Garlic Bulb Extract

CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:

Effect of Garlic on Blood Pressure: A Meta‐Analysis

Abstract

Garlic supplements are thought to reduce blood pressure (BP). The authors performed a meta‐analysis to investigate garlic's effect on BP. Ovid Medline, Cochrane Library, and PubMed (1946 to November 2013) were used to search for randomized controlled trials. Seventeen trials were included. Pooled analysis showed that garlic intake caused a 3.75‐mm Hg reduction (95% confidence interval [CI], −5.04 to −2.45, I 2=30.7%; P<.001) in systolic BP and a 3.39‐mm Hg reduction (95% CI, −4.14 to −2.65, I 2=67%; P<.001) in diastolic BP compared with controls. Meta‐analysis of subgroups showed a significant reduction in systolic BP in hypertensive (−4.4 mm Hg; 95% CI, −7.37 to −1.42, I 2=0.0%; P=.004) but not normotensive patients. No significant reduction in diastolic BP was seen. After sensitivity analysis, heterogeneity disappeared and significant diastolic BP reduction (−2.68 mm Hg, 95% CI, −4.93 to −0.42, I 2=0.0%; P=.020) was shown in hypertensive patients. This meta‐analysis suggests that garlic supplements are superior to controls (placebo in most trails) in reducing BP, especially in hypertensive patients.

Conclusions: Our meta‐analysis suggests that garlic supplementation is superior to placebo in reducing BP in hypertensive patients, especially in those with high SBP. More trials should be performed to explore the association between dosage and duration of garlic and change in BP. The safety of long‐term use should also be investigated before garlic is used as conventional therapy for hypertension.

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC8031974/

Garlic: a review of potential therapeutic effects

Abstract

Throughout history, many different cultures have recognized the potential use of garlic for prevention and treatment of different diseases. Recent studies support the effects of garlic and its extracts in a wide range of applications. These studies raised the possibility of revival of garlic therapeutic values in different diseases. Different compounds in garlic are thought to reduce the risk for cardiovascular diseases, have anti-tumor and anti-microbial effects, and show benefit on high blood glucose concentration. However, the exact mechanism of all ingredients and their long-term effects are not fully understood. Further studies are needed to elucidate the pathophysiological mechanisms of action of garlic as well as its efficacy and safety in treatment of various diseases.
Placebo group, resulting in fewer days of illness in the garlic group compared with the placebo group. However, claims of effectiveness of garlic on common cold appear to rely largely on poor quality evidence (Lissiman et al., 2012 ▶). Many countries have used garlic extract for clinical treatments, but the untoward actions of garlic following long-term administration should be fully noted. Even though many studies on garlic and its derivatives have been performed, the exact biological mechanism of garlic extract still remains to be elucidated.

Conclusion: A recent increase in the popularity of alternative medicine and natural products has renewed interest in garlic and their derivatives as potential natural remedies. This review may be useful to increase our knowledge of garlic therapeutic effects and improve our future experimental and clinical research plans. Although it is shown that garlic may have a significant clinical potential either in their own right or as adjuvant therapy in different disorders, however, due to some issues, such as methodological inadequacies, small sample sizes, lack of information regarding dose rationale, variation between efficacy and effectiveness trials, the absence of a placebo comparator, or lack of control groups more standard experiments and researches are needed to confirm the beneficial effect of garlic in various diseases. Future trials on the effect of garlic should include information on the dosage of active ingredients of standardized garlic preparations for better comparison of trials. It would also be interesting to explore the effect of different forms of garlic extract on standard drug therapy, especially when used as adjuvant therapy.
Although garlic is believed to be a safe substance, long-term trials of reasonable duration would provide insights into the possible side-effects of different garlic extracts. The safety of garlic should be tested especially in pregnant or breastfeeding women as well as in young children (Budzynska et al., 2012; Dante et al., 2013). Long-term and large trials are also needed to evaluate the differences in mortality, serious adverse events, and morbidity of cancer and cardiovascular diseases after garlic therapy.

