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

Garlic and Hypertension: Efficacy, Mechanism of Action, and Clinical Implications

Hypertension is a major risk factor for heart disease and stroke. Garlic has a long history of use in traditional medicine for various conditions, including hypertension. This narrative review examined the scientific evidence on the efficacy of garlic in lowering blood pressure. It explores the historical uses of garlic in different cultures for medicinal purposes and delves into the phytochemical composition of garlic, highlighting key components, like allicin and ajoene, that are believed to contribute to its potential health benefits. Clinical studies that investigated the effects of garlic and garlic-based supplements on blood pressure are presented, with the findings suggesting that garlic consumption may modestly reduce blood pressure, particularly in individuals with mild hypertension. Potential mechanisms of action include increased nitric oxide production, improved endothelial function, and antioxidant properties. While garlic may offer some benefits for blood pressure management, it should not be considered a substitute for conventional antihypertensive medications. Further large-scale, long-term clinical trials are warranted to establish the efficacy of garlic in managing hypertension, including the optimal dosage and formulation.

Garlic consumption can reduce the risk of dyslipidemia: a meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

Garlic is used as an important medicinal food for treatment of many diseases, however, the association between garlic consumption and dyslipidemia have yielded inconsistent results. So we carried this meta-analysis to explore the blood lipid-lowering effects of garlic.

METHODS

Databases such as PubMed, Scopus, Web of science, Embase, Cochrane Library were systematically searched until June 2024. Heterogeneity among studies was examined using Q and I2 statistics. Also subgroup analysis were conducted to explore the potential heterogeneity. Combined weighted mean differences (WMD) with their 95% confidence interval (CI) were calculated using a random-effects model. The GRADE approach was used to evaluate the overall certainty of the evidence in the meta-analyses.

RESULTS

A total of 21 RCTs studies involved association between garlic consumption and blood lipids level of dyslipidemia patients were included in the meta-analysis. The pooled results showed that garlic consumption significantly reduced total cholesterol (TC)(WMD = -0.64mmol/L, 95%CI = -0.75 --0.54, P < 0.001), triglyceride (TG)(WMD = -0.17mmol/L, 95%CI = -0.26 --0.09, P < 0.001), low-density lipoprotein(LDL-C)(WMD = -0.44mmol/L, 95%CI = -0.57 --0.31, P < 0.001) while slightly increased high-density lipoprotein (HDL-C)(WMD = 0.04mmol/L, 95%CI = -0.00 - 0.08, P < 0.001). And subgroup analyses showed that TC, TG and LDL-C significantly decreased in patients aged > 50 years compared to those aged ≤ 50 years. And garlic oil greatly reduced TC and LDL-C compared with garlic power. Finally, sensitivity analysis and publication bias showed that the results were reliable.

CONCLUSIONS

Evidence from this meta-analysis suggested that garlic consumption could be effective in reducing the risk of dyslipidemia and preventing CVDs. Particularly the older people were more susceptible to the protective effects of garlic.

Garlic bioactive substances and their therapeutic applications for improving human health: a comprehensive review

Garlic (Allium sativum L.) is a widely abundant spice, known for its aroma and pungent flavor. It contains several bioactive compounds and offers a wide range of health benefits to humans, including those pertaining to nutrition, physiology, and medicine. Therefore, garlic is considered as one of the most effective disease-preventive diets. Many in vitro and in vivo studies have reported the sulfur-containing compounds, allicin and ajoene, for their effective anticancer, anti-diabetic, anti-inflammatory, antioxidant, antimicrobial, immune-boosting, and cardioprotective properties. As a rich natural source of bioactive compounds, including polysaccharides, saponins, tannins, linalool, geraniol, phellandrene, β-phellandrene, ajoene, alliin, S-allyl-mercapto cysteine, and β-phellandrene, garlic has many therapeutic applications and may play a role in drug development against various human diseases. In the current review, garlic and its major bioactive components along with their biological function and mechanisms of action for their role in disease prevention and therapy are discussed.

Effects of Garlic on Glucose Parameters and Lipid Profile: A Systematic Review and Meta-Analysis on Randomized Controlled Trials

(1) Background: The effect of garlic on glucose and lipid metabolism in humans remains controversial. The aim of this study was to investigate the effects of garlic on blood lipid levels and glucose levels in humans through a systematic review and meta-analysis. (2) Methods: We extensively searched four databases, including PubMed, Web of Science, Embase, and the Cochrane Library, up to February 2024. To assess the collective impact of garlic and its supplements on fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), an analysis was conducted using a random effects model. Subgroup analyses were performed when I2 < 50%. (3) Result: We found that the garlic intervention was effective in controlling FBG (mean difference = -7.01; 95% CI: -8.53, -5.49, p < 0.001), HbA1c (mean deviation = -0.66; 95% CI: -0.76, -0.55, p < 0.001, I2 = 62.9%), TC (mean difference = -14.17; 95% CI: -19.31, -9.03, p < 0.001), and LDL-C (mean difference = -8.20; 95% CI: -15.58, -0.81, p = 0.03); moreover, it also increased the level of HDL-C in humans (mean difference = 2.06; 95% CI: 1.54, 2.59; p < 0.001). Nonetheless, the intervention involving garlic did not yield a substantial impact on triglyceride (TG) levels. (4) Conclusion: The intervention of garlic is beneficial to control blood glucose and blood lipids in humans.

