Crab
Food · Protein · Food, Typed Supps
Crab is a lean seafood that packs a big dose of vitamin B12 and zinc into very few calories.
Stage by stage
- Chewing & Breakdown (Mouth): Chewing breaks delicate crab meat into pieces, with little for salivary enzymes to act on given its near-zero carbohydrate content.
- Acid Digestion (Stomach): Stomach acid and pepsin denature crab's proteins and begin releasing bound vitamin B12, zinc, copper, and selenium for later absorption.
- Nutrient Absorption (Small Intestine): In the small intestine, freed vitamin B12 binds intrinsic factor for absorption in the terminal ileum, while amino acids, zinc, copper, and selenium cross the intestinal wall into the bloodstream.
- Tissue Uptake (Muscle & Blood): Absorbed amino acids support muscle and tissue repair, zinc and copper power antioxidant and connective-tissue enzymes, and B12 reaches bone marrow and nerve tissue to support red blood cell formation and nervous system function.
Timing
Eating crab as part of a mixed meal, rather than alone on an empty stomach, supports steadier digestion and absorption of its protein and minerals.
Time to effect
- Days to weeks: A single serving of crab won't produce a noticeable effect, but consistent intake over days to weeks can help maintain healthy vitamin B12 and zinc status, particularly for people prone to mild deficiency.
Allergens
Contains: Crustaceans. Derived from what this food is, not from a product label.
Eating patterns
Fits: Pescatarian, Keto, Gluten-free. Depends on the product: Halal, Low-FODMAP.
Satiety
221 on the satiety index, where white bread is 100 — very high. Modelled from the Holt et al. (1995) measurements.
Environmental footprint
26.9 kg CO2e and 3515 litres of freshwater per kg, matched to "Prawns (farmed)" in Poore & Nemecek (2018), Science 360.
Cost band
Pricey — roughly £28 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
- Calories: 88.4
- Protein: 20.2g
- Carbohydrate: 0g
- of which sugars: 0g
- Fat: 0.7g
- of which saturated: 0.1g
- Fibre: 0g
- Sodium: 420mg
Food vs. supplement
Crab delivers vitamin B12, zinc, copper, and selenium together with complete, low-fat protein, a combination that isolated single-nutrient supplements can't fully replicate.
Kitchen tip
Steam, boil, or bake crab rather than frying it, and rinse canned crab meat to reduce added sodium.
Common myth
"Crab is essentially a cholesterol bomb you should avoid if you care about your heart." In reality: Crab is naturally low in saturated fat and calories; while it does contain dietary cholesterol (roughly 70-100 mg per 100 g cooked), current nutrition science shows saturated fat intake has a bigger impact on blood LDL cholesterol than dietary cholesterol itself for most healthy people, and lean crab prepared without heavy butter or frying is generally considered a heart-healthy protein choice.
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