Some animal studies suggest that garlic may improve insulin release, but there is no evidence to support this effect in humans.
Other studies show that garlic may improve the elasticity of the aorta. It may also keep atherosclerotic plaque from forming.
There is some evidence that says garlic can slightly lower cholesterol levels. But recent research done by the National Center for Complementary and Integrative Health found that garlic has no effect on cholesterol.
Some research shows that taking garlic by mouth can modestly reduce blood pressure. This effect was seen in people with high blood pressure. It was also seen in people with normal blood pressure. The evidence indicates that garlic, when used with a knowledgeable doctor, can help lower blood pressure in people with hypertension.