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

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.

Effect of garlic extract on markers of lipid metabolism and inflammation in coronary artery disease (CAD) patients: A systematic review and meta-analysis

Several preclinical studies have focused on the beneficial effects of garlic on cardiovascular diseases, but the results were inconsistent. We performed a systematic review and meta-analysis on the effect of garlic powder tablets and aged garlic extract (AGE) in CAD patients, mainly focusing on blood pressure, coronary artery calcification, lipid profile, and inflammatory markers. We searched PubMed, Cochrane CENTRAL, and Google Scholar to identify randomized controlled trials which examined garlic's effect on CAD patients. The standardized mean difference with 95% CI was calculated using fixed-effect or random-effect models. Garlic has shown statistically significant changes of HDL (SMD = 0.18; 95% CI = -0.00 to 0.37; p = .05); LDL (SMD = -0.27; 95% CI = -0.46 to -0.08; p = .004), apolipoprotein-A (SMD = 0.68; 95% CI = 0.24 1.13; p = .002), C-RP (SMD = -0.59; 95% CI = -0.92 to -0.25; p = .0007), IL-6 (SMD = -1.08; 95% CI = -2.17 to 0.01; p = .05), homocysteine (SMD = -0.66; 95% CI = -1.04 to -0.28; p = .0007) and CAC score (SMD = -1.61; 95% CI = -2.66 to -0.57; p = .003). In the case of subgroup analysis, the overall effect was significantly effective in reducing TC, LDL levels and improving HDL levels in CV risk patients. Our study findings provide consistent evidence that intake of garlic reduces CVD risk factors. However, garlic could be considered a safe natural medicine to debilitate inflammation in CAD patients.

Traditional uses, phytochemistry, pharmacology and toxicology of garlic (Allium sativum), a storehouse of diverse phytochemicals: A review of research from the last decade focusing on health and nutritional implications

Allium sativum L. (Garlic) is a fragrant herb and tuber-derived spice that is one of the most sought-after botanicals, used as a culinary and ethnomedicine for a variety of diseases around the world. An array of pharmacological attributes such as antioxidant, hypoglycemic, anti-inflammatory, antihyperlipidemic, anticancer, antimicrobial, and hepatoprotective activities of this species have been established by previous studies. A. sativum houses many sulfur-containing phytochemical compounds such as allicin, diallyl disulfide (DADS), vinyldithiins, ajoenes (E-ajoene, Z-ajoene), diallyl trisulfide (DATS), micronutrient selenium (Se) etc. Organosulfur compounds are correlated with modulations in its antioxidant properties. The garlic compounds have also been recorded as promising immune-boosters or act as potent immunostimulants. A. sativum helps to treat cardiovascular ailments, neoplastic growth, rheumatism, diabetes, intestinal worms, flatulence, colic, dysentery, liver diseases, facial paralysis, tuberculosis, bronchitis, high blood pressure, and several other diseases. The present review aims to comprehensively enumerate the ethnobotanical and pharmacological aspects of A. sativum with notes on its phytochemistry, ethnopharmacology, toxicological aspects, and clinical studies from the retrieved literature from the last decade with notes on recent breakthroughs and bottlenecks. Future directions related to garlic research is also discussed.

Roles and mechanisms of garlic and its extracts on atherosclerosis: A review

The prevention and treatment of cardiovascular diseases (CVDs) have achieved initial results, but the number of CVDs patients will increase rapidly in the next 10 years. Atherosclerosis (AS) is a significant risk factor for CVDs. The impact of lifestyle and daily diet varies considerably between different countries and continents and has been shown to affect the development of various diseases such as diabetes and CVDs. Primary and secondary prevention using alternative supplements and methods to avoid or reduce the use of traditional pharmacological drugs have also become popular. One of the reasons for this is that pharmacological drugs with lipid-lowering, and blood pressure-lowering effects cause many side effects that may negatively impact the quality of life. Patients are now emphasizing reliance on lifestyle changes to reduce cardiovascular risks. Garlic is a medicinal and edible plant that has been used for a long time. In order to reveal garlic application in the prevention and treatment of AS, reviewing the latest domestic and international studies through searching databases. The result shows that the antiatherogenic role of garlic is eximious. And the mechanisms are mainly related to hypolipidemic, antioxidant, antithrombotic, inhibiting angiogenesis, protecting endothelial cells, anti-inflammatory, anti-apoptotic, inhibiting vascular smooth muscle proliferation, and regulating gut microbiota. The main signaling pathways involve AMPK/TLRs, Keap1/Nrf2, PI3K/AKT, PPARγ/LXRα, GEF-H1/RhoA/Rac, etc. The antiatherogenic actions and molecular mechanism of garlic were reviewed in this study to obtain a robust evidence basis for the clinical application and mechanistic study and provide a theoretical basis for further utilization of garlic.

