Garlic (Allium sativum) and Blood sugar / diabetes support: evidence and sources

Type 2 diabetes mellitus (T2DM) is a metabolic disorder marked by chronic hyperglycemia and low-grade inflammation, contributing to various complications. Natural agents with immunomodulatory and antioxidant properties have gained attention as adjunct therapies. To review the effects of Allium sativum on inflammatory pathways and metabolic alterations associated with T2DM. A narrative review was performed using PubMed/MEDLINE, EMBASE, and Scielo databases. The search included terms such as "allium sativum", "inflammation", "oxidative stress", and "diabetes mellitus". Studies in English and Spanish - ranging from clinical trials to meta-analyses - were selected based on relevance. Bioactive compounds such as allicin, S-allyl cysteine, and diallyl disulfide exhibit anti-inflammatory, antioxidant, hypoglycemic, and lipid-lowering actions. Preclinical studies show improved glucose metabolism, insulin sensitivity, and organ function. Moreover, clinical evidence supports reductions in fasting glucose, hemoglobin A1c, blood pressure, and oxidative stress, with good safety profiles. Allium sativum appears to be a promising adjuvant in T2DM management, offering metabolic and anti-inflammatory benefits. Nonetheless, further high-quality clinical trials are needed to confirm its long-term efficacy and standardize its therapeutic use.

Allium sativum (garlic) certainly is one of the oldest horticultural crops in the world and presents bioactive compounds that are related to the garlic's effects on human health. Several authors have shown beneficial effects on diabetes, hypertension, dyslipidemia, obesity, and cardiovascular diseases (CVD), which are among the most relevant causes of mortality in the world. The aim of this systematic review was to evaluate the effects of garlic in the risk factors of CVD and evaluate its economic importance. MEDLINE-PubMed, COCHRANE, EMBASE, and Google Scholar databases were searched. The included studies showed that the use of garlic can reduce blood pressure, waist circumference, body mass index, LDL-c, non-HDL-c, total cholesterol, triglycerides, and inflammatory markers. It also can increase the levels of HDL-c and can improve cardiovascular parameters such as coronary artery calcium, microcirculation, epicardial and periaortic adipose tissue, post occlusive reactive hyperemia, low attenuation plaque, carotid intima-media thickness; and carotid intima-media thickness. Due to these reasons, garlic can be considered in the prevention and treatment of CVD risk factors.

Objective(s) Garlic (Allium sativum L. family Liliaceae) is well known in Iran and its leaves, flowers, and cloves have been used in traditional medicine for a long time. Research in recent decades has shown widespread pharmacological effects of A. sativum and its organosulfur compounds especially Allicin. Studies carried out on the chemical composition of the plant show that the most important constituents of this plant are organosulfur compounds such as allicin, diallyl disulphide, S-allylcysteine, and diallyl trisulfide. Allicin represents one of the most studied among these naturally occurring compounds. In addition to A. sativum, these compounds are also present in A. hirtifolium (shallot) and have been used to treat various diseases. This article reviews the pharmacological effects and traditional uses of A. sativum, A. hirtifolium, and their active constituents to show whether or not they can be further used as potential natural sources for the development of novel drugs. Materials and methods For this purpose, the authors went through a vast number of sources and articles and all needed data was gathered. The findings were reviewed and classified on the basis of relevance to the topic and a summary of all effects were reported as tables. Conclusion Garlic and shallots are safe and rich sources of biologically active compounds with low toxicity. Further studies are needed to confirm the safety and quality of the plants to be used by clinicians as therapeutic agents.