'Triangle Sushi': What It Is, Nutrition, and How to Make Your Own

Triangle sushi is a rice ball, also known as onigiri, that’s shaped into the form of a triangle.

Although onigiri can be made into various shapes, triangle-shaped onigiri is typically the most common.

This popular Japanese food can be eaten cold or pan-fried, with or without toppings, making it a versatile snack or lunchbox item.

It’s a good source of iodine, and — depending on the fillings added — of various other nutrients as well.

In this article, I’ll review triangle sushi, what it is, how to make it, the ways it may contribute to your health, and what to know if you’re considering adding it to your diet.

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What is triangle sushi?

Triangle sushi is, as the name implies, sushi in the shape of a triangle. It’s made with steamed sushi rice that’s wrapped in nori, which is a dried edible seaweed.

In its most basic version, a triangle sushi consists only of rice and seaweed. However, fillings like fish, tofu, beans, fruit, or vegetables can also be added to it.

Anecdotally, some people believe that shaping the rice balls into the form of mountains was originally a way for Japanese people to ask for protection against spirits.

Others suggest the triangle shape was simply preferred due to its space efficiency, which is easier to pack and carry around than the disk-, round-, or pillar-shaped onigiri – the three other most common shapes.

The biggest difference between triangle sushi and other sushi rolls is that regular sushi uses rice that’s been seasoned with sugar and rice vinegar. On the other hand, triangle sushi is usually made of steamed rice with no sugar or rice vinegar added to it.

Some people choose to add seasonings, such as furikake, to flavor the rice.

Furikake is a type of Japanese seasoning made from a blend of ingredients, such as fish, dried seaweed (nori), sesame seeds, salt, and spices. It sometimes also contains egg and sugar.

Traditional triangle sushi fillings include dried fish with soy sauce, pickled plum, salted salmon, tuna in mayonnaise, kombu, or furikake.

However, a variety of other fillings may be used, including vegan options like tofu, beans, fruit, veggies, and fresh seaweed.

SUMMARY

Triangle sushi is onigiri (rice balls) formed in the shape of a triangle. It consists of steamed sushi rice that’s sometimes seasoned wrapped in dried seaweed. It can be served as is or stuffed with your choice of fillings.

Nutritional profile of triangle sushi

The most basic version of a triangle sushi consists simply of steamed sushi rice and dried nori. Each triangle weighs around 1.4 ounces (41 grams) and offers approximately (1, 2, 3):

• Calories: 49 kcal
• Protein: 1 gram
• Carbohydrates: 11 grams
• Sugar: < 1 gram
• Fiber: < 1 gram
• Fat: < 1 gram
• Iodine: 23%
• Copper: 9% DV
• Selenium: 5% DV
• Zinc: 3% DV
• Magnesium: 3% DV
• Thiamin: 3% DV
• Iron: 2%
• Riboflavin: 2%
• Niacin: 2% DV

Adding fillings to your sushi rice will affect its nutritional value. For instance, adding fish, tofu, or beans will increase the protein, iron, and zinc contents, while adding fruit or veggies will provide some additional potassium and vitamins A and C.

Flavorings, such as soy sauce, pickled plum, or furikake, can significantly increase the salt content of triangle sushi, so it’s best to use a light hand or pick low sodium varieties when available.

SUMMARY

Triangle sushi is a good source of carbs, iodine, and selenium. Depending on the fillings you choose, it can also provide you with additional protein, iron, zinc, vitamin A, vitamin C, and omega-3s.

Benefits and downsides of triangle sushi

Adding triangle sushi to your diet can offer some potential health benefits. There are also some considerations to keep in mind.

May support thyroid function

Triangle sushi is typically rolled in a sheet of dried seaweed, which is considered a good source of the nutrient iodine.

Iodine is essential for your thyroid to function properly. The thyroid plays various important roles within the body, including regulating your metabolism.

