Pregnancy And Sushi: What's Safe?

Sushi is a delicious treat, but is it safe for pregnant women to eat? The answer is yes and no. Raw fish and seafood are off the menu due to the risk of harmful parasites and bacteria, but there are many cooked sushi dishes that are safe for pregnant women to eat.

Parasites and bacteria in raw fish

There are two types of parasites that can infect humans through food or water: parasitic worms and protozoa. Parasitic worms include roundworms (nematodes), tapeworms (cestodes), and flukes (trematodes). These worms vary in size, from barely visible to several feet in length. Protozoa are single-cell animals and cannot be seen without a microscope.

The Anisakis worm, for example, is a parasite that can cause nasty infections in humans who eat raw or undercooked fish. It is 2 cm long and is sometimes coughed up after ingestion. The Anisakis worm is a type of nematode or roundworm. It has a complex life cycle in which humans are an incidental host. Adult worms are found in the stomachs of marine mammals, and their eggs are passed in the feces. After the larvae hatch, they are ingested by shellfish. Infected shellfish are then eaten by fish and squid, where the larvae make their way into the muscle tissues. Ingestion of infected fish or squid by other fish allows the spread of the infection. Accidental human consumption of raw or undercooked marine fish that harbor the infected larvae can result in an allergic reaction and sometimes cause the individual to cough up the worms if swallowed. Penetration of the worms into the intestinal tissue causes anisakiasis, a severe immune response that can resemble appendicitis or Crohn's disease.

Fish tapeworm infection (Diphyllobothriasis) is another parasite that can affect humans who eat raw or undercooked fish. This type of tapeworm grows in hosts such as small organisms in the water and large mammals that eat raw fish. It is passed through the feces of animals, and humans become infected after ingesting improperly prepared freshwater fish that contain tapeworm cysts. Fish tapeworm infections rarely present noticeable symptoms, and they are most often discovered when people notice eggs or segments of the tapeworm in their stool. However, symptoms can include stomach cramps and pain, chronic hunger or lack of appetite, and unintended weight loss.

To kill parasites, fish must be frozen to an internal temperature of -4°F for at least 7 days. Home freezers may not be cold enough to kill parasites, and the effectiveness of freezing depends on several factors, including the temperature, the length of time the fish is frozen, the fat content of the fish, and the type of parasite present.

In summary, parasites and bacteria in raw fish are a concern during pregnancy due to the increased risk of infection and foodborne illnesses, which can potentially harm the baby. The Anisakis worm and fish tapeworm are examples of parasites that can affect humans who consume raw or undercooked fish, causing symptoms such as violent abdominal pain, nausea, vomiting, and weight loss. To prevent infection, it is important to freeze fish to the appropriate temperature for a sufficient period and follow proper food safety handling practices.

Mercury levels in fish

Mercury is a naturally occurring heavy metal that can be found in the air, water, and soil. It is released into the environment through human activities such as coal-fired power generation and natural events like eruptions. Mercury can be toxic to humans, especially in its organic form, methylmercury, which is highly toxic and can cause serious health problems when it reaches certain levels in the body.

Methylmercury is the most common form of mercury found in fish. Fish absorb low concentrations of mercury from water pollution, and over time, methylmercury can concentrate in their bodies. This process is known as bioaccumulation. Larger, longer-lived, and predatory fish tend to contain the most mercury as they accumulate higher levels from eating smaller fish. Shark, swordfish, fresh tuna, marlin, king mackerel, tilefish from the Gulf of Mexico, and northern pike are some of the fish species with the highest mercury levels.

The accumulation of mercury in the human body can lead to serious health problems. Higher levels of mercury in the body have been associated with brain problems, such as impaired brain function, decreased memory and attention, and seizures. Exposure to mercury has also been linked to high blood pressure, an increased risk of heart attacks, and higher levels of "bad" LDL cholesterol. In addition, recent studies suggest a link between exposure to heavy metals like mercury and the development of conditions such as Alzheimer's, Parkinson's, autism, depression, and anxiety.

Pregnant women, breastfeeding mothers, and young children are considered at-risk populations for mercury toxicity. Methylmercury can be passed from a pregnant mother to her fetus or a breastfeeding mother to her infant. Studies have shown that exposure to methylmercury during pregnancy can impair brain function and impact attention, memory, language, and motor function in children. Therefore, it is recommended that pregnant and breastfeeding women avoid consuming fish with high mercury levels and choose lower-mercury options like salmon, shrimp, cod, and sardines.

Cooked sushi that contains fish with low mercury levels is generally considered safe to consume during pregnancy. However, it is important to ensure that the fish is properly cooked to reduce the risk of parasites and bacteria that could cause foodborne illnesses.

Safe sushi options during pregnancy

If you're craving sushi during pregnancy, there's good news and bad news. The bad news is that raw sushi is best avoided due to the risk of parasites, bacteria and toxins that could harm your growing baby. The good news is that not all sushi is off the table! There are plenty of cooked sushi options that are safe for expectant mothers. Here are some tips and suggestions to satisfy those sushi cravings:

Raw or undercooked fish and seafood can carry harmful parasites and bacteria, which can lead to foodborne illnesses. The risk is heightened during pregnancy as your immune system is weakened, making you more susceptible to these parasites and bacteria. Additionally, certain types of fish used in sushi, such as bigeye and yellowfin tuna, swordfish, and marlin, contain high levels of mercury, a toxic metal that can cause serious birth defects.

