Previous studies of colorectal neoplasia and fecal composition have been inconsistent. Therefore a team from the United Kingdom and Germany tested fecal bile acids, calcium, and pH in patients who had participated in fecal occult blood screening.
They obtained fecal samples from 45 patients with cancer and 129 with adenoma. They also obtained samples from 155 fecal occult blood-positive patients in whom no cancer or adenoma had been found, and from 167 fecal occult blood-negative controls.
The concentrations of fecal bile acids, steroids, calcium, and pH were assessed. These were compared within and between patient groups.
The team observed no association between colorectal cancer and fecal bile acids or pH.
They also found no overall association between colorectal adenomas and fecal bile acids or pH.
| No association between colorectal adenomas and fecal bile acids.|
|Diseases of the Colon & Rectum|
However, it was discovered that villous adenomas were associated with increasing concentrations of major bile acids and decreasing concentration of minor bile acids.
In addition, there was a suggestion of an inverse association with an acid pH.
The researchers found that high levels of fecal calcium were linked with a reduced risk of both colorectal cancer and adenoma. This was not found to be statistically significant.
Dr Julian Little's team concluded, "The study does not support an association between colorectal cancer and fecal bile acids or pH".
"However, there is evidence that increases in major bile acids are associated with villous adenomas".