Metabolism And Health Effects Of Citrus Limonoids in Hypercholesterolemic Humans

December 9, 2013 updated by: USDA, Western Human Nutrition Research Center

A Pilot Study To Determine The Metabolism And Health Effects Of Citrus Limonoids in Hypercholesterolemic Human Subjects

Limonoids are compounds found in citrus juices, seeds and peel. Some research shows that they reduce blood cholesterol and also reduce the incidence of several forms of cancer. Although these compounds are part of the natural human diet, the dose required to provide health benefits and the risks associated with the intake of high doses by humans have not been studied. This study will examine metabolism, safety, lipid-lowering and anti-inflammatory effects of limonoids. The dose of limonoids in this study is equivalent to that found in six 8 oz glasses of orange juice per day. The investigators hypothesize that limonin glucoside supplementation will reduce total cholesterol, LDL cholesterol, ratio of LDL and HDL cholesterol, number of LDL particles, and serum markers of inflammation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a 127-day study with a cross-over design, divided into three metabolic periods (P1, P2, and P3). For the first 14 days (P1), all subjects will receive two placebo beverages and will be asked to consume one each with breakfast and dinner. Then in metabolic period 2 (P2), subjects will be randomly assigned to one of two groups (Group 1 and Group 2). For the next 56 days, Group 1 will continue to consume two placebo beverages per day, while Group 2 will consume two beverages containing limonoids (250 mg/beverage). During the final 56 days (P3), the beverages provided to Group 1 will contain limonoids, and beverages provided to Group 2 will be placebo. Both the placebo and limonoid beverages will be 12-oz buffered, sterile, orange flavored, artificially sweetened beverage, containing 60 mg vitamin C, 11 mg riboflavin and zero calories. Subjects are instructed that they must drink all the beverage provided each day. Beverages will contain a biomarker (riboflavin), and the biomarker is assayed in urine samples collected every 2 weeks at the beverage pickup appointments to monitor compliance. The subjects will be informed that they are being monitored for compliance. Limonin glucoside is obtained from citrus waste materials utilizing chromatographic methods that employ food grade approved media and solvents. The final pure limonin glucoside is fractionally crystallized from a concentrated water solution of a chromatographically purified extract. The crystalline material is separated from the mother liquor, dried and subjected to mass spectral and nuclear magnetic resonance assessment. The spectral data is compared to data acquired for a pure limonin glucoside standard to establish final purity which is better than 95%.

Blood samples (approximately 70 ml, less than five tablespoons) will be drawn after a 12 hour overnight fast on study days 1, 15, 71 and 127 by venipuncture. These blood samples will be used to determine serum limonoids, complete blood cell count (CBC), and comprehensive chemistry panel (CCP), serum lipids, markers of inflammation, lymphocyte and monocytes functions. In addition to the fasting blood draws on days 15 (Group 2) and day 71 (Group 1), repeated blood samples (5 ml each time, approximately one teaspoon) will be drawn at 2, 4, 6, 8, and 24 hr after taking two 12-oz limonoid beverages (total limonoids 500mg) to determine the absorption and metabolism of limonoids. The investigators note that the blood samples drawn 24-h after the limonoid intake will be on study day 16 for Group 2 and day 72 for Group 1. The total amount of blood drawn will be less than 500 ml (2 cups) in 127 days. A spot urine sample will be collected at the same visit as the fasting blood draws, and every two weeks at the beverage pickup appointments. Repeated blood draws at 0, 2, 4, 6, and 8 hr after the limonoid supplement will be accompanied by the collection of urine samples. No food will be allowed during the 8 hrs; water intake will be monitored and restricted to one liter. Subjects will be served two standardized meals during this time, each representing 35% of their daily caloric intake, one after the 0 hr blood draw and the other after the 8 hr blood draw.

