# Allium ampeloprasum var. porrum (Leek)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/allium-ampeloprasum-var-porrum
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-29
**Evidence Score:** 2 / 10
**Category:** Vegetable
**Also Known As:** leek, garden leek, common leek, cultivated leek, porrum, prei, poireau, porro, lauch, kurrat

## Overview

Leek (Allium ampeloprasum var. porrum) contains organosulfur compounds and polyphenols that demonstrate [antioxidant](/ingredients/condition/antioxidant) and [antimicrobial](/ingredients/condition/immune-support) properties. Research shows potential cardiovascular benefits through mechanisms involving [blood pressure regulation](/ingredients/condition/heart-health) and bacterial growth inhibition.

## Health Benefits

• Anti-hypertensive effects demonstrated in animal models at doses of 250-500 mg/kg (preliminary evidence only)
• Antibacterial activity against P. aeruginosa (MIC 20 mg/mL) and S. aureus (MIC 29 mg/mL) in laboratory studies (in vitro evidence)
• [Antioxidant](/ingredients/condition/antioxidant) properties through polyphenolic compounds and flavonoids, particularly in green leaves (mechanistic evidence only)
• [Anti-inflammatory](/ingredients/condition/inflammation) potential through suppression of COX-2 and iNOS pathways (theoretical based on compound analysis)
• Antifungal activity from spirostanol saponins and dibenzofurans including Porric acids A, B, and C (in vitro evidence)

## Mechanism of Action

Leek's bioactive organosulfur compounds and polyphenolic antioxidants work through multiple pathways including [free radical scaveng](/ingredients/condition/antioxidant)ing and bacterial cell membrane disruption. The anti-hypertensive effects likely involve vasodilation mechanisms, while antibacterial activity results from sulfur compounds interfering with bacterial protein synthesis and cell wall integrity.

## Clinical Summary

Current evidence for leek extract is primarily limited to animal and laboratory studies. Anti-hypertensive effects were demonstrated in animal models using 250-500 mg/kg doses, though human clinical trials are lacking. In vitro antibacterial studies show moderate activity against P. aeruginosa (MIC 20 mg/mL) and S. aureus (MIC 29 mg/mL). More robust human clinical research is needed to establish therapeutic efficacy and optimal dosing protocols.

## Nutritional Profile

Leek (raw, per 100g edible portion): Macronutrients — Calories: ~61 kcal; Carbohydrates: ~14.2g (of which sugars ~3.9g); Dietary fiber: ~1.8g (predominantly fructooligosaccharides and inulin-type fructans acting as [prebiotic](/ingredients/condition/gut-health)s); Protein: ~1.5g (containing all essential amino acids in modest amounts); Fat: ~0.3g. Key Micronutrients — Vitamin K1 (phylloquinone): ~47 µg (39% DV), among the highest in common vegetables; Vitamin A (as carotenoids): ~83 µg RAE, primarily from lutein (~1900 µg) and beta-carotene (~1000 µg) concentrated in green leaf portions; Folate (B9): ~64 µg (16% DV); Vitamin C: ~12 mg (13% DV); Vitamin B6: ~0.23 mg (18% DV); Manganese: ~0.48 mg (21% DV); Iron: ~2.1 mg (12% DV, non-heme form with moderate bioavailability enhanced by co-ingestion with vitamin C); Calcium: ~59 mg (6% DV); Potassium: ~180 mg; Phosphorus: ~35 mg; Magnesium: ~28 mg. Bioactive Compounds — Organosulfur compounds: allicin precursors (alliin ~0.02–0.05 g/100g), diallyl disulfide, and kaempferol-conjugated sulfur compounds; Polyphenols: kaempferol glycosides (primarily kaempferol-3-glucoside and kaempferol-4-glucoside, ~10–25 mg/100g), quercetin derivatives (~5–10 mg/100g), and ferulic acid; Anthocyanins: present in purple-tinged varieties (~1–5 mg/100g cyanidin equivalents); Fructans/Inulin: ~3–10 g/100g dry weight (significant prebiotic substrate for Bifidobacterium and Lactobacillus spp.). Bioavailability Notes — Lutein and beta-carotene absorption is fat-dependent (bioavailability increases ~3–5x when consumed with dietary fat); kaempferol bioavailability from leeks (~30–40%) is lower than from quercetin sources due to glycoside form; cooking (boiling) reduces vitamin C by ~30–40% and leaches water-soluble B vitamins but may mildly increase carotenoid bioaccessibility; iron absorption is inhibited by concurrent polyphenol intake (~25–75% reduction); fructan content may cause GI discomfort in FODMAP-sensitive individuals. Green leaf portions contain significantly higher concentrations of vitamins K, A, and polyphenols compared to white bulb portions.

## Dosage & Preparation

Animal studies used alcoholic extract doses of 250-500 mg/kg for anti-hypertensive effects. Antibacterial research tested aqueous extracts at 35-40 mg per disk in laboratory settings. No standardized human dosage recommendations are available from clinical research. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Leek extract is generally considered safe when consumed in food amounts, but supplement safety data is limited. Potential interactions may occur with anticoagulant medications due to organosulfur compounds affecting platelet function. Individuals with existing hypotension should use caution given the anti-hypertensive effects observed in animal studies. Pregnant and breastfeeding women should avoid supplemental doses due to insufficient safety data.

## Scientific Research

The available research consists primarily of in vitro studies and animal models, with no human clinical trials or meta-analyses found in the provided sources. One animal study demonstrated anti-hypertensive activity at oral doses of 250-500 mg/kg of alcoholic extract, while laboratory studies showed antibacterial efficacy with MICs of 20-29 mg/mL against common pathogens.

## Historical & Cultural Context

The search results do not provide specific information about leek's historical use in traditional medicine systems or the duration of traditional use. While noted as having "low toxicity" in Allium species research, specific traditional applications were not documented in the available sources.

## Synergistic Combinations

Garlic extract, Onion extract, Quercetin, Vitamin C, Aged black garlic

## Frequently Asked Questions

### What is the effective dosage of leek extract for blood pressure?

Animal studies used 250-500 mg/kg body weight to demonstrate anti-hypertensive effects. However, no established human dosage exists due to lack of clinical trials, and supplementation should be discussed with a healthcare provider.

### Can leek extract fight bacterial infections?

Laboratory studies show leek extract has antibacterial activity against P. aeruginosa and S. aureus with minimum inhibitory concentrations of 20-29 mg/mL. However, this doesn't translate to proven infection-fighting ability in humans and shouldn't replace conventional antibiotics.

### What compounds in leek provide health benefits?

Leek's primary bioactive compounds include organosulfur compounds (similar to other alliums) and polyphenolic antioxidants. These compounds are responsible for the observed antioxidant, antimicrobial, and potential cardiovascular effects in research studies.

### Is leek extract safe to take with blood pressure medication?

Leek extract may have additive blood pressure-lowering effects when combined with antihypertensive medications, potentially causing hypotension. Individuals on blood pressure medications should consult their doctor before using leek supplements to avoid dangerous interactions.

### How does leek extract compare to garlic supplements?

Both leek and garlic contain organosulfur compounds, but garlic has significantly more clinical research supporting its cardiovascular benefits. Leek extract research is primarily limited to animal and laboratory studies, while garlic has extensive human clinical trial data.

### What is the difference between leek extract and whole leek supplements in terms of bioavailability?

Leek extract concentrates the active compounds like polyphenols and flavonoids, potentially offering higher bioavailability per dose compared to whole leek powder. However, whole leek supplements retain fiber and other phytonutrients that may support additional health benefits through synergistic effects. The choice depends on whether you prioritize concentrated compound levels or the full nutritional profile of the whole plant.

### Is leek supplement safe for pregnant women and children?

While leeks are safe as food during pregnancy and childhood, clinical safety data for concentrated leek extracts in these populations is limited. Pregnant women and children should consult a healthcare provider before taking leek supplements, as most safety studies focus on adult populations. Whole leek consumption through diet is considered safe for both groups.

### How strong is the clinical evidence supporting leek supplements for anti-inflammatory benefits?

Current evidence for leek's anti-inflammatory effects is primarily mechanistic and derived from laboratory studies of its polyphenolic compounds, rather than human clinical trials. Most anti-hypertensive and antibacterial data comes from animal models and in vitro studies, which cannot be directly extrapolated to human efficacy. More rigorous clinical trials are needed to establish the strength and magnitude of anti-inflammatory effects in humans at practical supplement doses.

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