What explains the Achilles’ heel in certain Asian diets?
The Role of Kimchi and H. Pylori in Stomach Cancer
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
For decades, Japan has had the longest life expectancy in the world, while spending just a fraction on healthcare compared to other high-income countries. This longevity has been attributed in part to Japanese dietary patterns, which are thought to have contributed to their comparatively low rates of coronary artery disease. Japan has historically had among the lowest rates of colon cancer, breast cancer, ovarian cancer, prostate cancer, bladder cancer, and blood cancers. Japan, however, has among the highest rates of stomach cancer. Yes, Japanese men may have had seven times less prostate cancer than Americans but got six times more stomach cancer. Is there some Achilles’ heel in the Japanese diet?
One of the first theories, proposed in the 1970s, was that it was the talc used to polish white rice to give it a glossy sheen. That was the case with ovarian cancer, which led to billions in damages against Johnson & Johnson’s baby powder, as I detailed in a previous video, but that did not appear to be the case with stomach cancer. Is it just genetics? No. Studies on Japanese migrants show that as they and their children Westernize their diets and lifestyles, their stomach cancer rates drop accordingly.
Well, the most well-established risk factor for stomach cancer is H. pylori, a bacteria that infects the lining of the stomach and causes the chronic inflammation that can lead to cancer. H. pylori infection is considered a Group 1 carcinogen, indicating our highest level of certainty that it indeed causes cancer. Korea and Japan have the highest rates of stomach cancer, and among the highest incidence of H. pylori infection. Case closed, then, right? The mystery seemed to have been solved.
But then came the “African enigma.” Countries such as Nigeria had even more H. pylori, but only a fraction of Japan’s stomach cancer rates. Then came the “Indian enigma.” H. pylori is twice as prevalent in India than Japan, yet Indians get ten times less stomach cancer. Obviously, H. pylori alone can’t explain Japan’s epidemic.
Though most cases of stomach cancer are thought to be caused by H. pylori, most people with H. pylori don’t get cancer. H. pylori is one of the most common human infections. It has been estimated that half of the world’s adult population is infected with H. pylori, yet half of us don’t get stomach cancer. There must be some kind of co-factor in countries like Korea and Japan that explains their elevated cancer rates. The inflammation caused by H. pylori may just set the stage for cancer formation, increasing the susceptibility of the stomach lining to dietary carcinogens. But what’s so carcinogenic about Korean and Japanese diets?
Studies that have compared the dietary components of different Asian populations with similar H. pylori rates, but dramatically different stomach cancer rates, have suggested preserved, salted foods—both fish and vegetables—as the culprits. Fresh vegetables and fruits, on the other hand, were associated with an 85 percent reduction in stomach cancer odds, whereas consumption of fresh fish doesn’t appear associated with stomach cancer either way.
A review of sixty studies found that the consumption of pickled foods was associated with significantly higher rates of stomach cancer, though more so in Korea than Japan, perhaps because per-capita Korean consumption of salt-fermented vegetables, like kimchi, is five to eight times greater. You can’t know for sure though, until you put it to the test.
Pickled vegetable extracts can cause DNA damage in cells in a petri dish, but what about in people? Researchers in Vancouver fed people 30 ounces of fukujinzuke (assorted vegetables pickled in soy sauce) or pickled cucumbers over a three-day period. Biopsies taken from their stomach lining before the experiment started were normal, as were the biopsies taken after eating fresh carrots or cucumbers. But after just a few days of consuming pickled vegetables, moderate to severe tissue abnormalities were found, suggestive of stomach irritation.
The consumption of non-fermented soy foods, such as tofu, edamame, and soymilk, is linked to a lower risk of stomach cancer in Japan, whereas no association was found with fermented soy foods—even highly salted miso. The protection afforded by soy foods was attributed to the anti-inflammatory and anti-oxidant effects of the isoflavone compounds in soybeans.
Salt itself isn’t considered a direct carcinogen, but it may damage the stomach lining, thin the protective mucus layer, enhance H. pylori colonization, enhance the penetration of carcinogens, and enhance the formation of carcinogens. Even moderately high salt intake is associated with significantly increased risk of stomach cancer, though in Japan this effect may be limited to those already suffering from H. pylori-induced inflammation.
H. pylori is typically treated with a cocktail of multiple antibiotics. Is there any way to eradicate it naturally through diet? We’ll find out next.
Please consider volunteering to help out on the site.
- Murray CJ. Why is Japanese life expectancy so high? Lancet. 2011;378(9797):1124-5.
- Tada N, Maruyama C, Koba S, et al. Japanese dietary lifestyle and cardiovascular disease. J Atheroscler Thromb. 2011;18(9):723-34.
- Wynder EL, Fujita Y, Harris RE, Hirayama T, Hiyama T. Comparative epidemiology of cancer between the United States and Japan. A second look. Cancer. 1991;67(3):746-63.
