Supplementation with garlic lowers circulating markers of oxidative stress[1][2] (e.g., malondialdehyde) and inflammation (e.g., C-reactive protein and TNF-α).[3][4][5] Supplementation with garlic can also reduce total cholesterol levels,[6][7] particularly in people with cardiovascular disease, and improve other measures of cardiovascular health (coronary artery calcium, carotid intima-media thickness, etc.).[8] However, its direct effects on cardiovascular morbidity and mortality are currently unclear.[8][9]
Observational studies also show that garlic consumption, through food or as a supplement, is associated with a lower risk of gastric and colorectal cancers.[10]