Sushi During Pregnancy: Safe and Unsafe Toppings【Supervised by doctor】

Learn about safe and unsafe sushi toppings during pregnancy.

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Introduction

Sushi is a representative culinary tradition of Japan and is one of the foods that expectant mothers also look forward to enjoying. However, during pregnancy, careful attention to food is necessary as it can affect the development and health of the fetus.

In particular, sushi made with raw seafood carries risks of food poisoning and mercury intake. This article explains points to be cautious about when pregnant women eat sushi, as well as which toppings are safe to eat and which ones should be avoided.

Things to be cautious about when eating sushi during pregnancy

Sushi, because it utilizes raw seafood, carries the risk of food poisoning. Since food poisoning can potentially have adverse effects on fetal development, it’s advisable to take precautions to prevent it from happening.

Risks of food poisoning from raw seafood toppings

The bacteria and viruses that cause food poisoning proliferate when freshness and hygiene conditions are poor, so it’s important to ensure that food establishments maintain adequate hygiene standards.

Raw squid (about Listeria bacteria)

The Listeria bacteria found in raw squid can affect the fetus if pregnant women become infected. Infection can lead to miscarriage, premature birth, or severe disabilities in newborns. Therefore, consumption of raw squid should be avoided.

Bivalves (about Norovirus)

Bivalves are known as a source of Norovirus infection. Norovirus is a virus that causes symptoms such as vomiting and diarrhea, and when pregnant women become infected, it can also affect the fetus.

To kill Norovirus, heating to a core temperature of 85-90°C for at least 90 seconds is necessary. Therefore, it’s important to consume bivalves that have been thoroughly cooked.

Mackerel, sardines, bonito, salmon, squid, saury, horse mackerel, etc. (about Anisakis)

Anisakis is a type of roundworm that parasitizes fish such as mackerel, sardines, bonito, salmon, squid, saury, and horse mackerel. Infection with Anisakis can cause symptoms such as abdominal pain, nausea, vomiting, and diarrhea. Furthermore, it can trigger allergic reactions, potentially leading to severe anaphylactic shock. Therefore, consumption of these seafood items raw should be avoided.

Food poisoning due to raw seafood or secondary contamination during the cooking process (about Vibrio cholerae)

Vibrio parahaemolyticus is a bacterium that can cause food poisoning transmitted through seafood, potentially leading to gastroenteritis due to secondary contamination from raw or mishandled seafood during preparation. Symptoms of infection may include diarrhea, abdominal pain, vomiting, and fever. To prevent secondary contamination during the handling and cooking of seafood, it’s crucial to pay careful attention to the freshness of ingredients and maintain proper hygiene practices during food preparation.

Risk of mercury intake

Mercury is widely present in the environment and is primarily released into water and soil from sources such as mining and industrial activities. Mercury is known to accumulate in the food chain, often found in seafood, particularly in large predatory fish.

Since mercury can affect the central nervous system, excessive intake can potentially impact health. Fetuses and infants are particularly vulnerable to its effects. Therefore, caution is necessary for pregnant and breastfeeding women when consuming seafood high in mercury, as it may adversely affect the neurological development of the fetus or infant.

Risks of food poisoning from raw seafood toppings

Seafood with high mercury content includes large, apex predators such as whales, tuna, swordfish, and sharks, as well as deep-sea fish like alfonsino and blackthroat seaperch.

For pregnant women, it is recommended to limit the consumption of seafood with high mercury levels, such as tuna, shark, and deep-sea fish, to no more than once a week (generally around 80g per week or less).

Imbalance in nutritional balance

Dietary balance is crucial during pregnancy to ensure the intake of nutrients necessary for fetal development.

Sushi tends to be skewed towards carbohydrates and protein, so it’s important to complement it with side dishes such as vegetables to achieve a balanced meal. Make sure to strive for a well-rounded diet.

Insufficient vegetables and dietary fiber

A menu consisting solely of sushi may lack vegetables and dietary fiber. It’s advisable to accompany it with seaweed miso soup or a vegetable salad to ensure a balanced meal.

During pregnancy, constipation is common, so it’s crucial to actively consume dietary fiber.

