Tuesday, August 2, 2011

Fruit On An Empty Stomach

As a dietitian, I often get questions about nutrition claims that people hear on television or read on the internet.  One such claim that has been popping up lately is “Is it bad to eat fruit with other foods?”  This question seems to mainly come from an email forward that is attributed to Dr. Oz which claims: “Fruit should be eaten on an empty stomach.”  The article further goes on to say:
          “Let’s say you eat two slices of bread and then a slice of fruit. The slice of fruit is ready to go straight through the stomach into the intestines, but it is prevented from doing so.  In the meantime the whole meal rots and ferments and turns to acid. The minute the fruit comes into contact with the food in the stomach and digestive juices, the entire mass of food begins to spoil….”
First, there is nothing on Dr. Oz’s website or other publications that says or supports this theory, so his authorship is highly questionable.  Second, this email is so widespread that The New York Times asked a gastroenterologist for the answer.  Here is an excerpt from the article which does a great job of explaining why this is untrue:
Q:  Must you eat fruit on an empty stomach, so it won’t mix with other foods and cause fermentation and rot?
A:  “The answer is a definite no,” said Dr. Mark Pochapin, director of the Monahan Center for Gastrointestinal Health at NewYork-Presbyterian Hospital/Weill Cornell Medical Center. “Fruit can be eaten at any time.”  Nothing can rot in the stomach, Dr. Pochapin said. Rotting, or fermentation, means bacterial action on food resulting in decomposition. And because of the presence of hydrochloric acid, the stomach has very few bacteria.  “One of the main purposes of the stomach,” he said, “is to sterilize food by mixing and churning it within the muscular, acid-containing stomach.”  In the days before refrigeration and supermarkets, food spoiled easily, and stomach acid helped protect the body from food poisoning, he said.  “The place where fruit produces gas is in the colon, not the stomach,” Dr. Pochapin said. The colon is loaded with bacteria and acts as the body’s sewage system.  Food takes 6 to 10 hours to reach the colon, which explains why it does not really matter when fruit is eaten, Dr. Pochapin said. Fruit contains sugar and vitamins, which are absorbed in the small intestine, and complex fibers, which pass through the gastrointestinal tract without much digestion. When the fiber reaches the colon, the colonic bacteria feed on the fiber and produce gas as a byproduct, regardless of when and with what the fiber was ingested.
The lesson:  don't believe everything you read in email forwards :)

Reference:  Ray, C. (2010, February 23).  Fruit and fermentation.  The New York Times, p.D2. 


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