Tuna
Food · Protein · Food, Typed Supps
One of the most concentrated omega-3 sources, with a real mercury caveat.
Stage by stage
- Intake (Dense muscle & fat): Chewing breaks down its dense muscle protein and fat structure.
- Stomach (Protein & fat digestion): Protein and fat digestion begins.
- Small intestine (Omega-3 & selenium absorbed): Omega-3 fats and selenium are absorbed alongside amino acids.
- Bloodstream & tissues (Membrane incorporation): Omega-3s are incorporated into cell membranes; selenium supports antioxidant enzyme function.
Timing
Larger tuna species (like albacore) are generally recommended less frequently than smaller fish due to mercury accumulation.
Time to effect
- Weeks: Regular intake gradually shifts cell membrane fatty acid composition.
Allergens
Contains: Fish. Derived from what this food is, not from a product label.
Eating patterns
Fits: Pescatarian, Kosher, Keto, Low-FODMAP, Gluten-free. Depends on the product: Halal.
Satiety
217 on the satiety index, where white bread is 100 — very high. Modelled from the Holt et al. (1995) measurements.
Environmental footprint
13.6 kg CO2e and 3691 litres of freshwater per kg, matched to "Fish (farmed)" in Poore & Nemecek (2018), Science 360.
Cost band
Pricey — roughly £20 per kg, as a band midpoint rather than a price.
Key nutrients
Nutrition per 100g
- Calories: 104
- Protein: 23.4g
- Carbohydrate: 0g
- of which sugars: 0g
- Fat: 1g
- of which saturated: 0.2g
- Fibre: 0g
- Sodium: 37mg
Food vs. supplement
A 3.5oz serving of tuna provides EPA/DHA comparable to salmon, but larger tuna species accumulate more mercury than smaller fish — a tradeoff a fish oil supplement doesn’t carry, though the supplement also skips the protein and selenium.
Kitchen tip
Canned light tuna generally has lower mercury than canned albacore, worth knowing if eating it several times a week.
Common myth
“All fish have the same mercury risk.” In reality: Larger, longer-lived predatory fish like albacore tuna and swordfish accumulate meaningfully more mercury than smaller fish like salmon or sardines.
Recipes that use it
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