From laboratory to industrial storage - Translating volatile organic compounds into markers for assessing garlic storage quality

Garlic (Allium sativum L.) has long been grown for its culinary and health-promoting qualities. The seasonal nature of garlic cropping requires that bulbs be stored for many months after harvest to ensure a year-round supply. During this time, quality is known to deteriorate, and efforts have been made to improve the longevity of stored bulbs. Cold temperatures within the stores prolong shelf life, but fine temperature control is needed to avoid freezing damage or cold induced stress. Here, quality traits (alliinase activity, firmness, and water content) are measured in response to a 96 h - 5 °C cold stress, to simulate the effect of non-isothermic temperature control in a - 1.5 °C warehouse. Volatile organic compounds (VOCs) are measured by thermal desorption gas chromatography time of flight mass spectrometry to identify markers of non-isothermic storage in garlic. 129 compounds were putatively identified and four (L-lactic acid, 2,6-dimethylhetpadecane, 4-methyldodecane, and methylcyclopentane) showed high predictive accuracy for cold stress. VOCs were also sampled directly from a cold storage facility and the whole profile discriminated between sampling time points. Five VOCS were highly predictive for storage time in the warehouse but were different to VOCs previously shown to discriminate between storage times in a laboratory setting. This indicates the need for realistic warehouse experiments to test quality markers.

Oxidative Stress in Plasma from Patients with Marfan Syndrome Is Modulated by Deodorized Garlic Preliminary Findings

Marfan syndrome (MFS) is a genetic disorder of connective tissue that affects the fibrillin-1 protein (FBN-1). It is associated with the formation of aneurysms, damage to the endothelium and oxidative stress (OS). Allium sativum (garlic) has antioxidant properties; therefore, the goal of this study was to show the antioxidant effect of deodorized garlic (DG) on antioxidant enzymes and OS markers in the plasma of patients with MFS. The activity of antioxidant enzymes such as extracellular superoxide dismutase (EcSOD), peroxidases, glutathione peroxidase (GPx), gluthatione-S-tranferase (GST), and thioredoxin reductase (TrxR) was quantified, and nonenzymatic antioxidant system markers including lipid peroxidation (LPO), carbonylation, nitrates/nitrites, GSH, and vitamin C in plasma were determined in patients with MFS before and after treatment with DG. The results show that DG increased the activity of the EcSOD, peroxidases, GPx, GST, TrxR (p ≤ 0.05) and decrease LPO, carbonylation, and nitrates/nitrites (p ≤ 0.01). However, glutathione was increased (p = 0.01) in plasma from patients with MFS. This suggests that treatment with garlic could lower the OS threshold by increasing the activity of antioxidant enzymes and could help in the prevention and mitigation of adverse OS in patients with MFS.

Biological Functions of Diallyl Disulfide, a Garlic-Derived Natural Organic Sulfur Compound

Garlic is widely accepted as a functional food and an excellent source of pharmacologically active ingredients. Diallyl disulfide (DADS), a major bioactive component of garlic, has several beneficial biological functions, including anti-inflammatory, antioxidant, antimicrobial, cardiovascular protective, neuroprotective, and anticancer activities. This review systematically evaluated the biological functions of DADS and discussed the underlying molecular mechanisms of these functions. We hope that this review provides guidance and insight into the current literature and enables future research and the development of DADS for intervention and treatment of multiple diseases.

Effect of Genistein Intake on Some Cardiovascular Risk Factors: An Updated Systematic Review and Meta-analysis

