Comparing Effects of 3 Sources of Garlic on Cholesterol Levels

Sponsor

National Center for Complementary and Integrative Health (NCCIH) (NIH)

Overall Status

Completed

CT.gov ID

NCT00056511

Collaborator

Office of Dietary Supplements (ODS) (NIH)

220

Enrollment

Location

Duration (Months)

6.3

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Hypercholesterolemia	Drug: Fresh garlic or garlic supplements	Phase 2/Phase 3

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 Design

Study Type:

Interventional

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double

Primary Purpose:

Treatment

Official Title:

Comparing Effects of 3 Sources of Garlic on Serum Lipids

Study Start Date :

May 1, 2002

Study Completion Date :

Apr 1, 2005

Outcome Measures

Primary Outcome Measures

LDL-cholesterol; measured at baseline, once a month, and post-intervention []

Secondary Outcome Measures

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 []

Eligibility Criteria

Criteria

Ages Eligible for Study:

30 Years to 65 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

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