A tapeworm is like something out of a horror movie. It's a wiggly, creepy looking ribbon-shaped creature that lives inside you, absorbing your nutrients and laying millions of eggs. They can reach 20 feet (6.1 meters) or more in length and live for years. And if the idea of having a worm living inside of you doesn't have you shuddering in revulsion, just wait until you hear how they reproduce.
Despite the extreme "gross" factor of tapeworms, some people have suggested that acquiring one intentionally would be a relatively simple way to lose weight. In fact, tapeworm pills may have been sold as weight-loss aids in the past. In some ways, it seems to make a certain amount of sense -- that is, if you can get past the gross-out factor. If a tapeworm is absorbing your body's nutrients and calories, you can eat all you want and enjoy the taste. Then the worm diverts it all before it hits your waistline, right?
We'll find out. Actually, there are lots of rumors and myths surrounding tapeworms, so we're going to untangle this bizarre mystery. How do you get a tapeworm, anyway? Once you have one, how does it come out? Did a legendary opera singer lose her girth (and some say, her voice) by intentionally ingesting a tapeworm? Also, how much weight could a tapeworm really help you lose?
A tapeworm is a parasite through and through. It obtains all its nutrients from the digestive system of its host animal. But here's a strange fact, a tapeworm doesn't even have a digestive system of its own. It absorbs nutrients (mostly carbohydrates and sugars) that have already been partially broken down by the host's digestive system.
An adult tapeworm lives inside the intestines of the host animal, which could be a pig, cow, dog, sheep, fish or even a human. Different species of worm prefer different hosts; although, most can infect several different types of animal. At the top of the worm is the head, called the scolex. The scolex has suckers or hooks that it uses to attach to the intestinal wall. Without this feature, the peristaltic action in the host's intestines -- the rhythmic muscular contractions that move material through the digestive tract -- would push the worm out. Below the scolex is the neck. The rest of the worm's body buds off of the neck.
Here where it starts to get really creepy. The tapeworm's body, called the strobila, is made up of many segments, sometimes thousands. Each individual segment is known as a proglottid. A proglottid is either male or female. The segments closest to the neck are mostly male and produce sperm. Segments farther along the body are female and are basically egg sacks. A tapeworm can produce millions of fertilized eggs. Proglottids frequently break off from the worm and are passed out of the host along with feces. However, each proglottid has functional muscles, allowing it to crawl. Sometimes, a detached proglottid will crawl out of the host through the anus. More often, a proglottid crawls away from the pile of fecal matter left by the host, increasing the chances that it will be eaten by a different animal. Eventually, the proglottid disintegrates, leaving behind the eggs.
When the eggs are eaten by an herbivore, they are "hatched" by the conditions within this intermediate host's digestive system. The larval stage, known as a hexacanth, uses hooks to burrow through the host's intestinal walls to reach the bloodstream. There, it turns into a scolex and forms a cyst. The resulting condition is known as cysticercosis. Pigs, cows and sheep are most commonly infected. Humans can act as an intermediate host for the pig-born species of tapeworm, and therefore can contract cysticercosis. We'll get back to the horrors of cysticercosis in a minute.
Once the cysts form, the parasite simply waits within the host. When the host animal dies, the meat may be eaten by other animals (or by humans) raw or undercooked. The ingested cysts pass into the primary host's digestive system, where the scolex attaches to the intestine wall and the whole cycle begins again.
Cysticercosis, the condition resulting from tapeworm hexacanths burrowing their way into your bloodstream, is not pleasant. The cysts can end up pretty much anywhere in your body, including in your eyes or your brain. The cysts sometimes grow, and they inflame the surrounding tissue. The resulting pressure can cause temporary symptoms or permanent damage, including blindness, brain damage or even death in some extreme cases.
Let's assume that, after reading all of this, you've decided against intentionally acquiring a tapeworm. How can you prevent them? The good news is that, in the United States at least, inspection of meat keeps tapeworms out of the food supply. You apparently can see the cysts in the meat if you know what to look for. Thoroughly freezing meat at 14 degrees F (-10 degrees C) for 10 days, or making sure it is thoroughly cooked will kill any parasites. And if you do acquire a tapeworm, a single dose of praziquantel, an anti-worm medication, will kill it by forcing all its muscles to permanently contract. The tapeworm will then leave your body along with your feces.
Despite all of this grim information, there's still a chance that some people have intentionally acquired a tapeworm to lose weight. Well, did it really happen, and does it work?