- McCarty MF. Minimizing the cancer-promotional activity of cox-2 as a central strategy in cancer prevention. Med Hypotheses. 2012;78(1):45-57.
- Stemmermann GN, Kolonel LN. Talc-coated rice as a risk factor for stomach cancer. Am J Clin Nutr. 1978;31(11):2017-9.
- Inoue M, Tsugane S. Epidemiology of gastric cancer in Japan. Postgrad Med J. 2005;81(957):419-24.
- Asaka M, Mabe K. Strategies for eliminating death from gastric cancer in Japan. Proc Jpn Acad Ser B Phys Biol Sci. 2014;90(7):251-8.
- Humans IWG on the E of CR to. Schistosomes, Liver Flukes and Helicobacter Pylori. IARC. 1994;61:220.
- Peleteiro B, Bastos A, Ferro A, Lunet N. Prevalence of Helicobacter pylori infection worldwide: a systematic review of studies with national coverage. Dig Dis Sci. 2014;59(8):1698-709.
- Holcombe C. Helicobacter pylori: the African enigma. Gut. 1992;33(4):429-31.
- Misra V, Pandey R, Misra SP, Dwivedi M. Helicobacter pylori and gastric cancer: Indian enigma. World J Gastroenterol. 2014;20(6):1503-9.
- Fock KM. Review article: the epidemiology and prevention of gastric cancer. Aliment Pharmacol Ther. 2014;40(3):250-60.
- Plummer M, de Martel C, Vignat J, Ferlay J, Bray F, Franceschi S. Global burden of cancers attributable to infections in 2012: a synthetic analysis. Lancet Glob Health. 2016;4(9):e609-16.
- Yamaguchi N, Kakizoe T. Synergistic interaction between Helicobacter pylori gastritis and diet in gastric cancer. Lancet Oncol. 2001;2(2):88-94.
- Goh KL, Cheah PL, Md N, Quek KF, Parasakthi N. Ethnicity and H. pylori as risk factors for gastric cancer in Malaysia: A prospective case control study. Am J Gastroenterol. 2007;102(1):40-5.
- Fang X, Wei J, He X, et al. Landscape of dietary factors associated with risk of gastric cancer: A systematic review and dose-response meta-analysis of prospective cohort studies. Eur J Cancer. 2015;51(18):2820-32.
- Ren JS, Kamangar F, Forman D, Islami F. Pickled food and risk of gastric cancer—a systematic review and meta-analysis of english and chinese literature. Cancer Epidemiol Biomarkers Prev. 2012;21(6):905-15.
- Cheng SJ, Sala M, Li MH, Wang MY, Pot-Deprun J, Chouroulinkov I. Mutagenic, transforming and promoting effect of pickled vegetables from Linxian county, China. Carcinogenesis. 1980;1(8):685-92.
- MacDonald WC, Anderson FH, Hashimoto S. Histological effect of certain pickles on the human gastric mucos. Can Med Assoc J. 1967;96(23):1521-5.
- Wada K, Tsuji M, Tamura T, et al. Soy isoflavone intake and stomach cancer risk in Japan: From the Takayama study. Int J Cancer. 2015;137(4):885-92.
- Ko KP, Park SK, Yang JJ, et al. Intake of soy products and other foods and gastric cancer risk: a prospective study. J Epidemiol. 2013;23(5):337-43.
- Kim HJ, Lim SY, Lee JS, et al. Fresh and pickled vegetable consumption and gastric cancer in Japanese and Korean populations: A meta-analysis of observational studies. Cancer Sci. 2010;101(2):508-16.
- Rojas‐Campos N, Sigarán MF, Bravo AV, Jimenez‐Ulate F, Correa DP. Salt enhances the mutagenicity of nitrosated black beans. Nutr Cancer. 1990;14(1):1-3.
- D’Elia L, Rossi G, Ippolito R, Cappuccio FP, Strazzullo P. Habitual salt intake and risk of gastric cancer: A meta-analysis of prospective studies. Clin Nutr. 2012;31(4):489-98.
- Shikata K, Kiyohara Y, Kubo M, et al. A prospective study of dietary salt intake and gastric cancer incidence in a defined Japanese population: The Hisayama study. Int J Cancer. 2006;119(1):196-201.
- Chey WD, Leontiadis GI, Howden CW, Moss SF. Acg clinical guideline: treatment of helicobacter pylori infection. Am J Gastroenterol. 2017;112(2):212-39.
- Coleman J. Johnson & Johnson ordered to pay $2.1 billion in baby powder lawsuit. The Hill. June 23, 2020.
