# Leek (Allium ampeloprasum var. porrum)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/leek
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-24
**Evidence Score:** 2 / 10
**Category:** Vegetable
**Also Known As:** Allium ampeloprasum var. porrum, Allium porrum, Garden leek, Common leek, Wild leek, Broadleaf wild leek, Elephant garlic relative, Porrum

## Overview

Leek (Allium ampeloprasum var. porrum) contains organosulfur compounds like allicin and diallyl disulfide that may reduce cancer risk through enhanced detoxification enzyme activity. The polyphenols in leeks provide [antioxidant protection](/ingredients/condition/antioxidant) with ABTS radical scavenging activity of 31-37 mg TE/100g.

## Health Benefits

• May reduce cancer risk - Epidemiologic studies link consumption to reduced prostate, colorectal, stomach, and breast cancer risk (preliminary evidence)
• [Antioxidant activity](/ingredients/condition/antioxidant) - Polyphenol extracts show ABTS radical scavenging (31-37 mg TE/100g ww) and FRAP activity (5-7 mg Fe(II)/100g ww) in vitro
• Potential [blood pressure](/ingredients/condition/heart-health) support - Animal studies show anti-hypertensive effects from oral alcoholic extract at 250-500 mg/kg (no human data)
• Radical scavenging properties - Leaf oil demonstrates DPPH inhibition (28%) and H2O2 scavenging (12%) in laboratory tests
• Traditional [antimicrobial](/ingredients/condition/immune-support) uses - Historical applications include antiseptic and antibacterial properties (traditional use only)

## Mechanism of Action

Leek's organosulfur compounds, including allicin and diallyl disulfide, enhance [phase II detox](/ingredients/condition/detox)ification enzymes like glutathione S-transferase and quinone reductase, promoting carcinogen elimination. The polyphenolic compounds provide [antioxidant activity](/ingredients/condition/antioxidant) through direct radical scavenging and metal chelation. These mechanisms work synergistically to reduce oxidative DNA damage and support cellular protection pathways.

## Clinical Summary

Epidemiologic studies suggest leek consumption is associated with reduced risk of prostate, colorectal, stomach, and breast cancers, though most evidence comes from observational dietary surveys rather than controlled trials. In vitro studies demonstrate [antioxidant activity](/ingredients/condition/antioxidant) with ABTS radical scavenging of 31-37 mg trolox equivalents per 100g wet weight and FRAP activity of 5-7 mg Fe(II) per 100g. Current evidence is preliminary and primarily from population studies, with limited randomized controlled trials specifically examining leek supplementation. More rigorous clinical research is needed to establish definitive therapeutic benefits.

## Nutritional Profile

Leek (Allium ampeloprasum var. porrum) per 100g fresh weight (raw, edible portion): Macronutrients - Energy ~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 sulfur-containing amino acids including alliin precursors), Fat ~0.3g, Water ~83g. Key Vitamins - Vitamin K1 (phylloquinone) ~47µg (39% DV, highest micronutrient by DV contribution), Vitamin C ~12mg (13% DV, bioavailability moderate, losses significant with boiling ~30-50%), Folate (B9) ~64µg (16% DV), Vitamin B6 ~0.23mg (14% DV), Vitamin A (as carotenoids) ~83µg RAE primarily from beta-carotene (~1000µg) and lutein+zeaxanthin (~1900µg, concentrated in dark green leaves). Key Minerals - Manganese ~0.48mg (21% DV), Iron ~2.1mg (12% DV, non-heme form, bioavailability enhanced by co-consumed Vitamin C), Copper ~0.12mg, Potassium ~180mg, Calcium ~59mg, Magnesium ~28mg, Phosphorus ~35mg. Bioactive Organosulfur Compounds - Alliin, allicin precursors, kaempferol glycosides (~5-10mg/100g, predominantly kaempferol-3-glucoside and kaempferol-3,7-diglucoside), quercetin derivatives present at lower concentrations than onion (~1-3mg/100g). Polyphenol total content ~30-50mg GAE/100g fresh weight. Thiosulfinates formed upon tissue damage via alliinase activity. Fructans (inulin-type) ~3-10g/100g dry weight supporting gut microbiota. Bioavailability notes: Fat-soluble carotenoids (beta-carotene, lutein) require dietary fat for absorption; cooking increases carotenoid bioaccessibility but reduces Vitamin C and water-soluble polyphenols; the white shaft portion is lower in carotenoids and polyphenols compared to dark green leaf portions.

## Dosage & Preparation

No clinically studied dosage ranges exist for leek extracts, powders, or standardized forms as human trials are absent. Animal studies used alcoholic extract at 250-500 mg/kg orally, but this cannot be translated to human doses. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Leek is generally recognized as safe when consumed as food, with minimal reported adverse effects in healthy individuals. High consumption may cause gastrointestinal upset, bloating, or breath odor due to sulfur compounds. Individuals taking anticoagulant medications should exercise caution as alliums may have mild blood-thinning properties. Pregnant and breastfeeding women can safely consume leeks as part of a normal diet, though concentrated supplements should be avoided without medical supervision.

## Scientific Research

No human clinical trials, RCTs, or meta-analyses specific to leek were identified in the research. Evidence is limited to epidemiologic observations linking consumption to cancer risk reduction and preclinical studies showing [antioxidant activity](/ingredients/condition/antioxidant) in optimized polyphenol extracts.

## Historical & Cultural Context

Leek has historical use in traditional medicine similar to other Allium species for anti-asthma, antiseptic, diuretic, antibacterial, [antioxidant](/ingredients/condition/antioxidant), antifungal, and gastrointestinal protection applications. Modern epidemiology supports its traditional role in cancer risk reduction, building on its longstanding dietary importance.

## Synergistic Combinations

Garlic, Onion, Quercetin, Vitamin C, Green Tea Extract

## Frequently Asked Questions

### What compounds in leeks provide health benefits?

Leeks contain organosulfur compounds like allicin and diallyl disulfide, plus polyphenols that provide antioxidant activity. These compounds work through enhanced detoxification enzyme activity and direct radical scavenging mechanisms.

### How much antioxidant activity do leeks have?

Laboratory studies show leek extracts have ABTS radical scavenging activity of 31-37 mg trolox equivalents per 100g wet weight. They also demonstrate FRAP antioxidant activity of 5-7 mg Fe(II) equivalents per 100g wet weight.

### Can leeks really reduce cancer risk?

Epidemiologic studies suggest leek consumption is associated with reduced prostate, colorectal, stomach, and breast cancer risk. However, this evidence comes primarily from observational dietary surveys rather than controlled clinical trials.

### Are there any side effects from eating leeks?

Leeks are generally safe when consumed as food, though high amounts may cause gastrointestinal upset, bloating, or breath odor. People taking blood-thinning medications should use caution due to potential mild anticoagulant effects.

### What's the difference between leeks and other allium vegetables?

Leeks (Allium ampeloprasum var. porrum) contain similar organosulfur compounds to garlic and onions but in different concentrations. Leeks have a milder flavor profile and different polyphenol composition, providing 31-37 mg TE/100g antioxidant activity.

### How much leek should I consume daily to get potential health benefits?

Epidemiologic studies linking leek consumption to reduced cancer risk typically involve regular dietary intake as part of a balanced diet, though specific optimal daily amounts have not been established in clinical trials. Most studies suggest that including leeks as part of a regular vegetable intake pattern (several servings per week) may contribute to potential health benefits, but individual requirements may vary based on overall diet and health status. Consult with a healthcare provider for personalized recommendations based on your specific health goals.

### Are leeks safe to consume during pregnancy and for young children?

Leeks are generally recognized as safe food for both pregnant women and children when consumed as part of a normal diet, as they are nutrient-dense vegetables commonly included in cooking. However, pregnant women and caregivers of young children should ensure proper preparation and cooking to minimize foodborne pathogen risk, as with all fresh produce. Those with specific allergies to allium vegetables or concerns about individual health conditions should consult their healthcare provider.

### Does cooking leeks affect their antioxidant content and health benefits?

Cooking methods can influence the bioavailability and concentration of polyphenols and other antioxidant compounds in leeks, though research on optimal preparation methods is limited. In vitro studies have measured antioxidant activity in polyphenol extracts, but the effect of common cooking techniques (steaming, boiling, roasting) on these compounds in whole leeks requires further investigation. Consuming leeks through various preparation methods—both raw and cooked—as part of a regular diet may help ensure exposure to their beneficial compounds.

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