Garlic (Allium sativum) is a popular food ingredient and a traditional medicinal plant. Its health benefits are attributed to its active compounds, including organosulfur compounds (OSCs), flavonoids, and phenolic acids. Garlic has been used for centuries to treat a variety of health conditions, and modern research supports its traditional use. Here are 10 health benefits of consuming garlic, along with the latest scientific evidence supporting each benefit.
Boosts the immune system
Garlic has been shown to boost the immune system by enhancing the activity of immune cells and increasing the production of cytokines and other immune factors. A randomized controlled trial (RCT) of 120 healthy volunteers found that daily consumption of garlic extract (2.56 grams/day) for 12 weeks increased the activity of natural killer (NK) cells, a type of immune cell that plays a key role in defending against viruses and cancer cells. The garlic group also had higher levels of interleukin-12 (IL-12), a cytokine that stimulates the production of NK cells and other immune cells. Another RCT of 146 healthy volunteers found that daily consumption of aged garlic extract (2.56 grams/day) for 90 days increased the production of gamma-delta T cells, a type of immune cell that is important for mucosal immunity and defense against pathogens.
The immune-boosting effects of garlic may be attributed to its OSCs, which have been shown to have immunomodulatory effects. One study found that diallyl disulfide, a major OSC in garlic, increased the production of cytokines and chemokines by immune cells and enhanced their migration to the site of infection. Another study found that allicin, another OSC in garlic, increased the phagocytic activity of macrophages, which are immune cells that engulf and digest foreign particles and microbes.
Reduces the risk of heart disease
Garlic has been shown to have cardioprotective effects by lowering cholesterol levels, reducing blood pressure, and preventing the formation of blood clots. A meta-analysis of 26 RCTs found that garlic supplementation (doses ranging from 300 to 900 mg/day) significantly reduced total cholesterol levels by 17 mg/dL and LDL cholesterol levels by 9 mg/dL, compared to placebo. Garlic supplementation was also associated with a modest reduction in triglyceride levels, but had no effect on HDL cholesterol levels. The cholesterol-lowering effects of garlic may be attributed to its OSCs, which have been shown to inhibit the synthesis of cholesterol and promote its excretion.
Garlic has also been shown to lower blood pressure, a major risk factor for heart disease. A meta-analysis of 17 RCTs found that garlic supplementation (doses ranging from 300 to 2400 mg/day) significantly reduced systolic blood pressure by 5.1 mmHg and diastolic blood pressure by 2.5 mmHg, compared to placebo. The blood pressure-lowering effects of garlic may be attributed to its ability to relax blood vessels and increase the production of nitric oxide, a vasodilator that lowers blood pressure.
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