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC4103721/

A review of studies of garlic (Allium sativum) on serum lipids and blood pressure before and after 1994: does the amount of allicin released from garlic powder tablets play a role?

Abstract

Objective: To identify studies measuring garlic powder tablets effects on systolic and diastolic blood pressure and to investigate if studies published prior to January 1994 would perform better than those published later.

Methods: Using MEDLINE (January 1966 through December 2004) studies involving human subjects that examined the effect of garlic (Allium sativum) on serum lipids and blood pressure were obtained. Studies that were conducted using garlic in the form of garlic powder tablets were included in the data extraction. Correlation coefficients were calculated for total serum cholesterol, systolic and diastolic blood pressure with respect to date of publication. Trials published prior to January 1994 were placed into an “earlier” group and compared to the “latter” group of studies published from January 1994 onward.

Results: Eighteen trials were identified whereupon the inverse associations between total serum cholesterol, systolic and diastolic blood pressures with respect to time of publication were correlated (−0.614, −0.627, and −0.587 respectively, p < 0.05). No significant associations were observed between systolic and diastolic blood pressure with respect to total serum cholesterol (0.388 and 0.431 respectively). The following differences between the earlier and later groups were observed for total serum cholesterol (31.4 ± 19.0 vs. 3.5 ± 5.8 mg/dl, p = .004); systolic blood pressure (11.0 ± 9.2 vs. 2.0 ± 4.4 mmHg, p = .133) and diastolic blood pressure (5.8 ± 3.4 vs. 0.9 ± 2.4 mmHg, p = .018).

Conclusions: Publications published prior to January 1994 performed better than those published after January 1994, suggesting that allicin may be responsible for the antihypertensive effects of garlic powder tablets. However, a lack of correlation between changes in total serum cholesterol and blood pressure suggests that other organo-sulfur compounds may also play a role in the antihyper-tensive mechanisms of garlic.

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC2647046/

Garlic Lowers Blood Pressure in Hypertensive Individuals, Regulates Serum Cholesterol, and Stimulates Immunity: An Updated Meta-analysis and Review

Abstract

Background: Garlic has been shown to have cardiovascular protective and immunomodulatory properties.

Objectives: We updated a previous meta-analysis on the effect of garlic on blood pressure and reviewed the effect of garlic on cholesterol and immunity.

Methods: We searched the Medline database for randomized controlled trials (RCTs) published between 1955 and December 2013 on the effect of garlic preparations on blood pressure. In addition, we reviewed the effect of garlic on cholesterol and immunity.

Results: Our updated meta-analysis on the effect of garlic on blood pressure, which included 20 trials with 970 participants, showed a mean ± SE decrease in systolic blood pressure (SBP) of 5.1 ± 2.2 mm Hg (P < 0.001) and a mean ± SE decrease in diastolic blood pressure (DBP) of 2.5 ± 1.6 mm Hg (P < 0.002) compared with placebo. Subgroup analysis of trials in hypertensive subjects (SBP/DBP ≥140/90 mm Hg) at baseline revealed a larger significant reduction in SBP of 8.7 ± 2.2 mm Hg (P < 0.001; n = 10) and in DBP of 6.1 ± 1.3 mm Hg (P < 0.001; n = 6). A previously published meta-analysis on the effect of garlic on blood lipids, which included 39 primary RCTs and 2300 adults treated for a minimum of 2 wk, suggested garlic to be effective in reducing total and LDL cholesterol by 10% if taken for >2 mo by individuals with slightly elevated concentrations [e.g., total cholesterol >200 mg/dL (>5.5 mmol/L)]. Garlic has immunomodulating effects by increasing macrophage activity, natural killer cells, and the production of T and B cells. Clinical trials have shown garlic to significantly reduce the number, duration, and severity of upper respiratory infections.

