, Volume 10, Issue 6, pp 379–384 | Cite as

The intestinal microflora and its colon cancer connection

  • S. L. Gorbach
The Fifth Sils Maria Symposium


Epidemiologic studies suggest that the incidence of colon cancer is influenced by environmental factors, especially diet. The high beef-high fat-low fiber diet of Western societies is associated with a high risk of colon cancer. The intestinal microflora may play a role in colon cancer by metabolic activation of procarcinogens in the lumen of the large bowel. The link between diet and colon cancer can be explained, in part, by the alterations in fecal bacterial enzyme activity induced by a Western-style diet. For example, fecal bacterial β-glucuronidase, nitroreductase, azoreductase and steroid 7-α-dehydroxylase activities are increased in animals or humans consuming a high beef diet. These enzyme activities can be reduced by eating a grain diet, by the addition ofLactobacillus acidophilus to the diet, or by administration of low dose antibiotics. In experimental animals these three measures to reduce the activity of the microflora also produce few colon tumors in animals given the chemical carcinogen dimethylhydrazine. Further studies are needed to establish whether alterations in the metabolism of the colonic microflora can reduce the risk of large bowel cancer in humans.


Colon Cancer Fiber Diet Large Bowel Intestinal Microflora Chemical Carcinogen 
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Die Darmflora und ihre Beziehung zum Kolonkarzinom


Epidemiologische Studien lassen annehmen, daß die Inzidenz des Dickdarmkarzinoms von Umweltfaktoren, insbesondere der Ernährung, beeinflußt wird. Die faserarme Nahrung westlicher Länder mit ihrem hohen Gehalt an Rindfleisch und Fett ist mit einem hohen Risiko für Dickdarmkrebs assoziiert. Die Mikroflora des Darmes beeinflußt möglicherweise den Dickdarmkrebs durch metabolische Aktivierung von Prokarzinogenen. Der Zusammenhang zwischen Ernährung und Kolonkarzinom kann zum Teil dadurch erklärt werden, daß westliche Ernährungsgewohnheiten die Enzymaktivität der Darmbakterien ändern. Bei Tieren oder bei Menschen, die mit viel Rindfleisch ernährt werden, sind beispielsweise die Aktivitäten der Darmbakterien-Enzyme β-Glukuronidase, Nitroreduktase, Azoreduktase und Steroid-7-α-dehydroxylase erhöht. Durch Körnerdiät, durch Zusatz vonLactobacillus acidophilus zur Nahrung oder durch Gabe von nieder dosierten Antibiotika können diese Enzymaktivitäten vermindert werden. Diese drei Maßnahmen zur Verminderung der Aktivität der Mikroflora führen bei Laboratoriumstieren dazu, daß nach Gabe des chemischen Karzinogens Dimethylhydrazin nur wenige Kolontumoren auftreten. Daß Änderungen im Stoffwechsel der Darmflora auch beim Menschen das Risiko für den Dickdarmkrebs vermindern, muß erst durch weitere Untersuchungen belegt werden.


