The National Institutes of Health's National Cancer Institute drew similar conclusions after reviewing 37 studies involving garlic and sulfur-containing compounds. Twenty-eight of those studies indicated garlic possessed at least some anticancer activity, especially toward prostate and stomach cancer. Because the studies in question were merely observational (they compared people who reported eating a lot of garlic to those who did not), more studies are needed.
As few as two servings a week of garlic
might prevent colon cancer.
What gives garlic this wonderful gift? Several factors, including antioxidants and those same sulfur-containing agents we've discussed before, including allicin. (Antioxidants help protect cells from damage; continual cell damage can eventually lead to cancer.) Allicin appears to protect colon cells from the toxic effects of cancer-causing agents. For instance, when meat is cooked with garlic, the herb reduces the production of cancer-causing compounds that would otherwise form when meat is grilled at high temperatures.
Garlic's potential ability to decrease H. pylori bacteria in the stomach may help prevent gastritis (inflammation of the stomach lining) from eventually evolving into cancer. (H. pylori is most famous for its link to stomach ulcers, but it can also cause chronic gastritis.) Numerous studies around the world indicate that garlic's sulfur-containing compounds have the potential to help prevent stomach cancer.
The American Institute for Cancer Research (AICR), an organization that supports research into the roles diet and nutrition play in the prevention and treatment of cancer, has cited two large studies -- one in China and the other in Italy -- in which garlic intake was associated with lower death rates from stomach cancer.
In addition, a Korean study indicated garlic consumption led to a lower risk of developing stomach cancer. And the AICR has reported that the Iowa Women's Health Study revealed that women had a lower risk of colon cancer if they ate garlic regularly. (The report did not define what amount and frequency constituted regular use.)
The amount of garlic you eat, along with the number of years you eat it regularly, may determine its ability to decrease cancer risk. This makes sense because cancer takes a long time to develop. In general, researchers suspect that garlic delivers anticancer benefits if you eat substantial amounts of it for three to five years or longer (again, the report did not define how much garlic should be eaten). That's when they begin to see a possible link in the reduction of laryngeal, gastric, colon, and endometrial (uterine) cancers.
Most studies do not show a reduction in breast cancer risk related to garlic intake. The data about whether garlic helps prevent development of prostate cancer is less definitive. And in a preliminary study that looked at consumption of fruits and vegetables, garlic appeared to be the only variable that might slightly decrease the risk of ovarian cancer; clearly, however, more studies are needed.
Garlic might defend against skin cancer when applied topically to tumors. In a study that appeared in the July 2003 issue of Archives of Dermatological Research, ajoene significantly shrunk skin cancer tumors in 17 out of 21 patients. The AICR has reported that in laboratory studies, the garlic compounds diallyl disulfide and ajoene protect against skin cancer.
Don't try treating skin cancer or unidentified/suspect skin lesions with garlic yourself, however. Skin cancer is a serious disease, and if you have it or suspect it, you should be following your physician's treatment guidelines. If you have a suspicious lesion, bring it to your physician's attention before using any home remedies.
For a smelly little bulb, garlic has some amazing health-affirming properties. Now that you know what garlic can do for you, you can add it to your meals and health regimen with no remorse.
Want more information about garlic? Try:
- Vegetable Recipes: Find delicious recipes that feature garlic.
- Nutrition: Find out how garlic fits in with your overall nutrition plans.
- Vegetable Gardens: Grow a full harvest of great vegetables this year.
- Gardening: We answer your questions about all things that come from the garden.