Study Questions Ability of Garlic to Lower LDL Cholesterol

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A study published in the Archives of Internal Medicine this week concluded that garlic supplementation does not improve cholesterol profiles in people with moderately high levels of LDL cholesterol (defined here as a fasting plasma LDL cholesterol concentration of 130 to 190 mg/dL, a triglyceride level less than 250 mg/dL and body mass index, calculated as weight in kilograms divided by height in meters squared, of 19 to 30). The study is the first independent, long-term assessment of raw garlic and two popular garlic supplements. Raw garlic (4g/day for 6 months), powdered garlic and aged garlic extract supplement were tested on 192 adults with moderately high levels of LDL cholesterol. None of the garlic forms studied had statistically or clinically significant effects on LDL cholesterol or other plasmid lipid concentrations. The results contradict other recent findings suggesting that garlic may be beneficial in heart health by reducing moderately high levels of LDL cholesterol in adults [1-2].

The results of the trial should not be generalized to other populations or health effects. Since the trial focused on people with moderately hight levels of LDL cholesterol, garlic may lower LDL cholesterol levels in people with higher LDL concentrations or help regulate cholesterol levels in healthy people. Additionally, the trial studied only one dosage level and effects on LDL cholesterol may emerge at higher doses. The trial results do not refute scientific evidence suggesting that garlic has antithrombotic effects (meaning intravascular coagulation of the blood in any part of the circulatory system, including the arteries) [3-6].

References

1. Kannar et al. Hypocholesterolemic effect of an enteric-coated garlic supplement. J Am Coll Nutr. 2001 Jun;20(3):225-31.
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2. Mahmoodi et al. Study of the effects of raw garlic consumption on the level of lipids and other blood biochemical factors in hyperlipidemic individuals. Pak J Pharm Sci. 2006 Oct;19(4):295-8.
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3. Bordia et al. Effect of garlic on platelet aggregation in humans: a study in healthy subjects and patients with coronary artery disease. Prostaglandins Leukot Essent Fatty Acids. 1996 Sep;55(3):201-5.
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4. Bordia et al. Effect of garlic (Allium sativum) on blood lipids, blood sugar, fibrinogen and fibrinolytic activity in patients with coronary artery disease. Prostaglandins Leukot Essent Fatty Acids. 1998 Apr;58(4):257-63.
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5. Ohaeri and Adoga. Anticoagulant modulation of blood cells and platelet reactivity by garlic oil in experimental diabetes mellitus. Biosci Rep. 2006 Feb;26(1):1-6.
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6. Fukao et al. Antithrombotic effects of odorless garlic powder both in vitro and in vivo. Biosci Biotechnol Biochem. 2007 Jan;71(1):84-90.
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