Meta-Analysis: Does Garlic Intake Reduce Risk of Gastric Cancer?

Abstract

In the past 2 decades, various epidemiological studies investigated whether garlic can positively modify the risk of gastric cancer. Garlic contains numerous sulfide compounds, including diallyl trisulfide, which have anticarcinogenic properties. We conducted a meta-analysis to determine if garlic intake reduces the risk of gastric cancer. An electronic search of MEDLINE, PubMed, and EMBASE to June 2014 was completed. There were 14 case control studies, 2 randomized controlled studies, and 1 cohort study that fulfilled our inclusion criteria. We used a random effects model to calculate pooled odds ratios (OR) and 95% confidence intervals (CIs) for risk of gastric cancer with garlic consumption. Meta-analysis of a total of 8,621 cases and 14,889 controls was conducted. Significant variability in duration of garlic intake and reference categories for amount of intake was noted. High, low, and any garlic intake were all associated with reduced risk of gastric cancer. High intake had the most significant risk reduction, OR = 0.49 (95% CI: 0.38-0.62). Heterogeneity was low (I² = 30.85, P = 0.17). A more modest risk reduction was associated with low intake, OR = 0.75 (95% CI: 0.58-0.97). Half of the studies did not separate garlic intake into high or low amounts, intake was only noted as consumption vs. non-consumption. Any amount of consumption still showed a risk reduction similar to low intake, OR = 0.77 (95% CI: 0.60-1.00). Low and any amount of consumption showed moderate heterogeneity (58% and 45%, respectively). Garlic intake appears to be associated with reduced risk of gastric cancer. Further high quality studies are required to confirm this finding and to assess the amount of garlic that needs to be consumed for protective effect.

Allium vegetable consumption and health: An umbrella review of meta‐analyses of multiple health outcomes

“…Among the 31 studies, 11 studies (Chiavarini et al, ; Fleischauer et al, ; Guercio et al, ; Hu et al, ; Kodali & Eslick, ; Li et al, ; Turati et al, , ; Zhou et al, , ; Zhu et al, ) were about cancer and tumor outcomes (gastric cancer, colorectal cancer, upper aerodigestive tract cancer, prostate cancer, and colorectal adenomatous polyps), 13 studies (Emami et al, ; Khoo & Aziz, ; Kwak et al, ; Reinhart et al, ; Ried, ; Ried, Toben, et al, ; Sahebkar et al, ; Shabani et al, ; Stevinson et al, ; Sun et al, ; Wang et al, ; Warshafsky et al, ; Zeng et al, ) were about metabolic outcomes (serum total cholesterol [TC], high‐density lipoprotein [HDL], low‐density lipoprotein [LDL], triglycerides [TGs], fasting blood glucose [FBG], serum HbA1c, serum fructosamine, serum lipoprotein (a), and apolipoprotein B), seven studies (Reinhart et al, ; Ried, ; Ried et al, ; Rohner et al, ; Silagy & Neil, ; Wang et al, ; Xiong et al, ) were about cardiovascular outcomes (systolic blood pressure and diastolic blood pressure), and only one systematic review and meta‐analysis (Taghizadeh et al, ) was about serum C‐reactive protein levels. Finally, 50 unique outcomes extracted from the 16 most recent meta‐analyses were analyzed in this umbrella review, and the map of allium vegetable‐related outcomes is reported in Figure .…”

“…Then, 19,023 articles remained after removing the duplicates, and 18,992 articles were excluded after reviewing the titles and abstracts. Finally, 31 full-text articles (Chiavarini et al, 2016;Emami, Rouhani, & Azadbakht, 2017;Fleischauer, Poole, & Arab, 2000;Guercio, Turati, La Vecchia, Galeone, & Tavani, 2016;Hu et al, 2014;Khoo & Aziz, 2009;Kodali & Eslick, 2015;Kwak et al, 2014;Li, Ying, Shan, & Ji, 2018;Reinhart, Coleman, Teevan, Vachhani, & White, 2008;Reinhart, Talati, White, & Coleman, 2009;Ried, 2016;Ried, Frank, Stocks, Fakler, & Sullivan, 2008;Ried, Toben, & Fakler, 2013;Rohner, Ried, Sobenin, Bucher, & Nordmann, 2015;Sahebkar et al, 2016;Shabani et al, 2018;Silagy & Neil, 1994;Stevinson, Pittler, & Ernst, 2000;Sun, Wang, & Qin, 2018;Taghizadeh, Hamedifard, & Jafarnejad, 2018;Turati et al, 2014;Turati, Pelucchi, Guercio, La Vecchia, & Galeone, 2015;Wang, Yang, Qin, & Yang, 2015;Wang, Zhang, Lan, & Wang, 2017;Warshafsky, Kamer, & Sivak, 1993;Xiong et al, 2015;Zeng et al, 2012;Zhou, Ding, & Liu, 2013;Zhou et al, 2011;Zhu, Zou, Qi, Zhong, & Miao, 2014) were reviewed for further assessment.…”

Spices for Prevention and Treatment of Cancers

“…In addition, apoptosis of MGC803 human gastric carcinoma cells was markedly increased by allicin, accompanied with an enhancement of expression levels of cleaved caspase-3, and the protein expression levels of p38 were also increased [153]. Notably, epidemiological studies also showed that garlic intake resulted in reduced risk of gastric cancer [154,155]. …”

The association of garlic with Helicobacter pylori infection and gastric cancer risk: A systematic review and meta‐analysis

“…Epidemiological evidence, mainly from case‐control studies, has likewise suggested a protective effect of garlic consumption against gastric cancer. Several meta‐analyses and one systematic review have been conducted to examine the association between garlic intake and gastric cancer risk since 2000 . The most up‐to‐date meta‐analysis included 12 case‐control studies with 11 175 patients and concluded high intake of garlic may prevent gastric cancer, with an acknowledge that further data from large cohorts are needed for conclusive confirmation .…”