Conclusions: Our review suggests that garlic supplements have the potential to lower blood pressure in hypertensive individuals, to regulate slightly elevated cholesterol concentrations, and to stimulate the immune system. Garlic supplements are highly tolerated and may be considered as a complementary treatment option for hypertension, slightly elevated cholesterol, and stimulation of immunity. Future long-term trials are needed to elucidate the effect of garlic on cardiovascular morbidity and mortality.

Source: https://www.sciencedirect.com/science/article/pii/S0022316623005199

Garlic lowers blood pressure in hypertensive subjects, improves arterial stiffness and gut microbiota: A review and meta-analysis

Abstract

Garlic supplements have shown effectiveness in reducing blood pressure in hypertensive patients, similarly to first-line standard anti-hypertensive medications. Kyolic garlic has also shown promise in improving cardiovascular health by reducing arterial stiffness, elevated cholesterol levels and blood ‘stickiness’. In addition, the prebiotic properties in garlic increase gut microbial richness and diversity. This article systematically reviews previously published trials investigating the effects of garlic on blood pressure, and provides an updated meta-analysis of hypertensive participants. In addition, we summarise the findings of recent clinical trials investigating the effects of Kyolic aged garlic extract on arterial stiffness, and gut microbiota in hypertensive subjects. We searched online electronic databases, including PubMed and Google Scholar for randomised controlled trials (RCTs) published between 1955 and December, 2018 examining the effects of garlic on high blood pressure. The meta-analysis of 12 trials and 553 hypertensive participants confirmed that garlic supplements lower systolic blood pressure (SBP) by an average of 8.3±1.9 mmHg and diastolic blood pressure (DBP, n=8 trials, n=374 subjects) by 5.5±1.9 mmHg, similarly to standard anti-hypertensive medications. This reduction in blood pressure was associated with a 16–40% reduction in the risk of suffering from cardiovascular events. Additionally, this review summarises new evidence for the vitamin B12 status playing an important role in the responsiveness of blood pressure to garlic. Furthermore, Kyolic aged garlic extract significantly lowered central blood pressure, pulse pressure, pulse wave velocity and arterial stiffness, and improved the gut microbiota, evidenced by higher microbial richness and diversity, with a marked increase in the numbers of Lactobacillus and Clostridia species found following 3 months of supplementation. Thus, Kyolic aged garlic extract is considered to be highly tolerable with a high safety profile either as a stand-alone or adjunctive anti-hypertensive treatment, with multiple benefits for cardiovascular health.

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC6966103/

Garlic powder intake and cardiovascular risk factors: a meta-analysis of randomized controlled clinical trials

Abstract

Background/Objectives: Although preclinical studies suggest that garlic has potential preventive effects on cardiovascular disease (CVD) risk factors, clinical trials and reports from systematic reviews or meta-analyses present inconsistent results. The contradiction might be attributed to variations in the manufacturing process that can markedly influence the composition of garlic products. To investigate this issue further, we performed a meta-analysis of the effects of garlic powder on CVD risk factors.

Materials/Methods: We searched PubMed, Cochrane, Science Direct and EMBASE through May 2014. A random-effects meta-analysis was performed on 22 trials reporting total cholesterol (TC), 17 trials reporting LDL cholesterol (LDL-C), 18 trials reporting HDL cholesterol (HDL-C), 4 trials reporting fasting blood glucose (FBG), 9 trials reporting systolic blood pressure (SBP) and 10 trials reporting diastolic blood pressure (DBP).

Results: The overall garlic powder intake significantly reduced blood TC and LDL-C by -0.41 mmol/L (95% confidence interval [CI], -0.69, -0.12) (-15.83 mg/dL [95% CI, -26.64, -4.63]) and -0.21 mmol/L (95% CI, -0.40, -0.03) (-8.11 mg/dL [95% CI, -15.44, -1.16]), respectively. The mean difference in the reduction of FBG levels was -0.96 mmol/L (95% CI, -1.91, -0.01) (-17.30 mg/dL [95% CI, -34.41, -0.18]). Evidence for SBP and DBP reduction in the garlic supplementation group was also demonstrated by decreases of -4.34 mmHg (95% CI, -8.38, -0.29) and -2.36 mmHg (95% CI, -4.56, -0.15), respectively.

