Legume

Natto

Health
ScoreA+

Natto is fermented soybeans with a distinctive sticky, pungent character that delivers high-quality plant protein, probiotics, and vitamin K2—a form crucial for bone and cardiovascular health that is rarely found in plant sources.

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Why Natto scores 90

Nutrient density35

Protein quality12

Fiber content7

Healthy fats8

Bioactive compounds13

Glycemic impact10

Top nutrients

% Daily Value per ½ cup (90 g)

Copper 67%Manganese 60%Iron 43%Zinc 25%Magnesium 25%

Nutrition

per_100g

211

Calories

19.4g

Protein

12.7g

Carbs

11g

Fat

5.4g

Fiber

Health benefits

Supports bone mineralization and cardiovascular calcification prevention via vitamin K2

moderate evidence

Vitamin K2 (menaquinone) activates osteocalcin and matrix Gla protein, proteins essential for directing calcium to bones rather than arterial walls

Provides complete plant-based protein with all nine essential amino acids

strong evidence

Fermentation increases amino acid bioavailability and reduces antinutrient factors like phytates, enhancing protein digestibility to near animal-protein levels

Supports fibrinolytic activity and healthy blood viscosity via nattokinase

emerging evidence

Nattokinase, a serine protease produced during fermentation, may help dissolve excess fibrin and support healthy blood flow

Promotes healthy gut microbiota composition via probiotics and prebiotic carbohydrates

moderate evidence

Live Bacillus subtilis and partially fermented oligosaccharides feed beneficial bacteria, supporting intestinal barrier function and immune signaling

Supports cognitive and mood health via GABA and choline content

moderate evidence

Fermentation generates GABA (a calming neurotransmitter), while 57mg choline per 100g supports acetylcholine synthesis and brain cell membrane integrity

Pairs well with

·Pair with brown rice or soba noodles because their complex carbohydrates slow gastric emptying, extending nutrient absorption and moderating blood glucose response
·Combine with raw leafy greens (spinach, arugula) because natto's vitamin K2 works synergistically with K1 from greens for comprehensive bone and vascular support
·Serve with fermented vegetables (kimchi, sauerkraut) because complementary probiotic species enhance microbial diversity and reinforce intestinal barrier integrity
·Mix with avocado or olive oil because natto's fat-soluble vitamin K2 absorption is enhanced by dietary lipids

Practical tips

·Best timing: Natto's complete protein, probiotics, and K2 support multiple physiological processes that benefit from distributed intake throughout the day. However, consuming with meals (especially breakfast or lunch) maximizes fat-soluble K2 absorption and provides sustained protein availability for satiety and muscle protein synthesis.
·Purchase frozen natto packages and thaw overnight in the refrigerator; freeze immediately upon arrival if not used within 2-3 days, as Bacillus viability declines with age
·Mix natto vigorously for 30-50 seconds before eating to maximize the development of mucopolysaccharides and activate nattokinase; stir with the provided condiment packet for optimal flavor and umami enhancement
·Consume natto in its raw, unheated form to preserve heat-sensitive probiotics, nattokinase activity, and vitamin K2; heating above 70°C significantly reduces bioactive enzyme activity
·Start with a small portion (1-2 tablespoons) if new to natto to allow digestive adaptation; some individuals experience temporary bloating as the microbiome adjusts to increased fermented foods
·Store unopened packages in the freezer (below -18°C) for up to 6 months; once thawed, keep refrigerated and consume within 24-48 hours for optimal probiotic viability