Leeks

Overview

Leeks are allium vegetables providing fructooligosaccharides (FOS) prebiotic fiber, supporting gut microbiome diversity.

Within the BRAIN Diet framework, fructooligosaccharides (FOS) are found in onions, garlic, leeks, and asparagus, and are part of the allium family with prebiotic benefits [1][2].

Key Nutritional Highlights

• Allium vegetables including leeks supply organosulfur compounds and prebiotic fructans [1]
• Fermentable fibres from alliums support beneficial gut microbiota taxa [2]
• Leeks are allium vegetables providing fructooligosaccharides (FOS) prebiotic fiber, supporting gut microbiome diversity. [1]
• Fructooligosaccharides (FOS) are found in onions, garlic, leeks, and asparagus, and are part of the allium family with prebiotic benefits. [2]
• Leeks are allium vegetables providing fructooligosaccharides (FOS) prebiotic fiber, supporting gut microbiome diversity.

Food Context

Synergies

• Part of diverse prebiotic fiber strategy
• Pair with other allium vegetables

Preparation

• Can be consumed cooked or raw
• Supports Bifidobacterium growth

Recipes

no recipes found

Nutrient Tables (per 100 g)

Core nutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Protein	1.5 g	—
Sugars	3.1 g	—
Fibre	3 g	—

Key micronutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Iron	0.8 mg	4.2%
Zinc	0.3 mg	2.7%
Magnesium	15.7 mg	3.7%
Calcium	51.4 mg	5.1%
Potassium	319 mg	9.4%
Vitamin B6	0.2 mg	12.3%

Reference intakes: US Dietary Reference Intakes for adults (19–50 years; using the higher of male/female values where they differ).

Data provenance (core / micronutrient panel): USDA FoodData Central, Leeks, bulb and greens, root removed, raw, FDC ID 2727584, API, per 100 g edible portion, last checked 2026-03-14

Substances

Substances in this food: editorial (Overview / literature) plus analytical (nutrition table).

7 substances in this food

Vitamin K2 (MK forms)

Calcium handling; potential roles in brain health; often co-occurs with fat-soluble vitamins

Fe²⁺

Iron

Oxygen transport; dopamine synthesis (tyrosine hydroxylase cofactor)

Zn²⁺

Zinc

Cofactor in neurotransmission and antioxidant enzymes; dopamine modulation

Mg²⁺

Magnesium

Enzymatic cofactor (>300 reactions); neurotransmitters; mitochondria; redox balance

Ca²⁺

Calcium

Bone health; neurotransmission; interacts with vitamin D and K2

K⁺

Potassium

Electrolyte for nerve transmission, muscle function, and blood pressure regulation

Vitamin B6 (Pyridoxine → PLP)

PLP cofactor for neurotransmitter synthesis; relies on brain PDXK activation

References

[1] Allium vegetables including leeks supply organosulfur compounds and prebiotic fructans. Nicastro et al. 2015. Garlic and onions: their cancer prevention properties

[2] Fermentable fibres from alliums support beneficial gut microbiota taxa. Pouille et al. 2022. Chicory: Understanding the Effects and Effectors of This Functional Food