If the unmistakable aroma of garlic makes your mouth water, you are in good company. For centuries, garlic has been a beloved staple of many cuisines worldwide. Garlic benefits not only your taste buds, but also your overall health, as it is said to have many health benefits. Since we are prone to looking for positive qualities in the foods we love to eat, you may wonder, is garlic good for you? If so, what is garlic good for?
“Every plant-based food has health benefits,” says Michelle Dodd, RD, LD, a dietitian in Cleveland Clinic’s Section of Preventive Cardiology & Rehabilitation. “It is polyphenols, which are antioxidants, that make garlic good for you.”
Garlic Benefits
Most of garlic’s health benefits derive from allicin and diallyl disulfide, two sulfur compounds that give garlic its signature odor. Garlic also contains vitamins C and B6, manganese and trace amounts of other nutrients.
The health effects of garlic have been examined in multiple studies primarily conducted on small numbers of individuals. Due to the inherent difficulties of studying a food that is normally ingested in small amounts with other foods, many of these studies were performed with garlic supplements. However, raw, black and aged garlic, powdered garlic and garlic oil have also been investigated.
The National Center for Complimentary and Integrative Health (NCCIH), a branch of the National Institutes of Health, summarized research on garlic benefits for specific issues:
- High cholesterol: Garlic supplements may reduce levels of total cholesterol and artery-clogging low-density lipoprotein cholesterol (LDL-C) to a small extent in people who have high blood cholesterol levels.
- Elevated blood sugar: Garlic supplements may reduce blood sugar to a small extent in people with diabetes.
- High blood pressure: Limited evidence suggests that garlic supplements may modestly reduce blood pressure in people who have high blood pressure.
- Immune system support: Dietary supplements that contain garlic have been promoted as boosters for the immune system, particularly during cold and flu season. However, very little research has been done on this topic. Two studies have suggested a possible benefit, but they had a small number of participants and had weaknesses in the research.
Other potential garlic benefits not mentioned by the NCCIH include the following:
- Lead toxicity: a study of employees at a car battery plant found that garlic reduced blood levels of lead by 19% and lowered the symptoms of toxicity, including headaches and hypertension.
- Dementia: Antioxidants help protect against cognitive decline resulting from cell damage and aging. Garlic contains antioxidants. Therefore, garlic may reduce the risk of dementia or slow its progression.
- Bone health: One study suggested that garlic supplements reduced oxidative stress leading to postmenopausal osteoporosis. Another found that garlic supplements reduced knee pain in overweight women with knee osteoarthritis.
Is Garlic Good for You?
If you are looking for a natural product to treat one of the aforementioned conditions, you might consider adding garlic to your diet. However, you should not rely on it to work in place of a medication.
“Garlic has benefits, but it’s not a miracle food or a quick fix. Instead, it should be incorporated into a healthy diet and lifestyle,” Dodd says. “Frankly, you need to consume a variety of antioxidants. Brussels sprouts, kale and wheat berries may have similar effects to garlic.”
Not a Miracle Food
The problem with garlic is that its effects are not very strong, but its odor is. “You would have to consistently take super doses of garlic—meaning multiple supplements equivalent to several cloves of garlic a day—for three to six months to see any benefit,” says Dodd. “The downfall is that you will reek. The garlic smell will ooze from every pore in your body.”
And the payoff would be minimal. “We warn people that the effects are not large enough that garlic can be taken in place of an antihypertension, cholesterol-lowering or anti-diabetes medication,” says Cleveland Clinic preventive cardiologist Luke J. Laffin, MD.
Dr. Laffin and his colleagues know what they are talking about. In response to requests for natural alternatives to pharmaceuticals, they conducted a placebo-controlled clinical trial to see how garlic and five other common supplements compared with a 5-milligram dose of a cholesterol lowering statin drug (low-dose rosuvastatin). None of the natural supplements came close to lowering LDL-C as significantly as the statin did. After 28 days of continuous usage, the statin reduced LDL-C an average of 37.9%, while LDL-C actually rose 5.1% among garlic users. In other studies, garlic has been found to lower LDL-C up to 10%.
Overall, it’s not a good idea to take garlic instead of a pharmaceutical, and for individuals with high cholesterol, hypertension or diabetes, “Its effects are not significant enough to be a danger to people already taking medications for these conditions,” says Dr. Laffin.
Heed this Warning About Garlic
Garlic is generally considered safe for people who are not allergic to it. However, garlic does have one well-documented, serious, negative effect: It interferes with blood clotting.
In some studies, high-dose garlic extracts (more than 600 to 900 milligrams a day of aged garlic or 4 or 5 grams of raw garlic) significantly prolonged bleeding time and reduced platelet aggregation in healthy volunteers.
“Lower doses or dietary garlic usually do not cause clinically significant bleeding,” Dr. Laffin says.
Nevertheless, if you take aspirin or an antiplatelet medication such as clopidogrel (Plavix), be sure to talk with your physician before consuming large amounts of garlic or garlic supplements.