Getting too little iodine in your diet can cause your thyroid function to slow down, giving rise to symptoms like dry skin, low energy, forgetfulness, depression, weight gain, and tingling in the hands and feet (4).

The recommended amount of iodine for adults is 150 mcg per day. One triangle sushi rolled in a half-sheet of nori typically provides around 35 mcg of iodine, or 23% of the daily value (DV) (3).

Could help promote gut health

Due to its seaweed content, triangle sushi also contains agars, fucoidans, and carrageenans, which are all compounds with prebiotic functions.

Prebiotics are non-digestible fibers that feed the beneficial bacteria lining your gut. The higher the amount of good bacteria in your gut, the less space for harmful bacteria there is. That balance helps keep your gut healthy (5).

In addition to a healthy gut, prebiotics may also improve your immunity, brain health, and heart health (6).

Moreover, researchers believe that the prebiotics in seaweed may also possess some antibacterial and anti-inflammatory effects, which could further benefit your overall health (5).

May contain heavy metals

If your triangle sushi contains seaweed, fish, or shellfish, it may inadvertently be tainted with heavy metals, such as arsenic or mercury.

The amount of heavy metals found in fish depends on the species and level of pollution found in the environment in which they grow.

In recent studies, close to one-third of all fish samples examined contained mercury levels that exceeded the safe limits set by the World Health Organization (7).

Exposure to heavy metals, such as mercury, has been linked to a variety of symptoms, including loose teeth, tremors, headaches, fatigue, and dementia (8).

Generally speaking, the larger and older the fish, the more mercury it will likely contain. For instance, shark, swordfish, king mackerel, and bluefish, bluefin tuna, and striped bass contain the most (9).

Seaweed can also become contaminated with heavy metals, especially arsenic. Just like fish, the amount it contains will depend on the level of pollution in the area the seaweed grew in (10).

The amount of arsenic in most seaweed doesn’t usually appear to exceed the safe limit, though.

Moreover, the amount of seaweed you’d be eating from a normal portion triangle sushi will be quite low, making your risk of arsenic overload also low.

However, this risk may be worth keeping in mind for those who ingest large amounts of seaweed regularly, be it through sushi, seaweed salad, or seaweed-based supplements (10).

Often contains high amounts of salt

Triangle sushi can contain large amounts of sodium (salt), especially if you use salty condiments like soy sauce and coconut aminos to flavor to it (11, 12).

An overly salty diet may increase blood pressure in some people, which can in turn increase your risk of heart failure (13, 14, 15).

High salt diets have also been linked to an increased risk of stomach cancer. However, we need more research to better understand that association in humans (16).

You can decrease the overall salt content of your triangle sushi by opting for low sodium condiments and seasonings, whenever possible.

SUMMARY

Triangle sushi may promote thyroid function, immunity, and brain, gut, and heart health. However, it can be high in sodium and may be contaminated with heavy metals. Choosing your toppings, seasonings, and condiments carefully can maximize health benefits while minimizing any potential risks.

How to make your own triangle sushi

Triangle sushi is relatively easy to make on your own. Here’s what you’ll need and the steps to follow to make about four servings.

Ingredients

• 1 cup (255 grams) sushi rice, uncooked
• 1 cup (240 mL) water
• 2 nori sheets, each cut in half
• Furikake mix, to taste (optional)
• Shredded or diced fruit and veggies; cooked beans, lentils, or peas; crushed nuts or nut butter; cooked meat or fish, to taste (optional)

Method

Rinse your sushi rice under cold running water and cook according to the package instructions. For best results, continue onto the following steps while your rice is still warm.

If using seasoning, add it to your cooked rice and mix evenly.

Wet your hands and rub a pinch or two of salt into them to prevent the rice from sticking to your skin. Then scoop up about one-fourth of your rice.

If adding a filling, flatten out the rice, scoop out about one tablespoon (15 mL) of filling, and fold the edges of the rice over to cover your filling.

