Greasy and smelly stools

Question

Why do people with CF have stools that look greasy and smell badly?

Answer

Dear questioner,

The answer to your question is very important and helps to understand why patients with CF need to take pancreatic enzymes with every meal. In 90% of the patients with CF, the secretory ducts of the pancreas, an organ lying in the upper belly behind the liver, are obstructed so that pancreatic enzymes do not reach the first part of the intestine. The normal function of pancreatic enzymes is to digest food so that small particles can go through the intestinal wall and be absorbed in the body. In patients with CF undigested food will appear in the stools. Fat digestion is more disturbed than digestion of carbohydrates and protein. In healthy people more than 93% of the food fat will be digested and absorbed through the intestine. In patients with CF a lot of fat (up to 40% and more of the food fat) will reach the large intestine undigested. That is why the stool will have a greasy aspect. The protein digestion is not normal but to a smaller degree than the fat digestion. Undigested proteins will be digested by bacteria in the large intestine. But in the large intestine small particles of food can no longer pass through the intestinal wall. Protein contains nitrogen and these nitrogen containing ?? products cause the typical bad smell of the stools of CF patients who are not or only partially treated with substitution of pancreatic enzymes. With intake at every meal of the right amount of pancreatic enzymes (several preparations are available commercially) a near normal fat absorption and uptake of food substances is possible and patients no longer have this problem of bad smelling stools. A patient with greasy stools or with realy poorly smelling stools should thus consult his CF-doctor and dietician to see how his situation can be improved.
Yours sincerely,
L. Vanharen, K. De Boeck, M. Proesmans, F. Vermeulen, L. Dupont

24.11.2008