Conclusions: This meta-analysis provides consistent evidence that garlic powder intake reduces the CVD risk factors of TC, LDL-C, FBG and BP.

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC4252524/

The effect of garlic on vascular function: A systematic review of randomized clinical trials

Abstract

Background and Aims: Atherosclerosis and its associated cardiovascular disease (CVD) represent a major global health problem worldwide and vascular dysfunction is important in its pathogenesis. Clinical trials investigating the effect of garlic on vascular function measured by several non-invasive methods and their results are inconsistent. This study aimed to summarize the current evidence regarding the effectiveness of garlic as one of the world's most ancient medicines on measures of vascular reactivity and/or stiffness in adults.

Methods: All published RCTs in English were systematically searched on PubMed, Scopus and Google Scholar search engines up to Oct 2019. The exposure and outcome variable of interest were garlic and vascular function measurements. Ten trials which met inclusion criteria were included in this study.

Results: A total of 45 studies were found through search databases. After excluding duplicates, the 25 remaining studies were screened by title and abstract which 15 of them excluded. Finally, ten trials were included in this review study, which were published between 2004 and 2018.

Conclusions: Findings were inconsistent. However, garlic has the potential to improve vascular function, particularly in subjects with cardiovascular risk factors. Additional human studies on garlic and its constituents should consider the population and the specific type of garlic preparation.

Source: https://pubmed.ncbi.nlm.nih.gov/32143889/

Effect of garlic on blood pressure: a systematic review and meta-analysis

Abstract

Background: Non-pharmacological treatment options for hypertension have the potential to reduce the risk of cardiovascular disease at a population level. Animal studies have suggested that garlic reduces blood pressure, but primary studies in humans and non-systematic reviews have reported mixed results. With interest in complementary medicine for hypertension increasing, it is timely to update a systematic review and meta-analysis from 1994 of studies investigating the effect of garlic preparations on blood pressure.

Methods: We searched the Medline and Embase databases for studies published between 1955 and October 2007. Randomised controlled trials with true placebo groups, using garlic-only preparations, and reporting mean systolic and/or diastolic blood pressure (SBP/DBP) and standard deviations were included in the meta-analysis. We also conducted subgroup meta-analysis by baseline blood pressure (hypertensive/normotensive), for the first time. Meta-regression analysis was performed to test the associations between blood pressure outcomes and duration of treatment, dosage, and blood pressure at start of treatment.

Results: Eleven of 25 studies included in the systematic review were suitable for meta-analysis. Meta-analysis of all studies showed a mean decrease of 4.6 +/- 2.8 mm Hg for SBP in the garlic group compared to placebo (n = 10; p = 0.001), while the mean decrease in the hypertensive subgroup was 8.4 +/- 2.8 mm Hg for SBP (n = 4; p < 0.001), and 7.3 +/- 1.5 mm Hg for DBP (n = 3; p < 0.001). Regression analysis revealed a significant association between blood pressure at the start of the intervention and the level of blood pressure reduction (SBP: R = 0.057; p = 0.03; DBP: R = -0.315; p = 0.02).

Conclusion: Our meta-analysis suggests that garlic preparations are superior to placebo in reducing blood pressure in individuals with hypertension.

Source: https://pubmed.ncbi.nlm.nih.gov/18554422/

Garlic for the prevention of cardiovascular morbidity and mortality in hypertensive patients

Abstract

Background: Garlic is widely used by patients for its blood pressure lowering effects. A meta-analysis published in 2008 concluded that garlic consumption lowers blood pressure in hypertensive and normotensive patients. Therefore, it is important to review the currently available evidence to determine whether garlic may also have a beneficial role in the reduction of cardiovascular events and mortality rates in patients with hypertension.

Objectives: To determine whether the use of garlic as monotherapy, in hypertensive patients, lowers the risk of cardiovascular morbidity and mortality compared to placebo.