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  1. 1.
    Moore, W. E. C., Holdeman, L. V. Discussion of current bacteriologic investigations of the relationship between intestinal flora, diet, and colon cancer. Cancer Res. 35 (1975) 3418–3420.Google Scholar
  2. 2.
    Drasar, B. S., Shiner, M., McLeod, G. M. Studies on the intestinal flora. I. The bacterial flora of the gastrointestinal tract in healthy and achlorhydric persons. Gastroenterology 56 (1969) 71–79.Google Scholar
  3. 3.
    Gorbach, S. L., Levitan, R. Intestinal flora in health and in gastrointestinal diseases. In:Glass, G. B. J. (ed.): Progress in gastroenterology. Vol. II. Gruene and Stratton, New York 1970, pp. 252–275.Google Scholar
  4. 4.
    Gorbach, S. L., Plaut, A. G., Nahas, L., Weinstein, L. Studies of intestinal microflora. II. Microorganisms of the small intestine and their relations to oral and fecal flora. Gastroenterology 53 (1967) 856–867.Google Scholar
  5. 5.
    Cregan, J., Hayward, N. J. The bacterial content of the healthy human small intestine. Br. Med. J. 1 (1953) 1356–1359.Google Scholar
  6. 6.
    Donaldson, Jr., R. M. The relation of enteric bacterial population to gastrointestinal function and disease. In:Sleisenger, M. H., Fordtran, J. S. (eds.): Gastrointestinal disease. W. B. Saunders, Philadelphia 1978, pp. 79–92.Google Scholar
  7. 7.
    Gorbach, S. L. Intestinal microflora. Gastroenterology 60 (1971) 1110–1129.Google Scholar
  8. 8.
    Donaldson, Jr., R. M. Normal bacterial populations of the intestine and their relation to intestinal function. N. Engl. J. Med. 270 (1964) 938–945, 994–1001, 1050–1056.Google Scholar
  9. 9.
    Moore, W. E. C., Holdeman, L. V. Human fecal flora; the normal flora of 20 Japanese-Hawaiians. Appl. Microbiol. 27 (1974) 961–979.Google Scholar
  10. 10.
    Finegold, S. M., Sutter, V. L., Sugihara, P. T., Elder, H. A., Lehamm, S. M., Phillips, R. L. Fecal microbial flora in Seventh Day Adventist populations and control subjects. Am. J. Clin. Nutr. 30 (1977) 1781–1792.Google Scholar
  11. 11.
    Gorbach, S. L., Nahas, L., Lerner, P. I., Weinstein, L. Studies of intestinal microflora. I. Effects of diet, age, and periodic sampling on numbers of fecal microorganisms in man. Gastroenterology 53 (1967) 845–855.Google Scholar
  12. 12.
    Hill, M. J., Drasar, B. S. The normal colonic bacterial flora. Gut 16 (1975) 318–323.Google Scholar
  13. 13.
    Haenszel, W., Berg. J. W., Seig, M., Kurihara, M., Locke, F. B. Large bowel cancer in Hawaiian Japanese. J. Natl. Cancer Inst. 51 (1973) 1765–1779.Google Scholar
  14. 14.
    Drasar B. S., Irvind, D. Environmental factors and cancer of the colon and breast. Br. J. Cancer 27 (1973) 167–172.Google Scholar
  15. 15.
    Armstrong, B., Doll, R. Environmental factors and cancer incidence and mortality in different countries, with special reference to dietary practices. Int. J. Cancer 15 (1975) 617–631.Google Scholar
  16. 16.
    Hill, M. J., Drasar, B. S., Hawksworth, G., Williams, R. E. Bacteria and aetiology of cancer of large bowel. Lancet I (1971) 95–100.Google Scholar
  17. 17.
    Reddy, B. S., Wynder, E. L. Large bowel carcinogenesis: Fecal constituents of populations with diverse incidence rates of colon cancer. J. Natl. Cancer Inst. 50 (1973) 1437–1442.Google Scholar
  18. 18.
    Fischer, L. J., Millburn, P., Smith, R. L., Williams, R. T. The fate of (14C) stilboestrol in the rat. Biochem. J. 100 (1966) 69.Google Scholar
  19. 19.
    Laqueur, G. L., Mickelsen, O., Whiting, M. G., Kurland, L. T. Carcinogenic properties of nuts fromCycas circinalis indigenous to Guam. J. Natl. Cancer Inst. 31 (1963) 919–933.Google Scholar
  20. 20.
    Laqueur, G. L. Carcinogenic effects of cycad meal and cycasin, methylazoxymethanol glycoside, in rats and effects of cycasin in germ free rats. Fed. Proc. 23 (1964) 1386–1387.Google Scholar
  21. 21.
    Laqueur, G. L., McDaniel, E. G., Matsumoto, H. Tumor induction in germ free rats with methylazoxymethanol (MAM) and synthetic MAM acetate. J. Natl. Cancer Inst. 39 (1967) 355–371.Google Scholar
