Comparing the Effect of Whey and Soy Protein on the Absorption of Pomegranate Polyphenols in the Human Body

Dietary Protein in Pomegranate Ellagitannin Bioavailability

This study is comparing the quantity of active metabolites from consuming pomegranate juice in three different preparations. People who participate in this study will come in to the Center for a screening visit, which includes a blood test and medical history. If you qualify based on the screening visit, you will then come in to the Center while fasting in the morning on three different days. You will eat a standardized breakfast and drink one of three juices, and then remain for metabolic testing at the Center for a period of time after eating. You will also be provided a standardized lunch and water during this period. Each of those visits will last about 7 hours. During this time, and for the rest of the 24 hours following drinking the juice, you will collect all of your urine. Following all three of these 7-hour visits, you will return to the Center again the next day for a fasting blood draw, drop off your urine sample, and pick up a new container to collect another 24 hour urine sample. The following day, you will return to the Center to drop off your second urine sample collection.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Dietary supplement: Pomegranate Juice; Dietary supplement: Soybean Flour Protein; Dietary supplement: Soy Isolate Protein

Detailed Description

Pomegranate (Punica granatum L.) fruits are widely consumed as pomegranate juice (PJ), and their health benefits have been studied extensively in animals and humans (1-6). The pomegranate fruit is a rich source of polyphenols, most of which are ellagitannins (ETs). Pomegranate extracts,which incorporate these major polyphenols from the pomegranate fruit, have been developed in dry and liquid forms to provide alternative convenient sources for obtaining the bioactive polyphenols found in PJ. We have previously reported on the pharmacokinetics and metabolism of pomegranate polyphenols, after the consumption of PJ in normal healthy human volunteers (7). In humans, ETs are converted to ellagic acid (EA) in the small intestines and absorbed with a maximum plasma concentration observed at approximately 1 hour. EA disappears from plasma 6 hours after administration of PJ. Ellagitannins and ellagic acid remaining in the intestine and are then further converted by gut microflora to urolithin-A, absorbed and derivatives, which are metabolized by phase II enzymes and excreted in human urine for up to 48 hours after consumption of PJ(7).

Polyphenols are dietary constituents of plants associated with health-promoting effects. In the human diet, polyphenols are generally consumed in foods along with macronutrients. Because the health benefits of polyphenols are critically determined by their bioavailability, the effect of interactions between plant phenols and food macronutrients is a very important topic. The protein-polyphenol complexes can significantly change the plasma kinetics profile. (8) Protein-polyphenol binding is mediated by a combination of hydrogen and hydrophobic bonding depending on chemical (polarity) and structural (size/shape) properties of interacting molecules. Covalent interactions between purified glycinin, a soybean storage protein, and selected flavonoids and phenolic acids have also been reported. Recently it is reported that protein-rich defatted soybean flour protects anthocyanins during transit through upper digestive tract for subsequent colonic delivery/metabolism (9).

• Study Type: Interventional
• Enrollment (Actual): 18
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90095
      • UCLA Center for Human Nutrition

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Male or female >20 and < 45 years of age at the time the consent form is signed.
• Subject must sign the Institutional Review Board-approved written informed consent prior to the initiation of any study specific procedures or randomization. A subject will be excluded for any condition that might compromise the ability to give truly informed consent for participation in the study.

Exclusion Criteria:

• Any subject who is eating more than 4 servings per day of fruits and vegetables, taking vitamin supplements or taking any antibiotics or other medication or dietary supplement which interfere with the absorption of polyphenols.
• Any subjects with a history of gastrointestinal surgery (except for appendectomy), diabetes mellitus, or other serious medical condition, such as chronic hepatitis or renal disease, bleeding disorder, congestive heart disease, chronic diarrhea disorders, myocardial infarction, coronary artery bypass graft, angioplasty within 6 months prior to screening, current diagnosis of uncontrolled hypertension (defined as BP >160mmHg, diastolic BP>95mmHg), active or chronic gastrointestinal disorders, bulimia, anorexia, laxative abuse, or endocrine diseases (except thyroid disease corrected with medication to normal laboratory values) as indicated by medical history or routine physical examination.
• Major surgery within 12 weeks prior to subject randomization and/or screening, especially cardiac surgery
• Is currently a smoker who has a therapeutic plan to quit smoking anytime during the study period; or if not a current smoker, has quit smoking within the past 3 months.
• Known HIV positive.
• Clinical evidence of current malignancy with the exception of basal cell or squamous cell carcinoma of the skin and cervical intraepithelial neoplasia.
• Currently receiving systemic chemotherapy and/or radiotherapy.
• Active bleeding.
• Subject has any disorder (excluding illiteracy or visual impairment) that compromises the ability of the subject to give written informed consent and/or to comply with study procedures.
• Subject who is allergic to soy protein.
• In the opinion of the study investigator has a risk of non-compliance with study procedures, or can not read, understand or complete study related materials.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Pomegranate Juice; Subjects will be asked to take a dietary supplement on the day of intervention. Prior to intervention, subjects will be asked to avoid high-polyphenol foods, certain vitamins, minerals, herbs and dietary supplements for 4 days, dietary instruction will be provided. Blood samples will be taken at screen for safety labs. On study days 5, 13 and 21 a spot urine will be collected and a 7 hr serial blood draw will be performed at 0 hr, 30 min, 1 hr, 2 hr, 3 hr, 4 hr and 6 hr. Subjects will be provided with a light lunch with foods low in polyphenols. Subjects will only be able to eat the foods provided on the intervention days. Subjects will be asked to drink 32oz of water during the 7-hr period. Subjects will also be asked to collect all of their urines for 24 hrs, 2 consecutive days.	Dietary supplement: Pomegranate Juice; Pomegranate Juice alone
Active Comparator: Soybean Flour Protein; Subjects will be asked to take a dietary supplement on the day of intervention. Prior to intervention, subjects will be asked to avoid high-polyphenol foods, certain vitamins, minerals, herbs and dietary supplements for 4 days, dietary instruction will be provided. Blood samples will be taken at screen for safety labs. On study days 5, 13 and 21 a spot urine will be collected and a 7 hr serial blood draw will be performed at 0 hr, 30 min, 1 hr, 2 hr, 3 hr, 4 hr and 6 hr. Subjects will be provided with a light lunch with foods low in polyphenols. Subjects will only be able to eat the foods provided on the intervention days. Subjects will be asked to drink 32oz of water during the 7-hr period. Subjects will also be asked to collect all of their urines for 24 hrs, 2 consecutive days.	Dietary supplement: Pomegranate Juice; Pomegranate Juice alone; Dietary supplement: Soybean Flour Protein; Soybean Flour Protein combined with Pomegranate Juice; Other Names: Nutrasorb
Active Comparator: Soy Isolate Protein; Subjects will be asked to take a dietary supplement on the day of intervention. Prior to intervention, subjects will be asked to avoid high-polyphenol foods, certain vitamins, minerals, herbs and dietary supplements for 4 days, dietary instruction will be provided. Blood samples will be taken at screen for safety labs. On study days 5, 13 and 21 a spot urine will be collected and a 7 hr serial blood draw will be performed at 0 hr, 30 min, 1 hr, 2 hr, 3 hr, 4 hr and 6 hr. Subjects will be provided with a light lunch with foods low in polyphenols. Subjects will only be able to eat the foods provided on the intervention days. Subjects will be asked to drink 32oz of water during the 7-hr period. Subjects will also be asked to collect all of their urines for 24 hrs, 2 consecutive days.	Dietary supplement: Pomegranate Juice; Pomegranate Juice alone; Dietary supplement: Soy Isolate Protein; Soy Isolate Protein combined with Pomegranate Juice; Other Names: Solae

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma Ellagic Acid Concentration 0 to 24 Hours Post-dose Area Under the Curve	Blood samples were collected at baseline, 0.5, 1, 2, 3, 4, 6 and 24 h after ingestion of pomegranate juice (PJ) alone, or PJ mixed with soy protein, or PJ mixed with soybean flour. Plasma concentration of ellagic acid at each time point was determined to create a pharmacokinetic parameter area under the curve.	Baseline, 0.5, 1, 2, 3, 4, 6 and 24 hr after 1 dosing of each intervention during the 3-week period

Collaborators and Investigators

• Sponsor: University of California, Los Angeles
• Investigators: Principal Investigator: Zhaoping Li, MD, PhD, UCLA Department of Medicine

Study record dates

Study Major Dates

• Study Start: August 1, 2014
• Primary Completion (Actual): January 1, 2015
• Study Completion (Actual): January 1, 2015

Study Registration Dates

• First Submitted: August 15, 2014
• First Submitted That Met QC Criteria: September 3, 2014
• First Posted (Estimate): September 8, 2014

Study Record Updates

• Last Update Posted (Actual): September 19, 2019
• Last Update Submitted That Met QC Criteria: August 15, 2019
• Last Verified: August 1, 2019

More Information

Terms related to this study

• Keywords: Soy Protein; Pomegranate polyphenols; Ellagitannins
• Other Study ID Numbers: 14-000905