A meta-analysis of randomized, double-blind, placebo-controlled trials for the effects of garlic on serum lipid profiles
Inconsistent results were obtained for the lipid-regulating effects of garlic in clinical trials. With increasing interest in complementary medicine for hyperlipoidemia, it is important to explore the real effects of garlic. This meta- analysis was performed to investigate the influence of garlic on serum lipid parameters.
A total of 26 studies were included into meta-analysis. Overall, garlic was superior to placebo in reducing serum total cholesterol (TC) and triglyceride (TG) levels. Compared with the placebo groups, serum TC and TG levels in the garlic group were reduced by 0.28 (95% CI, -0.45, -0.11) mmol L⁻¹ (P = 0.001) and 0.13 (95% CI, -0.20, -0.06) mmol L⁻¹ (P < 0.001), respectively. The effects of garlic were more striking in subjects with long-term intervention and higher baseline TC levels. Garlic powder and aged garlic extract were more effective in reducing serum TC levels, while garlic oil was more effective in lowering serum TG levels. In contrast, garlic did not influence other lipid parameters, including low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), apolipoprotein B, and TC/HDL-C ratio.
Garlic could reduce serum TC and TG levels, and garlic therapy should benefit patients with risk of cardiovascular diseases.
Available from: Muinat Olanike Kazeem
- "Garlic can be prepared in various forms, namely oil, powder, raw juice and extracts   . The therapeutic effect of garlic has been attributed to its organosulfur constituents, which also are responsible for its typical flavour and odour   . Other studies have implicated thiosulfinates in the antibiotic activity of garlic [22,25–28]. "
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ABSTRACT: Allium sativum, Hibiscus sabdariffa and Zingiber officinale are medicinal plants with wide use in traditional medicine; however, the increasing use of crude extracts for traditional medicine applications raises safety concerns. We made a preliminary determination of the phytochemical constituents and antimicrobial and safety profiles of aqueous extracts of A. sativum, H. sabdariffa and Z. officinale. The extracts were administered orally to Wistar rats for 30 days: a control group received distilled water, three groups received the three extract, and a fifth group received a combination of the three extracts. All three extracts, either individually or in combination, had antimicrobial activity, and all extracts influenced the activities of marker enzymes. The evidence lends credence to use of these plants in traditional medicine but also suggests the probable toxic potential of crude plant extracts.
- "2012; Neil et al., 1996) have demonstrated a wide range of therapeutic effects due to its high content of phytochemicals, including sulfur-containing compounds, vitamins, saponins, flavonoids and moderate levels of carotenoids. The synergistic interactions between these components contribute to provide the observed health benefits from garlic as well as antibacterial, antifungal, hypolipidemic, antihypertensive, antiatherosclerotic, anticoagulant, hypoglycemic and chemopreventive (Patumraj et al., 2000; Ohaeri, 2001; Zeng et al., 2012; Rahman, 2007; Lau, 2001). "
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ABSTRACT: Several studies have demonstrated a wide range of therapeutic effects due to garlic high content of phytochemicals, including sulfur-containing compounds, vitamins, saponins, flavonoids and moderate levels of carotenoids. The synergistic interactions between these components seem to explain the outcomes of certain healing properties from garlic. This study evaluates the health promoting phytochemicals (ascorbic acid, flavonoids and carotenoids) content and antioxidant capacity in four “typical garlic varieties” (Rosso di Castelliri, Bianco Piacentino, Rosso di Sulmona, Rosso di Proceno), grown in different geographical areas. b-carotene content ranged from 5.68 to 7.41 mg/100g and 6.36 to 7.46 mg/100g for Viterbo and Alvito bulbs respectively. Overall, vitamin C levels were statistically higher in samples from Alvito compared with same cultivars from Viterbo; among them Rosso Sulmona and Rosso Castelliri displayed the higher content (21.59 ± 2.75 and 18.91 ± 0.34 mg/100g respectively). FRAP values were positively correlated (r = 0.74 and P = 0.03) with vitamin C levels and highly correlated (r = 0.86 and P = 0.005) with myricetin levels. Our findings have revealed that genotype and environmental conditions (production areas and pedoclimatic factors), as well as their interaction, could influence the phytochemical composition and the antioxidant properties of Italian garlic bulb varieties.
Available from: Tabinda Ashfaq
- "A recent meta-analyses conducted by Zeng et al. in 2012 clearly illustrated that garlic therapy is more effective if used for a long term with higher baseline total cholestrol levels; they also concluded that garlic powder and aged garlic extract were more effective in reducing serum TC levels, while garlic oil was more effective in lowering serum TG levels . A trial comparing garlic with a commercial lipid-lowering drug (bezafibrate) found them to be equally effective in decreasing lipids to a statistically significant extent . "
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ABSTRACT: Introduction. Rapidly growing prevalence of cardiovascular disease is a major threat for the developed as well as developing world warranting urgent need of intervention. Complementary and alternative medicines are gaining popularity among general population because of their safety profile and easy administration. Garlic, in particular, is considered to be one of the best disease-preventive foods because of its potent and widespread effects. This study was done to find out the role of garlic usage in cardiovascular disease prevention. Methodology. Major databases including Google, PubMed, MEDLINE, and Cochrane library view were used for the literature search. Clinical trials conducted on humans assessing role of garlic usage in cardiovascular disease prevention and the possible mechanisms responsible for such therapeutic actions were assessed. Results. Various clinical trials and meta-analyses conducted have shown positive impact of garlic in cardiovascular-disease prevention especially its effects on lipid levels; however, some contradictory results are also reported. Similarly, its effects on hypertension control, and platelet are also mild with limited data availability. The possible reason for these inconsistent results is the difference in preparations with diverse composition, variations in sulphur content present in different garlic preparations used, and methodological variations in subject recruitment, duration of study, dietary control and so forth. Conclusion. Garlic can be used as an adjuvant with lipid-lowering drugs for control of lipids, however, its role as a main therapeutic agent cannot be recommended and it is suggested that more meta-analyses using standardized preparations with a close watch on methodological shortfalls should be conducted to prove its role.
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