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Fermented Garlic: Are There Health Benefits?

Reviewed by Dan Brennan, MD on September 29, 2020

Chances are, you’ve heard something about the health benefits of garlic. It’s been used in traditional medicine around the world and has purported health benefits like boosting the body’s immune response.

In fact, garlic was used as medicine by Hippocrates, the ancient Greek physician whom some consider the father of modern medicine. It was also used medicinally by the Egyptians, Babylonians, Romans, and Chinese.

Fermented garlic also known as “black garlic” is made from fresh garlic (Allium sativum L.) that has been fermented. The fermentation process turns the garlic into a dark brow color and dulls the intense taste that raw garlic is known for. Fermented garlic is described as sweet with a chewy and jelly-like texture.  Fermented garlic is fairly easy to make, just follow these steps:

  1. Peel your garlic.
  2. Put the cloves in a jar or other container.
  3. Add water, salt and herbs of your choice.
  4. Store in a cool place.
  5. Let sit for 3-6 weeks at room temperature.

The fermentation process not only changes the taste of garlic, but also the minerals and nutrients available. Compared to regular garlic, fermented garlic exhibits enhanced bioactivity. Bioactive components in food help your body function and promote better health. Several studies have some that black garlic has several functions in your body, such as:

  • Antioxidation
  • Antiallergic
  • Antidiabetes
  • Anti-inflammation
  • Anticarcinogenic

Nutrition Information

The nutritional contents of black garlic will vary depending on the conditions during the fermentation process.

One tablespoon (15 grams) of raw garlic contains: 

  • Calories: 35
  • Protein: 1 grams
  • Fat: 0 grams
  • Carbohydrates: 8 gram
  • Fiber: 0.1 grams
  • Sodium 0 grams
  • Sugar: 0 grams

Raw garlic is a good source of: 

  • Manganese
  • Vitamin B6

Garlic also contains calcium, copper, potassium, phosphorus, iron, and vitamin B1.

Studies have shown that the fermentation process increases the amount of nutrients in garlic and makes them easier to absorb by the body. The highest protein content was available after 60 days of fermentation while the highest fat and carbohydrate content was found after 90 days of fermentation.

Research has also shown that antioxidants such as polyphenol and flavonoids increase during the aging process. Antioxidants help prevent damage to your cells that can cause diseases.

Since salt is involved in the fermentation process, fermented garlic will have a higher sodium content than regular raw garlic if you make it at home. Fermented garlic with no sodium is also available at grocery stores.

One study showed fermented garlic had higher levels of riboflavin, α-tocopherol, and most amino acids, but lower levels of thiamin and ascorbic acid (vitamin C).

Potential Health Benefits of Fermented Garlic

Garlic in all its forms is rich in nutrients for its size — including B vitamins and cancer-fighting antioxidants — that can provide a range of health benefits. It may, however, interfere with certain medications.

Research has found a number of potential health benefits to eating garlic, including fermented garlic: 

Immune-Boosting Effects

Some studies have found that garlic may boost the body’s immune response, though more evidence is needed. One 12-week study in humans found that a daily garlic supplement reduced colds by 63% when compared to a placebo.

Another study found that aged garlic extract taken in high doses (2.56 grams per day) reduced sick days from cold or flu by 61%.

A third study found the evidence to be insufficient and said more data was needed.

Reduce Blood Pressure

Multiple studies conducted in humans show garlic can have a significant impact on blood pressure in people with hypertension, or high blood pressure.

In fact, one study found that 600 to 1,500 milligrams of aged garlic extract was just as effective as the blood pressure medication Atenolol at reducing hypertension over a 24-week period.

You have to take a pretty high amount of garlic per day — about four cloves’ worth — to see these benefits.

Improves Cholesterol Levels

Eating garlic can lower your LDL or “bad” cholesterol and total cholesterol levels. 

Research has shown that taking garlic supplements may reduce LDL and total cholesterol in people with high cholesterol levels by 10 to 15%. 

