Seaweed

Overview

Seaweed provides iodine, EPA (in red algae), glycolipids, magnesium, and fiber, supporting thyroid function and brain health.

Within the BRAIN Diet framework, seaweed can be added to soups, stews, or salads and provides trace amounts of creatine (e.g., nori) and taurine [1][2].

Key Nutritional Highlights

• Seaweed is a primary dietary iodine source supporting thyroid hormone synthesis [1]
• Marine algae contribute variable B12 analogues and should be interpreted cautiously for cobalamin status [2]
• Seaweed provides iodine, EPA (in red algae), glycolipids, magnesium, and fiber, supporting thyroid function and brain health. [1]
• Seaweed can be added to soups, stews, or salads and provides trace amounts of creatine (e.g., nori) and taurine. [2]
• Seaweed provides iodine, EPA (in red algae), glycolipids, magnesium, and fiber, supporting thyroid function and brain health.

Food Context

Synergies

• Part of diverse plant food strategy

Preparation

• Can be added to soups, stews, or salads
• Important for iodine intake (especially for plant-based diets)
• Low bioavailable EPA; consider algal oil for direct DHA

Essential Amino Acid Profile

Seaweed contribute plant protein. Pair with complementary protein sources (e.g. grains and legumes) for a 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	306 kcal	—
Protein	6.2 g	—
Total fat	0.3 g	—
Saturated fat	0.1 g	—
Carbohydrates	80.9 g	—
Fibre	7.7 g	—

Key micronutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Iron	21.4 mg	118.9%
Zinc	5.8 mg	52.7%
Magnesium	770 mg	183.3%
Selenium	7.4 µg	13.5%
Calcium	625 mg	62.5%
Potassium	1125 mg	33.1%
Choline	63.3 mg	11.5%
Folate	580 µg	145%
Vitamin B12	0 µg	0%
Vitamin B6	0.3 mg	17.8%

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
EPA	87 mg	—

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.

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, Seaweed, agar, dried, FDC ID 170090, API, per 100 g edible portion, last checked 2026-03-14

Substances

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

11 substances in this food

I^-

Iodine

Thyroid hormone synthesis; neurodevelopment; neurotransmitter regulation

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

Choline

Acetylcholine precursor; methyl donor; phospholipid synthesis for membranes

Vitamin B9 (Folate; 5-MTHF)

One-carbon metabolism; methylation; homocysteine recycling

Vitamin B6 (Pyridoxine → PLP)

PLP cofactor for neurotransmitter synthesis; relies on brain PDXK activation

EPA (Eicosapentaenoic Acid)

Potent anti-inflammatory; precursor to E-series resolvins; modulates dopamine and serotonin signalling

References

[1] Seaweed is a primary dietary iodine source supporting thyroid hormone synthesis. Arterburn et al. 2008. Algal-oil capsules and cooked salmon: nutritionally equivalent sources of docosahexaenoic acid

[2] Marine algae contribute variable B12 analogues and should be interpreted cautiously for cobalamin status. Watanabe et al. 2002. Characterization and Bioavailability of Vitamin B12-Compounds from Edible Algae.