A Grapefruit Feeding Trial in Healthy, Overweight Adults

Efficiency of Daily Grapefruit Exposure in Reducing Body Weight and Inflammatory Markers

Folklore has suggested that consuming grapefruit may promote weight control. Sparse data exist to support this hypothesis, though there is some evidence of health promotional effects regarding blood pressure and lipid profiles. The aims of this randomized controlled trial are to determine the role of grapefruit in:

1. Reducing weight
2. Reducing blood pressure
3. Reducing inflammation
4. Improving the lipid profile.

The investigators hypothesize that six weeks of daily consumption of grapefruit will reduce weight, blood pressure, and inflammation while improving the lipid profile in overweight, healthy adults.

Study Overview

• Status: Completed
• Conditions: Obesity; Weight Loss; Cardiovascular Risk Factors
• Intervention / Treatment: Other: Grapefruit; Other: Control

• Study Type: Interventional
• Enrollment (Actual): 85
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Tucson, Arizona, United States, 85721
      • University of Arizona

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Adults, men and premenopausal women
• BMI: 25-45 kg/m2
• Willing to maintain current exercise regimen (not to exceed 10 hours/week)
• Willing to follow a diet low in bioactive rich fruits and vegetables and with no citrus

Exclusion Criteria:

• History of chronic disease
• Metabolic disease
• Inflammatory disease
• High cholesterol (>225 mg/dL)
• Smoker
• Taking medications metabolized by the Cytochrome P450 3A enzyme
• History of alcohol or drug abuse

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control	Other: Control; Participants followed a diet low in bioactive rich fruits and vegetables and avoided citrus for six weeks
Experimental: Grapefruit Consumption	Other: Grapefruit; 1.5 Rio Red Grapefruit consumed daily for 6 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Weight reduction	Participants consumed 1/2 grapefruit before each meal (1.5 grapefruit per day) for six weeks. Weight was measured before and after grapefruit consumption to assess weight change. Weight change was considered statistically significant at p<0.05.	6 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure reduction	Previous studies in animals and humans consuming citrus have resulted in reductions in blood pressure, though no direct effect of grapefruit has ever been demonstrated. Blood pressure was measured at baseline and after the 6 week intervention period (consuming either the control diet or supplementing the diet with 1/2 grapefruit before each meal).	6 weeks
Lipid Profile Improvements	Previous studies in humans and animal models consuming grapefruit or grapefruit bioactives have shown reductions in triglycerides, LDL, and total cholesterol and increases in circulating HDL. These parameters were measured via a common point-of-care system, LDX Cholestech. Lipids were measured at baseline and after the 6 week intervention period (consuming either the control diet or supplementing the diet with 1/2 grapefruit before each meal).	6 weeks
Reductions in markers of chronic inflammation	Markers of chronic inflammation, which are also associated with endothelial dysfunction and heart disease, like tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and soluble vascular cellular adhesion molecule-1 (sV-CAM1) were measured. Inflammatory markers were measured at baseline and after the 6 week intervention period (consuming either the control diet or supplementing the diet with 1/2 grapefruit before each meal).	6 weeks

Collaborators and Investigators

• Sponsor: University of Arizona
• Collaborators: Texas A&M University
• Investigators: Principal Investigator: Cynthia Thomson, PhD, RD, University of Arizona

Study record dates

Study Major Dates

• Study Start: August 1, 2009
• Primary Completion (Actual): April 1, 2011
• Study Completion (Actual): April 1, 2011

Study Registration Dates

• First Submitted: July 21, 2011
• First Submitted That Met QC Criteria: October 14, 2011
• First Posted (Estimate): October 17, 2011

Study Record Updates

• Last Update Posted (Estimate): October 17, 2011
• Last Update Submitted That Met QC Criteria: October 14, 2011
• Last Verified: October 1, 2011

More Information

Terms related to this study

• Keywords: blood pressure; inflammation; weight loss; lipids; grapefruit
• Additional Relevant MeSH Terms: Body Weight; Body Weight Changes; Weight Loss
• Other Study ID Numbers: 09-0695-02