Sushi Health Risks
I have gotten many questions as to the health concerns of eating fish. As with any raw food there is some degree of risk of food borne pathogens, but with seafood the current hot topic is contaminants. Basically, the answer to the question "is sushi good for you" is a resounding ‘yes’, however anyone eating fish, especially raw should be aware of the potential health concerns. The recent talk is the contaminant such as heavy metals that can be present in some fish, especially the larger predatory fish such as tuna and swordfish. Essentially, the higher up the food chain a fish is, the the more contaminants concentrate. While studies swing wildly one way or another, there clearly is some degree of heavy metal content in the larger predatory fish, but the health questions to focus on are to what degree and how much is bad for you.
Due to the potential for contaminants such as mercury (as well as pathogens) pregnant women are told to avoid the larger, predatory fish, and any raw meat, something that those with weakened immune systems are told avoid as well. However, in moderation, any cooked seafood is not only safe, but a healthful choice due to the beneficial nutritional profile of sea foods in general and the presence of Omega-3 fatty acids, required for proper health. Traces of other contaminants have been reported as well (e.g. PCBs, flame retardants) however studies have not shown the presence of concentrations large enough to hurt someone who eats seafood in moderation. Essentially, by polluting our planet we are soiling our oceans and its denizens as well, a process that reverberates throughout the food chain and finally affecting us. Naturally occurring substances (e.g. mercury in seawater) also contribute to contaminants found in fish as well. Fortunately, a recent report from the Institute of Medicine has concluded that the benefits of eating seafood far outweigh the potential risks, and anyone worried about the potential health concerns would do well to review the article. A recent article by the New York Times highlights the increasing risk of mercury contamination in tuna, and while it was countered by a recent trade group press release, the research was again supported by an article published in Newsweek magazine. I have summarized the entire argument in two blog entries, "Some more mercury with your tuna?" and "A tuna tempest" which I encourage everyone to read. As with many foods, eating sushi does in fact carry with it some small risk of pollution related contaminants being consumed, however in moderation, it is a perfectly safe food. But that said, please do remember that there can be other risks.
Aside from contaminants, raw seafood can also be the vector for various pathogens, viral, bacterial, as well as larger parasitic creatures. Proper sanitary conditions must always be met or any raw food could possibly make one sick. Anisakiasis is a particularly nasty and potentially fatal infection caused by microscopic larval worms that live in some marine creatures that can be avoided by thorough cooking, or certain deep freezing techniques, which are required by law in the United States for certain sushi grade items. While rare, it is one of the many risks inherent in all uncooked sea foods. Fortunately incidents of illness from sushi are few and far between. More people are sickened by contaminated produce in the US than by sushi, so at least for now, purveyors of sushi seem to be maintaining proper sanitary practices. And before you ask, tapeworms require a freshwater stage in their life cycle, so as long as you stick to the saltwater fish you should be fine. No one should ever eat freshwater fish raw under any circumstances as the risks of parasitic infection increase dramatically due to the large number of freshwater parasites that exist, the freshwater ecosystem being a much better environment for parasitic creatures.
Fortunately, sushi is as safe as any other food as long as proper handling conditions are met. While certain individuals should take steps to minimize particular risks due to their current condition, for most people, sushi is as safe as it is good for us. That said, it is wise to make sensible decisions as to where you will be eating sushi, and if an establishment looks as though it may not be taking the proper precautions, it is best avoided. Be smart and you should have no problems finding an enjoyable and delicious sushi meal.