"Let food be thy medicine, and medicine be thy food."
Those are famous words from the ancient Greek physician Hippocrates, often called the father of Western medicine.
He actually used to prescribe garlic to treat a variety of medical conditions.
Modern science has recently confirmed many of these beneficial health effects.
Here are 11 health benefits of garlic that are supported by human research.
Garlic is a plant in the Allium (onion) family.
It is 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, the main use of garlic was for its health and medicinal properties ( 1 ).
Its use was well documented by many major civilizations, including the Egyptians, Babylonians, Greeks, Romans and Chinese ( 2 ).
Scientists now know that most of its health benefits are caused by sulfur compounds formed when a garlic clove is chopped, crushed or chewed.
Perhaps the most famous of those is known as allicin. However, allicin is an unstable compound that is only briefly present in fresh garlic after it’s been cut or crushed ( 3 ).
Other compounds that may play a role in garlic’s health benefits include diallyl disulfide and s-allyl cysteine ( 4 ).
The sulfur compounds from garlic enter the body from the digestive tract and travel all over the body, where it exerts its potent biological effects.
Summary
Calorie for calorie, garlic is incredibly nutritious.
One clove (3 grams) of raw garlic contains ( 5 ):
- Manganese:
- Vitamin B6:
- Vitamin C:
- Selenium:
- Fiber:
- Decent amounts of calcium, copper, potassium, phosphorus, iron and vitamin B1
This comes with 4.5 calories, 0.2 grams of protein and 1 gram of carbs.
Garlic also contains trace amounts of various other nutrients. In fact, it contains a little bit of almost everything you need.
Summary
Garlic supplements are known to boost the function of the immune system.
One large, 12-week study found that a daily garlic supplement reduced the number of colds by 63% compared to a placebo ( 6 ).
The average length of cold symptoms was also reduced by 70%, from 5 days in the placebo group to just 1.5 days in the garlic group.
Another study found that a high dose of aged garlic extract (2.56 grams per day) reduced the number of days sick with cold or flu by 61% ( 7 ).
However, one review concluded that the evidence is insufficient and more research is needed ( 8 ).
Despite the lack of strong evidence, adding garlic to your diet may be worth trying if you often get colds.
Summary
Cardiovascular diseases like heart attacks and strokes are the world's biggest killers.
High blood pressure, or hypertension, is one of the most important drivers of these diseases.
Human studies have found garlic supplements to have a significant impact on reducing blood pressure in people with high blood pressure ( 9 , 10 , 11 ).
In one study, 600–1,500 mg of aged garlic extract was just as effective as the drug Atenolol at reducing blood pressure over a 24-week period ( 12 ).
Supplement doses must be fairly high to have the desired effects. The amount needed is equivalent to about four cloves of garlic per day.
Summary