Nori

Overview

Nori is a red seaweed (Porphyra species) commonly used in sushi and Japanese cuisine. It is a primary dietary source of iodine, an essential trace mineral critical for thyroid function and brain development. Nori also provides supporting amounts of folate (B9) and non-heme iron, along with contextual contributions of magnesium, vitamin K, and carotenoids.

Within the BRAIN Diet framework, while nori may contain variable amounts of vitamin B12 depending on species and processing, it should not be relied upon as a sole B12 source. The seaweed polysaccharides and soluble fibre in nori contribute to gut barrier and microbiome modulation through cumulative, supportive effects [1][2].

Key Nutritional Highlights

• Seaweed foods may contribute variable vitamin B12 compounds; nori should not be relied on as a sole B12 source [1]
• Marine algae and seaweed are primary iodine sources critical for thyroid and brain development [2]
• Nori is a red seaweed (Porphyra species) commonly used in sushi and Japanese cuisine. [1]
• It is a primary dietary source of iodine, an essential trace mineral critical for thyroid function and brain development. [2]
• Nori also provides supporting amounts of folate (B9) and non-heme iron, along with contextual contributions of magnesium, vitamin K, and carotenoids.
• While nori may contain variable amounts of vitamin B12 depending on species and processing, it should not be relied upon as a sole B12 source.

Food Context

Synergies

• Part of diverse plant food intake strategy

Preparation

• Commonly used in sushi rolls and as a garnish
• Important for iodine intake, especially in plant-based diets
• Folate and iron contributions are context-dependent and work best as part of a varied diet
• Seaweed polysaccharides provide cumulative gut health benefits when consumed regularly

Essential Amino Acid Profile

Nori 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	486 kcal	—
Protein	57.1 g	—
Total fat	0 g	—
Saturated fat	0 g	—
Carbohydrates	57.1 g	—
Fibre	57.1 g	—

Key micronutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Iron	51.4 mg	285.7%
Calcium	286 mg	28.6%

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, NORI, FDC ID 1662188, API, per 100 g edible portion, last checked 2026-03-14

Substances

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

6 substances in this food

I^-

Iodine

Thyroid hormone synthesis; neurodevelopment; neurotransmitter regulation

Fe²⁺

Iron

Oxygen transport; dopamine synthesis (tyrosine hydroxylase cofactor)

Mg²⁺

Magnesium

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

Vitamin B12 (Cobalamin)

Methylation; myelin; mitochondrial odd-chain FA metabolism

Vitamin B9 (Folate; 5-MTHF)

One-carbon metabolism; methylation; homocysteine recycling

Ca²⁺

Calcium

Bone health; neurotransmission; interacts with vitamin D and K2

References

[1] Seaweed foods may contribute variable vitamin B12 compounds; nori should not be relied on as a sole B12 source. Watanabe et al. 2002. Characterization and Bioavailability of Vitamin B12-Compounds from Edible Algae.

[2] Marine algae and seaweed are primary iodine sources critical for thyroid and brain development. Arterburn et al. 2008. Algal-oil capsules and cooked salmon: nutritionally equivalent sources of docosahexaenoic acid