Garlic is well known for its ability to boost immune function, reduce blood pressure and protect against heart disease. But what about garlic oil pills, garlic extract and other dietary supplements? Depending on the ingredients used, these products can have their place in a balanced diet.
Crushing or chopping fresh garlic promotes the release of alliinase, according to the Linus Pauling Institute. This enzyme helps convert alliin into allicin, a sulfur compound with potential health benefits. Garlic oil pills are made from crushed garlic, offering large doses of allicin.
Garlic supplements, including garlic oil pills, are touted as a cure-all. However, their potential benefits are subject to debate. The compounds in garlic pills may differ in composition and dosage from those in fresh garlic. Their safety and efficacy depend on the processing method used.
Is Garlic Really That Healthy?
This spice has been used as food and medicine for centuries. Modern science confirms its antioxidant, anti-cancer, anti-inflammatory and cholesterol-lowering properties.
For example, a December 2014 review published in the journal Integrated Blood Pressure Control suggests that garlic might be just as effective as conventional antihypertensive drugs. Researchers believe that it contains certain compounds that widen the blood vessels and help reduce blood pressure.
Garlic is also prized for its role in the prevention of heart disease, high blood sugar and even cancer. A review featured in the A_vicenna Journal of Phytomedicine_ (AJP) in the January-February 2014 issue analyzed these claims.
As the scientists note, garlic exhibits antimicrobial, antihypertensive and antioxidant effects. Animal and human studies suggest that it may lower cholesterol levels, reduce plaque buildup in the arteries and inhibit platelet aggregation, leading to improved cardiovascular health.
Read more: 9 Foods That Do Not Raise Cholesterol
This spice may suppress tumor growth and stop cancer cells from spreading, as noted in the above review. These effects are attributed to its high levels of sulfur compounds, especially allyl sulfide derivatives. Furthermore, garlic may have hypoglycemic properties, although it's unclear how it affects human blood sugar levels.
Allicin, an organosulfur compound in this spice, fights disease-causing bacteria. In some studies, garlic has been proven effective against Candida albicans, Trypanosomes, giardia and other pathogens.
The problem is that most studies are small, inaccurate or vague, as the researchers point out. Some have been conducted on mice and other rodents, so it's hard to say how they apply to humans. Its long-term safety requires further investigation, as well.
The National Center for Complementary and Integrative Health states that garlic is recognized as a potential anticancer agent. However, medical professionals don't recommend using garlic supplements to prevent this disease. Additionally, its antihypertensive and cholesterol-lowering effects are questionable.
Garlic Oil Uses and Benefits
Garlic supplements are widely available in health stores, pharmacies and online. Some are made with aged garlic extract, while others contain garlic oil. Manufacturers prepare garlic oil using steam distillation, according to the Linus Pauling Institute. The primary ingredient is crushed garlic.
Read more: 10 Incredible Garlic Hacks
Steam distillation results in a product that is rich in diallyl sulfide, diallyl trisulfide, allyl methyl disulfide and other allyl sulfides. These organosulfur compounds are dissolved in vegetable oil and sold in capsule form. Studies cited in the Avicenna Journal of Phytomedicine review state that S-allyl cysteine, allicin and other substances in garlic oil are responsible for its anti-atherosclerotic action.
Allicin, one of the primary compounds in this spice, has been subject to extensive research. However, most clinical trials are inconclusive.
For example, a June 2016 review published in Trends in Food Science & Technology assessed the antifungal and antibacterial properties of allicin. Current evidence shows promising results, as the scientists note. Most studies have been conducted in vitro, though, so it's hard to say whether or not their findings are relevant to humans. "In vitro" means a lab-controlled environment, such as a test tube or plastic vessel.
The journal BioMedicine reviewed the health benefits of garlic in January 2012. Researchers found that garlic oil reduced both systolic and diastolic blood pressure in hypertensive subjects. The study was small, so its results require further investigation.
Other similar studies cited in the above review suggest that garlic may lower total cholesterol and LDL (the "bad") cholesterol, improve endothelial function and protect against diabetes. Furthermore, this spice is high in antioxidants that may help reduce oxidative stress, a major risk factor for age-related diseases, inflammation, atherosclerosis, diabetes and premature aging.
Are Garlic Oil Pills Safe?
Garlic oil pills are unlikely to cure diseases or replace conventional drugs. However, they can make it easier to manage your blood pressure and blood sugar levels, as reported in the above reviews. Plus, garlic is a good source of antioxidants, which may help in disease prevention.
According to the Center for Science in the Public Interest, garlic supplements might not be as effective as once thought. The compounds in garlic oil, garlic powder and other similar products may differ in composition or concentration from those in fresh garlic. The Linus Pauling Institute, on the other hand, states that their potential benefits and nutritional value depends on the processing method used.
Garlic supplements may increase the risk of bleeding and should not be used by those taking blood thinners or preparing for surgery.
Beware that any of these products may cause adverse reactions. Vomiting and nausea, bad breath, body odor, stomach pain, diarrhea and gas are all common symptoms, reports the Linus Pauling Institute. Garlic supplements may lead to uncontrolled bleeding, so they might not be safe for those who take blood thinners.
Little is known about the long-term safety of garlic oil pills and garlic extract. In general, it's not recommended to take these supplements when also taking HIV drugs, vitamin E, high-dose fish oil or warfarin and other anticoagulants. Consult your doctor before popping pills. This applies to any dietary supplement.
Steer clear of garlic if you're preparing for surgery. Due to its blood-thinning effects, it may increase bleeding and slow healing.
Also, be aware that garlic may cause allergic reactions ranging from mild to severe. You may experience breathing problems, indigestion, swelling, vomiting or itching, among other symptoms. Anaphylaxis, a severe reaction, can be fatal and requires emergency care.
The good news is that spice allergies account for only 2 percent of all food allergy cases, as reported by the University of Manchester. However, if you're allergic to garlic, it's recommended to avoid garlic oil pills, garlic powder and other supplements containing this spice.
- Linus Pauling Institute: "Organosulfur Compounds From Garlic"
- NCBI: "Potential of Garlic (Allium sativum) in Lowering High Blood Pressure: Mechanisms of Action and Clinical Relevance"
- Avicenna Journal of Phytomedicine: "Garlic: A Review of Potential Therapeutic Effects"
- NIH: "Garlic"
- Trends in Food Science & Technology: "Antifungal and Antibacterial Activities of Allicin: A Review"
- National Cancer Institute: "In Vitro"
- BioMedicine: "Garlic: Health Benefits and Actions"
- NCBI: "Oxidative Stress, Aging, and Diseases"
- CSPI: "The Truth About Your Garlic Supplement"
- University of Manchester: "Allergy Information For: Garlic (Allium sativum)"