What Are the Health Benefits of Garlic?
Since ancient times, garlic has played a central role in many cultures—both as a culinary ingredient and as a natural remedy. Traditionally used to prevent infections, strengthen the immune system, and support cardiovascular health, garlic is now widely recommended in herbal medicine.
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| What Are the Health Benefits of Garlic? |
But what do we really know about its effects? Are its benefits scientifically proven? In which forms is garlic most effective, and what precautions should be taken? This article provides a clear overview of traditional uses, scientific evidence, mechanisms of action, and safety considerations related to garlic.
Traditional Uses and Active Compounds in Garlic
Originally from Central Asia, garlic (Allium sativum) has been cultivated for over 5,000 years. In ancient civilizations, crushed garlic cloves were commonly used as a natural antiseptic.
Traditionally, garlic has been consumed to relieve:
Colds and respiratory infections
Digestive discomfort
Intestinal parasites
Applied externally, it has also been used against warts and fungal skin infections.
From a biochemical perspective, garlic contains:
Phenolic acids with antiseptic properties
Flavonoids with antioxidant effects
Alliin, a sulfur-containing amino acid
When garlic is chopped or crushed, alliin is converted into allicin, a compound that leads to the formation of sulfur compounds known for their antioxidant, anti-inflammatory, and antimicrobial properties. These compounds are believed to be largely responsible for garlic’s health effects.
Garlic Benefits Supported by Scientific Research
Garlic has been the subject of more than 2,000 clinical studies, mainly focusing on its cardiovascular, metabolic, and antimicrobial effects. Overall, results suggest moderate but meaningful benefits, which vary depending on the form used (fresh garlic, aged extract, powder).
Cardiovascular Health
Several studies show that garlic can moderately reduce:
Total cholesterol
LDL (“bad”) cholesterol
Garlic may also slightly lower blood pressure and has anticoagulant properties, which together could contribute to the prevention of cardiovascular disease.
Blood Sugar and Diabetes
A meta-analysis of seven clinical studies suggests a moderate reduction in fasting blood glucose levels. However, larger and longer-term studies are still needed to confirm these effects.
Immunity and Infections
In laboratory settings, garlic’s sulfur compounds demonstrate antimicrobial activity. However, clinical evidence supporting garlic as a preventive treatment for infections remains limited and inconclusive.
Other Uses
Claims regarding the treatment of respiratory infections, intestinal parasites, or skin conditions are mainly based on traditional use. To date, no robust clinical trials have conclusively validated these applications.
How to Use Garlic Safely and Effectively?
Dosage and Forms
Garlic can be consumed:
Raw
Cooked (less active)
As dietary supplements (powder, aged extract, oil, odorless capsules)
Cooking garlic reduces some of its active compounds. For raw garlic, recommendations vary:
The World Health Organization (WHO) suggests up to four cloves per day
Other authorities (e.g., Commission E) recommend one clove per day
To maximize allicin formation, garlic should rest for about 10 minutes after chopping or crushing before consumption.
When using supplements, dosage depends on the preparation and should follow the manufacturer’s instructions. Garlic is best taken with meals to reduce stomach irritation.
Topical use of fresh garlic or garlic oil should be approached with caution, as it may irritate the skin.
Precautions and Contraindications
Garlic is generally well tolerated when consumed in normal dietary amounts. However, caution is advised in the following situations:
Before surgery or dental procedures (due to anticoagulant effects)
When taking antihypertensive or antidiabetic medications
When using anticoagulants such as warfarin
When combined with certain medications (e.g., saquinavir, tacrolimus, thyroid or prostate treatments)
In children
During pregnancy or breastfeeding
In these cases, medical advice is strongly recommended.
White, Purple, or Black Garlic: What’s the Difference?
White garlic: Most commonly used; known for cardiovascular, digestive, and immune benefits
Purple garlic: Rich in anthocyanins; higher antioxidant potential
Black garlic: Fermented white garlic; more digestible and richer in antioxidants, often promoted for metabolic health
Conclusion
Garlic is a food whose benefits are recognized by several scientific authorities, particularly for its moderate effects on blood pressure, cholesterol levels, and blood clotting. While it should never replace medical treatment, garlic can be integrated into a global preventive health approach, provided it is used wisely and adapted to individual circumstances.
For personalized guidance, consulting a doctor or pharmacist is always recommended.
Medical Sources
Vidal – Garlic (Ail)
https://www.vidal.frMSD Manuals – Garlic
https://www.msdmanuals.com
