Do tapeworms really make you hungry?

Answers to your questions about the news.
March 31 2006 6:17 PM

I've Got a Tapeworm in Me

Am I hungry?

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Head of a tape worm
Click on image to expand.
Head of a tape worm

After his team advanced to the NCAA Tournament's Final Four on Saturday, LSU's Glen "Big Baby" Davis proclaimed, "We've still got tapeworms in our bellies. We're still hungry." A few days later, ESPN's Rick Majerus predicted a loss for the Tigers in the next round: Big Baby "will have to look elsewhere to feed his tapeworm because he won't be able to eat a [UCLA] Bruin." Do tapeworms really make you hungry?

Daniel Engber Daniel Engber

Daniel Engber is a columnist for Slate

Not usually. In fact, a tapeworm is more likely to make you lose your appetite. That's because the worm can irritate your bowels when it attaches to them with its circular suckers (and, in some cases, its movable hooks). Though the parasite does absorb some of your digested food through its skin, it won't eat enough to make you hungry. (One variety—the "fish tapeworm"—can cause a vitamin B-12 deficiency in some patients.) The worm won't starve you, but irritation of your intestines can cause abdominal pain, diarrhea, nausea, reduced appetite, and weight loss.

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Most patients don't experience any of these symptoms. You probably wouldn't know you had an infection unless you found stray worm segments—called "proglottids"—swimming in your stool. Each proglottid constitutes a self-contained (hermaphroditic) reproductive organ holding up to 100,000 eggs. A tapeworm reproduces by detaching these sections from its tail, so that the eggs can find their way out of your body and into a new host.

Doctors have described several other symptoms that go along with tapeworm infection in rare cases. Some patients develop headaches, convulsions, or skin rashes. Others actually do see an increase in appetite, just like Glen "Big Baby" Davis. Few comprehensive studies of these unusual symptoms have been completed, and parasitologists don't have a good sense of how prevalent these side effects are.

We do know that the eggs of some kinds of parasites—like the "pork tapeworm"—can become implanted inside your body. * This can cause much more serious complications, as the eggs embed themselves in bodily organs and cause cysts in your liver, lungs, or brain.

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Explainer thanks Peter Schantz of the Centers for Disease Control.

Corrections, April 3, 2006: This piece originally stated that the "pork tapeworm" is notable because it can lay its eggs inside your body. Both beef tapeworms and pork tapeworms can release eggs in your body; pork tapeworms are noteworthy because their eggs can become implanted in your organs. Also, the photograph in this story was originally mislabeled a "beef tapeworm" because of inaccurate caption information provided by Corbis. Beef tapeworms do not have hooks attached to their heads. The specimen pictured belongs to one of the many tapeworm species that do have hooks, such as the pork tapeworm.

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