High colonic pH promotes colorectal cancer

Lancet. 1981 May 16;1(8229):1081-3. doi: 10.1016/s0140-6736(81)92244-3.


Considerable evidence suggests that the carcinogens or co-carcinogens responsible for the development of colorectal cancer are either bacterially degraded bile acids or cholesterol. It is proposed that a high colonic pH promotes co-carcinogen formation from these substances and that acidification of the colon either by dietary fibre (following its bacterial digestion to short-chain fatty acids) or milk (in lactose-intolerant individuals) may prevent this process.

MeSH terms

  • Bacteria / metabolism
  • Bile Acids and Salts / metabolism
  • Cholesterol / metabolism
  • Cocarcinogenesis*
  • Colon / microbiology
  • Colonic Neoplasms / etiology*
  • Humans
  • Hydrogen-Ion Concentration*
  • Rectal Neoplasms / etiology*
  • Risk


  • Bile Acids and Salts
  • Cholesterol