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Metabolism And Health Effects Of Citrus Limonoids in Hypercholesterolemic Humans

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ClinicalTrials.gov Identifier: NCT02011789
Recruitment Status : Completed
First Posted : December 13, 2013
Last Update Posted : December 13, 2013
Sponsor:
Collaborators:
The Beverage Institute for Health & Wellness
United States Department of Agriculture (USDA)
Information provided by (Responsible Party):
USDA, Western Human Nutrition Research Center

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Hypercholesterolemia Dietary Supplement: Citrus Limonoid Beverage Dietary Supplement: Placebo beverage Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 10 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Basic Science
Official Title: A Pilot Study To Determine The Metabolism And Health Effects Of Citrus Limonoids in Hypercholesterolemic Human Subjects
Study Start Date : April 2007
Actual Primary Completion Date : July 2010
Actual Study Completion Date : July 2010

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
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.




Primary Outcome Measures :
  1. 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.


Secondary Outcome Measures :
  1. 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.


Other Outcome Measures:
  1. 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.



Information from the National Library of Medicine

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Ages Eligible for Study:   20 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02011789


Locations
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United States, California
USDA Western Human Nutrition Research Center
Davis, California, United States, 95616
Sponsors and Collaborators
USDA, Western Human Nutrition Research Center
The Beverage Institute for Health & Wellness
United States Department of Agriculture (USDA)
Investigators
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Principal Investigator: Darshan S Kelley, PhD USDA, Western Human Nutrition Research Center

Additional Information:
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Responsible Party: USDA, Western Human Nutrition Research Center
ClinicalTrials.gov Identifier: NCT02011789    
Other Study ID Numbers: FL45
First Posted: December 13, 2013    Key Record Dates
Last Update Posted: December 13, 2013
Last Verified: December 2013
Keywords provided by USDA, Western Human Nutrition Research Center:
hypercholesterolemia
inflammation
citrus limonoids
Additional relevant MeSH terms:
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Hypercholesterolemia
Hyperlipidemias
Dyslipidemias
Lipid Metabolism Disorders
Metabolic Diseases