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Comparing Effects of 3 Sources of Garlic on Cholesterol Levels

Comparing Effects of 3 Sources of Garlic on Serum Lipids

Status
Completed
Phases
Phase 2Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT00056511
Enrollment
220
Registered
2003-03-18
Start date
2002-05-31
Completion date
2005-04-30
Last updated
2006-08-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hypercholesterolemia

Keywords

Garlic, Supplements, Adults, Hypercholesterolemics, Randomized Clinical Trial

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.

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.

Interventions

DRUGFresh garlic or garlic supplements

Sponsors

Office of Dietary Supplements (ODS)
CollaboratorNIH
National Center for Complementary and Integrative Health (NCCIH)
Lead SponsorNIH

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE

Eligibility

Sex/Gender
ALL
Age
30 Years to 65 Years
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

Design outcomes

Primary

MeasureTime frame
LDL-cholesterol; measured at baseline, once a month, and post-intervention

Secondary

MeasureTime frame
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

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026