Butterfish and Digestion

Your digestive system is made up of a series of hollow organs and twisted tubes that run from your mouth to your anus. The digestive system produces juices and enzymes that can digest almost any type of food. Certain foods can affect the proper functioning of your gastrointestinal tract, however, and lead to symptoms such as upset stomach, diarrhea and nausea. Butterfish is one such food.

True butterfish, or Scatophagus species, have a distinctive, rich flavor -- hence, the name butterfish. Some other varieties of fish such as escolar, oilfish and rudderfish are also sold as butterfish. All of these varieties of fish generally have a dark color that grows darker with age. They swim fast and are found in tropical and temperate waters around the world. The distinguishing characteristic of these fish is their inability to digest waxy esters called gempylotoxins that are commonly found in their diet. Their consumption of these compounds leads to an increase in the total fat content of these fish.

The gempylotoxin waxy esters found in some butterfish varieties also accumulate in the human body and are discharged via the rectum. This buildup can lead to orange, oily stools or oily diarrhea, according to a study published in a 2009 issue of the journal "Advances in Food and Nutrition Research." The condition is known as keriorrhea. Keriorrhea also leads to other disturbances in the digestive tract including nausea, vomiting and abdominal cramps, reports the study. Health Canada points out that not all people who eat butterfish get keriorrhea. Symptoms begin in 24 to 48 hours, but because no loss of body fluids occurs during the diarrhea, the condition is not life threatening. Butterfish also contain mercury and histidine, which may lead to toxic reactions, warns the website.

Yiu H. Hui, author of the book "Foodborne Disease Handbook," states that no treatment is necessary for gempylotoxin-associated digestive problems. The symptoms generally subside within a few days. If you develop these problems, however, you must be cautious because you may develop unexpected oily stools in some cases.

You must check the type of fish you are eating. Heating does not affect the waxy esters of butterfish. You can reduce the risk of keriorrhea by grilling the fish in a way that removes most of the oil. Pregnant women, children, older adults and those with bowel problems should be cautious when eating butterfish, says Health Canada. A study published in the September 2008 issue of the journal "Food Chemistry" also reveals that certain chemical tests can help identify toxic butterfish that have been mislabeled as other species before they enter the supply chain, and implementation of these tests by suppliers may help prevent outbreaks.