Search Methods: A systematic search for trials was conducted in the Cochrane Hypertension Group Specialised Register, CENTRAL, MEDLINE, EMBASE, AGRICOLA, AMED, and CINAHL up to November 2011. A hand search of reference lists of identified reviews was conducted. Experts in the area were also contacted to identify trials not found in the electronic search. Clinicaltrials.gov was searched for ongoing trials.

Selection criteria: Randomized, placebo-controlled trials of any garlic preparation versus placebo for the treatment of hypertension were included.

Data collection and analysis: Two reviewers independently extracted data and assessed trial quality using the risk of bias tool. Data synthesis and analysis was performed using RevMan 5.

Main Results: The search identified two randomized controlled trials for inclusion. One trial included 47 hypertensive patients and showed that garlic significantly reduces mean supine systolic blood pressure by 12 mmHg (95% CI 0.56 to 23.44 mmHg, p=0.04) and mean supine diastolic blood pressure by 9 mmHg (95% CI 2.49 to 15.51 mmHg, p=0.007) versus placebo. The authors state that garlic was "free from side effects" and that no serious side effects were reported. There were 3 cases "where a slight smell of garlic was noted."The second trial could not be meta-analysed as they did not report the number of people randomized to each treatment group. They did report that 200 mg of garlic powder given three times daily, in addition to hydrochlorothiazide-triamterene baseline therapy, produced a mean reduction of systolic blood pressure by 10-11 mmHg and of diastolic blood pressure by 6-8 mmHg versus placebo.Neither trial reported clinical outcomes and insufficient data was provided on adverse events.

Authors' conclusions: There is insufficient evidence to determine if garlic provides a therapeutic advantage versus placebo in terms of reducing the risk of mortality and cardiovascular morbidity in patients diagnosed with hypertension. There is also insufficient evidence to determine the difference in withdrawals due to adverse events between patients treated with garlic or placebo.Based on 2 trials in 87 hypertensive patients, it appears that garlic reduces mean supine systolic and diastolic blood pressure by approximately 10-12 mmHg and 6-9 mmHg, respectively, over and above the effect of placebo but the confidence intervals for these effect estimates are not precise and this difference in blood pressure reduction falls within the known variability in blood pressure measurements. This makes it difficult to determine the true impact of garlic on lowering blood pressure.

Source: https://pubmed.ncbi.nlm.nih.gov/22895963/

Aged Garlic Extract Reduces IL-6: A Double-Blind Placebo-Controlled Trial in Females with a Low Risk of Cardiovascular Disease

Abstract

Background: Chronic inflammation is a risk factor for cardiovascular disease. The aim of the study was to evaluate whether a daily supplementation of aged garlic extract (AGE) could reduce inflammation in females with low risk for cardiovascular disease. The study was conducted at a single center, as a parallel randomized placebo-controlled trial.

Method: 63 females with a Framingham risk score over 10 underwent cardiac computed tomography (CT) scan. Of those, patients with a coronary artery calcium (CAC) scores less than 5 (n = 31) met the inclusion criteria and were randomized, in a double-blind manner to an intake of placebo or AGE (2400 mg daily) for 1 year.

Results: Main outcome measure was changes in inflammatory biomarkers, blood pressure, fastening blood glucose, and blood lipids. A total of 29 patients (14 in the AGE group and 15 in the placebo group) completed the study and were analyzed. Females treated with AGE showed lower levels of inflammatory marker IL-6 after 12 months of treatment compared to females receiving placebo (p < 0.05). The blood lipids had a trend towards a lowering effect in females treated with AGE; however, this trend was not significant.

Conclusion: The present study concludes that AGE lowers IL-6 in females with a risk profile of cardiovascular disease. We could also conclude that risk prediction with cardiac CT scan turned out to be superior in estimating the risk of cardiac disease compared to Framingham risk score. This trial is registered with NCT03860350.

