Hypercholesterolemia is associated with an increased risk of heart disease.
Regular intake of Allium sativum, commonly known as garlic has been suggested to have beneficial impact on cholesterol levels.
Garlic is a plant of the family Alliaceae. It is universally used as a flavouring agent and in traditional medicine to enhance physical and mental health. Unique organosulphur compounds found in garlic provide its characteristic flavour and odour and most of its biological activity. One of the sulfur-based compound, allicin is attributed to garlic cholesterol-lowering effects even though the exact mechanism of its action remains unclear.
The effect of garlic on blood lipids has been studied in numerous trials and also summarized in meta-analyses, with conflicting results.
We critically reviewed and summarised the evidence on the effect of garlic on serum cholesterol. We carried out a comprehensive search of the Cochrane Library, MEDLINE, EMBASE, electronic publishing sites, reference lists of relevant papers and manual searches of relevant journals. Experts and local manufacturers and distributors of garlic products were also contacted to identify additional studies. To evaluate the effects of garlic on cholesterol levels in both healthy and hypercholesterolaemic subjects, we only included in the review, randomised controlled trials of garlic ranging from 11 to 24 weeks in duration. Data were extracted and trial quality was assessed independently by two reviewers. The data were meta-analysed.
Thirteen trials including 1056 subjects were eligible for the meta-analysis. Overall, administration of garlic did not show any significant difference in effects on all outcome measures examined when compared with placebo. Garlic therapy did not produce any statistically significant reduction in serum total cholesterol level [mean difference (MD), -0.04 mmol/L; 95% CI -0.15 to 0.07 mmol/L], LDL-cholesterol level (MD, 0.01 mmol/L; 95% CI -0.10 to 0.11 mmol/L), triglycerides level (MD, -0.05 mmol/L; 95% CI -0.17 to 0.06 mmol/L) or apolipoprotein B level (MD, -0.02 g/L; 95% CI -0.03 to 0.001 g/L). There was also no statistically significant difference between garlic and placebo on HDL-cholesterol level (MD, 0.01 mmol/L; 95% CI -0.03 to 0.05 mmol/L). Moderate to high heterogeneity exists among pooled studies. Garlic preparations were tolerable in all trials and were associated with minimal side effects.
The available evidence from randomised controlled trial does not demonstrate any beneficial effects of garlic on serum cholesterol. Thus, with the current evidence, garlic cannot be considered as an alternative option to conventional cholesterol-lowering medications in patients with slightly elevated cholesterol.
Source:
Khoo YS, Aziz Z. Garlic supplementation and serum cholesterol: a meta-analysis. J Clin Pharm Ther. 2009 Apr;34(2):133-45. doi: 10.1111/j.1365-2710.2008.00998.x. PMID: 19250134.