  22. 22.
    Laqueur, G. L. The induction of intestinal neoplasms in rats with the glycoside cycasin and its aglycone. Virchow Arch. Pathol. Anat. 340 (1965) 151–163.Google Scholar
  23. 23.
    Laqueur, G. L., Spatz, M. Toxicology of cycasin. Cancer Res. 28 (1968) 2262–2267.Google Scholar
  24. 24.
    Asatoor, A. M. Aromatisation of quinic acid and shikimic acid by bacteria and the production of urinary hippurate. Biochim. Biophys. Acta 100 (1965) 290–292.Google Scholar
  25. 25.
    Randomski, J. L., Mellinger, T. J. The absorption, fate and excretion in rats of the water-soluble azo dyes, FD&C Red No. 4 and FD&C Yellow No. 6. J. Pharmacol. Exp. Ther. 136 (1962) 259–266.Google Scholar
  26. 26.
    Maier, B. R., Flynn, M. A., Burton, C. G., Tsutakawa, R. K., Hentges, D. J. Effects of a high-beef diet on bowel flora: A preliminary report. Am. J. Clin. Nutr. 27 (1974) 1470–1474.Google Scholar
  27. 27.
    Drasar, B. S., Jenkins, D. J., Cummings, J. H. The influence of a diet rich in wheat fibre on the human faecal flora. J. Med. Microbiol. 9 (1976) 423–431.Google Scholar
  28. 28.
    Mastromarino, A., Reddy, B. S., Wynder, E. L. Metabolic epidemiology of colon cancer: Enzymic activity of fecal flora. Am. J. Clin. Nutr. 29 (1976) 1455–1460.Google Scholar
  29. 29.
    Reddy, B. S., Weisburger, J. H., Wynder, E. L. Fecal bacterial beta-glucuronidase: Control by diet. Science 183 (1974) 416–417.Google Scholar
  30. 30.
    Weisburger, J. H., Grantham, P. H., Horton, R. E., Weisburger, E. K. Metabolism of the carcinogen N-hydroxy-N-2-fluorenylacetamide in germ-free rats. Biochem. Pharmacol. 19 (1970) 151–162.Google Scholar
  31. 31.
    Grantham, P. H., Horton, R. E., Weisburger, E. K., Weisburger, J. H. Metabolism of the carcinogen N-2 fluorenylacetamide in germ-free and conventional rats. Biochem. Pharmacol. 19 (1970) 163–171.Google Scholar
  32. 32.
    Goldin, B. R., Gorbach, S. L. The relationship between diet and rat fecal bacterial enzymes implicated in colon cancer. J. Natl. Cancer Inst. 57 (1976) 371–375.Google Scholar
  33. 33.
    Paul, D., Hoskins, L. C. Effect of oralLactobacillus feedings on fecal lactobacillus counts. Am. J. Clin. Nutr. 25 (1972) 763–765.Google Scholar
  34. 34.
    Macbeth, W. A., Kass, E. H., McDermott, W. V., Jr. Treatment of hepatic encephalopathy by alteration of intestinal flora withLactobacillus acidophilus. Lancet I (1965) 399–403.Google Scholar
  35. 35.
    Read, A. E., McCarthy, C. F., Heaton, K. W., Laidlaw, J. Lactobacillus acidophilus (enpac) in treatment of hepatic encephalopathy. Br. Med. J. 5498 (1966) 1267–1269.Google Scholar
  36. 36.
    Report from the International Agency for Research on Cancer Intestinal Microecology Group: Dietary fibre, transit time, faecal bacteria, steroids, and colon cancer in two Scandinavian populations. Lancet II (1977) 207.Google Scholar
  37. 37.
    Goldin, B. R., Gorbach, S. L. Alterations in fecal microflora enzymes related to diet, age, lactobacillus supplements, and dimethylhydrazine. Cancer 40 (1977) 2421–2426.Google Scholar
  38. 38.
    Goldin, B. R., Swenson, L., Dwyer, J., Sexton, M., Gorbach, S. L. Effect of diet and lactobacillus supplements on human fecal bacterial enzymes. J. Natl. Cancer Inst. 64 (1980) 255.Google Scholar
  39. 39.
    Goldin, B. R., Gorbach, S. L. The effect ofLactobacillus acidophilus dietary supplement on DMH-induced colon cancer in rats. J. Natl. Cancer Inst. 64 (1980) 263–265.Google Scholar
  40. 40.
    Goldin, B. R., Gorbach, S. L. Effect of antibiotics on incidence of rat intestinal tumors induced by 1, 2-dimethylhydrazine dihydrochloride. J. Natl. Cancer Inst. 67 (1981) 877–880.Google Scholar

Copyright information

© MMW Medizin Verlag 1982

Authors and Affiliations

  • S. L. Gorbach
    • 1
  1. 1.Department of MedicineInfectious Disease Division, Tufts-New England Medical CenterBostonUSA

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