There are a few tapeworm legends floating around in addition to the weight-loss one, so let's clear some of those up first. One is that you can get rid of a tapeworm by coaxing it out with a bowl of milk and cookies placed near your mouth. Not true. A tapeworm is not Santa Claus, and not only does it live in your intestine -- with a stomach and esophagus between it and anything near your mouth -- but it doesn't even have any sensory organs that would allow it to detect the presence of food. Remember, this is a very simple creature. It can't smell or see. This is the same reason that putting some enticing food near the other end of your digestive tract won't draw out a tapeworm either. If you have a tapeworm, simply take your pill and let nature take its course.
Opera singer Maria Callas was rumored to have used a tapeworm to achieve a remarkable loss of weight in the mid 1950s. She did, in fact, lose more than 60 pounds over several months. She was also known to have contracted a tapeworm at some point in her life. However, the two incidents are probably unconnected. Callas enjoyed rare steak, so she probably got her tapeworm accidentally. These two aspects of her life were jumbled into a persistent rumor.
There is evidence of advertising, from the late 19th and early 20th century, hawking "sanitized tapeworms" to help women maintain a slim figure. Whether the pills sold actually contained tapeworms or whether women actually ingested them hoping to acquire a tapeworm is difficult to verify. Such a pill would likely contain the cyst part of the tapeworm's lifecycle, but one would imagine that cultivating a large supply of these would make for a rather unpleasant day's work. It seems unlikely, but there's also a good chance that somewhere in the long, strange history of humanity, someone somewhere did try using a tapeworm to lose weight. So, the answer to the question, "Did it happen?" is most likely yes, but it was probably never widespread.
That leaves us with just a few more interesting questions. What happens to your body when you have a tapeworm? Do the pounds just melt away? Can you stuff your face with all manner of delicious, unhealthy foods and get off consequence-free? Well, not exactly. For one thing, tapeworms are not large enough to absorb all the calories a human takes in. If your diet is already limited, the tapeworm could steal enough from you to cause malnutrition. If you're chowing-down on carbs, both you and the tapeworm will probably pack on the pounds. In most cases, a tapeworm infection is completely symptom-free. In fact, you might never know you have one until a proglottid makes its presence known in your toilet.
Some tapeworm hosts do suffer from intestinal discomfort or diarrhea. And some also experience reduced appetite, which could lead to weight loss. However, we can assure you that simply reading about tapeworms can cause a similar loss of appetite, so more drastic measures might not be necessary. But even if a tapeworm did trim some pounds, it still wouldn't be a good way to lose weight.
For most people, the goal of losing weight is to look better. However, as a tapeworm steals certain vitamins from your body, notably vitamin B12, you'll suffer ill health due to a shortage of those nutrients. Sure, you might slim down, but no one is going to be impressed with your sickly appearance. If that weren't enough, there's always ascites. Ascites is a condition in which the body's immune response to a parasitic infection leads to a build-up of fluid in the abdominal cavity. This manifests itself physically as a swollen, distended belly. Not exactly the intended result of a tapeworm diet plan.
And don't forget about good old cysticercosis, with the brain damage, blindness and possible death. Given this information, we think it's safe to say that if you really want to lose some weight, eat less and ride your bike.
If you were fascinated (or possibly even nauseated) by these parasites, then you might want to take a look at a few similar articles and other related links on the following page.
Related HowStuffWorks Articles
More Great Links
More Great Links
- Becker, Hank. "Out of Africa: The Origins of the Tapeworms." United States Department of Agriculture - Agricultural Research Service. March 18, 2005. (Dec. 10, 2008) http://www.ars.usda.gov/is/AR/archive/may01/worms0501.htm
- Mayo Clinic. "Tapeworm Infection: Treatments and Drugs." Nov. 29, 2007. (Dec. 10, 2008) http://www.mayoclinic.com/health/tapeworm/DS00659/DSECTION=treatments-and-drugs
- The Parasitology Group. "Parasitology: The Biology of Cestodes." Aberystwyth University. (Dec. 10, 2008) http://www.aber.ac.uk/parasitology/Edu/Cestodes/CestTxt.html
- Time Magazine. "The Persistent Parasites." April 8, 1957. (Dec. 10, 2008) http://www.time.com/time/magazine/article/0,9171,809356-1,00.html
- University of South Carolina - School of Medicine. "Parasitology - Chapter 5: Cestodes (Tapeworms)." Sept. 20, 2007. (Dec. 10, 2008) http://pathmicro.med.sc.edu/parasitology/cestodes.htm