Barley

Overview

Barley is a whole grain valued for beta-glucan soluble fibre and sustained energy release. Barley is among the richest common grain sources of cereal beta-glucan, which supports fermentable-fibre intake and glycaemic regulation in mixed-meal contexts [1]. Beta-glucan is an intrinsic barley component (also present in oats and some mushrooms), distinct from downstream fermentation products such as SCFAs.

Within the BRAIN Diet framework, barley contributes plant protein that is relatively higher in methionine but lysine-limited like other grains; pairing with legumes improves essential amino-acid balance [2,3]. Soaking before cooking can reduce phytate and support mineral bioavailability from cereal staples [4].

Key Nutritional Highlights

• Highest fibre among BRAIN Diet grain and pseudograin pages (per 100 g; fibre ~12.8 g).
• Rich source of beta-glucan, the viscous cereal fibre most strongly associated with barley's metabolic effects [1].
• Grain protein is lysine-limited (~8.7 g protein per 100 g), so amino-acid balance improves when paired with legumes [2,3].
• Soaking before cooking can reduce phytates and improve mineral bioavailability [4].

Food Context

Synergies

• Part of whole grain diversity strategy

Preparation

• Soak before cooking to reduce phytates and improve mineral bioavailability [4].
• 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

Mg²⁺

Magnesium

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

Fe²⁺

Iron

Oxygen transport; dopamine synthesis (tyrosine hydroxylase cofactor)

Zn²⁺

Zinc

Cofactor in neurotransmission and antioxidant enzymes; dopamine modulation

Se^2-

Selenium

Antioxidant enzyme cofactor (GPx); supports 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

Beta-glucan

References

[1] Rich source of beta-glucan, the viscous cereal fibre most strongly associated with barley's metabolic effects. Massimino & McBurney 1998. Fermentable Dietary Fiber Increases GLP-1 Secretion and Improves Glucose Homeostasis Despite Increased Intestinal Glucose Transport Capacity in Healthy Dogs

[2] Report recommending the Digestible Indispensable Amino Acid Score (DIAAS) as the preferred method for evaluating dietary protein quality, replacing PDCAAS, and detailing methodology and implications for human nutrition. FAO 2013. Dietary Protein Quality Evaluation in Human Nutrition: Report of an FAO Expert Consultation

[3] \textlessp\textgreaterWhile animal products are rich in protein, the adequacy of dietary protein intake from vegetarian/vegan diets has long been controversial. Mariotti & Gardner 2019. Dietary Protein and Amino Acids in Vegetarian Diets—A Review

[4] Soak before cooking to reduce phytates and improve mineral bioavailability. Gibson & Perlas 2006. Improving the bioavailability of nutrients in plant foods at the household level