FermentTraditional use
Miso
Fermented soybean paste (koji, Aspergillus oryzae)
- Category
- Ferment
- Evidence
- Traditional use
- Used
- In the kitchen
- In the library
- Book II, Chapter 5
- Pairs with
- Kimchi, Bone Broth
Overview
Japan's foundational ferment — soybeans, salt, and koji — a daily source of live cultures, umami, and the gut-skin axis in a bowl.
What it is
Miso soup opens the traditional Japanese breakfast and anchors ichiju sansai. Unpasteurized miso contains live cultures, enzymes, and the products of months or years of fermentation.
Its Korean cousin doenjang is bolder and longer-aged; both sit at the heart of the book's fermentation chapter.
How it works
- Fermentation produces peptides, organic acids, and microbial metabolites; live cultures may contribute to gut microbial diversity.
- Observational research associates fermented soy intake with various health markers; direct skin evidence is limited.
Potential benefits
- A daily, savory source of live cultures
- Supports a diverse dietary pattern linked to gut health
- Fast, comforting, and endlessly adaptable
Potential benefits describe what research and use suggest may occur for many people — not guaranteed outcomes. Individual responses vary.
Who might consider it
- Anyone beginning to explore fermented foods
- Readers rebuilding meals around the ichiju sansai structure
How it’s used
- Stir into warm (not boiling) dashi or broth to preserve cultures.
- Look for unpasteurized, refrigerated paste with live cultures.
Pairing with other ingredients
- KimchiTwo ferments, two traditions, one gut-skin idea.
- Bone BrothMiso soup on a broth base — a Book II meal-plan breakfast.
Things to know
- High in sodium; a teaspoon or two per bowl is traditional.
- Pasteurized miso is still nutritious but lacks live cultures.
Research
References & further reading
- 01
Fermented soy foods and health
Critical Reviews in Food Science and Nutrition
Reviews fermented soy composition and observational associations.
Art of Radiance distinguishes established evidence from emerging research and traditional practice. Read our science & sources approach.