Be cautious of excessive intake of vitamin A

Vitamin A is a nutrient essential for fetal development, but excessive intake should be avoided. Among sushi toppings, eel and freshwater eel particularly contain high levels of vitamin A, so it’s important to be cautious not to consume them excessively.

Excessive intake of vitamin A can lead to fetal developmental abnormalities and congenital malformations, so it’s crucial to consume it in appropriate amounts.

Be cautious of excessive intake of carbohydrates and salt

Sushi rice contains more carbohydrates and salt compared to regular rice due to the addition of sushi vinegar. Additionally, sushi is often consumed with soy sauce, leading to excessive salt intake.

Excessive intake of carbohydrates and salt can increase the risk of weight gain during pregnancy, as well as conditions such as gestational hypertension and gestational diabetes. Therefore, caution is necessary.

Other raw foods to be cautious of, not just sushi

During pregnancy, caution is necessary not only with sushi but also with other raw foods. Items like natural cheese, meat or fish pâtés, raw ham, smoked salmon, horse sashimi, raw eggs, etc., may potentially contain pathogens such as Salmonella bacteria, Listeria bacteria, viruses, and parasites like Toxoplasma in their raw state. Since these pathogens can affect fetal growth, vigilance is required.

Toxoplasma is one particularly concerning pathogen. While it’s commonly known to be transmitted through cats and their feces, infection can also occur from consuming raw meat, especially pork, lamb, and beef.

Symptoms of fetal infection with Toxoplasma include stillbirth, miscarriage, hydrocephalus, visual impairment due to choroidoretinitis, cerebral calcifications, and psychomotor impairments. Even if asymptomatic at birth, symptoms may appear during adulthood.

When you really want to eat sushi during pregnancy

If you want to eat sushi while pregnant, you can do so safely by choosing the type of sushi carefully.

Types of sushi toppings that are safe to eat during pregnancy

You can safely eat the following types of sushi while pregnant:

• Cooked seafood such as crab, shrimp, octopus, and tuna mayo
• Vegetable sushi rolls like avocado, cucumber, natto, and kanpyo
• Cooked meat sushi rolls, tamagoyaki (Japanese omelet), etc.

Even though they’re cooked, it’s important that they are properly handled and fresh. Before eating, make sure to inspect them thoroughly for any abnormalities.

Types of sushi toppings to avoid during pregnancy

Pregnant women should generally avoid consuming raw foods, and particularly during pregnancy, it’s recommended to avoid the following sushi toppings:

• Otoro and Chutoro: These are fatty portions of tuna and may contain methylmercury, so pregnant women should avoid them.
• Squid (Ika): Raw squid may contain Listeria bacteria and parasites like Anisakis, which can cause food poisoning.
• Raw shellfish such as oysters, and sea urchin (Uni): Since they feed on plankton in seawater, they can accumulate bacteria and viruses from seawater, potentially causing food poisoning.

Conclusion

During pregnancy, it’s recommended to minimize the risk of food poisoning by avoiding raw foods. However, you can still enjoy sushi by choosing safely cooked options.

Nevertheless, always ensure the hygiene of the sushi before consuming it. Additionally, it’s important to consult with your obstetrician regularly during pregnancy and strive for a well-balanced diet that considers nutritional needs.

Fetal health status is examined with NIPT (Non-Invasive Prenatal Testing)

NIPT (Non-Invasive Prenatal Testing), also known as non-invasive prenatal genetic testing, refers to prenatal diagnosis.

As indicated by “non-invasive,” there is no direct invasion (damage) to the fetus, and it is a screening test that assesses the risk of chromosomal abnormalities in the baby using only maternal blood. Furthermore, NIPT is considered a highly accurate test for Down syndrome in terms of sensitivity and specificity.

At Hiro Clinic, NIPT testing is available once pregnancy is confirmed via ultrasound. Consider undergoing this test for a healthier pregnancy and childbirth experience.

Learn about safe and unsafe sushi toppings during pregnancy.

Read more about NIPT

Article Editorial Supervisor

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Dr Hiroshi Oka

NIPT specialist clinic, MD

Graduated from Keio University, School of Medicine