Barley

Overview

Barley is a whole grain valued for beta-glucan prebiotic fibre and sustained energy release. Beta-glucan supports gut microbiome diversity and stable blood glucose; it is an intrinsic component of barley (and oats, mushrooms), not to be confused with downstream metabolites such as SCFAs produced by fermentation.

Key Nutritional Highlights

• Highest fibre among BRAIN Diet grain and pseudograin pages (per 100 g).
• Rich source of beta-glucan, the viscous cereal fibre most strongly associated with barley's metabolic effects.
• Beta-glucan-rich barley can support glycaemic control and satiety in mixed-meal contexts.
• Grain protein is lysine-limited, so amino-acid balance improves when paired with legumes.

Food Context

Synergies

• Part of whole grain diversity strategy

Preparation

• Soak before cooking to reduce phytates and improve mineral bioavailability
• Beta-glucan in barley supports gut microbiome health (mechanisms include fermentation to SCFAs such as butyrate; improved gut barrier)

Essential Amino Acid Profile

Barley provides a useful plant protein source but is not a complete protein.

Notable amino acids:

• Methionine (relatively higher than in legumes)

Limiting amino acids:

• Lysine (typical of grains)

Protein pairing strategy:

Grains such as barley are relatively higher in methionine but lysine-limited. Combining barley with legumes (e.g. lentils, chickpeas) creates a more balanced essential amino acid profile.

Recipes

no recipes found

Nutrient Tables (per 100 g)

Core nutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Energy	357.2 kcal	—
Protein	8.7 g	—
Total fat	2.5 g	—
Carbohydrates	77.4 g	—
Fibre	12.8 g	—

Key micronutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Iron	3.3 mg	18.3%
Zinc	2.1 mg	19.5%
Magnesium	88 mg	21%
Selenium	13.1 µg	23.8%
Calcium	35.6 mg	3.6%
Potassium	366.6 mg	10.8%
Vitamin B6	0.2 mg	11.7%

Bioactive compounds

Values below are often from specialist compositional databases or literature, not the standard USDA panel. Asterisks (*) refer to source notes at the bottom of this section.

Compound / class	Amount per 100 g	Notes
Beta-glucan	4 g *	Soluble cereal β-glucan; barley is among the richest common grain sources.

Note: Bioactive-compound values vary substantially by cultivar, species, cocoa or oil percentage, processing, and brand formulation. Show quantitative values only where a defensible source exists; otherwise prefer qualitative presence statements or ranges in source notes.

Source notes (bioactive / supplementary):

• * Beta-glucan: Representative value for barley flour; beta-glucan content varies by cultivar and processing (e.g. USDA and literature values for barley).

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, Flour, barley, FDC ID 2512376, API, per 100 g edible portion, last checked 2026-03-14

Substances

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

8 substances in this food

Magnesium

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

Iron

Oxygen transport; dopamine synthesis (tyrosine hydroxylase cofactor)

Zinc

Cofactor in neurotransmission and antioxidant enzymes; dopamine modulation

Selenium

Antioxidant enzyme cofactor (GPx); supports redox balance

Calcium

Bone health; neurotransmission; interacts with vitamin D and K2

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

Beta-glucan

References

[1] Protein quality evaluation framework (DIAAS) FAO 2013

[2] Plant-protein adequacy, limiting amino acids, and practical complementarity Mariotti & Gardner 2019

[3] Barley beta-glucan fermentation to SCFAs (in vitro evidence) Hughes et al. 2008