Research has found that garlic may deliver a wide range of health benefits, from regulating blood pressure and cholesterol to cancer prevention and relief of cold symptoms. The findings suggest the pungent ingredient commonly used in cooking could also contribute to cardiovascular disease prevention and immune system support.
U.S. health media outlet Verywell Health on Monday introduced four health benefits of garlic based on the views of Sohaib Imtiaz, M.D.
First, allicin and bioactive compounds found in garlic can help lower blood pressure. They inhibit the action of angiotensin-converting enzyme (ACE), which constricts blood vessels and raises blood pressure, and promote vasodilation — a mechanism similar to ACE inhibitors used in hypertension treatment.
Antioxidant components also prevent blood vessel damage and promote nitric oxide (NO) production, which relaxes blood vessel walls. However, patients already diagnosed with hypertension should consult their healthcare provider before consumption, and garlic cannot replace existing medication.
Cholesterol improvement effects have also drawn attention. Some studies have reported that allicin lowers LDL (bad) cholesterol and total cholesterol levels while raising HDL (high-density lipoprotein) cholesterol. A meta-analysis of 22 studies involving 1,567 participants conducted by a research team at Southeast University in China found that longer garlic consumption periods were associated with greater improvements in total cholesterol and LDL cholesterol.
Korea's Ministry of Food and Drug Safety has officially recognized that consuming 0.6 to 1 gram of garlic powder per day can help improve blood cholesterol levels. The World Health Organization (WHO) also recommends daily intake of 0.4 to 1.2 grams of garlic powder based on the same criteria. However, garlic consumption alone has its limits, and dietary management, exercise, and medication should be combined to effectively reduce the risk of heart disease and stroke.
Some evidence for cancer prevention has also been presented. Allicin is produced when garlic is chopped or crushed but decreases in content when heated or microwaved. Flavonoids in garlic suppress free radicals that can damage cells and DNA and potentially cause cancer, while also reducing inflammation.
Selenium and allyl sulfides also contribute to inhibiting cellular DNA damage. Some observational studies have suggested that raw garlic may lower the risk of liver cancer and esophageal cancer, but meta-analyses have also noted that clinical evidence remains insufficient, indicating further research is needed.
Garlic is also effective in boosting immunity. It inhibits viral replication and activates immune cells, strengthening the overall immune system. Regular consumption may help reduce the frequency of colds, and aged garlic extract has been shown to be effective in relieving cold symptoms such as sore throat, cough, and nasal congestion. According to the MSD Manual, black garlic extract (AGE) aged for at least 20 months is known to have more stable active compounds and fewer side effects than regular garlic.
Meanwhile, a research team at the University of Vienna in Austria published findings in the international journal Frontiers in Nutrition showing that raw garlic consumption has broad positive effects on cardiovascular health, including stabilizing systolic and diastolic blood pressure, activating antioxidant enzymes, and improving blood sugar metabolism.
However, the researchers acknowledged that many of the observational studies were conducted in Asian populations and that results varied depending on study design. The recommended daily intake is one to two cloves of raw garlic, and excessive consumption may cause diarrhea, indigestion, and bad breath, requiring caution.