Subjects will be instructed not to change their diets, exercise or lifestyle during the course of the study. They will also be instructed not to consume any citrus fruit/juice (orange, grape fruit) throughout the study. Three 24-hour dietary recalls will be collected by telephone during the last week of each metabolic period (P1, P2, P3). A standardized diet will be served for all three meals for each day prior to the blood draws.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
10

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Locations

  • United States
    • California
      • Davis, California, United States, 95616
        • USDA Western Human Nutrition Research Center

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

20 years to 65 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Hypercholesterolemic, total blood cholesterol 200-300 mg/dL
  • BMI 20-35 kg/m2
  • normal Complete Blood Count
  • normal serum transaminases, alkaline phosphatase, and creatinine
  • normal thyroid function
  • LDL cholesterol > 130 mg/dL
  • Triglyceride < 300 mg/dL
  • serum C-Reactive Protein 1.0-25 mg/L

Exclusion Criteria:

  • current pregnancy or lactation
  • smoking
  • use of alcohol > 1 drink per day (1 oz distilled liquor, 3 oz wine, 12 oz beer)
  • reported history of cardiovascular disease or chronic inflammatory diseases
  • current users of oral contraceptives
  • lipid-lowering, anti-inflammatory, anti-coagulant, or thyroid medications
  • currently drinking more than 4 glasses per day of orange or grapefruit juice

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: BASIC_SCIENCE
  • Allocation: RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: DOUBLE

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
EXPERIMENTAL: Group1
Group 1 consumes Placebo beverage for 56 days followed by Citrus Limonoid Beverage for 56 days.
Dietary supplement: Citrus Limonoid Beverage
The limonoid containing beverage will be 12-oz buffered, sterile, orange flavored, artificially sweetened, containing 60 mg vitamin C, 11 mg riboflavin and 250 mg limonin glucoside.
Dietary supplement: Placebo beverage
The placebo beverage will be 12-oz buffered, sterile, orange flavored, artificially sweetened, containing 60 mg vitamin C and 11 mg riboflavin.
ACTIVE_COMPARATOR: Group 2
Group 2 consumes Citrus Limonoid Beverage for 56 days followed by Placebo beverages for 56 days
Dietary supplement: Citrus Limonoid Beverage
The limonoid containing beverage will be 12-oz buffered, sterile, orange flavored, artificially sweetened, containing 60 mg vitamin C, 11 mg riboflavin and 250 mg limonin glucoside.
Dietary supplement: Placebo beverage
The placebo beverage will be 12-oz buffered, sterile, orange flavored, artificially sweetened, containing 60 mg vitamin C and 11 mg riboflavin.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in plasma lipids
Time Frame: 1, 15, 71 and 127 days
Plasma cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride (TG), and remnant chylomicron particle concentrations will be determined. Lipid particle sizing will be performed by using nuclear magnetic resonance (NMR) technology. Plasma concentrations of apoproteins A1, B, C-III, and E will be measured.
1, 15, 71 and 127 days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in liver and renal function
Time Frame: 1, 15, 71 and 127 days
Serum sodium, potassium, chloride, carbon dioxide, urea nitrogen, creatinine, glucose, calcium, protein, albumin, alkaline phosphatase, asparagine transaminase (AST), bilirubin, alanine transaminase (ALT), and lactate dehydrogenase (LDH) were performed at the Pathology Laboratory of the University of California Davis Medical Center to assess liver and renal function.
1, 15, 71 and 127 days

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in inflammatory markers
Time Frame: 1, 15, 71 and 127 days
Plasma concentrations of c-reactive protein (CRP), tumor necrosis factor (TNF-alpha), interleukin-1 (IL-1beta) and interleukin-6 (IL-6) will be determined.
1, 15, 71 and 127 days

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
USDA, Western Human Nutrition Research Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
United States Department of Agriculture (USDA)
The Beverage Institute for Health & Wellness

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Darshan S Kelley, PhD, USDA, Western Human Nutrition Research Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

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

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 1, 2007

Primary Completion (ACTUAL)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 1, 2010

Study Completion (ACTUAL)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2010

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 4, 2013

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 9, 2013

First Posted (ESTIMATE)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 13, 2013

Study Record Updates

Last Update Posted (ESTIMATE)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 13, 2013

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 9, 2013

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • FL45

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings