# Brassica oleracea var. gongylodes (Kohlrabi)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/brassica-oleracea-var-gongylodes
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-01
**Evidence Score:** 2 / 10
**Category:** Vegetable
**Also Known As:** Kohlrabi, German turnip, Turnip cabbage, Cabbage turnip, Gongylodes, Mounji (Kashmir region), Knol-kohl

## Overview

Kohlrabi (Brassica oleracea var. gongylodes) is a cruciferous vegetable rich in glucosinolates, vitamin C, and polyphenols including kaempferol and quercetin. Its primary bioactive compounds exert antioxidant and potential chemopreventive effects through [free radical scaveng](/ingredients/condition/antioxidant)ing and modulation of detoxification enzyme activity.

## Health Benefits

[{"benefit": "Exhibits [Antioxidant Activity](/ingredients/condition/antioxidant) (In-Vitro)", "description": "Aqueous extracts from kohlrabi leaves demonstrated up to 50% radical scavenging activity against DPPH and ABTS in laboratory settings, an effect attributed to its phenol and flavonoid content.[1]", "evidence_quality": "Preliminary (in-vitro)"}, {"benefit": "Rich Source of Phenolic Compounds", "description": "Compositional analyses show kohlrabi contains significant levels of phenols (up to 2.14 mg GAE/g dw), which are compounds known for their antioxidant potential.[1]", "evidence_quality": "Compositional Analysis"}, {"benefit": "Contains Potentially Fungicidal Isothiocyanates", "description": "Kohlrabi contains glucosinolates that hydrolyze into isothiocyanates, such as 4-methylthiobutyl isothiocyanate (55.6% of total), which have been investigated for fungicidal properties.[3][5]", "evidence_quality": "Compositional & Functional Analysis"}, {"benefit": "Provides Anthocyanins in Purple Varieties", "description": "Metabolic profiling identified 12 types of anthocyanins, primarily cyanidin derivatives, in purple kohlrabi, which are pigments with known antioxidant capabilities.[2]", "evidence_quality": "Compositional Analysis"}, {"benefit": "Source of Phenylpropanoids", "description": "Purple kohlrabi flesh contains 12.7-fold higher concentrations of phenylpropanoids like trans-cinnamic acid compared to white varieties, which are bioactive plant compounds.[2]", "evidence_quality": "Compositional Analysis"}]

## Mechanism of Action

Kohlrabi's glucosinolates are hydrolyzed by the enzyme myrosinase upon cell disruption, yielding isothiocyanates such as sulforaphane, which induce [Phase II detox](/ingredients/condition/detox)ification enzymes including glutathione S-transferase and quinone reductase via Nrf2 pathway activation. Its flavonoids, particularly kaempferol and quercetin, directly scavenge [reactive oxygen species](/ingredients/condition/antioxidant) (ROS) and chelate pro-oxidant metal ions, reducing oxidative stress at the cellular level. Additionally, vitamin C in kohlrabi regenerates oxidized vitamin E and contributes to collagen biosynthesis by acting as a cofactor for prolyl and lysyl hydroxylase enzymes.

## Clinical Summary

Most available evidence for kohlrabi is derived from in-vitro and animal studies rather than controlled human trials. Aqueous leaf extracts demonstrated up to 50% radical scavenging activity against DPPH and ABTS assays, attributed to phenolic and flavonoid concentrations. Epidemiological data on cruciferous vegetables broadly associate higher intake with reduced colorectal and lung cancer risk, though kohlrabi-specific human intervention studies with defined sample sizes and endpoints are lacking. Overall, the evidence base remains preliminary, and clinical efficacy in humans has not been established through rigorous randomized controlled trials.

## Nutritional Profile

Kohlrabi (Brassica oleracea var. gongylodes) is a low-calorie, nutrient-dense vegetable. Per 100g raw edible portion (bulb): Energy ~27 kcal, Water ~91g, Carbohydrates ~6.2g (of which sugars ~2.6g), Dietary Fiber ~3.6g, Protein ~1.7g, Fat ~0.1g. Key Vitamins: Vitamin C (ascorbic acid) ~62mg (69% DV) — notably high and well-bioavailable in raw form but significantly reduced by cooking; Vitamin B6 (pyridoxine) ~0.15mg; Folate (B9) ~16µg; Thiamine (B1) ~0.05mg; Riboflavin (B2) ~0.02mg; Vitamin K1 ~0.1µg (bulb; leaves contain substantially more, ~170µg per 100g). Key Minerals: Potassium ~350mg, Phosphorus ~46mg, Calcium ~24mg, Magnesium ~19mg, Manganese ~0.14mg, Copper ~0.13mg, Iron ~0.4mg (non-heme; bioavailability enhanced by co-consumption with Vitamin C). Bioactive Compounds: Glucosinolates — primarily glucoiberin (3-methylsulfinylpropyl glucosinolate) and sinigrin, ranging approximately 1.5–4.5µmol/g dry weight depending on cultivar and growing conditions; these are hydrolyzed by myrosinase upon tissue disruption to bioactive isothiocyanates (e.g., iberin, allyl isothiocyanate) with chemoprotective associations. Phenolic compounds: total phenolics approximately 50–150mg gallic acid equivalents per 100g fresh weight (higher in leaves vs. bulb); predominant phenolics include hydroxycinnamic acids (sinapic acid, ferulic acid), flavonoids (kaempferol glycosides, quercetin derivatives), and anthocyanins in purple-skinned cultivars (primarily cyanidin-3-sophoroside-5-glucoside). Carotenoids: lutein and beta-carotene present in modest quantities (~1–3mg/100g combined), concentrated predominantly in the leaves. Fiber composition: mix of cellulose, hemicellulose, and pectin; supports gut motility. Bioavailability notes: Glucosinolate hydrolysis is optimal in raw or lightly steamed kohlrabi; boiling significantly leaches water-soluble Vitamin C and glucosinolates (up to 40–60% loss). Chopping or chewing before cooking activates myrosinase. Oxalate content is low (~20mg/100g), posing minimal concern for [calcium absorption](/ingredients/condition/bone-health) interference.