Garlic does not appear to have any effect on HDL (“good” cholesterol) or triglycerides. High triglycerides are a known risk factor for heart disease.

Detoxify Heavy Metals

The sulfur compounds found in garlic have been shown to help protect against organ damage from heavy-metal toxicity, when garlic is taken in high doses.

A study that tracked employees of a car battery plant — who were exposed to high levels of lead during their work — for four weeks found that taking garlic reduced the lead levels in their blood by 19%. It also reduced signs of toxicity like headaches and high blood pressure.

The employees took three doses of garlic per day, which ultimately proved  better than the drug D-penicillamine at reducing symptoms.

Potential Risks of Fermented Garlic

Though rare, some people can have adverse reactions to garlic or fermented garlic. It can also react negatively with certain medications. Be sure to talk to your doctor before adding garlic to your diet or taking a garlic supplement, especially in high doses.

Medication Risks

Because it can thin your blood, eating large amounts of garlic can increase bleeding risk. It can also react with other blood thinners, including:

Garlic may also interfere with the anti-HIV drug saquinavir.

Allergy Risk

In some people, garlic can be misidentified as a threat by the body’s immune system, causing an allergic reaction. Symptoms of garlic allergy include:

  • skin inflammation
  • hives
  • tingling sensation of the lips, mouth, or tongue
  • nasal congestion or runny nose
  • itchy nose
  • sneezing
  • itchy or watery eyes
  • shortness of breath or wheezing
  • nausea and vomiting
  • stomach cramps
  • diarrhea

Symptoms can vary in severity, and come on anywhere from immediately after being ingested to a couple of hours after exposure. If you suspect you have a garlic allergy, tell your doctor. They may refer you to an allergist for testing.

Show Sources

SOURCES:

Advances in Therapy: “Preventing the common cold with a garlic supplement: a double-blind, placebo-controlled survey.”

Annals of Internal Medicine: “Garlic for treating hypercholesterolemia. A meta-analysis of randomized clinical trials.”

Basic and Clinical Pharmacology and Toxicology: “Comparison of therapeutic effects of garlic and d-Penicillamine in patients with chronic occupational lead poisoning.”

Clinical Infectious Diseases: “The Effect of Garlic Supplements on the Pharmacokinetics of Saquinavir.”

Clinical Nutrition: “Supplementation with aged garlic extract improves both NK and γδ-T cell function and reduces the severity of cold and flu symptoms: a randomized, double-blind, placebo-controlled nutrition intervention.”

Foodborne Pathogens and Disease: “Anaphylaxis induced by ingestion of raw garlic”

International Journal of Health Sciences: “Nutrition content and antioxidant activity of black garlic.”

Journal of Agricultural Food Chemistry: “Vitamin Content and Amino Acid Composition of Pickled Garlic Processed with and without Fermentation.”

Journal of Atherosclerosis and Thrombosis: “Lipid-lowering effects of time-released garlic powder tablets in double-blinded placebo-controlled randomized study.”

Journal of Food and Drug Analysis: “Black garlic: A critical review of its production, bioactivity, and application.”

The Journal of Nutrition: “Historical perspective on the use of garlic.”

Journal of the Royal College of Physicians of London: “Garlic as a lipid lowering agent–a meta-analysis.”

Lipids in Health and Disease: “Effects of anethum graveolens and garlic on lipid profile in hyperlipidemic patients.”

Maturitas: “Aged garlic extract lowers blood pressure in patients with treated but uncontrolled hypertension: a randomised controlled trial.”

Molecular and Cellular Biochemistry: “Garlic supplementation prevents oxidative DNA damage in essential hypertension.”

Molecular Nutrition and Food Research: “Garlic as an anti-fatigue agent.”

NIH National Center for Complementary and Integrative Health: “Garlic”

Pakistan Journal of Pharmaceutical Sciences: “Effects of Allium sativum (garlic) on systolic and diastolic blood pressure in patients with essential hypertension.”

The Cochrane Database of Systematic Reviews: “Garlic for the common cold.”

USDA Food Data Central: “Search Results - Garlic.”

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