# Tatsoi (Brassica rapa subsp. narinosa)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/tatsoi
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-31
**Evidence Score:** 2 / 10
**Category:** Vegetable
**Also Known As:** Brassica rapa subsp. narinosa, spinach mustard, spoon mustard, rosette bok choy, flat black cabbage, tah tsai, Asian spinach, spinach pak choi

## Overview

Tatsoi (Brassica rapa subsp. narinosa) is a dark leafy green containing glucosinolates that convert to bioactive isothiocyanates with potential cellular protective effects. This Asian brassica vegetable provides exceptionally high levels of vitamin K (163% DV per 100g) and vitamin A for bone and vision health.

## Health Benefits

• May support cellular protection through glucosinolates and their metabolites, though human clinical evidence is lacking
• Contains high levels of vitamin K (163% DV per 100g), essential for blood clotting and [bone health](/ingredients/condition/bone-health) - based on nutritional analysis only
• Provides significant vitamin A (89% DV per 100g) from carotenoids that may support vision and [immune function](/ingredients/condition/immune-support) - evidence from compositional studies
• Rich in antioxidants including flavonoids, sulforaphane, and carotenoids that function as [free radical scaveng](/ingredients/condition/antioxidant)ers - mechanistic evidence only
• Contains potassium (370mg per 100g) which aids [blood pressure](/ingredients/condition/heart-health) control and cardiac function - based on nutrient content analysis

## Mechanism of Action

Tatsoi's glucosinolates undergo hydrolysis by myrosinase enzyme to form isothiocyanates, which activate [phase II detox](/ingredients/condition/detox)ification enzymes and Nrf2 transcription factor pathways. Vitamin K functions as a cofactor for gamma-glutamyl carboxylase, enabling proper calcium binding to osteocalcin for [bone mineralization](/ingredients/condition/bone-health). The high vitamin A content supports retinal function through rhodopsin formation and maintains epithelial cell integrity.

## Clinical Summary

No human clinical trials have specifically evaluated tatsoi's health effects. Research on related Brassica vegetables shows glucosinolate intake of 10-40mg daily may support [antioxidant](/ingredients/condition/antioxidant) enzyme activity, though individual tatsoi studies are lacking. Nutritional analysis confirms vitamin K content of 163μg per 100g and vitamin A levels of 890μg RAE per 100g. Evidence for tatsoi's benefits relies primarily on nutritional composition data and extrapolation from other cruciferous vegetable research.

## Nutritional Profile

Tatsoi is a low-calorie leafy green (~20 kcal per 100g raw) with high micronutrient density. Macronutrients: carbohydrates ~2.2g, protein ~1.8g, fat ~0.3g, dietary fiber ~1.8g per 100g. Key micronutrients: Vitamin K1 (phylloquinone) ~197-250mcg (~163-208% DV per 100g), Vitamin A equivalents ~450-500mcg RAE (~89% DV) primarily from beta-carotene (~5,000-6,000mcg), lutein, and zeaxanthin; Vitamin C ~45-60mg (~50-67% DV); Folate (B9) ~60-80mcg (~15-20% DV); Calcium ~105-120mg (~10-12% DV); Potassium ~250-300mg (~5-6% DV); Iron ~1.5-2.0mg (~8-11% DV); Magnesium ~18-22mg. Bioactive compounds: glucosinolates (notably glucobrassicin, sinigrin, and gluconasturtiin) at approximately 15-30 µmol/g dry weight, which hydrolyze via myrosinase to isothiocyanates and indoles upon chopping or chewing; chlorophyll a and b contributing [antioxidant](/ingredients/condition/antioxidant) capacity; flavonoids including quercetin and kaempferol glycosides. Bioavailability notes: beta-carotene absorption is enhanced ~2-3 fold when consumed with dietary fat; Vitamin K1 bioavailability is moderate (~15-25%) and enhanced by fat co-ingestion; calcium bioavailability is modestly reduced by oxalates present at low-moderate levels (~50-100mg/100g), estimated absorption ~40-50% compared to dairy; iron is non-heme form with lower bioavailability (~5-12%), improved by concurrent Vitamin C intake; glucosinolate hydrolysis is maximized in raw or lightly cooked preparations, as prolonged heat inactivates myrosinase, though gut microbiota can partially compensate.

