Garlic (Allium sativum) has been used for centuries as both a delicious culinary herb and a powerful medicinal plant.
Modern research has found significant evidence that garlic may help you if you’re dealing with metabolic disorders like type 2 diabetes (T2DM).
T2DM is a common condition that happens when your body doesn’t produce enough insulin or can’t use it effectively. This typically leads to high blood glucose levels in your body.
This article outlines the scientific literature on garlic’s effect on diabetes. Read on to find out how Garlic may affect Diabetes and Blood Sugar.
Table of Contents
Garlic and Blood Sugar Control
Research suggests that garlic may help regulate your blood sugar levels in several ways.
Impact on Fasting Blood Glucose
Numerous studies suggest that adding garlic to your daily routine can reduce fasting blood glucose (FBG).
A large meta-analysis of nine randomized controlled trials found that garlic supplementation reduced FBG levels among those with T2DM. These studies ranged from one week to 24 weeks (1).
Another meta-analysis found that individuals consuming garlic had significantly lower FBG than those who did not (2).
Just four weeks of consuming raw crushed garlic in one study led to a significant reduction in FBG for people with metabolic syndrome (3).
Time-released garlic tablets sold over the counter have also been found to improve metabolic control. Lower levels of FBG were found in T2DM patients, according to a double-blinded, placebo-controlled study (4).
Impact on HbA1c and Other Markers
HbA1c (glycated hemoglobin) is a measure of your average blood sugar levels over the past 2-3 months. It’s one of the most important markers healthcare providers use to track how well your diabetes is controlled over time.
A systematic review and meta-analysis found that garlic significantly lowered both FBG and HbA1c in T2DM (5).
Can Garlic Improve Insulin Resistance?
Insulin resistance is one of the main contributors to Type 2 Diabetes.
One clinical trial of consuming aged garlic extract in T2DM patients with high cardiovascular risk did not show significant improvements in insulin resistance (6). Other studies, however, do offer more promise.
A randomized clinical trial on metabolic syndrome patients concluded that garlic may reduce fasting insulin and improve insulin resistance (7).
Animal studies support these findings as well. Garlic significantly reduced fasting blood glucose and fasting insulin in diet-induced nonalcoholic fatty liver disease (NAFLD) models, indicating that garlic may help with glycemic control (8).
Does Garlic Work Well with Diabetes Medications?
Several studies investigate whether garlic supplementation can enhance the effectiveness of common diabetes drugs like metformin.
In a 24-week study, participants who consumed both garlic supplements and metformin experienced a greater reduction in fasting blood sugar compared to those taking metformin only (9).
Similarly, another clinical trial found that time-released garlic powder tablets may be effective for patients on a diet or those on sulfonylurea drugs. This combination shows improvement in blood sugar, fructosamine, and triglyceride levels (4).
How Can Garlic Help Protect Your Heart?
If you have diabetes, you’re at higher risk for heart disease. Enhancing cholesterol and other lipid markers can be very beneficial for your overall health.
Reviews and trials report a decrease in total cholesterol, lower low-density lipoprotein cholesterol (LDL-C) and triglycerides, and increase high-density lipoprotein cholesterol (HDL-C) with garlic consumption (1, 5).
A randomized controlled trial studied women with polycystic ovary syndrome (PCOS), which is a condition that sometimes involves insulin resistance. The study found that consuming garlic significantly reduced total cholesterol and LDL-C (10) in women with PCOS.
Researchers have also studied garlic’s effects on non-alcoholic fatty liver disease (NAFLD), a condition that increases your risk of developing diabetes.
Animal studies involving diet-induced NAFLD also support garlic’s ability to reduce harmful blood fats while increasing healthier HDL (8).
How Does Garlic Work in the Body?
The positive impact of garlic on high blood sugar and abnormal cholesterol may be attributed to its antioxidant and anti-inflammatory activities (11, 12).
By increasing antioxidants in your body, garlic may help protect insulin-producing cells in the pancreas.
Some garlic compounds are also believed to stimulate more insulin release and/or decrease sugar production in the liver (10, 8).
Limitations and Contradictory Evidence
While most research results are encouraging, not all studies are consistent.
Various forms of garlic along with differing dosages and study durations make direct comparisons challenging (13).
Some studies also include a small number of participants, which may reduce the power to detect meaningful differences (4).
Moreover, studies have found more moderate effects in other areas than on blood sugar and insulin.
For instance, one investigation examined “Garlicin injectio” for unstable angina (also known as chest pain). The study noted greater improvements in cardiac-related symptoms than in blood sugar levels (14).
Potential Side Effects of Taking Garlic
Garlic is generally considered safe when consumed in regular food amounts.
However, at higher doses, it can pose risks for some individuals. Gastrointestinal discomfort, such as heartburn or indigestion, is sometimes reported (1).
Garlic may increase bleeding risk when taken with blood-thinning medications (15).
If you’re already taking anti-diabetic drugs, be aware of the possibility of hypoglycemia (low blood sugar) when adding high-dose garlic supplements on top of your standard medications (9).
Garlic has also been studied for other health issues, such as preventing pre-eclampsia in pregnancy, but the research for that use remains limited (16).
Conclusion
Numerous studies suggest that garlic may help you regulate blood sugar, enhance insulin function, and promote healthier cholesterol and triglyceride levels if you have T2DM.
These potential benefits, such as reductions in fasting blood glucose, HbA1c, and improved lipid profiles, appear repeatedly in the scientific literature.
However, some findings conflict due to variations in garlic preparations, dosages, study durations, and participant characteristics.
Garlic is typically safe for most people. However, it’s recommended that you consult a healthcare professional before starting a garlic supplement, particularly if you’re taking blood-thinning or diabetes medications.
Larger-scale studies with standardized garlic preparations are still needed to determine the best forms and doses for long-term diabetes management.