Motion graphics by Avo Media
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
For decades, Japan has had the longest life expectancy in the world, while spending just a fraction on healthcare compared to other high-income countries. This longevity has been attributed in part to Japanese dietary patterns, which are thought to have contributed to their comparatively low rates of coronary artery disease. Japan has historically had among the lowest rates of colon cancer, breast cancer, ovarian cancer, prostate cancer, bladder cancer, and blood cancers. Japan, however, has among the highest rates of stomach cancer. Yes, Japanese men may have had seven times less prostate cancer than Americans but got six times more stomach cancer. Is there some Achilles’ heel in the Japanese diet?
One of the first theories, proposed in the 1970s, was that it was the talc used to polish white rice to give it a glossy sheen. That was the case with ovarian cancer, which led to billions in damages against Johnson & Johnson’s baby powder, as I detailed in a previous video, but that did not appear to be the case with stomach cancer. Is it just genetics? No. Studies on Japanese migrants show that as they and their children Westernize their diets and lifestyles, their stomach cancer rates drop accordingly.
Well, the most well-established risk factor for stomach cancer is H. pylori, a bacteria that infects the lining of the stomach and causes the chronic inflammation that can lead to cancer. H. pylori infection is considered a Group 1 carcinogen, indicating our highest level of certainty that it indeed causes cancer. Korea and Japan have the highest rates of stomach cancer, and among the highest incidence of H. pylori infection. Case closed, then, right? The mystery seemed to have been solved.
But then came the “African enigma.” Countries such as Nigeria had even more H. pylori, but only a fraction of Japan’s stomach cancer rates. Then came the “Indian enigma.” H. pylori is twice as prevalent in India than Japan, yet Indians get ten times less stomach cancer. Obviously, H. pylori alone can’t explain Japan’s epidemic.
Though most cases of stomach cancer are thought to be caused by H. pylori, most people with H. pylori don’t get cancer. H. pylori is one of the most common human infections. It has been estimated that half of the world’s adult population is infected with H. pylori, yet half of us don’t get stomach cancer. There must be some kind of co-factor in countries like Korea and Japan that explains their elevated cancer rates. The inflammation caused by H. pylori may just set the stage for cancer formation, increasing the susceptibility of the stomach lining to dietary carcinogens. But what’s so carcinogenic about Korean and Japanese diets?
Studies that have compared the dietary components of different Asian populations with similar H. pylori rates, but dramatically different stomach cancer rates, have suggested preserved, salted foods—both fish and vegetables—as the culprits. Fresh vegetables and fruits, on the other hand, were associated with an 85 percent reduction in stomach cancer odds, whereas consumption of fresh fish doesn’t appear associated with stomach cancer either way.
A review of sixty studies found that the consumption of pickled foods was associated with significantly higher rates of stomach cancer, though more so in Korea than Japan, perhaps because per-capita Korean consumption of salt-fermented vegetables, like kimchi, is five to eight times greater. You can’t know for sure though, until you put it to the test.
Pickled vegetable extracts can cause DNA damage in cells in a petri dish, but what about in people? Researchers in Vancouver fed people 30 ounces of fukujinzuke (assorted vegetables pickled in soy sauce) or pickled cucumbers over a three-day period. Biopsies taken from their stomach lining before the experiment started were normal, as were the biopsies taken after eating fresh carrots or cucumbers. But after just a few days of consuming pickled vegetables, moderate to severe tissue abnormalities were found, suggestive of stomach irritation.
The consumption of non-fermented soy foods, such as tofu, edamame, and soymilk, is linked to a lower risk of stomach cancer in Japan, whereas no association was found with fermented soy foods—even highly salted miso. The protection afforded by soy foods was attributed to the anti-inflammatory and anti-oxidant effects of the isoflavone compounds in soybeans.
Salt itself isn’t considered a direct carcinogen, but it may damage the stomach lining, thin the protective mucus layer, enhance H. pylori colonization, enhance the penetration of carcinogens, and enhance the formation of carcinogens. Even moderately high salt intake is associated with significantly increased risk of stomach cancer, though in Japan this effect may be limited to those already suffering from H. pylori-induced inflammation.
H. pylori is typically treated with a cocktail of multiple antibiotics. Is there any way to eradicate it naturally through diet? We’ll find out next.
Please consider volunteering to help out on the site.
- Murray CJ. Why is Japanese life expectancy so high? Lancet. 2011;378(9797):1124-5.
- Tada N, Maruyama C, Koba S, et al. Japanese dietary lifestyle and cardiovascular disease. J Atheroscler Thromb. 2011;18(9):723-34.
- Wynder EL, Fujita Y, Harris RE, Hirayama T, Hiyama T. Comparative epidemiology of cancer between the United States and Japan. A second look. Cancer. 1991;67(3):746-63.
- McCarty MF. Minimizing the cancer-promotional activity of cox-2 as a central strategy in cancer prevention. Med Hypotheses. 2012;78(1):45-57.
