Kimchi and soybean pastes are risk factors of gastric cancer.
OBJECTIVE
This case-control study investigated the effects of kimchi, soybean paste, fresh vegetables, nonfermented alliums, nonfermented seafood, nonfermented soybean foods, and the genetic polymorphisms of some metabolic enzymes on the risk of gastric cancer in Koreans.


METHODS
We studied 421 gastric cancer patients and 632 age- and sex-matched controls. Subjects completed a structured questionnaire regarding their food intake pattern. Polymorphisms of cytochrome P450 1A1 (CYP1A1), cytochrome P450 2E1 (CYP2E1), glutathione S-transferase mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1) and aldehyde dehydrogenase 2 (ALDH2) were investigated.


RESULTS
A decreased risk of gastric cancer was noted among people with high consumption of nonfermented alliums and nonfermented seafood. On the other hand, consumption of kimchi, and soybean pastes was associated with increased risk of gastric cancer. Individuals with the CYP1A1 Ile/Val or Val/Val genotype showed a significantly increased risk for gastric cancer. Increased intake of kimchi or soybean pastes was a significant risk factor for the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the GSTM1 non-null, the GSTT1 non-null, or the ALDH2 *1/*1 genotype. In addition, eating soybean pastes was associated with the increased risk of gastric cancer in individuals with the GSTM1 null type. Nonfermented alliums were significant in individuals with the CYP1A1 Ile/Ile, the CYP2E1 c1/c2 or c2/c2, the GSTT1 null, the GSTT1 non-null, or the ALDH2 *1/*2 or *2/*2 genotype, nonfermented seafood was those with the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the ALDH2 *1/*1 genotype or any type of GSTM1 or GSTT1. In homogeneity tests, the odds ratios of eating kimchi for gastric cancer according to the GSTM1 or GSTT1 genotype were not homogeneous.


CONCLUSIONS
Kimchi, soybean pastes, and the CYP1A1 Ile/Val or Val/Val are risk factors, and nonfermented seafood and alliums are protective factors against gastric cancer in Koreans. Salt or some chemicals contained in kimchi and soybean pastes, which are increased by fermentation, would play important roles in the carcinogenesis of stomach cancer. Polymorphisms of the CYP1A1, CYP2E1, GSTM1, GSTT1, and ALDH2 genes could modify the effects of some environmental factors on the risk of gastric cancer.
Nan
Hong-Mei
HM
Department of Preventive Medicine, College of Medicine, Chungbuk National University, 12 Kaeshin-dong, Hungdok-gu, Cheongju-si, Chungbuk 361-763, Korea.
Park
Jin-Woo
JW
Song
Young-Jin
YJ
Yun
Hyo-Yung
HY
Park
Joo-Seung
JS
Hyun
Taisun
T
Youn
Sei-Jin
SJ
Kim
Yong-Dae
YD
Kang
Jong-Won
JW
Kim
Heon
H
D000328:Adult; D000368:Aged; D000444:Aldehyde Dehydrogenase / Q000235:genetics; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D001937:Brassica / Q000009:adverse effects*; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics; D019392:Cytochrome P-450 CYP2E1 / Q000235:genetics; D005260:Female; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D045730:Soy Foods / Q000009:adverse effects*; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000235:genetics*
D000444:Aldehyde Dehydrogenase; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D019363:Cytochrome P-450 CYP1A1; D019392:Cytochrome P-450 CYP2E1; D005982:Glutathione Transferase; C096127:ALDH2 protein, human; C413545:glutathione S-transferase T1