Can you get worms from eating sushi?

Illustration by Slug Signorino

Cecil replies:

Mike, I have to be honest with you. There is a big potential problem here. It involves something that’s small, pink, and crawls. HINT: You’re not likely to chuck it under the chin and go, “Ooh, CUTE Baby Snookums.” You got it, pal. Worms. Eating raw fish can result in anisakiasis, an infection caused by an infestation of Anisakis worm larvae. Now, don’t panic, it’s not that bad. They’re not BIG worms. Not like one of those tapeworms, which can be a foot or two in length and take up more room in your abdominal cavity than you do. No, these are LITTLE worms. They grow up to a mere one inch in length. This is not comforting you, I can tell. Sorry, I’m doing the best I can. If you’re lucky, the worms will wind up in your stomach, where the chief symptom is generally a sudden attack of intolerable pain. It starts within 12 hours after eating the affected fish and continues for two or three days, until the worms expire. If you’re not as fortunate, the larvae head down to your intestines, where they can take up permanent residence. You could think of them as low-maintenance pets. I mean, you don’t have to walk them. To be considerate, every once in a while you could sort of jiggle, so they get some exercise. As for eating — well, I guess they take care of that on their own.

Maybe you don’t want to think about it.

Cases of anisakiasis turn up from time to time in Japan and the Netherlands, where raw fish eating is common. Here the disorder is often misdiagnosed as appendicitis, peptic ulcer, or stomach cancer. The only treatment is to poke a tube down your craw and remove the larvae one by one. The only preventive measure is to cook the fish or else freeze it at least three days. (Mercifully, many Japanese restaurants purchase squid and whatnot frozen. Shrimp, eel, and octopus are often cooked.) Some of the assassins who run sushi bars will tell you they can check for worms by “candling,” holding the fish up to the light and cutting out the larvae before slapping what’s left on your platter. The Centers for Disease Control, however, say the efficacy of this method is on a par with rain dancing. Now understand, I’m not saying you’re GUARANTEED to get worms if you eat sushi, or, for that matter, sashimi, ceviche, or some other type of raw fish cuisine. Think of it as kind of a remote threat, like nuclear war. Or else stick to Chicken McNuggets.

The raw fish lobby registers a complaint

Dear Cecil:

You recently carried an item about sushi in which your querent (nice term, n’est-ce pas? Got it from a tarot card reader) says “sushi is just raw fish.” I am tired of hearing this. Sushi is not just raw fish. Not even sashimi is just raw fish, although it’s a hell of a lot closer than sushi is. Many sushi dishes contain cooked fish and/or vegetables. You can start with kappa-maki, which generally contains seaweed, sushi-rice, cucumber, and wasabi. (Wasabi, incidentally, is not horseradish, or mustard either. It’s Wasabia japonica, and is sui generis as far as I’m concerned.) Then there is salmon-skin handroll, for which they carefully cook the fish so you needn’t worry about it. A good place will put such goodies as gobo (pickled Burdock root) into this, and it becomes a major delight.Also there is “tiger eye,” which is cooked, as is most eel sushi. I generally end with ume-jiso-maki, which contains umeboshi plum paste, shiso, leaves, rice, and seaweed, and is a bit salty but wonderful. There are plenty more where these came from.

— Jon S., Boulder, Colorado

Dear Cecil:

You recently recommended that people avoid sushi since raw fish is prone to parasitic infestation. Unfortunately, the issue is not that clear cut. Hours after reading your column, I sat through a pathology lecture in which the professor described the risks associated with eating COOKED fish. Sugimura has demonstrated that the pyrolosis products [what results when you expose fish to flame] of fish protein are strongly mutagenic and carcinogenic. So maybe we should avoid fish altogether. On the other hand, fish is very high in monounsaturated fats, and in this respect it seems to be one of the best dietary interventions for preventing coronary heart disease, the nation’s leading cause of death. What to do?

— Keith B., Chicago

I’d say the benefits of fish clearly outweigh the risks, even though I’m not all that crazy about the raw version (and I say this as much from as aesthetic standpoint as anything else; the actual danger of parasite infestation is pretty low). Here’s a quick rundown on what researchers have found: (1) Greenland Eskimos, who eat a high-fish diet, rarely die of heart disease. (2) In a 20-year study of 852 men conducted by the University of Leiden in the Netherlands, men who ate one ounce of fish a day were half as likely to suffer a heart attack. Studies also show a low heart-disease rate among Japanese fish-lovers. (3) According to researchers at Oregon Health Sciences University, a high fish-oil diet reduced dangerous triglyceride (“bad fat”) levels. Triglycerides are thought to increase the risk of heart disease. So I guess the answer is, pass the fish cakes. Just don’t eat ’em if they move.

Eating it raw: An update

To the Teeming Millions:

Readers who recall Cecil’s discussion of the hazards of eating raw fish will be fascinated by a recent report in the New England Journal of Medicine. It seems a 24-year-old student with a pain in his right side underwent surgery for appendicitis. His appendix was found to be normal, but surgeons were startled to see a 10-inch pinkish-red worm crawl out of the guy’s body. Turned out to be a Eustrongylides, a parasite normally found in fish-eating birds. The victim, obviously not a regular reader of the Straight Dope, said he ate sushi and sashimi once a month. My feeling is, if you must eat this stuff, make sure you first give it a good going-over with a rock.

An update update: OK to use small rock

Dear Cecil:

Re the 10-inch post-sushi stomach worm, enclosed is a page from a recent Nutrition Action Healthletter. Turns out the Sushi Worm From Hell was “only” about 1-1/2 inches long. Some comfort.

— Junu Kim, Chicago

It seems the editors of Nutrition Action, from which I got this horrifying item, multiplied instead of dividing when converting from the metric. I am surrounded by schmucks.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.