Safe sushi options:

The key to enjoying sushi safely during pregnancy is to choose cooked options. Here are some suggestions:

• Steak and chicken rolls: Opt for rolls with cooked meats like steak or chicken instead of raw fish.
• Tempura rolls: These are always fully cooked and can include shrimp, crab, or vegetables.
• California rolls: These usually contain steamed crab sticks, avocado, cucumber, and sesame seeds, and sometimes mango for a touch of sweetness.
• Shrimp rolls: Shrimp is safe to eat when cooked, so go for shrimp tempura rolls or grilled eel topped with shrimp.
• Eel rolls: Grilled or freshwater eel is a safe option for sushi during pregnancy.
• Vegetable rolls: Veggie rolls are a great choice as they only contain vegetables and no raw fish.
• Cooked salmon rolls: While raw salmon is a no-go, you can enjoy sushi made with cooked salmon.
• Other cooked fish: Canned tuna, tuna mayo, or grilled fish are all safe options for sushi.

Additional tips:

• Check the menu: Most sushi menus will indicate whether the rolls are cooked or raw. If in doubt, don't hesitate to ask.
• Clean cutting board: Request that your sushi be prepared on a clean cutting board to avoid any cross-contamination with raw fish.
• Mercury levels: Be mindful of mercury levels in fish. Avoid fish with high mercury content, such as swordfish and tuna, and opt for lower-mercury options like freshwater eel, shrimp, or crab.
• Safe sides: Wasabi, pickled ginger, and soy sauce are all safe condiments to enjoy with your sushi.
• Homemade sushi: If you're making sushi at home, stick to cooked toppings and follow good food hygiene practices. Eat freshly made sushi and store any leftovers in the fridge, wrapped securely, for up to a couple of days.

Risks of eating raw fish during pregnancy

Eating raw fish during pregnancy is generally not recommended due to the risk of bacteria, parasites, and toxins that could harm both the mother and the baby. Here are some detailed reasons why it is risky to eat raw fish during pregnancy:

Bacteria and Foodborne Illnesses

Raw fish can be contaminated with bacteria such as listeria, which can cause listeriosis, a type of food poisoning. Pregnant women are at a higher risk of getting listeriosis, which can lead to vomiting, diarrhoea, preterm labour, stillbirth, and miscarriage. Additionally, if a baby is born with listeriosis, they may experience problems with their kidneys and heart, as well as infections of the blood or brain.

During pregnancy, the mother's immune system is weakened, making her more susceptible to foodborne illnesses, which can have serious negative consequences for both her and the baby.

Parasites

Raw or undercooked fish may contain parasites such as tapeworms and anisakis worms, which can cause health problems for anyone, not just pregnant women. Anisakiasis, the infection caused by anisakis worms, can cause severe abdominal pain, vomiting, stomach pain, bloating, blood and mucus in the stool, and mild fever. It can also lead to an allergic reaction, such as an itchy rash or even anaphylaxis.

Mercury Exposure

Some types of fish, especially large predatory fish like swordfish, shark, king mackerel, and tilefish, contain high levels of mercury. Mercury is a toxic metal that can cause serious neurological issues in the developing baby, including brain damage, hearing problems, and vision problems. Even small amounts of mercury can become toxic to the nervous system.

Other Risks

In addition to the risks mentioned above, raw fish may also contain other toxins or contaminants, such as PCB chemicals, which can be harmful during pregnancy.

To avoid these risks, it is recommended that pregnant women avoid eating raw fish and opt for cooked fish or vegetarian sushi options instead. Cooked sushi with low-mercury seafood, like eel or shrimp, and vegetarian sushi rolls with avocado or cucumber are generally considered safe choices during pregnancy.

Safe sushi ingredients

If you're pregnant and craving sushi, there are some options that are safer than others. While it's best to avoid raw or undercooked fish due to the risk of parasites, bacteria, and toxins that could harm your growing baby, there are still ways to enjoy sushi safely. Here are some safe sushi ingredients to look out for:

Cooked seafood options:

• Crab: Crab is a great option for sushi as it is usually cooked and made from lower-mercury fish.
• Cooked prawns: Prawns are safe to eat when cooked, but raw or lightly cooked prawns should be avoided as they may contain bacteria, viruses, or toxins that can cause food poisoning.
• Cooked eel: Eel is another cooked seafood option that is safe to include in your sushi.
• Salmon: Opt for cooked salmon in your sushi, as it is a low-mercury fish that provides healthy omega-3 fatty acids.
• Shrimp: Shrimp is safe to eat when cooked and provides a good source of iron, which is beneficial during pregnancy.
• Scallops, clams, lobster, crab, oysters: These shellfish options are safe to eat when cooked.

Vegetarian options:

• Cooked egg: Sushi with cooked egg is a safe and nutritious option during pregnancy.
• Avocado: Avocado is a healthy ingredient that can help meet your daily need for folate, which is important for your baby's growth and development.
• Cucumber: Cucumber avocado rolls are a popular and safe vegan sushi option.
• Shiitake mushrooms: Sushi rolls with shiitake mushrooms are another vegetarian option that is safe during pregnancy.
• Vegetables: Opting for vegetable rolls ensures that you avoid the risks associated with raw seafood.

Remember, when eating out or ordering sushi, always ask about the ingredients and specify that you cannot eat raw fish. It's important to make sure that any cooked seafood options you choose are made with low-mercury fish and heated to a temperature of 145°F to reduce the risk of foodborne illnesses. Enjoy your sushi safely!

Frequently asked questions