Onions and garlic are both part of the allium family of vegetables that contain substances to possibly benefit your health in many ways, reports the American Institute for Cancer Research. While onions and garlic cloves do give off strong odors, the sulfur compounds responsible for those aromas are the same substances that provide health benefits if you eat onions and garlic, the Linus Pauling Institute says.
Both onions and garlic might help you combat infections. Onions might reduce the symptoms of bronchitis and the common cold, and they also can fight harmful bacteria, notes the November 2002 issue of "Phytotherapy Research." Garlic has both antibacterial and antifungal properties, according to the Linus Pauling Institute, and it also might strengthen your immune system overall, making you less vulnerable to contracting infections.
Onions and garlic might also help you resist cancer. The American Institute of Cancer Research says the chemical compounds inside allium vegetables such as onions and garlic can slow or stop cancer cells from proliferating in various places in the body, such as the lungs, colon, esophagus and breasts. The compounds that onions and garlic contain can also reduce the rate at which cancer tumors grow, or even stop tumor growth altogether, reports the American Institute of Cancer Research. The Linus Pauling Institute says garlic, in particular, might be especially effective as a weapon against gastric and colorectal cancer.
Fighting Heart Disease
Consuming onions and garlic also might help you prevent heart disease. Onions are rich in natural chemicals called flavonoids, which can protect you from heart disease, says Vegetarian Nutrition.info., and onions also might reduce your risk of blood clots, which can lead to heart attacks and other forms of heart disease. Garlic might also decrease your risk of blood clots, help keep your arteries flexible and help reduce your blood pressure, the Linus Pauling Institute reports.
Adding Onions and Garlic to Your Diet
Allium vegetables such as onions and garlic are the richest food sources of healthy sulfur compounds, which recommends eating them regularly to obtain their full health benefits, rather than taking supplements that might contain widely varying amounts of the healthy compounds. Onions and garlic have complementary tastes, so you might eat them together in the same meals. You can also add onions to stir fry dishes and use them to flavor soups, salads and dips. The Linus Pauling Institute recommends eating garlic cloves raw, or crushing or chopping garlic cloves before cooking them to help them retain their beneficial compounds during the cooking process.