TORONTO – Eating raw garlic at least twice a week may help prevent lung cancer, according to new research conducted in China. But one expert says while garlic may be helpful, he wouldn’t rely on its cancer-prevention power based on this study alone.
Researchers from the Jiangsu Provincial Center for Disease Control and Prevention interviewed 1,424 people with lung cancer and 4,543 healthy subjects using a standard questionnaire. They found raw garlic consumption at least twice a week to be “inversely associated” with the disease.
“Raw garlic consumption may potentially serve as a chemopreventive agent for lung cancer,” said the study, where ‘chemopreventive’ refers to the use of a substance to interfere with a disease process.
The study, published online Wednesday in the journal Cancer Prevention Research, notes that Chinese medicine has used garlic since 2000 BCE. The authors suggest compounds such as diallyl sulfide—that are released when a garlic bulb breaks into cloves—may contribute to the herb’s potential preventative powers. The researchers did not look at cooked garlic in this study.
Researchers also confirmed that risk factors for lung cancer included tobacco smoking, exposure to pollution and high-temperature cooking oil, frequently eating fried foods and a family history of the disease.
However, the study found a decreased association between eating raw garlic and lung cancer even after adjusting for such risk factors, including a significant inverse association among smokers.
The authors add that only a borderline association was seen among those who never smoked, though they wrote it may be explained by the small sample size of non-smokers.
In China, lung cancer is one of the leading causes of cancer death, while in Canada it is the leading cause of cancer death.
According to the most recent Canadian Cancer Statistics report, an estimated 20,200 people will die out of an estimated 25,500 lung cancer cases in 2013, making it significantly more deadly than breast or prostate cancer. The incidence rate of lung cancer for men has been decreasing since the mid-1980s, but is still rising in women, according to the Canadian Cancer Society.
The society’s Cancer Control Policy Acting Director Robert Nuttall told Global News that there has been some research on garlic conducted in Canada, but suggests there may be some limitations to Wednesday’s study.
Nuttall said we don’t know if the results are unique to Chinese populations, or if it could apply to the general population. He also notes that the questionnaire used in the study was asking people who had already been diagnosed with lung cancer what their current food consumption is.
“We know that it takes many years for lung cancer to develop, and so it’s not entirely clear what the individuals’ garlic consumption was in the past,” he said.
While Nuttall notes that individual foods such as garlic are still being investigated for their protective properties, he believes a balanced diet is a better approach than stocking up on garlic alone.
“For lung cancer, the number one thing a person can do is not smoke, and we also know that healthy diets…with combinations of fruits and vegetables, can reduce the risk of cancer,” he said. “And garlic is one component of that diet.”
Editor’s note: This story was updated from a previous version to include the number of lung cancer deaths estimated for 2013. The previous version cited the number of cancer deaths projected for 2010.