11 Proven Health Benefits of Garlic
Garlic is a plant in the Allium (onion) family. It’s closely related to onions, shallots, and leeks.
Each segment of a garlic bulb is called a clove. There are about 10–20 cloves in a single bulb, give or take.
Garlic grows in many parts of the world and is a popular ingredient in cooking due to its strong smell and delicious taste.
However, throughout ancient history, people widely used garlic for its health and medicinal properties. There is documented evidence of its use by many major civilizations, including the Egyptians, Greeks, Romans, Chinese, and Indians.
Scientists now know that most of garlic’s health benefits are due to the formation of sulfur compounds when you chop, crush, or chew a garlic clove.
Perhaps the most well-known compound is allicin. However, allicin is an unstable compound that is only briefly present in fresh garlic after you cut or crush it.
Other compounds that may play a role in garlic’s health benefits include diallyl disulfide and s-allyl cysteine.
The sulfur compounds from garlic enter your body from the digestive tract. They then travel all over your body, exerting strong biological effects.
Calorie for calorie, garlic is incredibly nutritious.
A single clove (about 3 grams) contains 4.5 calories, 0.2 grams of protein, and 1 gram of carbs.
Garlic is a good source of several nutrients, notably:
- vitamin B6
- vitamin C
Garlic also contains trace amounts of various other nutrients.
Research from 2016 suggests that aged garlic extract (AGE) can boost your immune system.
The study found that people who took AGE supplements for 3 months during the cold and flu season experienced less severe symptoms and fewer days missed of school or work.
Other research suggests that the compounds in garlic may have antiviral properties. In addition to boosting your immune system, it may help prevent viruses from entering host cells or from replicating within your cells.
According to the World Health Organization, cardiovascular diseases like heart attack and stroke are responsible for more deaths than almost any other condition.
High blood pressure, or hypertension, is one of the most important factors that may lead to these diseases.
A 2020 meta-analysis of studies found garlic supplements to reduce blood pressure in people with high blood pressure. Researchers linked this effect to a 16–40% reduced risk of experiencing cardiovascular events.
The analysis noted that the effect of garlic was similar to some blood pressure medications but with fewer side effects.
A 2019 review notes that allicin in garlic may limit the production of angiotensin II, a hormone that increases blood pressure. It may also relax your blood vessels, allowing blood to flow more easily.
A 2018 research review suggests that garlic can lower total and LDL (bad) cholesterol.
According to 2016 research, taking garlic supplements for more than 2 months could reduce your LDL by up to 10%. Researchers noted this effect in people with slightly raised cholesterol levels.
But garlic does not seem to have the same effect on triglyceride levels, another risk factor for heart disease.
Research also suggests that garlic does not have an effect on HDL (good) cholesterol.
Oxidative damage from free radicals contributes to the aging process and related cognitive decline.
Garlic contains antioxidants that support your body’s protective mechanisms against oxidative damage. Research suggests these antioxidants may significantly reduce oxidative stress and lower your risk of related diseases like Alzheimer’s disease, the most common form of dementia.
Animal studies suggest that allicin in garlic may also help protect against cognitive decline. Human research is needed before we can fully understand its potential.
Some studies have found garlic supplements to benefit people with Alzheimer’s disease directly.
The potential effects of garlic on longevity are basically impossible to prove in humans.
But given the beneficial effects on important risk factors like blood pressure, it makes sense that garlic could help you live longer.
In a 2019 Chinese study, older adults who consumed garlic at least weekly lived longer than those who consumed garlic less than once a week.
The fact that it can help defend against infectious diseases is also important. Such diseases are common causes of death, especially in older adults or people with weakened immune systems.
Garlic was one of the earliest “performance-enhancing” substances.
Ancient civilizations used garlic to reduce fatigue and improve the work capacity of laborers. Olympic athletes in ancient Greece consumed garlic to improve their performance.
While rodent studies have shown that garlic helps with exercise performance, there have been very few human studies.
A recent study found that garlic didn’t improve cyclists’ performance in a 40-km time trial. However, it may have reduced exercise-related oxidative stress and muscle damage.
A small 2015 study also noted that garlic supplements might increase oxygen capacity during exercise. But more research is needed to confirm this potential benefit.
At high doses, the sulfur compounds in garlic have been shown to protect against organ damage from heavy metal toxicity.
Allicin in garlic can help reduce levels of lead in your blood and vital organs.
A 2012 study involving employees at a car battery plant (who had excessive exposure to lead) found that garlic reduced lead levels in the blood by 19%. It also reduced many clinical signs of toxicity, including headaches and high blood pressure.
Three doses of garlic each day even outperformed the drug D-penicillamine in reducing symptoms.
A few recent studies have measured the effects of garlic on bone health, specifically in women after menopause.
Results of a clinical trial published in 2017 showed that garlic can reduce oxidative stress that leads to osteoporosis. The participants took garlic tablets equal to about 2 grams of fresh garlic per day.
A 2018 study found that 12 weeks of garlic supplements (1 gram per day) helped reduce pain in women with knee osteoarthritis and obesity or overweight.
The last one isn’t a health benefit but is still important.
Garlic is very easy to include in your current diet. It complements most savory dishes, particularly soups and sauces. The strong taste of garlic can also add a punch to otherwise bland recipes.
Garlic comes in several forms, from whole cloves and smooth pastes to powders and supplements like garlic extract and garlic oil.
A common way to use garlic is to press a few cloves of fresh garlic with a garlic press, then mix it with extra virgin olive oil and a bit of salt. This works as a very simple and nutritious salad dressing.
Keep in mind that garlic has some downsides, such as bad breath. Some people are also allergic to garlic.
Garlic may also affect your blood clotting ability. If you have a bleeding disorder or are taking blood-thinning medications, talk with a doctor before increasing your garlic intake.
Frequently Asked Questions
The 10-minute garlic rule typically refers to how long you should let garlic stand after cutting or crushing it before you cook it. This may maintain some of the allicin, a beneficial but unstable compound in garlic that degrades when fresh garlic is heated.
While many people eat garlic as part of a meal, some people believe eating it on an empty stomach may improve the health benefits associated with it. However, more research is needed to prove whether eating garlic on an empty stomach provides additional benefits.
Eating garlic raw may provide additional benefits, as some of the beneficial compounds in garlic are sensitive to heat.
Garlic is likely safe for most people to consume in the amounts used in food preparation. But some people, including those with gastroesophageal reflux disease (GERD) and those taking blood thinners may have negative effects from drastically increasing their garlic intake.
People have believed in garlic’s medicinal properties for thousands of years. Science is now beginning to confirm it.
Garlic is safe and healthy for most people. But if you’re taking blood thinners, talk with a doctor before drastically increasing your garlic intake.