# Crambe maritima (Sea Kale)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/crambe-maritima
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-01
**Evidence Score:** 2 / 10
**Category:** Vegetable
**Also Known As:** Crambe maritima, Sea Cabbage, Sea Colewort, Scurvy Grass, Strand Kale, Beach Cabbage, Wild Cabbage, Maritime Crambe

## Overview

Crambe maritima, commonly called sea kale, is a coastal cruciferous vegetable containing glucosinolates, vitamin C, and potassium as its primary bioactive constituents. Its glucosinolates are hydrolyzed by myrosinase into isothiocyanates, compounds studied for [antioxidant](/ingredients/condition/antioxidant) and potential chemoprotective activity.

## Health Benefits

["\u2022 Provides Vitamin C: Nutritional comparisons suggest it is a rich source of vitamin C, similar to asparagus. Evidence Quality: Nutritional data, not from clinical trials.[4][6]", "\u2022 Source of Potassium: Its nutritional profile is noted to be a good source of potassium. Evidence Quality: Nutritional data, not from clinical trials.[4][6]", "\u2022 Source of Minerals: It is generally considered a source of various minerals, comparable to other nutrient-dense vegetables. Evidence Quality: Nutritional data, not from clinical trials.[4][6]", "\u2022 Historical Antiseptic Use: Traditionally, pickled sea kale was valued for supposed antiseptic properties on long sea voyages. Evidence Quality: Anecdotal/Traditional, lacks clinical validation.[4][6]", "\u2022 Historical Purifying Use: Historical accounts claim it has purifying properties, though this has not been empirically tested. Evidence Quality: Anecdotal/Traditional, lacks clinical validation.[4]"]

## Mechanism of Action

Sea kale contains glucosinolates that are enzymatically converted by myrosinase into bioactive isothiocyanates upon chewing or cellular disruption, which can activate the Nrf2-Keap1 antioxidant pathway to upregulate cytoprotective enzymes including [glutathione](/ingredients/condition/detox) S-transferase and heme oxygenase-1. Its vitamin C content acts as a water-soluble antioxidant by donating electrons to neutralize [reactive oxygen species](/ingredients/condition/antioxidant) and regenerating tocopherol radicals. Potassium in sea kale supports Na+/K+-ATPase pump function, contributing to membrane potential regulation and fluid balance.

## Clinical Summary

No published human clinical trials have specifically investigated Crambe maritima as a supplement or therapeutic intervention. Available evidence is limited to nutritional composition analyses and food science literature, which characterize its glucosinolate, vitamin C, and mineral content. Broader research on cruciferous vegetable glucosinolates and their isothiocyanate metabolites in human studies suggests modest [antioxidant](/ingredients/condition/antioxidant) and phase-II enzyme-inducing effects, but these findings cannot be directly extrapolated to sea kale without dedicated trials. The overall evidence base for sea kale-specific health claims remains preliminary and largely observational or compositional in nature.

## Nutritional Profile

Sea Kale (Crambe maritima) has limited comprehensive nutritional data compared to common vegetables, but available information indicates the following profile per 100g fresh weight (blanched shoots/young leaves): Calories: approximately 20-30 kcal. Macronutrients: Carbohydrates ~3-4g, Protein ~2-3g (notably higher than many leafy vegetables), Fat <0.5g, Dietary Fiber ~2g. Micronutrients: Vitamin C: estimated 20-40mg per 100g (comparable to asparagus), contributing meaningfully to daily requirements; Potassium: estimated 200-300mg per 100g, supporting electrolyte balance; Calcium: moderate levels consistent with brassica family members (~40-60mg per 100g); Sulfur-containing compounds: as a member of Brassicaceae, it contains glucosinolates (specific compounds include gluconapin and related sinigrin-type compounds), which upon hydrolysis yield isothiocyanates with potential [antioxidant](/ingredients/condition/antioxidant) and chemoprotective properties. Iron and Magnesium: present in modest amounts typical of brassica vegetables. Bioactive Compounds: Flavonoids and phenolic acids are present, contributing to antioxidant capacity. Chlorophyll content varies significantly depending on whether shoots are blanched (etiolated, lower chlorophyll) or unblanched (green, higher). Bioavailability Notes: Blanching reduces glucosinolate content and bitterness; vitamin C bioavailability is good from fresh/lightly cooked material but degrades with prolonged heat. Oxalate levels are considered low, posing minimal mineral absorption interference. Data is primarily derived from nutritional comparisons and botanical family extrapolation rather than direct laboratory analysis.

## Dosage & Preparation

No clinically studied dosage ranges, forms (e.g., extract, powder), or standardization protocols are documented, as no human clinical studies exist. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Sea kale, like other cruciferous vegetables, contains goitrogens that can interfere with [thyroid](/ingredients/condition/hormonal) iodine uptake when consumed in large quantities, posing a concern for individuals with hypothyroidism or iodine deficiency. Its glucosinolate metabolites may modestly induce cytochrome P450 enzymes (particularly CYP1A2), potentially altering the [metabolism](/ingredients/condition/weight-management) of drugs such as caffeine, clozapine, or theophylline at high dietary intakes. No clinical data on sea kale supplementation safety in pregnant or breastfeeding women exists, so caution is advised beyond normal culinary amounts. Individuals on anticoagulants such as warfarin should note that cruciferous vegetables containing vitamin K analogs may affect INR stability, though sea kale's specific vitamin K content is not well characterized.

## Scientific Research

No human clinical trials, randomized controlled trials (RCTs), or meta-analyses on Crambe maritima were identified in the available research dossier. Consequently, no PubMed PMIDs are available to cite for clinical efficacy.[1][2][3][4][5][6][7][8]

## Historical & Cultural Context

Sea kale has a history of culinary and medicinal use in European coastal traditions, especially in Britain. Young shoots are blanched and eaten like asparagus, while its high vitamin C content made it valuable when pickled for long sea voyages to prevent scurvy.[1][3][4][6]

## Synergistic Combinations

Vitamin C, Iodine, Selenium, Sulforaphane

## Frequently Asked Questions

### What vitamins and minerals does sea kale contain?

Sea kale is documented in nutritional analyses as a source of vitamin C, comparable in concentration to asparagus, and a good source of potassium. It also contains glucosinolates, dietary fiber, and modest amounts of calcium and magnesium, though precise quantified values per 100g serving vary across cultivated versus wild specimens. These nutrients contribute to its classification as a nutritionally relevant leafy coastal vegetable.

### Is sea kale the same as regular kale?

No, sea kale (Crambe maritima) is a distinct species from common kale (Brassica oleracea var. acephala), despite both belonging to the Brassicaceae family. Sea kale grows natively on Atlantic coastlines and produces broad waxy leaves, whereas common kale is a domesticated Brassica. Their glucosinolate compositions differ and sea kale has received far less clinical investigation than Brassica-derived vegetables.

### Can sea kale affect thyroid function?

Sea kale contains glucosinolates that are metabolized into goitrin and thiocyanate ions, compounds that competitively inhibit thyroid peroxidase and reduce iodine uptake by the thyroid gland. This effect is generally relevant only at high, repeated intake levels and is largely mitigated by adequate dietary iodine. Individuals with pre-existing hypothyroidism or those on thyroid hormone replacement therapy such as levothyroxine should moderate high-dose sea kale supplementation and consult a healthcare provider.

### Does sea kale have antioxidant properties?

Yes, sea kale's antioxidant activity is primarily attributed to its vitamin C content and the isothiocyanates derived from glucosinolate hydrolysis. Isothiocyanates such as allyl isothiocyanate activate the Nrf2 transcription factor, upregulating endogenous antioxidant enzymes including superoxide dismutase and glutathione peroxidase. However, these mechanistic effects have been demonstrated in laboratory and animal studies using related cruciferous compounds, not in dedicated sea kale clinical trials.

### Are there any sea kale supplements available, and what dose is used?

Standardized sea kale supplements are not widely commercially available, and no established clinical dosage has been determined through human trials. Sea kale is consumed primarily as a culinary vegetable in European coastal cuisines, particularly in the UK and France, with young blanched shoots eaten like asparagus. In the absence of pharmacokinetic or dose-response data specific to Crambe maritima, no evidence-based supplemental dose recommendation can currently be made.

### What foods contain sea kale, and can I get enough nutrients from eating it fresh?

Sea kale is a leafy green vegetable that can be found in specialty produce markets, farmers markets, and some grocery stores, typically in spring and early summer months. You can obtain its vitamin C, potassium, and mineral content through fresh consumption, though availability may be limited compared to common kale varieties. Many people incorporate it into salads, steamed dishes, or sautés to meet nutrient needs, though supplemental forms are available for those without regular access to fresh sea kale.

### How does sea kale compare nutritionally to other cruciferous vegetables like broccoli or cabbage?

Sea kale shares the nutrient profile of cruciferous vegetables with notable vitamin C and potassium content similar to asparagus and other leafy greens. While broccoli and cabbage are more commonly cultivated, sea kale offers a distinct mineral composition that may provide complementary nutritional benefits. The choice between them often depends on availability, personal taste preference, and specific nutrient goals rather than significant nutritional superiority.

### What is the evidence quality for sea kale's health benefits, and are there clinical studies supporting its use?

Most evidence for sea kale's nutritional value comes from compositional and nutritional analysis data rather than rigorous clinical trials. The available research quality is primarily based on its documented vitamin and mineral content, not controlled human studies demonstrating specific health outcomes. To establish stronger evidence for therapeutic claims, more clinical research would be needed beyond current nutritional profiling data.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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