Proof Lacking That Garlic Combats Cancer
Eating it isn't harmful, but it might not help, either
(HealthDay News) -- Garlic may not be the cancer-fighter that some have believed it was.
It's been suggested that garlic can help reduce cancer risk in a number of ways, including repairing oxidative stress caused by "free radical" molecules, which can increase the risk for cancer and other health problems.
But some experts aren't convinced.
"The public wants to believe that garlic may be effective in reducing the risk of cancer, but so far scientific evidence is limited to conclude [it works] for all types of cancer," Dr. Oran Kwon, a researcher at Ewha Women's University in Seoul, South Korea, told HealthDay.
Kwon was lead author of a study that analyzed the results of 19 published and scientifically sound studies that examined garlic consumption and risk reduction for certain types of cancer. For their analysis, the researchers used the U.S. Food and Drug Administration's review system for evaluating the scientific evidence for making a health claim about food.
Based on the FDA criteria, Kwon and her colleagues concluded there was no credible evidence that consuming garlic reduces the risk for gastric, lung, breast or endometrial cancer. They did find very limited, but credible, evidence that garlic intake was associated with a reduced risk for colon, prostate, ovarian, laryngeal, esophageal, oral and renal cell cancer.
The authors of the review said that food labeling should inform consumers that garlic is "highly unlikely" to reduce colon cancer risk and "highly uncertain" to reduce prostate cancer risk and that there is a "highly uncertain" link between garlic consumption and reduced risk of esophageal, laryngeal, oral, ovarian or renal cell cancer.
The review was published in the January 2009 issue of the American Journal of Clinical Nutrition.
"The bottom line is, there is certainly not enough evidence for garlic for a health claim for any cancer prevention," Colleen Doyle, director of nutrition and physical activity for the American Cancer Society, told HealthDay. "There is weak evidence it may have an impact on some cancer sites."
However, people who love garlic should continue to eat it, she said.
"It's not going to be harmful to you," Doyle said. "If, down the line, stronger evidence emerges that garlic has an impact on cancer, great."
It would be better, though, for people to do things that are known to reduce cancer risk, such as eating a well-balanced diet, she said.
"We do know that people who eat a diet with a mixture of fruits and vegetables, who eat mostly a plant-based diet, do tend to have lower rates of cancer," Doyle said.
Garlic is recognized as one of several foodstuffs with potential anticancer properties, according to the U.S. National Cancer Institute. The agency says the protective effects of garlic could be due to its antibacterial properties or to its ability to block formation or activation of cancer-causing substances, to enhance DNA repair, reduce cell proliferation or induce cell death.
On the Web
The U.S. National Library of Medicine has more on garlic and health.
SOURCES: HealthDay News; Colleen Doyle, M.S., R.D., director, nutrition and physical activity, American Cancer Society, Atlanta; Oran Kwon, Ph.D., department of nutritional science and food management, Ewha Women's University, Seoul, South Korea; January 2009, American Journal of Clinical Nutrition; U.S. National Cancer Institute (www.cancer.gov)
Author: Robert Preidt
Publication Date: Jan. 31, 2010
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