Raw Garlic Consumption and Lung Cancer in a Chinese Population

BACKGROUND: Evidence of anti-cancer properties of garlic for different cancer sites has been reported previously in in-vitro and in-vivo experimental studies but there is limited epidemiological evidence on the association between garlic and lung cancer. METHODS: We examined the association between raw garlic consumption and lung cancer in a case-control study conducted between 2005 and 2007 in Taiyuan, China. Epidemiological data was collected by face-to-face interviews from 399 incident lung cancer cases and 466 healthy controls. We used unconditional logistic regression models to estimate crude and adjusted odds ratios (aOR) and their 95% confidence intervals (CI). Adjusted models controlled for age, sex, average annual household income 10 years ago, smoking, and indoor air pollution. RESULTS: Compared to no intake, raw garlic intake was associated with lower risk of development of lung cancer with a dose-response pattern (aOR for <2 times per week = 0.56, 95% CI: 0.39–0.81 and aOR for ≥2 times per week = 0.50, 95% CI: 0.34 – 0.74; P(trend) = 0.0002). Exploratory analysis showed an additive interaction of raw garlic consumption with indoor air pollution and with any supplement use in association with lung cancer. CONCLUSIONS: The results of the current study suggest that raw garlic consumption is associated with reduced risk of lung cancer in a Chinese population. IMPACT: This study contributes to the limited research in human population on the association between garlic and lung cancer and advocates further investigation into the use of garlic in chemoprevention of lung cancer

The Role of Alliums and Their Sulfur and Selenium Constituents in Cancer Prevention

Garlic and its sulfur and selenium-containing components are widely known for their cancer preventive activities primarily in preclinical in vitro and in vivo model systems. Most of our common foods including garlic contain very low levels of selenium compounds relative to those of sulfur. Humans consume a substantial portion of their dietary sulfur and selenium in organic forms. Selenium-enriched foods such as garlic, broccoli and wheat are more effective chemopreventive agents than the corresponding regular dietary items. Naturally occurring and synthetic organoselenium compounds are superior cancer chemopreventive agents compared to their corresponding sulfur analogs. Mechanistic studies demonstrate that sulfur and selenium compounds are capable of cell growth inhibition, cell cycle arrest, induction of apoptosis, alterations of phase I and phase II enzyme activities, and histone deacetylase (HDAC) inhibition. The fact that organosulfur and organoselenium compounds can target multiple pathways suggests that these agents can be used directly as chemopreventive and/or therapeutic agents or in combination with other medicinal compounds. The effect of these agents on the aforementioned parameters varies depending on the dose and form (structure) and whether cells are normal or transformed. Whether the protective effects observed in animals and in cell cultures can be applicable to humans remain to be determined. Thus, studies using genomic, proteomic, and metabolomic techniques in well designed small-scale clinical trials are needed to unequivocally evaluate the potential of allium vegetable constituents on biomarkers of risk for specific cancers prior to entering into long-term expensive phase III clinical chemoprevention trials