The Effect of Increasing Dietary Protein on the Gut Microbiome and Its Metabolites

Not Applicable

Completed

• Conditions: Health Adults

• Registration Number: NCT06677333
• Lead Sponsor: Louisiana State University Health Sciences Center in New Orleans

Brief Summary

This study will determine the effect of dietary protein not absorbed in the small intestine on the bacteria in the large intestine and the metabolites those bacteria produce when they break down the protein. The three specific goals are:

1. Determine if increasing dietary protein increases the purine breakdown product, allantoin, as observed in our previous study.

2. Establish a model to examine the effect of dietary protein on the gut microbiota and metabolites.

3. Identify gut bacteria and metabolite changes that occur with increased consumption of animal (whey) or plant (pea) protein sources.

Detailed Description

Healthy male and female participants were recruited following specific inclusion/exclusion criteria. Participants were excluded if they 1) were less than 25 years of age, 2) consumed pre or probiotics in the last week, 3) had taken any antibiotics in the last three months, 4) were taking any prescribed medicines for a chronic disease such as diabetes, hypertension, cancer, anxiety, depression, or GI-related diseases. and 4) had taken any laxatives or antidiarrhea inhibitors in the last week. The study design was pre/post, with each person serving as their own control. Interested participants were randomly assigned to one of two study groups: 50 g whey protein supplement or 50 g pea protein supplement. They were asked to consume the supplement along with their usual dietary intake. Participants were located within the contiguous USA and were sent a fecal collection kit, the protein supplement, and a shaker bottle using overnight shipping. We used the fecal collection kit developed by the Biocollective. A fecal sample was collected before and after the participant consumed the protein supplement daily for seven days. At both time points, the participants were asked to recall the foods they ate during the previous 24 hours using ASA24-2020, provide information on their physical activity (International Physical Activity Questionnaire, IPAQ), and answer questions about the stool sample they collected. The stool sample will be analyzed for the microbes and metabolites present. These will be correlated with the dietary protein they consume.

Study Timeline

• Study Start: 2023-02-01
• Primary Completion: 2023-11-30
• Study Completion: 2023-11-30
• Status Verified: 2024-09
• Study First Submitted: 2024-11-04
• Study First Submitted QC: 2024-11-05
• Last Update Submitted: 2024-11-05
• Study First Posted: 2024-11-06
• Last Update Posted: 2024-11-06

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 87

Inclusion Criteria

• 25 years old or older
• male or female
• located in the contiguous United States

Exclusion Criteria

• Taken any prebiotics in the last week
• Taken any probiotics in the last week
• Taken any prescription medications other than oral contraceptives
• Taken antibiotics sometime in the last three months
• Taken any diarrhea inhibitors in the last week
• Taken any laxatives in the last week
• Taken any dietary supplement(s)
• Diagnosed with cancer
• Diagnosed with an inflammatory disease of the GI tract, such as irritable bowel disease
• Experienced long-haul COVID fatigue
• Were physically inactive (<600 METS per week)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Fecal allantoin	A fecal sample is collected before and after consuming a protein supplement (pea or whey) for seven days.	A cross-sectional study the investigators conducted found that healthy individuals who reported consuming, on average, 150 gms of protein daily had a higher fecal allantoin. This study is a pre/post-randomized controlled trial to confirm that observation. It will determine if consuming 50 gms more protein daily increases fecal allantoin.

Secondary Outcome Measures

Name	Time	Method
Changes in fecal bacterial species before and after increasing dietary protein intake (pea or whey) by 50 grams for seven days	A fecal sample is collected before and after consuming a protein supplement (pea or whey) for seven days.	The relative abundance of fecal bacterial species before and after consuming an additional 50 grams of pea or whey protein above the participant's usual dietary protein intake for seven days will be compared for each group to identify which species have significantly increased or decreased.
Changes in fecal metabolites before and after increasing dietary protein intake (pea or whey) by 50 grams for seven days	A fecal sample is collected before and after consuming a protein supplement (pea or whey) for seven days.	The intensity of fecal metabolites will be measured using mass spectrometry. The difference before and after consuming an additional 50 grams of pea or whey protein above the participant's usual dietary protein intake for seven days will be compared for each group to identify those metabolites that have significantly increased or decreased.

Trial Locations

Locations (1)

Louisiana State University Health Sciences Center New Orleans; 🇺🇸 New Orleans, Louisiana, United States