Vitamin B12 contributes to normal energy-yielding metabolism, to the normal function of the immune system and to the reduction of tiredness and fatigue.
How many calories are in seaweed?
109kcal
in an 80 g portion
136 kcal per 100 g.
Source: UK CoFID 2021, record 13-340. Checked 5 October 2026.
1.2 gFat
24.6 gProtein
35.5 gFibre
880 %Daily vitamin B12

What’s in an 80 g portion
About a third of a portion is fibre.
- 1.2 gFat
- 24.6 gProtein
- 35.5 gFibre
- 7 gWater
- 11.8 gMinerals and the rest
Above average for vegetables
Seaweed is 136 kcal per 100 g. The 240 vegetables in this database average 59.9.
High in fibre
44.4 g of fibre per 100 g; the UK “high fibre” line is 6 g.
Vitamins and minerals in seaweed
Eleven of the 16 reach the “high in” level, led by vitamin B12.
Show all 16 with amounts
Badges use the UK legal thresholds per 100 g: 15 % of the reference intake for “source of”, 30 % for “high in”.
What seaweed doesn’t give you. And where to find it.
No recorded vitamin D, and only 3.2 % of the magnesium reference intake and 5 % of the vitamin B6 reference intake per 100 g.
Vitamin D

Magnesium

Vitamin B6

100 mgVitamin C, 125 %
0.075 mgSelenium, 136 %
0.00125 mgVitamin D, 25 %
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Made in the UK since 1998, with every nutrient and its declared amount listed on the label.

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Questions about seaweed
What the numbers say to the questions people actually search.
How many calories are in a portion of seaweed?
Is seaweed high in vitamin B12?
Which vitamins and minerals does seaweed have most of?
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How these numbers were made
More vegetables
From the same group, with calories per 100 g, and the foods with the most vitamin B12.



More vegetables
- Peas, frozen, raw68 kcal
- Tannia, raw107 kcal
- Artichoke, Jerusalem, boiled41 kcal
- Carrots, old, raw34 kcal
- Drumstick pods, raw37 kcal
- Mushrooms, Jew's ear, tender, dried, soaked, raw29 kcal
- All 240 vegetables
Most vitamin B12
- Seaweed, kombu, dried, raw0.0028 mg
- Seaweed, wakame, dried, raw0.0025 mg
- Ackee, canned, drained0 mg
- Liver, ox, raw0.11 mg
- Liver, ox, stewed0.11 mg
- Liver, lamb, fried0.083 mg
- Vitamin B12 guide