Most of the bacteria in the intestine can be divided into two categories: lactic acid bacteria (feed on sugars/carbohydrates) and putrefactive bacteria (feed on proteins).
One theory holds that these intestinal bacteria transform fat into a carcinogen. Another possibility is that – since a person eating meat or egg takes in protein as well as fat – the proteins are being transformed into carcinogens.
Putrefactive bacteria (e.g. Bacteroides, E. coli, Veillonella, and Clostridium) break down proteins into ammonia, hydrogen sulfide, amines, phenol, and indole. Phenol and indole are known promoters of intestinal and other cancers. (They are also components of coal tar.)
A portion of the phenol is reabsorbed by the digestive tract and is detoxified in the liver, either by combining with glucuronic acid or sulfuric acid to form a harmless compound which is then eliminated in the urine; or by being released into the intestines and mixed with bile. The glucuronic acid compound with the bile is reconverted to phenol by the action of an enzyme known as beta-glucuronidase (It is most active in putrefactive bacteria such as E. coli and Clostridium welchii.), which is produced by some intestinal bacteria.
beta-glucuronidase formula This circulation between the intestines and the liver (It is known as enterohepatic circulation.) indicates that some carcinogens are not eliminated, but remain in the body.
enterohepatic circulation diagramBile acids are the main ingredient of bile which aids in the digestion and absorption of fat. However, the remaining bile acids are not absorbed and returned to the liver, but flow into the large intestine. They are converted into secondary bile acids such as deoxycholic acid (deoxycholate) and lithocholic acid (lithocolate) by the action of Veillonella, Bacteroides, and other putrefactive bacteria. When the intestinal wall’s mucous membrane is stimulated by secondary bile acids, it changes appearance. This action is believed to raise the risk of colon cancer.
Lactic acid bacteria feed on sugars to produce lactic acid. Intestine dominated by lactic acid bacteria leans toward acidity that suppresses growth in putrefactive bacteria (which favor an alkaline environment). By weakening the influence of the putrefactive bacteria that produce carcinogens and induce enterohepatic circulation, Lactobacilli can play a significant role in improving the intestinal environment.
(The stool’s color is mainly from bilirubin, a reddish-yellow bile pigment produced in the liver from the hemoglobin contained in old red blood cells. Bilirubin’s color varies with acidity.
Acidic environment: Yellow
Neutral environment: Orange to brown
Alkaline environment: Greenish- or Blackish-brown.)
Lactic acid bacteria feed on sugars to produce lactic acid. Intestine dominated by lactic acid bacteria leans toward acidity that suppresses growth in putrefactive bacteria (which favor an alkaline environment). By weakening the influence of the putrefactive bacteria that produce carcinogens and induce enterohepatic circulation, Lactobacilli can play a significant role in improving the intestinal environment.
(The stool’s color is mainly from bilirubin, a reddish-yellow bile pigment produced in the liver from the hemoglobin contained in old red blood cells. Bilirubin’s color varies with acidity.
Acidic environment: Yellow
Neutral environment: Orange to brown
Alkaline environment: Greenish- or Blackish-brown.)
Reference:
Yoshio Aso (1997) “Lactic Acid Bacteria and Cancer Prevention” Shufunotomo
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