## Dosage & Preparation

No clinically studied dosage ranges for kohlrabi or its extracts have been established due to a lack of human trials.[1] Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Kohlrabi is generally recognized as safe when consumed in typical dietary amounts, with no established upper intake limit. Individuals taking warfarin (Coumadin) should moderate intake, as its vitamin K content can interfere with anticoagulant therapy and alter INR values. Those with hypo[thyroid](/ingredients/condition/hormonal)ism or taking thyroid hormone medications (e.g., levothyroxine) should be cautious, as raw kohlrabi contains goitrogenic glucosinolates that may inhibit thyroid peroxidase and reduce iodine uptake, though cooking partially deactivates these compounds. Kohlrabi is considered safe during pregnancy as a whole food, but concentrated extracts or supplements have not been evaluated for gestational safety.

## Scientific Research

No human clinical trials, randomized controlled trials (RCTs), or meta-analyses specific to kohlrabi supplementation were identified in the provided research, and therefore no PMIDs are available.[1][2] The existing scientific literature is limited to compositional analyses and in-vitro studies on the plant's chemical and [antioxidant](/ingredients/condition/antioxidant) properties.

## Historical & Cultural Context

Originating in Northern Europe, kohlrabi is traditionally consumed as a cooked vegetable or fermented into dishes like “Mounji Achar” in the Jammu and Kashmir region of India.[1][6] Ground kohlrabi meal has also been used in Taiwan as a fungicidal seed treatment, though no formal medicinal uses in systems like Ayurveda or TCM are documented.[5]

## Synergistic Combinations

Sulforaphane, Turmeric (Curcumin), Green Tea Extract (EGCG), Vitamin C, Resveratrol

## Frequently Asked Questions

### What vitamins and minerals are in kohlrabi?

Kohlrabi is a notable source of vitamin C (approximately 62 mg per 100g raw, exceeding 60% of the RDA), potassium (~350 mg per 100g), and vitamin B6. It also provides modest amounts of folate, copper, and manganese, alongside dietary fiber at roughly 1.8g per 100g.

### Does kohlrabi have cancer-fighting properties?

Kohlrabi contains glucosinolates that break down into isothiocyanates, compounds shown in cell and animal studies to activate Nrf2-mediated detoxification pathways and promote apoptosis in cancer cell lines. However, no human clinical trials have specifically tested kohlrabi for cancer prevention or treatment, so this benefit cannot currently be claimed for humans with confidence.

### Is kohlrabi good for weight loss?

Kohlrabi provides approximately 27 kcal per 100g with about 1.8g of dietary fiber, making it a low-calorie, high-volume food that may support satiety. Its fiber content slows gastric emptying and may blunt postprandial glucose spikes, which can be relevant for metabolic health, though no dedicated weight-loss trials using kohlrabi specifically exist.

### Can you eat kohlrabi raw or does it need to be cooked?

Kohlrabi can be eaten raw or cooked; raw consumption preserves its vitamin C content and intact myrosinase enzyme, which maximizes isothiocyanate production from glucosinolates. Cooking deactivates myrosinase, reducing isothiocyanate yield, but also reduces goitrogenic activity, making cooked kohlrabi preferable for individuals with thyroid concerns.

### How does kohlrabi compare to other cruciferous vegetables like broccoli?

Compared to broccoli, kohlrabi contains lower concentrations of sulforaphane precursors (glucoraphanin) but offers comparable vitamin C levels and meaningful amounts of kaempferol. Broccoli florets are generally considered more glucosinolate-dense per gram, while kohlrabi's bulb and leaves provide a broader polyphenol profile including anthocyanins in the purple variety, making it nutritionally complementary rather than superior.

### What is the difference between kohlrabi bulbs and kohlrabi leaves in terms of nutritional content?

Kohlrabi leaves contain significantly higher concentrations of phenolic compounds and flavonoids compared to the bulbs, making them particularly rich in antioxidants. The bulbs are primarily valued for their vitamin C, fiber, and minerals, while the leaves offer enhanced phytonutrient density and should not be discarded when preparing kohlrabi. Both parts are edible and contribute unique nutritional profiles to the diet.

### Is kohlrabi safe to consume for people taking blood thinners or anticoagulant medications?

Kohlrabi is generally safe for people taking blood thinners, though moderation is advised due to its vitamin K content, which plays a role in blood clotting. Individuals on warfarin or similar anticoagulants should maintain consistent vitamin K intake rather than making dramatic increases, and should consult their healthcare provider about portion sizes. Cooking kohlrabi does not significantly reduce its vitamin K levels.

### How does the antioxidant content of fresh kohlrabi compare to cooked kohlrabi?

Cooking kohlrabi can reduce some heat-sensitive phenolic compounds and flavonoids, though the degree of loss depends on cooking method and duration; steaming and quick cooking preserve more antioxidants than boiling. Raw kohlrabi retains the full spectrum of its in-vitro demonstrated antioxidant activity from phenolic and flavonoid compounds. For maximum antioxidant benefit, consuming kohlrabi raw or lightly steamed is preferable to prolonged cooking methods.

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