- Stemmermann GN, Kolonel LN. Talc-coated rice as a risk factor for stomach cancer. Am J Clin Nutr. 1978;31(11):2017-9.
- Inoue M, Tsugane S. Epidemiology of gastric cancer in Japan. Postgrad Med J. 2005;81(957):419-24.
- Asaka M, Mabe K. Strategies for eliminating death from gastric cancer in Japan. Proc Jpn Acad Ser B Phys Biol Sci. 2014;90(7):251-8.
- Humans IWG on the E of CR to. Schistosomes, Liver Flukes and Helicobacter Pylori. IARC. 1994;61:220.
- Peleteiro B, Bastos A, Ferro A, Lunet N. Prevalence of Helicobacter pylori infection worldwide: a systematic review of studies with national coverage. Dig Dis Sci. 2014;59(8):1698-709.
- Holcombe C. Helicobacter pylori: the African enigma. Gut. 1992;33(4):429-31.
- Misra V, Pandey R, Misra SP, Dwivedi M. Helicobacter pylori and gastric cancer: Indian enigma. World J Gastroenterol. 2014;20(6):1503-9.
- Fock KM. Review article: the epidemiology and prevention of gastric cancer. Aliment Pharmacol Ther. 2014;40(3):250-60.
- Plummer M, de Martel C, Vignat J, Ferlay J, Bray F, Franceschi S. Global burden of cancers attributable to infections in 2012: a synthetic analysis. Lancet Glob Health. 2016;4(9):e609-16.
- Yamaguchi N, Kakizoe T. Synergistic interaction between Helicobacter pylori gastritis and diet in gastric cancer. Lancet Oncol. 2001;2(2):88-94.
- Goh KL, Cheah PL, Md N, Quek KF, Parasakthi N. Ethnicity and H. pylori as risk factors for gastric cancer in Malaysia: A prospective case control study. Am J Gastroenterol. 2007;102(1):40-5.
- Fang X, Wei J, He X, et al. Landscape of dietary factors associated with risk of gastric cancer: A systematic review and dose-response meta-analysis of prospective cohort studies. Eur J Cancer. 2015;51(18):2820-32.
- Ren JS, Kamangar F, Forman D, Islami F. Pickled food and risk of gastric cancer—a systematic review and meta-analysis of english and chinese literature. Cancer Epidemiol Biomarkers Prev. 2012;21(6):905-15.
- Cheng SJ, Sala M, Li MH, Wang MY, Pot-Deprun J, Chouroulinkov I. Mutagenic, transforming and promoting effect of pickled vegetables from Linxian county, China. Carcinogenesis. 1980;1(8):685-92.
- MacDonald WC, Anderson FH, Hashimoto S. Histological effect of certain pickles on the human gastric mucos. Can Med Assoc J. 1967;96(23):1521-5.
- Wada K, Tsuji M, Tamura T, et al. Soy isoflavone intake and stomach cancer risk in Japan: From the Takayama study. Int J Cancer. 2015;137(4):885-92.
- Ko KP, Park SK, Yang JJ, et al. Intake of soy products and other foods and gastric cancer risk: a prospective study. J Epidemiol. 2013;23(5):337-43.
- Kim HJ, Lim SY, Lee JS, et al. Fresh and pickled vegetable consumption and gastric cancer in Japanese and Korean populations: A meta-analysis of observational studies. Cancer Sci. 2010;101(2):508-16.
- Rojas‐Campos N, Sigarán MF, Bravo AV, Jimenez‐Ulate F, Correa DP. Salt enhances the mutagenicity of nitrosated black beans. Nutr Cancer. 1990;14(1):1-3.
- D’Elia L, Rossi G, Ippolito R, Cappuccio FP, Strazzullo P. Habitual salt intake and risk of gastric cancer: A meta-analysis of prospective studies. Clin Nutr. 2012;31(4):489-98.
- Shikata K, Kiyohara Y, Kubo M, et al. A prospective study of dietary salt intake and gastric cancer incidence in a defined Japanese population: The Hisayama study. Int J Cancer. 2006;119(1):196-201.
- Chey WD, Leontiadis GI, Howden CW, Moss SF. Acg clinical guideline: treatment of helicobacter pylori infection. Am J Gastroenterol. 2017;112(2):212-39.
- Coleman J. Johnson & Johnson ordered to pay $2.1 billion in baby powder lawsuit. The Hill. June 23, 2020.
Motion graphics by Avo Media
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The Role of Kimchi and H. Pylori in Stomach Cancer
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Content URLDoctor's Note
Stay tuned for the follow-up video: How to Treat H. Pylori Naturally with Diet.
The talc video I mentioned was Talcum Powder and Fibroids.
I previously talked about Japan’s stomach cancer rates in Vegetarians and Stroke Risk Factors: Saturated Fat, and Is Miso Healthy? has more on salt consumption and cancer.
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