## Dosage & Preparation

No clinically studied dosage ranges are available for tatsoi extracts or standardized preparations. Nutritional sources indicate a typical serving is approximately 100 grams of fresh tatsoi, providing 15 calories, 1.6g protein, and 1.8g dietary fiber. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Tatsoi is generally safe when consumed as food, with no documented adverse effects in healthy individuals. High vitamin K content may interfere with warfarin and other anticoagulant medications by affecting INR levels. Goitrogenic compounds in raw tatsoi could theoretically affect [thyroid function](/ingredients/condition/hormonal) in individuals with iodine deficiency, though cooking reduces this concern. Pregnant and breastfeeding women can safely consume tatsoi as part of a balanced diet.

## Scientific Research

The available research consists primarily of metabolite profiling studies examining phytochemical composition and nutritional analyses, with no human clinical trials, randomized controlled trials, or meta-analyses found in the provided sources. No PubMed PMIDs for clinical studies were available.

## Historical & Cultural Context

The research does not provide information about tatsoi's historical use in traditional medicine systems. Sources only indicate it is an Asian vegetable that has become popular in North American cuisine and is now grown worldwide.

## Synergistic Combinations

Vitamin D, Calcium, Omega-3 fatty acids, Iodine, Vitamin C

## Frequently Asked Questions

### How much vitamin K is in tatsoi?

Tatsoi contains approximately 163μg of vitamin K per 100g serving, which provides 163% of the daily value. This makes it one of the richest dietary sources of vitamin K among leafy greens.

### What are glucosinolates in tatsoi?

Glucosinolates are sulfur-containing compounds that convert to bioactive isothiocyanates when tatsoi is chopped or chewed. These metabolites may support cellular protection through activation of phase II detoxification enzymes, though human studies are limited.

### Can tatsoi interfere with blood thinners?

Yes, tatsoi's high vitamin K content (163% DV per 100g) can potentially interfere with warfarin and other vitamin K antagonist medications. Patients on anticoagulants should maintain consistent intake and consult their healthcare provider.

### Is tatsoi safe during pregnancy?

Tatsoi is safe for pregnant women when consumed as food and provides beneficial folate, vitamin A, and iron. The high vitamin K content supports proper blood clotting during delivery, making it a nutritious addition to prenatal diets.

### How does tatsoi compare to other leafy greens?

Tatsoi provides higher vitamin K levels than spinach (483μg vs 163μg per 100g) and comparable vitamin A to kale. Its glucosinolate profile is similar to other Brassica vegetables like bok choy and mizuna, offering unique sulfur compounds not found in non-cruciferous greens.

### What is the best way to prepare tatsoi to maximize nutrient retention?

Lightly steaming or stir-frying tatsoi for 2-3 minutes preserves more heat-sensitive vitamin C while making fat-soluble vitamins like vitamin K and carotenoids more bioavailable compared to raw consumption. Prolonged boiling can leach water-soluble nutrients, so shorter cooking methods are preferred. Consuming tatsoi with a source of dietary fat (olive oil, nuts, or seeds) further enhances absorption of its carotenoids and vitamin K.

### Who should consider eating more tatsoi as a dietary source of nutrients?

Individuals at risk for bone health issues, those requiring adequate vitamin K intake for blood clotting regulation, and people seeking nutrient-dense vegetables with high carotenoid content may benefit from regular tatsoi consumption. Those following plant-based diets can use tatsoi as a bioavailable source of multiple micronutrients in a single serving, though it should complement rather than replace medical treatments for any underlying conditions.

### How does the nutrient density of tatsoi per serving compare to taking a multivitamin supplement?

A 100-gram serving of tatsoi provides significant amounts of vitamin K and vitamin A along with bioactive compounds like glucosinolates, minerals, and fiber that work synergistically—a profile difficult to replicate in a single supplement. However, whole food nutrients from tatsoi and supplements serve different purposes: whole foods provide broader nutritional benefits and bioactive compounds, while supplements deliver standardized, concentrated micronutrient doses for specific deficiencies.

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