Modulation of Secondary Bile Acids Through the Intestinal Microbiota After Consumption of a High-protein Diet.

Study Overview
=================
Brief Summary
-----------------
This study will investigate whether changes in the gut microbiota generated after the consumption of a high protein diet in healthy subjects, modify the production of secondary bile acids. In addition, it will be seen whether a high protein intake modifies postprandial glucose response and its relationship with gut microbiota composition.

Detailed Description
-----------------
The gut microbiota is a set of microorganisms that inhabit the human digestive tract and are fundamental for the health of the host. Among the functions of the gut microbiota is the production of metabolites, such as the production of secondary bile acids from primary bile acids. On the other hand, evidence has shown that the amount of protein intake can modify the composition of the gut microbiota and in turn it increase the concentration of secondary biles acids in animal models. In addition, the consumption of a high-protein diet has been related to a decrease in postprandial glucose concentrations. Therefore, the aim of this study is to evaluate changes in secondary bile acids concentration derived from gut microbiota after the consumption of a high-protein diet in healthy subjects. Subjects with a BMI between 18.5 and 24.9 kg/m2 will be selected and will be continuously monitored with a continuous glucose monitor through 15 days. During the first 7 days participants will follow an isocaloric diet (50% carbohydrates, 30% fat and 20% protein), while during the last 7 days participants will receive an intervention with a supplement of protein (calcium caseinate) which will increase their protein intake to 30% of the total energy requirement. At the initial and final visit, blood samples will be taken for determination of biochemical parameters, amino acids and primary bile acids and a stool sample will be requested for sequencing gut microbiota and determined secondary bile acids.

Official Title
-----------------
Modulation of Secondary Bile Acids Through the Intestinal Microbiota After Consumption of a High-protein Diet.

Conditions
-----------------
Healthy

Intervention / Treatment
-----------------
* Dietary Supplement: High-protein diet


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Male and female. Between 18 and older BMI ≥ 18.5 and ≤ 24.9 kg/m2. Healthy Willing and able to sign written informed consent prior to trial entry Exclusion Criteria: Have previously diagnosed with any chronic disease Patients with high blood pressure. Patients who have suffered a cardiovascular event. Patients with gastrointestinal diseases. Weight loss > 3 kg in the last 3 months. Catabolic diseases such as cancer and acquired immunodeficiency syndrome. Pregnancy status. Antibiotic consumption 3 months prior to the study. Be an undergraduate or graduate student within the Institute. Subjects with creatinine > 1.3 mg/dL for men and >1 mg/dL for women and ureic nitrogen > 20 mg/dL. Positive smoking. Drug treatment: Antihypertensive drugs or treatment Treatment with hypoglycemic agents or insulin and antidiabetic drugs. Treatment with statins, fibrates or other drugs to control dyslipidemia. Use of antibiotics in the three months prior to the study. Use of steroid drugs, chemotherapy, immunosuppressants, or radiation therapy. Anorexigenic or that accelerate weight loss such as sibutramine or orlistat. Probiotic, prebiotic or symbiotic supplements.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High-protein diet<br>Participants will receive an isocaloric diet with a distribution of 50% carbohydrates, 30% fat and 20% protein for the two-week intervention. Additionally, they will receive a dietary supplement for the second week that will contribute another 10% of protein, obtaining 30% of protein consumption in the second week. | Dietary Supplement: High-protein diet<br>* Protein intake will be increased to be 30% calories from protein with calcium caseinate.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in faecal microbiota composition in response to high-protein diet | Changes to the faecal microbiota will be assessed on a high-protein diet compared to an isocaloric diet in a short period of time. Bacterial composition was measured by 16 ribosomal sequencing at baseline at day 7 and at the end of the second week. The relative change of each bacterial taxon was calculated based on the abundance of the given bacteria at baseline, at 7 days and after 14 days | baseline, 7 days and 14 days | 
| Increase of secondary bile acids production | Increase in the concentrations of lithocholic acid and deoxycholic acid in feces (mg/g of feces) measured by the method gas chromatography represented with the units micromol. | baseline, 7 days and 14 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Regulation of postprandial glucose response | Change in interstitial glucose determined by a continuous glucose monitor (mg/dL) within two weeks. | 14 days | 
| Increase in serum glucagon concentration | Change in serum glucagon concentration determined by ELISA (pg/mL) | Baseline, 7 days and 14 days | 
| Decrease in serum insulin concentration | Change in serum insulin concentration determined by ELISA (pg/mL) | Baseline, 7 days and 14 days |