The Food That Makes Kids Stop and Stare
Very few foods turn a kitchen table into a science demo the way natto does. One child twirls the strings up toward the ceiling to see how far they go; the sibling pinches their nose and leans as far away as the chair allows. Both reactions are completely normal, and both are a good starting point. Curiosity is the hook, and with natto you rarely have to manufacture it.
Natto (pronounced roughly “NAH-toh”) is whole soybeans that have been soaked, steamed, and fermented with a specific bacterium, Bacillus subtilis, often called the natto strain. During fermentation the beans develop their savory flavor, their strong aroma, and the sticky, stringy coating that makes natto famous. In Japan it is an everyday food rather than a delicacy: sold in small cups at every supermarket, eaten at breakfast, and stirred over a bowl of rice in countless homes.
For American families, natto usually shows up in one of a few ways: a parent who grew up in Japan wants to share it, a family is preparing to visit or move to Japan, or a kid saw it in a video and asked the big question. Whichever brought you here, the goal is not to make anyone love natto. It is to make it a fun, low-pressure food to explore, and to know the few practical points that keep it safe for small kids.
What It Tastes and Feels Like (Honestly)
It helps to tell kids what to expect before the lid comes off, because the surprise is what causes most instant refusals.
The natto preview, in kid language
- Smell: strong and funky, a bit like a sharp cheese or a well-used sneaker, depending on who you ask. The smell is bigger than the taste.
- Taste: savory, nutty, and earthy. Once the sauce is mixed in, it leans toward soy sauce.
- Texture: soft, cooked beans wrapped in slippery, stretchy strings. Stirring makes the strings longer and turns the coating a little foamy.
- The trick: heat tames it. Warm natto in an omelet or on toast is less stringy and less pungent than natto straight from the cup.
A small first portion matters more than any recipe. Offer a spoonful next to food your child already likes, let them stir and stretch it, and count “I touched it” or “I smelled it” as a win. Many Japanese parents will tell you that some kids love natto from the first bite and others warm up to it years later; both paths are fine.
Where to Buy Natto in the US
Natto is easier to find than most parents expect. The most dependable source is the freezer aisle of a Japanese or wider Asian grocery store. It usually comes as a stack of small foam or plastic cups, often three or four to a pack, each with a thin film over the beans and two tiny packets: a sauce (tare) and a mustard (karashi). Some larger supermarkets and natural-food stores stock it in their frozen section, and a small number of local producers sell fresh natto.
- Thawing: move one cup from the freezer to the refrigerator the night before. Eat it within the date on the package and follow any storage directions printed on it.
- Labels to know: “kotsubu” means small beans; “hikiwari” means the beans were cracked into pieces before fermenting. For young kids, hikiwari is the easiest starting point (more on that below).
- Check the ingredient list: the beans themselves are just soybeans and the culture, but the sauce packet usually contains wheat-based soy sauce and other seasonings. If your child has a wheat or other allergy, read the sauce label separately.
If natto is new to your household, it is worth buying one pack and treating it as an experiment rather than a meal plan. Soybeans also come in friendlier forms that make a good warm-up: young green soybeans in the pod (see our edamame snack ideas) and roasted soybean flour, covered in the kinako guide. A kid who already likes edamame has a familiar landmark when natto arrives.
How Japanese Kids Actually Eat It
In Japan, natto is mostly a home breakfast and lunch food, and the classic preparations are simple. These are the ones that translate best to an American kitchen:
- Natto gohan (natto over rice): stir the natto until stringy, add a little sauce, and spoon it over a bowl of warm short-grain rice. This is the everyday standard. Toppings like chopped green onion, a sprinkle of nori (dried seaweed), or bonito flakes (dried, shaved fish) add flavor without extra sauce.
- Natto toast: spread natto on a slice of bread, add shredded cheese, and toast until the cheese melts and the edges brown. Heat softens the smell and the strings, which makes this a popular gateway for picky eaters. Cut it into sticks for small hands.
- Natto omelet: mix natto into beaten eggs, or fold it into the middle of a rolled Japanese omelet (tamagoyaki). The egg wraps up the stickiness, and the whole thing turns mild and savory.
- Natto rice balls: mix chopped natto into rice and shape small balls. The stickiness helps the rice hold together. Our onigiri guide has shaping tips that work here too.
- In miso soup: a spoonful of natto stirred into a bowl of miso soup is a common home variation; the broth thins out the strings. See miso soup for kids for a simple base.
Notice what these have in common: natto is a topping or mix-in, rarely the whole plate. That is a useful model for US families too. A tablespoon on rice or eggs is plenty for a first month.
The Safety Notes That Matter for Little Kids
Natto is an ordinary food, but a few details deserve attention before it lands on a toddler tray.
Before you serve natto to a young child
- Soy is a major allergen. Under US labeling law, soybeans are one of the nine major food allergens the FDA requires to be declared on packaged foods (along with milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and sesame). If your child has not had soy before, or has eczema or other food allergies, talk with your pediatrician about how to introduce it. Families avoiding soy can find alternatives in our soy-free snack guide.
- Start with hikiwari (chopped) natto. The beans are cracked before fermenting, so the pieces are small and easier for little mouths to manage.
- Mash or chop whole beans for toddlers. Whole natto beans are soft, but they are round and slippery and can be swallowed without chewing. Until your child chews well with their back teeth, press whole beans with a fork or chop them with a knife. Japan’s Consumer Affairs Agency advises not giving hard beans or nuts to children age 5 and under; natto is not a hard bean, but the “round and easy to swallow whole” risk is shared, so the same habits apply.