Genistein, an isoflavone in soybean products has potential cardio-protective effects and is used also as an alternative for estrogen therapy in postmenopausal women. However, results in this regard are inconsistent and also, not all risk factors related to cardiovascular supportive effects have been meta-analyzed. We searched PubMed, Scopus, ISI Web of Science, and Google Scholar from inception up to October 2020. Random-effects meta-analysis was used for data synthesis. The search included studies with information on genistein supplementation and lipid profile [triglycerides (TG), total cholesterol (TC),low-density lipoprotein (LDL-C), and high-density lipoprotein HDL-C)], systolic and diastolic blood pressure (SBP & DBP), body mass index [BMI] and body weight. Pooled results of studies showed that genistein intake significantly reduced TC [95%CI: -0.49(-0.80, -0.18); P=0.002)], LDL-C [95%CI: -0.60(-1.10, -0.10); P=0.018)] and SBP [95%CI: -0.52(-0.90, -0.14); P=0.007)]. DBP, HLD-C, TG, BMI, and body weight showed no meaningful improvement. Subgroup analysis showed that LDL-C and SBP were reduced more effectively in postmenopausal women with metabolic syndrome. Genistein intake more than 6 months showed a greater effect on lowering cholesterol -0.76(-1.27, -0.24), SBP [-0.39(-0.70, -0.08)] and DBP -0.40(-0.81, -0.00) and increasing TG and LDL-C. This meta-analysis provides consistent evidence that genistein intake reduces the CVD risk factors of TC, LDL-C, and SBP significantly.

Therapeutic effects of garlic in cardiovascular atherosclerotic disease

Garlic (Allium sativum) is a widely known medicinal plant, potential of which remains to be fully evaluated. Its wide-range beneficial effects appear to be relevant for treatment and prevention of atherosclerosis and related diseases. It is generally believed that garlic-based preparations are able to improve lipid profile in humans, inhibit cholesterol biosynthesis, suppress low density lipoprotein oxidation, modulate blood pressure, suppress platelet aggregation, lower plasma fibrinogen level and increase fibrinolytic activity, thus providing clinically relevant cardioprotective and anti-atherosclerotic effects. It is important to assess the level of evidence available for different protective effects of garlic and to understand the underlying mechanisms. This information will allow adequate integration of garlic-based preparations to clinical practice. In this review, we discuss the mechanisms of anti-atherosclerotic effects of garlic preparations, focusing on antihyperlipidemic, hypotensive, anti-platelet and direct anti-atherosclerotic activities of the medicinal plant. We also provide an overview of available meta-analyses and a number of clinical trials that assess the beneficial effects of garlic.

The Possible Role of the Nitroso-Sulfide Signaling Pathway in the Vasomotoric Effect of Garlic Juice

The beneficial cardiovascular effects of garlic have been reported in numerous studies. The major bioactive properties of garlic are related to organic sulfides. This study aimed to investigate whether garlic juice works exclusively due to its sulfur compounds or rather via the formation of new products of the nitroso-sulfide signaling pathway. Changes in isometric tension were measured on the precontracted aortic rings of adult normotensive Wistar rats. We evaluated NO-donor (S-nitrosoglutathione, GSNO)-induced vasorelaxation and compare it with effects of hydrogen sulfide (H₂S)/GSNO and garlic/GSNO. Incubation with garlic juice increased the maximal GSNO-induced relaxation and markedly changed the character of the relaxant response. Although incubation with an H₂S donor enhanced the maximal vasorelaxant response of GSNO, neither the absolute nor the relative relaxation changed over time. The mixture of GSNO with an H₂S donor evoked a response similar to GSNO-induced relaxation after incubation with garlic juice. This relaxation of the H₂S and GSNO mixture was soluble guanylyl cyclase (sGC) dependent, partially reduced by HNO scavenger and it was adenosine triphosphate-sensitive potassium channels (K_ATP) independent. In this study, we demonstrate for the first time the suggestion that H₂S itself is probably not the crucial bioactive compound of garlic juice but rather potentiates the production of new signaling molecules during the GSNO-H₂S interaction.

Therapeutic Effects of Garlic on Hepatic Steatosis in Nonalcoholic Fatty Liver Disease Patients: A Randomized Clinical Trial

BACKGROUND AND AIMS

Emerging evidence suggests that garlic (Allium sativum L.) and its bioactive components can mitigate hepatic steatosis by the modulation of hepatic lipid metabolism. We aimed to assess the efficacy of the garlic administration on hepatic steatosis in patients with NAFLD.

PATIENTS AND METHODS

This clinical trial was conducted on adult patients with ultrasound-diagnosed NAFLD. Eligible participants were randomly assigned, with the use of the stratified blocked procedure, to receive 800 mg garlic or placebo for 15 weeks. The primary outcome was the improvement in the hepatic steatosis diagnosed by ultrasound technique after 15 weeks of intervention.

RESULTS

A total of 110 patients underwent randomization, and 98 patients completed the trial. Twenty-four (51.1%) patients in the garlic group achieved improvement in the hepatic steatosis compared to eight (15.7%) patients in the placebo group with the relative risk of 5.6 (95% CI: 2.17 to 14.5; P=0.001), which remained significant after adjusting for baseline value of hepatic steatosis. There were significant reductions in weight and serum ALT, AST, FBS, Hb A1C, total cholesterol, LDL-cholesterol, and TG concentration with the garlic intake compared to placebo (P<0.05). The results were also significant after adjusting for weight change, energy intake, and physical activity. No serious adverse effects were observed with the garlic intake.

CONCLUSION

The intake of garlic powder was accompanied by a significant improvement in the hepatic steatosis and comorbidity related to this condition among subjects with NAFLD.

Allium vegetable consumption and health: An umbrella review of meta-analyses of multiple health outcomes

Previously, our meta-analysis and other studies have suggested that allium vegetable consumption is beneficial for health, but no umbrella review has been conducted to assess the evidence of the various health benefits of allium vegetable consumption. Therefore, we conducted this umbrella review on this topic. This umbrella review included a total of 16 meta-analyses with 50 unique outcomes. The most beneficial cancer-related outcome was shown for gastric cancer (risk ratio 0.78; 95% confidence interval [CI] 0.67-0.91). In addition, only 8 weeks of garlic consumption significantly decreased serum total cholesterol (weighted mean differences -17.20 mg/dl; 95% CI -23.10 to -11.30), and patients with dyslipidemia who consumed garlic experienced more benefits than the whole population. Diabetic patients with longer durations of garlic intake experienced more benefits in terms of fasting blood glucose (FBG), HbA1c, and serum fructosamine than healthy participants, and garlic intake was associated with blood pressure reduction in hypertensive patients but not in normotensive participants. Limited side effects of garlic, such as garlic odor and gastrointestinal complaints, were reported among the included meta-analyses. Our results suggested that allium vegetables might be beneficial for cancer prevention. In particular, garlic was comparatively safe and is recommended as a long-term dietary component for patients with dyslipidemia, diabetes, and hypertension.

Bioactive Compounds and Biological Functions of Garlic (Allium sativum L.)

Garlic (Allium sativum L.) is a widely consumed spice in the world. Garlic contains diverse bioactive compounds, such as allicin, alliin, diallyl sulfide, diallyl disulfide, diallyl trisulfide, ajoene, and S-allyl-cysteine. Substantial studies have shown that garlic and its bioactive constituents exhibit antioxidant, anti-inflammatory, antibacterial, antifungal, immunomodulatory, cardiovascular protective, anticancer, hepatoprotective, digestive system protective, anti-diabetic, anti-obesity, neuroprotective, and renal protective properties. In this review, the main bioactive compounds and important biological functions of garlic are summarized, highlighting and discussing the relevant mechanisms of actions. Overall, garlic is an excellent natural source of bioactive sulfur-containing compounds and has promising applications in the development of functional foods or nutraceuticals for the prevention and management of certain diseases.

Bioactive Compounds and Biological Functions of Garlic (Allium sativum L.)

Garlic (Allium sativum L.) is a widely consumed spice in the world. Garlic contains diverse bioactive compounds, such as allicin, alliin, diallyl sulfide, diallyl disulfide, diallyl trisulfide, ajoene, and S-allyl-cysteine. Substantial studies have shown that garlic and its bioactive constituents exhibit antioxidant, anti-inflammatory, antibacterial, antifungal, immunomodulatory, cardiovascular protective, anticancer, hepatoprotective, digestive system protective, anti-diabetic, anti-obesity, neuroprotective, and renal protective properties. In this review, the main bioactive compounds and important biological functions of garlic are summarized, highlighting and discussing the relevant mechanisms of actions. Overall, garlic is an excellent natural source of bioactive sulfur-containing compounds and has promising applications in the development of functional foods or nutraceuticals for the prevention and management of certain diseases.

Immunomodulatory Effects of Glutathione, Garlic Derivatives, and Hydrogen Sulfide

Glutathione and aged garlic extract are sulfur-containing products that play important protective and regulatory roles within the immune system and in oxidative processes. Hydrogen sulfide (H₂S), an endogenous, gaseous, signaling transmitter, has also been shown to be involved in the regulation of inflammation. Recent studies have shown that sulfur-containing compounds from garlic have beneficial effects in attenuating outcomes associated with cardiovascular disease and inflammation by a mechanism that may be related to the H₂S signaling pathway. In this review, we summarize the main functions of glutathione (GSH), garlic derivatives and H₂S and their role in the immune response and impact on health and disease.

Biomarkers of food intake for Allium vegetables

Allium vegetables are widely consumed around the world and are known for their potential bioactive components improving human health. These effects have been extensively investigated; however, the results were inconsistent in human studies. Biomarkers of food intake (BFIs) could provide objective measurements of food intake in observational studies and assess compliance in intervention studies. Therefore, the discovery and application of BFIs for Allium vegetables would facilitate the exploring and understanding of the health benefit of Allium vegetables. In this manuscript, we reviewed the currently used and potential candidate BFIs for Allium vegetables and evaluated their levels of validation. S-Allylmercapturic acid (ALMA), allyl methyl sulfide (AMS), allyl methyl sulfoxide (AMSO), allyl methyl sulfone (AMSO2), and S-allylcysteine (SAC), which are derived from organosulfur compounds, were shown to be promising candidate BFIs for garlic consumption. Further validation is needed to assess their robustness and concordance with other measures. Their applicability for the whole food group should be evaluated as well. N-Acetyl-S-(2-carboxypropyl)cysteine (CPMA) was detected in high levels in urine after both garlic and onion intake, suggesting that it may be used for the assessment of intake of Allium food group. The available information regarding its kinetics, robustness, and analytical performance is limited and needs to be assessed in further studies. No candidate BFIs specific to intake of onion, leek, chives, shallots, or ramsons were found. Untargeted metabolomics studies and further validation studies should be performed to discover more reliable BFIs for individual Allium vegetables and the whole food group. This paper serves as an example of Biomarker of Food Intake Reviews (BFIRev) and biomarker of food intake validation procedures.

Roles of Spicy Foods and Their Bioactive Compounds in Management of Hypercholesterolemia

Hypercholesterolemia, as one of the major risk factors in development of cardiovascular diseases, is of mounting prevalence worldwide in recent years. Many nutraceuticals and phytochemical supplements serve as a promising complementary therapy in the management of hypercholesterolemia. Among them, spicy foods have attracted special attention. Plasma lipid-lowering activity of garlic, ginger, and turmeric have been well-studied in both humans and animals. Consumption of either 3 g/day of ginger or 2 g/day of curcumin for over 4 weeks effectively reduced blood cholesterol in hypercholesterolemia subjects. However, effects of chili and black peppers on blood cholesterol are studied little clinically. The present review is to summarize the findings of recent studies on the efficacy and mechanism of spicy foods and their primary bioactive components in management of hypercholesterolemia from preclinical studies to clinical trials.

Allicin Bioavailability and Bioequivalence from Garlic Supplements and Garlic Foods

Allicin is considered responsible for most of the pharmacological activity of crushed raw garlic cloves. However, when garlic supplements and garlic foods are consumed, allicin bioavailability or bioequivalence (ABB) has been unknown and in question because allicin formation from alliin and garlic alliinase usually occurs after consumption, under enzyme-inhibiting gastrointestinal conditions. The ABB from 13 garlic supplements and 9 garlic foods was determined by bioassay for 13 subjects by comparing the area under the 32-h concentration curve of breath allyl methyl sulfide (AMS), the main breath metabolite of allicin, to the area found after consuming a control (100% ABB) of known allicin content: homogenized raw garlic. For enteric tablets, ABB varied from 36–104%, but it was reduced to 22–57% when consumed with a high-protein meal, due to slower gastric emptying. Independent of meal type, non-enteric tablets gave high ABB (80–111%), while garlic powder capsules gave 26–109%. Kwai garlic powder tablets, which have been used in a large number of clinical trials, gave 80% ABB, validating it as representing raw garlic in those trials. ABB did not vary with alliinase activity, indicating that only a minimum level of activity is required. Enteric tablets (high-protein meal) disintegrated slower in women than men. The ABB of supplements was compared to that predicted in vitro by the dissolution test in the United States Pharmacopeia (USP); only partial agreement was found. Cooked or acidified garlic foods, which have no alliinase activity, gave higher ABB than expected: boiled (16%), roasted (30%), pickled (19%), and acid-minced (66%). Black garlic gave 5%. The mechanism for the higher than expected ABB for alliinase-inhibited garlic was explored; the results for an alliin-free/allicin-free extract indicate a partial role for the enhanced metabolism of γ-glutamyl S-allylcysteine and S-allylcysteine to AMS. In conclusion, these largely unexpected results (lower ABB for enteric tablets and higher ABB for all other products) provide guidelines for the qualities of garlic products to be used in future clinical trials and new standards for manufacturers of garlic powder supplements. They also give the consumer an awareness of how garlic foods might compare to the garlic powder supplements used to establish any allicin-related health benefit of garlic.

Functional foods and dietary supplements for the management of dyslipidaemia

Dyslipidaemia is characterized by increased blood levels of total or LDL cholesterol and triglycerides, or decreased HDL cholesterol levels, and is a risk factor for cardiovascular disease. Dyslipidaemia has a high worldwide prevalence, and many patients are turning to alternatives to pharmacotherapy to manage their lipid levels. Lifestyle modification should be emphasized in all patients to reduce cardiovascular risk and can be initiated before pharmacotherapy in primary prevention of cardiovascular disease. Many functional foods and natural health products have been investigated for potential lipid-lowering properties. Those with good evidence for a biochemical effect on plasma lipid levels include soy protein, green tea, plant sterols, probiotic yogurt, marine-derived omega-3 fatty acids and red yeast rice. Other products such as seaweed, berberine, hawthorn and garlic might confer some limited benefit in certain patient groups. Although none of these products can reduce lipid levels to the same extent as statins, most are safe to use in addition to other lifestyle modifications and pharmacotherapy. Natural health products marketed at individuals with dyslipidaemia, such as policosanol, guggulsterone and resveratrol, have minimal definitive evidence of a biochemical benefit. Additional research is required in this field, which should include large, high-quality randomized controlled trials with long follow-up periods to investigate associations with cardiovascular end points.