Source: https://pubmed.ncbi.nlm.nih.gov/33868439/

Effects of garlic extract on lipid profile in patients with coronary artery disease: A systematic review and meta-analysis of randomised clinical trials

Abstract

This meta-analysis was conducted to evaluate the effects of garlic extract on total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-c) and high-density lipoprotein-cholesterol (HDL-c), among the patients with coronary artery disease (CAD). Literature searches were conducted in EMBASE, Scopus, PubMed, Web of Science and Cochrane Library until Sep18th, 2020. Inter-study heterogeneity was examined using Cochrane's Q and I2 tests. The random-effect models were utilised to pool the weighted mean differences (WMDs) and the corresponding 95% confidence intervals (CIs). Six articles were enrolled in the current meta-analysis. Garlic consumption significantly reduced TC levels (WMD -16.32 mg/dL; 95% CI -31.22, -1.43; P = .032). We found no significant effects on TG (WMD -10.93 mg/dL; 95% CI -26.19, 4.32; P = .160), HDL-c (WMD 4.55 mg/dL; 95% CI -1.13, 10.23; P = .116) and LDL-c concentrations (WMD -3.65 mg/dL; 95% CI -13.21, 5.92; P = .455). Significant heterogeneity was observed for HDL-c (I2 = 76.8%). However, the findings of sensitivity analysis revealed that upon exclusion of the potential heterogeneity source, the pooled WMD on HDL-c levels were stable. Garlic supplementation may result in a decrease in TC, but will not affect TG, HDL-c and LDL-c levels among CAD patients.

Source: https://pubmed.ncbi.nlm.nih.gov/34627133/

Effect of garlic on the components of metabolic syndrome: A systematic review and meta-analysis of randomized controlled trials

Abstract

Ethnopharmacological relevance: Metabolic diseases are the major causes of macrovascular and microvascular complications which lead to morbidity and mortality. Traditionally, garlic has been used as food and medicine for more than 5000 years. However, efficacy studies have shown conflicting results regarding the garlic effect.

Aim of the study: This study aims to evaluate the efficacy of garlic on the components of metabolic syndrome (MetS) in metabolic disease patients.

Materials and methods: This study was a systematic review and meta-analysis of randomized controlled trials (RCTs). Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), and Google scholar were searched till December 25, 2021 for identifying the relevant studies that have shown the effects of garlic on components of metabolic syndrome in metabolic disease patients. The mean difference with 95% CI was calculated using fixed-effect or random-effect models.

Results: The effect of garlic has shown significant changes on waist circumference (p-value= <0.0001), total cholesterol (p < 0.0001), low density lipoprotein (p = 0.01), high density lipoprotein (p < 0.00001), triglycerides (p < 0.00001), systolic blood pressure (p < 0.00001), diastolic blood pressure (p < 0.00001), glucose (p < 0.00001), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (p = 0.04), C-reactive protein (p < 0.00001), tumor necrosis factor (TNF)-α (p = 0.002), interleukin (IL)-6 (p = 0.0001). Subgroup analysis has shown the favorable effects of garlic in metabolic disease patients.

Conclusion: Our meta-analysis results confirm the findings that garlic could be useful as an anti-hyperlipidemic, anti-hyperglycemic, anti-hypertensive and anti-inflammatory drug.

Source: https://www.sciencedirect.com/science/article/abs/pii/S0378874123008280?

References:

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC8031974/
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC4103721/
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC2647046/
4. https://www.sciencedirect.com/science/article/pii/S0022316623005199
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC6966103/
6. https://pmc.ncbi.nlm.nih.gov/articles/PMC4252524/
7. https://pubmed.ncbi.nlm.nih.gov/32143889/
8. https://pubmed.ncbi.nlm.nih.gov/18554422/
9. https://pubmed.ncbi.nlm.nih.gov/22895963/
10. https://pubmed.ncbi.nlm.nih.gov/33868439/
11. https://pubmed.ncbi.nlm.nih.gov/34627133/
12. https://www.sciencedirect.com/science/article/abs/pii/S0378874123008280?