- Seated, supervised, small bites. As with any food for young children, AAP and CDC choking guidance applies: kids sit to eat, an adult is watching, and bites stay small.
- Skip the mustard. The karashi packet is a sharp, hot Japanese mustard meant for adults.
- Mind the sauce. The tare packet is soy-sauce based and adds sodium and a bit of sugar. For small kids, use part of the packet or none, and let toppings carry the flavor.
A practical serving habit from Japanese homes: when the whole family shares natto, scoop out the child portion first, then add sauce and mustard to the adult bowls. Nobody has to fish the mustard back out.
If your child shows signs of an allergic reaction after eating any new food, such as hives, swelling of the lips or face, repeated vomiting, coughing, or trouble breathing, contact your pediatrician; for trouble breathing or sudden weakness, call 911.
Vitamin K2 and Warfarin: A Note for the Grown-Ups
Natto stands out among foods for one nutrient in particular. The NIH Office of Dietary Supplements lists natto as a notably rich source of vitamin K2 (menaquinone), a form of vitamin K made by bacteria during fermentation. Vitamin K is part of the normal blood-clotting process, and that is why natto matters for one group of people: those taking warfarin, a prescription blood thinner whose effect can change with vitamin K intake.
People on warfarin are commonly told to avoid natto or to keep their vitamin K intake steady, but the right guidance depends on the person. Anyone taking warfarin should ask their doctor or pharmacist before eating natto. If a grandparent or other family member takes it, keep their bowl and serving spoon separate on natto mornings. This note is about the adult on the medication; it does not change whether children can eat natto.
Beyond that, we will keep the nutrition talk simple. Natto is a soy food and a fermented food, and it fits into a varied plate the same way other bean dishes do. If you want the broader picture of soy for children, our soy evidence guide covers tofu, soy milk, and what the research does and does not show. And if the word “fermented” sparks questions about microbes and the gut, the probiotics and prebiotics guide explains what is known so far without the hype.
Turn the Strings Into a Kitchen Experiment
For a kid who will not eat natto yet, watching it can still be a real step. The stringiness is a product of fermentation (the same soybean made into tofu or soy milk never gets stringy), which makes natto a perfect “how did food change?” lesson.
- Stir test: stir one cup 10 times, then 30, then 50. Lift with a toothpick each time. What happens to the strings and the foam?
- Heat test: compare cold natto with a bite of natto toast. Where did the stickiness go?
- Soybean lineup: put edamame, tofu, kinako, and natto on small plates. Compare color, smell, and texture, and talk about how one bean became four foods.
The microbe side of the story is in fermentation science for kids. Eating is optional; noticing is the point.
Frequently Asked Questions
What does natto taste like?
Natto tastes savory, nutty, and earthy, a bit like a very mild aged cheese crossed with soy sauce. The smell is stronger than the flavor, and many people describe it as funky or cheese-like. The texture is the real headline: soft beans held together by sticky, stretchy strings that get longer the more you stir. Kids tend to react strongly one way or the other, so serve a spoonful, not a bowl, the first time.
Where can I buy natto in the US?
The most reliable place is the freezer section of a Japanese or wider Asian grocery store, where natto usually comes in small stacked foam or plastic cups, often three or four to a pack. Some larger supermarkets and natural-food stores carry it too, and a few local makers sell fresh natto. Frozen natto keeps well; move one cup to the refrigerator to thaw overnight and use it within the date on the package.
Is natto safe for toddlers?
Natto is a soft food, but whole beans are round and slippery and can be swallowed without chewing, so for toddlers mash them or chop them, or buy hikiwari natto, which is made from cracked beans. Serve it with your child seated and supervised. Leave out the mustard packet, use little or none of the sauce, and remember that soy is a major allergen, so introduce it the way your pediatrician recommends for any new allergenic food.
Should kids use the sauce and mustard that come with natto?
Skip the mustard for kids; it is a sharp Japanese karashi that most young children find painfully hot. The sauce, called tare, is soy-sauce based and adds sodium and a little sugar, so for small children use part of the packet or none at all. A sprinkle of bonito flakes, nori, sesame, or chopped green onion brings plenty of flavor without the sauce. Dish up the child portion first, then add mustard to the adult bowls.
Can someone taking warfarin eat natto?
Natto is an unusually rich source of vitamin K2, and vitamin K can change how warfarin works. People on warfarin are commonly advised to avoid natto or to keep their vitamin K intake steady, but the right answer depends on the person, so anyone taking warfarin should ask their doctor or pharmacist before eating it. If a family member takes warfarin, keep their plate and utensils separate when natto is on the table. This does not affect whether children can eat natto.
Sources
- US Food and Drug Administration (FDA), “Food Allergies: What You Need to Know” and information on the Food Allergen Labeling and Consumer Protection Act (FALCPA) and the FASTER Act, which made sesame the ninth major food allergen.
- NIH Office of Dietary Supplements, “Vitamin K: Fact Sheet for Health Professionals” (food sources including natto; interaction with warfarin).
- American Academy of Pediatrics, HealthyChildren.org, “Choking Prevention” and guidance on starting solid foods and introducing allergenic foods.
- Centers for Disease Control and Prevention (CDC), Infant and Toddler Nutrition, “Choking Hazards.”
- Consumer Affairs Agency, Japan, advisory on choking and aspiration accidents involving food in children (hard beans and nuts for children age 5 and under).
- US Food and Drug Administration (FDA), “How to Understand and Use the Nutrition Facts Label” (reading sodium on packaged foods and sauces).