Food and Cardiac Health

Emerging influence of Cardiovascular Diseases (CVDs) and its impact on the society has raised much awareness for its prevention. Healthy food habits and physical exercise has drawn a lot of attention of the people from scientific as well as common world. The role of food-based bioactive compounds in reducing risk of CVDs has been established with various health benefits apart from the basic nutrition have been reported. The present chapter provides an overview of the role of different foods on cardiovascular health of humans. Biological effects of plant derived food products and their bioactive compounds in the context of relevance to cardiovascular health promotion are discussed in detail. The chapter also covers the effects of the consumption of functional food on the intermediate clinical markers of CVDs including cholesterolemia, hypertension, endothelial function and inflammation. The chapter will enable the better understanding of the current knowledge on the potential health benefits of different functional foods and bioactive compounds on cardiovascular health.

An umbrella review of garlic intake and risk of cardiovascular disease

PURPOSE

To gain further insight into the strength of evidence and extent of possible biases in the scope of studies investigating the impact of garlic and garlic supplement intake on biomarkers of cardiovascular disease, we performed an umbrella review of all published meta-analyses synthesizing data from both observational studies and randomized controlled trials.

METHODS

Electronic database PubMed (between 1966 and June 2015) was searched for systematic reviews and meta-analyses using following search terms: ("garlic" OR "allium sativum" OR "allicin" OR "organosulfur") AND ("cardiovascular" OR "coronary" OR "cholesterol" OR "triglyceride" OR "atherosclerosis" OR "blood pressure" OR "hypertension" OR "blood glucose") AND ("systematic review" OR "meta-analysis"), with no restriction to calendar data and language. Hand-search of reference lists and relevant clinical guidelines was performed as well.

RESULTS

Nine systematic reviews investigated the effects of garlic on lipid parameters and eight systematic reviews analyzed the effects on blood pressure parameters were identified. Eight of nine meta-analyses synthesizing the effect of garlic on blood lipids reported significantly decreased total cholesterol levels. Inconsistent results could be detected for HDL-cholestrol, LDL-cholesterol, and triacylglycerols. The effect of garlic on systolic blood pressure showed consistent results across publications with 7 out of 8 meta-analyses demonstrating a substantial decrease in systolic blood pressure. Similar results could be reported regarding the effect of garlic on diastolic blood pressure, i.e. 6 out of 8 meta-analyses detected significant reductions in diastolic blood pressure levels following interventions with garlic.

CONCLUSION

According to the data summarized in the present umbrella review, garlic preparations as well as garlic exerted some positive effects on indicators and biomarkers of cardiovascular disease, typically without causing any serious side effects. However, with regard to the substantial heterogeneities between the different trials enrolled in the various meta-analyses of this review, a conservative interpretation of the outcome seems to be appropriate.

Potential of Food and Natural Products to Promote Endothelial and Vascular Health

Endothelial dysfunction is now well established as a pivotal early event in the development of major cardiovascular diseases including hypertension, atherosclerosis, and diabetes. The alteration of the endothelial function is often triggered by an imbalance between the endothelial formation of vasoprotective factors including nitric oxide (NO) and endothelium-dependent hyperpolarization, and an increased level of oxidative stress involving several prooxidant enzymes such as NADPH oxidase and, often also, the appearance of cyclooxygenase-derived vasoconstrictors. Preclinical studies have indicated that polyphenol-rich food and food-derived products such as grape-derived products, black and red berries, green and black teas and cocoa, and omega-3 fatty acids can trigger activating pathways in endothelial cells promoting an increased formation of nitric oxide and endothelium-dependent hyperpolarization. Moreover, intake of such food-derived products has been associated with the prevention and/or the improvement of an established endothelial dysfunction in several experimental models of cardiovascular diseases and in humans with cardiovascular diseases. This review will discuss both experimental and clinical evidences indicating that different types of food and natural products are able to promote endothelial and vascular health, as well as the underlying mechanisms.

Natural Products to Counteract the Epidemic of Cardiovascular and Metabolic Disorders

Natural products have always been exploited to promote health and served as a valuable source for the discovery of new drugs. In this review, the great potential of natural compounds and medicinal plants for the treatment or prevention of cardiovascular and metabolic disorders, global health problems with rising prevalence, is addressed. Special emphasis is laid on natural products for which efficacy and safety have already been proven and which are in clinical trials, as well as on plants used in traditional medicine. Potential benefits from certain dietary habits and dietary constituents, as well as common molecular targets of natural products, are also briefly discussed. A glimpse at the history of statins and biguanides, two prominent representatives of natural products (or their derivatives) in the fight against metabolic disease, is also included. The present review aims to serve as an "opening" of this special issue of Molecules, presenting key historical developments, recent advances, and future perspectives outlining the potential of natural products for prevention or therapy of cardiovascular and metabolic disease.

