina MiSeq amplicon sequencing of the 16S V4 variable region. Raw sequencing reads will be processed and curated using the mothur (v.1.39.5) software package, following the mothur MiSeq standard operating procedure, potentially chimeric sequences will be identified and removed using the Uchime (v4.2.40) algorithm, and taxonomic classifications will be assigned using the Bayesian classifier of the Ribosomal Database Project, and operational taxonomic units (OTUs) will be assigned in mothur using the VSEARCH distance-based clustering algorithm at the 97% sequence similarity threshold.

Metabolomic analysis: Samples will be analyzed by high resolution liquid chromatography mass spectrometry (LCMS). Hydrophilic interaction chromatography (HILIC) and reverse-phase (RP) columns will be used for deep coverage. Metabolite identification will use fragmentation pattern matching, authentic standards and database matching with METLIN and the Human Metabome Database (HDB). Novel features of significant interest will be characterized with liquid chromatography mass spectrometry solid phase extraction nuclear magnetic resonance (LCMS-SPE-NMR). Pathway analysis will use XCMS and mummichog.

Dietary analysis. Long-term dietary habits may create adaptations that influence the response to the short-term supplementation of Aronia and lentil. This study will use the most recent version (2018) of the web-based Diet History Questionnaire (DHQ III), a food frequency questionnaire designed for adults 19 and older, developed by staff at the Risk Factor Monitoring and Methods Branch (RFMMB) of the NIH National Cancer Institute. The outputs of the DHQ III include carbohydrate constituents, carotenoids and tocopherols, dietary constituents from supplements, fats, fatty acids and cholesterol, macronutrients and energy, minerals, protein constituents, and vitamins are dietary constituents and food groups available in the DHQ III output files.

Physical activity and sedentary behavior monitoring: Participants will wear an Actical omni-directional accelerometer during weeks 1 and 12 of the intervention to measure total physical activity, time in low intensity activity, moderate to vigorous activity, and vigorous activity, and sedentary activity in minutes.

Statistical analysis: H1 will be tested using two-sample t-tests to compare the difference between pre- and post-intervention assessments. Using preliminary data for TG responses and 50% effect sizes consistent with published findings in animal models, it was estimated that 18-24 participants will be required per group to achieve power of 0.76 to 0.86 at alpha = 0.05. To test H2, investigators will identify changes in the gut microbiome using the methods utilized in our preliminary research to identify characteristics of the gut microbiome that differentiate low versus high TG responders, and then use regression analysis to determine the level of variability in changes to the pulse and control treatments explained by changes in relative abundance of gut microbial species. To test H3, investigators will identify changes in the gut and serum metabolomes, and then determine the metabolic pathways associated with the metabolomic changes to identify potential mechanisms underlying health impacts of pulses.

Study Type

Interventional

Enrollment (Actual)

38

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

    • Montana
      • Bozeman, Montana, United States, 59717
        • Nutrition Research Laboratory

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Waist circumference > 35 inches for women and > 40 inches for men
  • Non-fasting serum triglyceride concentration > 175 mg/dl

Exclusion Criteria:

  • Allergy to wheat
  • Taking medication that will influence cholesterol, lipids, or inflammation
  • Pregnant or use of hormonal contraceptive method
  • Have diabetes, a pacemaker, or other health conditions that may interfere with the study outcomes
  • Planning to undergo a weight loss intervention or change in exercise regimen

