BETHESDA, Md.—More research is needed before garlic can be touted as a way to lower the risk of some types of cancer, according to a new review published in the January edition of the American Journal of Clinical Nutrition.
The review shows there is not enough credible evidence to link garlic to a lower risk of gastric, breast, lung or endometrial cancers. However, some evidence suggests that garlic may reduce the risk of some other cancers, including colon, prostate, ovarian, esophageal, larynx, mouth and kidney.
Many studies have suggested that garlic may reduce cancer risk, but researchers say few of these studies meet the scientific standards to support a health claim according to the FDA's criteria for food labeling.
Researchers say it's difficult to evaluate the potential benefits of garlic against cancer for several reasons, including the fact that because garlic is intended for use in small quantities as a seasoning, it is very difficult to analyze how much garlic a person consumes based on a questionnaire.
"Moreover, there are too many variables that can affect the chemical composition of garlic, such as the preparation method used (e.g. whether the garlic is raw or cooked, whole or extracted) and the conditions of cultivation," wrote researchers Ji Yeon Kim and Oran Kwon of the Korea Food and Drug Administration. "For some of these reasons, although this systemic review found many studies on garlic intake and cancer, most of the results indicate that additional studies are needed."