Lightly form your rice into a ball. Then, rest the ball into your palm and use your fingertips to form it into a triangular shape.

Position your nori sheet in front of you with the short edge towards you. Place your rice triangle onto the short edge of your nori sheet, with the tip facing down, towards you.

Fold the two lower edges of the nori sheet over the tip of the triangle, to cover it.

Roll your triangle over onto the nori sheet, away from you, as to cover the remaining rice with nori.

Trim the excess nori sheet with kitchen scissors. Place a grain of rice on each of the remaining corners and fold them over onto your nori sheet to close your triangle.

Here’s a visual guide of the method above to help you better visualize how to fold your triangle sushi.

Here are a few ideas for seasonings or fillings you can add when making your own triangle sushi.

Seasoning options

Along with or instead of furikake mix, you can purchase these either from an Asian supermarket or online.

• Goma shio (black sesame salt)
• Ume goma shio (plum sesame salt)
• Katuso fumi (fish flakes with seaweed and spices)
• Seasoned kombu (seaweed)
• Sesame seeds
• Low-sodium soy sauce
• Coconut aminos

Filling options

Triangle sushi can be served as is or filled with your fillings of choice. Feel free to choose from the suggestions below or make up your own!

Meat or fish-based fillings

• Canned tuna with mayonnaise
• Smoked salmon
• Shredded chicken with sun-dried tomatoes
• Stewed beef
• Salted cod roe

Plant-based fillings

• Diced smoked tofu
• Marinated tempeh
• Edamame beans in a peanut sauce
• Jackfruit in a spiced chili sauce
• Shredded carrots, apples, or zucchini
• Diced cucumber, strawberries, mango, or avocado
• Pickled plum or ginger
• Sauteed mushrooms or aubergine (eggplant)
• Wakame or simmered kombu seaweed

You can also make it super easy on yourself by turning any leftovers you have into a triangle sushi filling.

SUMMARY

Triangle sushi is relatively easy to make on your own. You can make these rice balls simply from seasoned rice and nori, or you can add a variety of fillings.

Additional tips when making your own

Triangle sushi is best enjoyed fresh. Storing it in the refrigerator can cause the nori to become soggy and the rice to become dry and clumpy.

Wrapping the sushis in a plastic wrap and storing them into an airtight container may keep them from drying out overnight.

It’s best to wrap the rice triangles alone, adding the nori only right before eating, to prevent it from becoming overly soft.

If, despite your best efforts, you find that the outer layer of your triangle sushi has dried out overnight, try pan-frying the rice balls in a little sesame oil.

This grilled version of onigiri is known as yaki-onigiri. The heat will create a crispy outer layer while maintaining a moist and tender inner layer.

SUMMARY

Triangle sushi is best eaten shortly after it has been prepared. If you want to store it, try wrapping the triangle-shaped rice in plastic wrap and rolling it in the nori only right before it’s time to eat it.

The bottom line

Triangle sushi is a rice ball shaped into the form of a triangle and wrapped into a sheet of dried seaweed.

Flavor can be added to it through seasonings, condiments, or various meat- fish- or plant-based fillings.

This versatile meal or snack is a particularly good source of iodine and prebiotics, which can benefit the health of your immune system, thyroid, brain, heart, and gut.

However, depending on the seasonings or fillings you choose, your triangle sushi may also be high in salt or heavy metals — both of which could negatively impact your health when eaten in excess.

To get the most health benefits with the least amount of risk, opt for low sodium seasonings and try to avoid over-filling your triangle sushi with seaweed or fish that’s high in mercury.

Moreover, try to opt for plant-based fillings whenever possible.

Just one thing

Try this today: Triangle sushi is an interesting way to recycle small amounts of leftovers and enjoy them in a new variation. I find that sauce-based leftovers such as a lentil Dahl or three-bean chili work best, but feel free to experiment to find your own personal favorite combinations!