Salmon vs Tuna vs Sardine: Which Has More Omega-3?

Omega-3 Content: The Full Comparison

Why Salmon Wins on Omega-3 — By a Wide Margin

Salmon delivers 8 to 10 times more omega-3 than canned tuna per 100g. A single 150g salmon fillet provides roughly 2,700 to 3,200mg of combined DHA and EPA — enough to cover nearly a week of the American Heart Association's recommended 250–500mg per day for general health, or several days' worth of the higher therapeutic intakes recommended for people with elevated triglycerides. The wild versus farmed comparison surprises most people. