Leeks
Food · Vegetable · Food, Typed Supps
A milder relative of onion and garlic, with its own prebiotic fibre.
Stage by stage
- Intake (Mild flavor, easy to chew): Cooked leeks are milder in flavor and easier to chew than raw onion.
- Stomach (Fiber & sulfur compounds digest): Digestion of its fibre and sulfur compounds begins.
- Small intestine (Prebiotic fibre feeds gut bacteria): Its prebiotic fibre feeds beneficial gut bacteria; vitamin K is absorbed.
- Gut & immune tissue (Microbiome support): A healthier gut microbiome from prebiotic fibre is linked to broader immune support.
Timing
The dark green tops are edible and flavorful in stock, even though most recipes call for just the white and light green parts.
Time to effect
- Weeks: Regular intake of its prebiotic fibre can gradually support a more diverse gut microbiome.
Allergens
None of the fourteen major allergens. Derived from what this food is, not from a product label.
Eating patterns
Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Keto, Gluten-free. Depends on the product: Low-FODMAP.
In season
September to April in the northern hemisphere, March to October in the southern.
Satiety
The satiety index is measured on 240 kcal servings. At 31 kcal per 100 g that is 784 g of this, which is not a serving anyone eats — so the index has nothing to say about it.
Environmental footprint
0.5 kg CO2e and 14 litres of freshwater per kg, matched to "Onions & leeks" in Poore & Nemecek (2018), Science 360.
Cost band
Cheap — roughly £2.5 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
- Calories: 30.6
- Protein: 1.6g
- Carbohydrate: 4.1g
- of which sugars: 4.1g
- Fat: 0.2g
- of which saturated: 0g
- Fibre: 3.1g
- Sodium: 12mg
Food vs. supplement
Leeks provide a food-based source of prebiotic fibre that feeds beneficial gut bacteria, a different delivery mechanism than an isolated prebiotic or probiotic supplement.
Kitchen tip
Slice them lengthwise and rinse well under running water — dirt tends to hide between the layers near the base.
Common myth
Leeks are basically the same as onions nutritionally. In reality: They share the allium family and some sulfur compounds with onions, but leeks are notably milder in flavor and have a different, gentler fibre profile.
Recipes that use it
More in Vegetable
In the glossary
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