Comparing Effects of 3 Sources of Garlic on Cholesterol Levels

August 16, 2006 updated by: National Center for Complementary and Integrative Health (NCCIH)

Comparing Effects of 3 Sources of Garlic on Serum Lipids

The purpose of this study is to determine whether fresh garlic can positively affect cholesterol in adults with moderately high cholesterol levels. This study will also determine whether the same effects can be found for two main types of garlic supplements: a dried powdered garlic (designed to yield the same effect as fresh garlic) and an aged garlic extract preparation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Garlic supplements are the most consumed herbal products in the United States. The most common health claim made for garlic supplements is cholesterol lowering activity. This claim has not been supported by recent clinical trials and meta-analyses. However, data suggest that it is not necessarily the garlic that has been ineffective, but rather the particular garlic preparations being used. To date, the predominant type of garlic preparation used in these clinical trials has been dried garlic powders. A few clinical trials have reported beneficial lipid effects using an aged garlic extract, and only a small number of inconclusive uncontrolled trials have used fresh garlic. A rigorous trial directly comparing different types of garlic preparations for their effects on serum lipids is needed.

Adults with moderately elevated low density lipoprotein cholesterol (LDL-C) will be randomized to one of four groups for 6 months: fresh garlic, dried powdered garlic tablets, aged garlic extract tablets, or placebo control. The fresh garlic will be provided to patients with "study sandwiches"; all other groups will receive the same study sandwiches without the garlic. All patients will take daily study tablets, but the tablet assignment will be double-blind. Patients will pick up study sandwiches twice a week and study tablets once every 2 weeks for 28 weeks. Blood samples will be taken once a month, with additional blood draws at the start and end of the study.

Study Type

Interventional

Enrollment

220

Phase

  • Phase 2
  • Phase 3

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
      • Palo Alto, California, United States, 94304-1583
        • Stanford Center for Research in Disease Prevention

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

Ages Eligible for Study

30 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • LDL-C 130-190 mg/dL (fasting single sample)
  • BMI (body mass index) 19-30 kg/m2 (42-66 lb/m2)
  • Weight stable for last 2 months
  • Not actively on a weight loss plan
  • Ethnicity representative of local population
  • No plans to move from the area over the next 9 months

Exclusion Criteria:

  • Pregnant, lactating, within 6 months postpartum, or planning to become pregnant in the next year
  • Diabetes (type I or II) or history of gestational diabetes
  • Heart disease
  • Active neoplasms
  • Renal or liver disease
  • Hyperthyroidism or hypothyroidism
  • Lipid lowering medications (known to affect lipid metabolism, platelet function, or antioxidant status)
  • Blood pressure medications
  • Excessive alcohol intake (self reported, more than 3 drinks/day)
  • Currently under psychiatric care or severely clinically depressed

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

What is the study measuring?

Primary Outcome Measures

Outcome Measure
LDL-cholesterol; measured at baseline, once a month, and post-intervention

Secondary Outcome Measures

Outcome Measure
HDL-cholesterol; measured at baseline, once a month, and post-intervention
Triacylglycerols; measured at baseline, once a month, and post-intervention
Blood pressure; measured at baseline, once a month, and post-intervention
Platelet aggregation; measured at baseline, once a month, and post-intervention

Collaborators and Investigators

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

Sponsor

National Center for Complementary and Integrative Health (NCCIH)

Collaborators

Office of Dietary Supplements (ODS)

Investigators

  • Principal Investigator: Christopher D. Gardner, Ph.D., Stanford Center for Research in Disease Prevention

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.

General Publications

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

May 1, 2002

Study Completion

April 1, 2005

Study Registration Dates

First Submitted

March 14, 2003

First Submitted That Met QC Criteria

March 17, 2003

First Posted (Estimate)

March 18, 2003

Study Record Updates

Last Update Posted (Estimate)

August 18, 2006

Last Update Submitted That Met QC Criteria

August 16, 2006

Last Verified

August 1, 2006

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R01AT001108-01 (U.S. NIH Grant/Contract)

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.

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