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Lentil
0.66 cups lentils
Participants in the Lentil arm of the study will consume midday meals containing 0.66 cups of lentils seven days per week for 12 weeks.
Sham Comparator: Control
0.0 cups lentils
Participants in the Control arm of the study will consume midday meals containing 0.00 cups of lentils seven days per week for 12 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postprandial Serum Triglyceride Response to High-fat Meal
Time Frame: 12 weeks
Area under the curve for triglyceride concentration after consuming a meal containing 50 g of fat
12 weeks
Peak Serum Triglyceride Response to High-fat Meal
Time Frame: 12 weeks
Greatest change in triglyceride concentration after consuming a meal containing 50 g of fat
12 weeks
Postprandial Serum Inflammatory Cytokine (tumor necrosis factor-alpha, interleukin-(IL)1beta, IL-6, IL-10, IL-17, IL-23, interferon-gamma, and granulocyte macrophage-colony stimulating factor; all in pg/ml) Response to High-fat Meal
Time Frame: 12 weeks
Area under the curve for inflammatory cytokine (tumor necrosis factor-alpha, interleukin-(IL)1beta, IL-6, IL-10, IL-17, IL-23, interferon-gamma, and granulocyte macrophage-colony stimulating factor; all in pg/ml) concentrations after consuming a meal containing 50 g of fat
12 weeks
Peak Cytokine (tumor necrosis factor-alpha, interleukin-(IL)1beta, IL-6, IL-10, IL-17, IL-23, interferon-gamma, and granulocyte macrophage-colony stimulating factor; all in pg/ml) Response to High-fat Meal
Time Frame: 12 weeks
Greatest change in inflammatory cytokine (tumor necrosis factor-alpha, interleukin-(IL)1beta, IL-6, IL-10, IL-17, IL-23, interferon-gamma, and granulocyte macrophage-colony stimulating factor; all in pg/ml) concentration after consuming a meal containing 50 g of fat
12 weeks
Gut Microbiome Composition
Time Frame: 12 weeks
Relative abundance (operational taxonomic units/10,000 reads) of microbial taxa measured from fecal samples
12 weeks
Postprandial Serum Metabolite (untargeted) Response to High-fat Meal
Time Frame: 12 weeks
Changes in concentrations of metabolites measured with untargeted liquid chromatography mass spectrometry (LCMS) metabolomic analysis after consuming a meal containing 50 g of fat
12 weeks
Fasting serum triglycerides
Time Frame: 12 weeks
Concentration of triglycerides in the serum after an overnight fast
12 weeks
Fasting inflammatory cytokine (tumor necrosis factor-alpha, interleukin-(IL)1beta, IL-6, IL-10, IL-17, IL-23, interferon-gamma, and granulocyte macrophage-colony stimulating factor; all in pg/ml) levels
Time Frame: 12 weeks
Concentration of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-(IL)1beta, IL-6, IL-10, IL-17, IL-23, interferon-gamma, and granulocyte macrophage-colony stimulating factor; all in pg/ml) in the serum after an overnight fast
12 weeks
Fasting serum metabolites (untargeted)
Time Frame: 12 weeks
Concentration of metabolites in the serum after an overnight fast
12 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Body Composition
Time Frame: 12 weeks
% body fat
12 weeks
Visceral Adipose Tissue
Time Frame: 12 weeks
Quantity of adipose in liters located within the abdominal compartment
12 weeks
Blood Pressure
Time Frame: 12 weeks
Systolic and Diastolic blood pressure measured in mmHg
12 weeks
Body mass index
Time Frame: 12 weeks
kg of mass per meter of height squared
12 weeks
Perceptions of Hunger, Fullness, Satiety, and Satisfaction after Mid-day Meal
Time Frame: 12 weeks
Ratings (1=lowest, 10=highest) of hunger, fullness, satiety, and satisfaction in response to mid-day meal
12 weeks
Gastrointestinal Symptoms of Bloating, Cramping, Discomfort, and Flatulence
Time Frame: 12 weeks
Qualitative ratings (none, mild, moderate, high) of gastrointestinal bloating, cramping, discomfort, and flatulence
12 weeks

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Physical Activity
Time Frame: 7 days
Time spent in low, moderate-to-vigorous, and vigorous physical activity per day
7 days
Diet
Time Frame: 12 months
Habitual dietary intake reported through a food frequency questionnaire for food intake
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Mary Miles, PhD, Montana State University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 22, 2020

Primary Completion (Actual)

November 19, 2023

Study Completion (Actual)

November 19, 2023

Study Registration Dates

First Submitted

February 5, 2020

First Submitted That Met QC Criteria

February 21, 2020

First Posted (Actual)

February 25, 2020

Study Record Updates

Last Update Posted (Estimated)

November 21, 2023

Last Update Submitted That Met QC Criteria

November 19, 2023

Last Verified

November 1, 2023

More Information

Terms related to this study

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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