Olestra and Gastrointestinal Problems

Olestra consumption has been implicated in causing several gastrointestinal problems. Here we will look at some of the common and somewhat infamous symptoms of olestra and the studies that describe them:

Steatorrhea

Steatorrhea is the gross appearance of fat in feces caused by the inadequate absorption of fat in the intestines. It is associated with sever diarrhea and with inadequate absorption of water and fat-soluble vitamins (McMurray 1983.) A study by Balasekaran et al. (2000) looked at the ingestion of olestra and the measurement of fecal fat content. They found that when participants ingested the largest amount of olestra, their fecal fat content was consistent with that of a patient with steatorrhea. Since olestra does not cause malabsorption of triglycerides and other normal fats, they concluded that olestra consumption gives false-positive results of steatorrhea.

Oil Leakage

Oil leakage is caused by liquid fat disassociating from fecal material and remaining in a liquid state through the large intestine. Olestra that has a low melting point remains a liquid through the digestive tract and is more likely to separate from hydrophilic fecal material because it is hydrophobic. The separation, which occurs when olestra is consumed in high quantities, results in leakage of liquid oil from the anal sphincter. Occurrences of leakage are measured by oil droplets in the toilet seen during bowel movements and by stains in subject’s underwear. There is a negative correlation between the occurrence of oil leakage and the stiffness of olestra; olestra with a higher boiling point remains more solid in the intestine and does not separate from feces while olestra with a lower boiling point is more liquid and tends to separate (Federal Register 1996.) Jandacek cautions that one should be mindful that this study tested amounts of olestra that were 3-4 times the 90 th percentile of chronic daily consumption. In studies where subjects ate olestra-containing foods at will, the results of oil leakage and all other potential gastrointestinal problems were not different from the results in the placebo group (Zorich et al 1997, Cheskin et al. 1998.)

Stool Softening and other Effects

McRorie, Kesler et al. (2000) compared consumption of wheat bran and olestra and subjective reports of gastrointestinal problems. They found that when consuming high amounts of olestra for several days, there is a gradual stool softening effect, but there is not a significant increase in stool output. The same study mentioned above that found an increase in oil leakage also found that there was a significantly higher report of soft and loose stools, flatulence, urgency, and abdominal pain and cramping than in the control group (Federal Register 1996.) Again, however, one must consider the increased dosage and the other studies that report no significant differences in symptoms when olestra ingestion is a normal amount.

Most studies look favorably on olestra and report that there are no significantly different gastrointestinal effects when olestra consumption is compared to normal dietary fat consumption. However, it is hard to ignore the case studies and personal testimonies of the effects of olestra on one’s gastrointestinal tract. Take for example Barlam’s and McCloud’s (2003) account of two children who had consumed olestra snacks. One patient, and 11-year-old girl, showed signs of oil leakage within hours of ingesting olestra chips. She developed lower abdominal pains and cramping with “foul-smelling, oily, diarrheal bowel movements three to four times daily.” Ttwo weeks after discontinuation of olestra ingestion, she developed rectal bleeding and was found to have ulcerative colitis throughout her colon. The second patient was a 13-year-old boy who after eating a few chips was unable to produce any stool. This was accompanied by cramping and lower back pain, explosive diarrhea and gas. He eventually had to undergo a colectomy. The doctors were unable to prove that olestra triggered these conditions in either patient. However, they believe that cases such as these serve as important reminders about the potential effects of olestra.