Stool Testing and Colon Health

Testing performed on fecal matter can provide useful information concerning colon health as well as providing information on pancreatic functioning, absorption, and digestion all along the intestinal pathway.

The short chain fatty acid(SCFA), n-butyrate, is absorbed easily from the colon and serve as a pool of energy for the colonic cells.1(451) The bacteria in the colon will ferment complex carbohydrates that are not digested in the small intestines, creating SCFAs such as acetate, proprionate, and butyrate that serve to promote the function of the large bowel.2 The SCFAs in the colon act to help regulate colonic motility, to promote visceral blood flow, and to help prevent bacteria overgrowth in the lumen.2 Higher levels of butyrate, in particular has been associated with a lowered risk of colorectal cancers.2

Diets higher in complex carbohydrates, non-starch polysaccharides (NSP), and resistant starch (RS) promote SCFA production.2 Studies have shown that diets higher in resistant starch(RS) favors butyrate production over non-starch polysaccharies (NSP).2 I found it interesting that in a study of Africans with diets high in RS over NSP as compared to Europeans with a diet higher in processed foods, but higher in total fiber revealed a lower colorectal cancer risk indicating that resistant starch is particularly protective due to its ability in butyrate production.2 Resistant starch is considered the third type of starch and is very resistant to digestion in the small intestines and goes to the colon and acts as a source of dietary fiber.3

There are four types of resistant starch:

• RS1 – this type of starch is physically undigestable that is found in seeds, legumes, and unprocessed whole grains.3
• RS2 – this type of starch is present in whole glandular form and is found in foods such as uncooked potatoes, green bananas, and high amylose corn.3
• RS3 – this type of starch is formed by cooking and cooling starch containing foods such as legumes, bread, cornflakes, potatoes, sushi rice, or pasta salad.3
• RS4 – this type of starch is synthetic and has been chemically modified to resist digestion.3

In individuals with low fecal butyrate levels could be at a higher risk for inflammatory bowel disease, ulcerative colitis, and colon cancer.1(451) Thus, the fecal stool test can be an invaluable tests in helping to evaluate an individuals’ diet and focus could be placed on encouraging the consumption of foods that promote SCFA production.

A stool analysis can provide useful information on Fecal pancreatic elastase along with fecal protein, meat and vegetable fibers can help determine pancreatic sufficiency and the need for supplemental pancreatic enzyme and betaine HCl supplementation.1(421)

Pancreatic enzymes also help facilitate fat absorption, and fat excretion is normally about 6g/day, but this doesn’t distinguish between poor fat digestion from poor fat absorption.1(422) By looking at fecal triglycerides a determination can be made as to why there is excessive fat in the stools. High triglycerides in the stool is indicative of incomplete fat hydrolysis (poor digestion of fat), most likely due to pancreatic lipase secretion or activation.1(422) Normal levels of triglycerides in the stool accompanied with excessive long-chained free fatty acids (carbon length > 12) is indicative of fat malabsorption.1(422)

A diet high in the ratio of polyunsaturated to saturated fatty acids will result in increased fecal steroids.1(422) Fecal cholesterol can be measured in the stool testing and can be manipulated by diet, as increasing the PUFA ratio to saturated fats in the diet can lower the absorption of cholesterol in the intestines.1(422) Further investigation of the stool sample can provide information on the presence of meat and vegetable fibers which can be an indirect measure of low stomach acid or a lack of pancreatic enzymes.1(422)

Leaky gut is a term that is given to a problem with the tight junctions that separate the intestinal lumen from the body. These tight junctions are important in preventing large molecules from penetrating the intestines that can cause an immune response, which happens when large quantities of food antigens pass through this barrier.1(425) The damage of these tight junctions can happen due to various reasons such as: NSAID use, alcohol ingestion, infections from viruses, bacteria, or protozoals.1(425) High oxidative stress produces reactive oxygen species (ROS) that can also contribute to leaky gut.1(425)

Once we gather information about the health of the intestines and its capability of absorbing nutrients we can formulate a plan of action on how to address the restoration and repair of gastric pH, pancreatic enzymes, and intestinal permeability.

1. Lord, R.S., Bralley, J.A. Laboratory Evaluations for Integrative and Functional Medicine. Revised 2nd Edition.2012. Metametrix Institute. Duluth, GA.
2. Mcorist A, Miller R, Bird A, etal. Fecal Butyrate Levels Vary Widely Among Individuals but are Usually Increased by a Diet High in Resistant Starch. The Journal of Nutrition. May 2011. Vol 141(5):883-9. doi: 10.3945/jn.110.128504.
3. Wikipedia Encyclopedia. http://en.wikipedia.org/wiki/Resistant_starch. Accessed April 30, 2015.