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Raw Fish and Swordfish: Everything You Need to Know

by Carly Neubert, BA, NC on August 03, 2022

Sushi has a long history in Asian cultures. From the 5th century BC to today, sushi has been a pivotal part of food culture worldwide. Once considered a delicacy for Japanese courts is now an American phenomenon, seen in the many, “All You Can Eat” Sushi restaurants in our local cities. Japanese and Chinese cultures are not the only ones that eat raw fish, however.

The Dutch eat soused herring, and the Russians eat a raw fish dish called “stroganina.” For the purpose of this article, I will be discussing FAQ’s surrounding raw fish, sushi in particular, and swordfish.

How Can Eating Raw Fish be Bad?

Raw fish can provide opportunities for harmful bacteria to invade the body. Some of these harmful bacteria types include Listeria, Clostridium, Vibrio, and Salmonella. When fish is cooked thoroughly and properly, there can be a variety of nutritional benefits and a reduction of risking a foodborne illness contraction. According to the Academy of Nutrition and Dietetics, foodborne diseases may affect each person differently. Those that are more at-risk may develop severe symptoms.

For example, pregnant women are advised not to consume sushi or other raw fish food items as there is a greater risk of a Listeria infection, which may cause the death of the fetus. Also, those with weakened immune systems may be at a higher risk because of their higher susceptibility to infection. 

What is the Safest Fish to Eat Raw?

Unfortunately, there is no way to determine if a fish is “100% safe” to eat raw. Some types of fish that should never be eaten raw are pollock and haddock, as they can make you quite sick if consumed raw. Looking for a label that says, “Sushi Grade Fish” may be a good way to go as well. While these labels are not standardized across all grocery stores, it does indicate that it is the freshest fish the store has.

Ultimately, it takes time, care, and dedicated thought to determine if a fish is safe to eat raw. Make sure to look at a trustworthy and reputable fishmonger or store. Ask the right questions about handling and duration on the shelf. When eating sushi, it is always responsible to make sure that everything is being prepared correctly, safely, and with care. A restaurant should be able to tell you how they store their raw fish and how they have prepared it with your safety in mind. 

Are There Any Benefits to Eating Raw Fish?

Studies have shown that certain nutritional qualities of fish decrease when the fish is cooked or grilled. For example, frying fish can reduce the amount of omega-3 fatty acids that can provide amazing health benefits. There are also benefits that have nothing to do with your health.

Appreciating cultural dishes made from raw fish (in a responsible way) can increase our appreciation and knowledge of a culture. While sushi may be a great way to get some more of these heart and eye-supporting fatty acids, make sure that the sushi rolls aren’t doused in high-calorie ingredients like cheap mayonnaise, made from low-quality oils, fried tempura, or other creamy sauces. 

How Often Should You Eat Raw Fish?

This question depends on whether or not you belong to a high-risk group. If you have a compromised immune system or are pregnant, a child, or elderly, you should avoid raw fish entirely. If you are not a part of these groups, the American Heart Association recommends a limit of 12 ounces per week of fish that is low-mercury. Some low-mercury options include dolphin-safe canned light tuna, wild-caught salmon, catfish, and wild Argentenian shrimp. 

Why Do I Feel Weird After Eating Sushi?

Stomach pain following consumption of sushi can have a couple of causes, according to Livestrong. They are food poisoning, parasitic infection, or a fish allergy. Food poisoning can be mild, with mild symptoms only lasting a short time. Or, it could be a severe case, with more pronounced symptoms.

A parasitic infection can result from Anisakis simplex being introduced into the stomach. This parasitic worm can go into the stomach lining and create abdominal pain from a few minutes to a few weeks after consumption. Lastly, the pain may be due to an allergy. Fish and shellfish account for two of the eight foods accounting for a majority of food-related reactions. 

Is it Safe to Eat Raw Salmon?

Like other raw fish dishes, you must take caution and be responsible when consuming. Raw salmon prepared incorrectly may still have pathogens and parasites present. To safely eat salmon, make sure that it has been internally cooked to 145 degrees Fahrenheit. This ensures that bacteria and parasites have been killed. 

Why do the Japanese Eat Raw Fish?

The Japanese eat raw fish because it is a part of their culture. Food is an important part of national culture. This practice can be traced back to the 7th century. When Buddhism became a part of Japanese culture, the Japanese were deterred from eating any other form of meat. Also, since Japan is an island nation, fishing is one of their biggest industries. 

How do You Know if You Have Parasites From Sushi?

The symptoms that one can look for in anisakiasis (herring worm disease) are abdominal pain, nausea, vomiting, and diarrhea. The parasite finds its way into your body through undercooked fish or squid. Anyone is at risk for developing this infection.

How Common are Worms in Sushi?

In 2020 the National Science Foundation came out with an article describing the increased occurrence of sushi parasites. A University of Washington study found a big increase in the prevalence of the Anisakis worm in raw fish. What does this mean for us?

If you love sushi, it would be wise to do research into the storage, handling, and preparation of your favorite sushi rolls in restaurants. If you’re buying fish at the supermarket, give the filets a once-over to see if there are any worms visible. Better be safe than sorry, in my opinion. 

Is it Healthy to Eat Swordfish?

Swordfish are a great source of selenium. Along with omega-3’s, swordfish also provides niacin, zinc, vitamin D, and vitamin B12. Because of the high mercury content, you should not go above 5 servings per week. 

Who Should Not Eat Swordfish?

Pregnant women (or those trying to get pregnant), should avoid swordfish. This is because of the high levels of mercury in the fish. Fish provide many benefits to a healthy diet, but those that are high in mercury should be limited (and avoided in some cases to protect the fetus or future fetus). 

Is it Ethical to Eat Swordfish?

In the 1990s the swordfish population was overfished. Today, however, we are seeing swordfish numbers fully rebuilt and sustainable fishing practices being implemented. With the International Commission for the Conservation of Atlantic Tunas, the US reduced fishing grounds to help the swordfish population grow back in larger numbers. With added work being done with sustainably fishing these creatures, the swordfish has become one of the most sustainable seafood choices.

Concluding Thoughts…

Culture can mold the way we look at different social aspects of our lives - like how and what we eat. With the rise in popularity of sushi, it is important to evaluate the health concerns and benefits that can come with this raw delicacy. While sushi is delicious and a great option for going out to eat with friends and family, be sure to take responsible measures to ensure the health and well-being of yourself as well as your sushi-loving friends. Are you interested in learning about other ways to get some good omega-3s? Schedule a consult with me, Carly Neubert BA, NC.