Quantitative ethnomedicinal survey of medicinal plants given for cardiometabolic diseases by the non-institutionally trained siddha practitioners of Tiruvallur district, Tamil Nadu, India

ETHNOBOTANICAL RELEVANCE

The burden of cardiometabolic diseases such as dyslipidemia, hyperglycemia, hypertension, visceral obesity and atherosclerotic cardiovascular diseases and the use of traditional medicine for the management of such diseases are high in India; hence there is a need to document and analyze such therapies.

AIM OF THE STUDY

This study documented and analyzed the medicinal plants prescribed for cardiometabolic diseases by the non-institutionally trained siddha practitioners of Tiruvallur district of Tamil Nadu, India.

METHODOLOGY

The field survey was conducted between December 2014 to November 2015. Successive free listing assisted with field-walks was used to interview the informants. After assessing the sampling sufficiency using rarefaction curve analysis, indices such as Informant Consensus Factor (Fic) and Index of Agreement on Remedies (IAR) were calculated for the data. The indicators of informant's medicinal plant knowledge such as Shannon's index, equitability index, etc., were regressed with the demographic profile of the informants.

RESULTS

For this study 70 non-institutionally trained Siddha medical practitioners were approached; the data from 36 practitioners who were treating cardiometabolic diseases were documented. This study recorded the use of 188 species which were used to prepare 368 formulations to treat illnesses categorized under cardiometabolic diseases. In this, 53.04% claims were singletons. Regression analysis showed that single species dominance was reduced and the diversity of medicinal plants was increased with the increase in the age and experience. Increase in the years of formal education increased the equitability in the uses. The plants such as Nelumbo nucifera Gaertn. (cardiovascular diseases), Allium sativum L. (dyslipidemia), Cuminum cyminum L. (hypertension), Macrotyloma uniflorum Verdc. (obesity) and Azadirachta indica A. Juss. (type 2 diabetes) were the highly cited medicinal plants.

CONCLUSION

This survey has identified the plants most commonly used by Siddha practitioners of Tiruvallur district, Tamil Nadu, India for cardiometabolic diseases. The prevalence of chronic, non-communicable metabolic illnesses such as type 2 diabetes, hypertension and obesity are increasing worldwide due to the rapid changes in the lifestyle. These ailments require a life-long care and in such instances, people tend to use complementary therapies in most cases, alongside with conventional therapies. In view of the high use of traditional therapies for treating cardiometabolic illnesses, this study supports the need for more research to evaluate the potential benefits of the treatments and to identify any safety concern.

An exploration of the antioxidant effects of garlic saponins in mouse-derived C2C12 myoblasts

In this study, we aimed to confirm the protective effects of garlic saponins against oxidative stress-induced cellular damage and to further elucidate the underlying mechanisms in mouse-derived C2C12 myoblasts. Relative cell viability was determined by 3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide assay. Comet assay was used to measure DNA damage and oxidative stress was determined using 2',7'-dichlorofluorescein diacetate to measure intracellular reactive oxygen species (ROS) generation. Western blot analysis and small interfering RNA (siRNA)-based knockdown were used in order to investigate the possible molecular mechanisms. Our results revealed that garlic saponins prevented hydrogen peroxide (H2O2)-induced growth inhibition and exhibited scavenging activity against intracellular ROS. We also observed that garlic saponins prevented H2O2-induced comet tail formation and decreased the phosphorylation levels of γH2AX expression, suggesting that they can prevent H2O2-induced DNA damage. In addition, garlic saponins increased the levels of heme oxygenase-1 (HO-1), a potent antioxidant enzyme associated with the induction and phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the translocation of Nrf2 from the cytosol into the nucleus. However, the protective effects of garlic saponins on H2O2-induced ROS generation and growth inhibition were significantly reduced by zinc protoporphyrin Ⅸ, an HO-1 competitive inhibitor. In addition, the potential of garlic saponins to mediate HO-1 induction and protect against H2O2‑mediated growth inhibition was adversely affected by transient transfection with Nrf2-specific siRNA. Garlic saponins activated extracellular signal‑regulated kinase (ERK) signaling, whereas a specific ERK inhibitor was able to inhibit HO-1 upregulation, as well as Nrf2 induction and phosphorylation. Taken together, the findings of our study suggest that garlic saponins activate the Nrf2/HO-1 pathway by enabling ERK to contribute to the induction of phase Ⅱ antioxidant and detoxifying enzymes, including HO-1 in C2C12 cells.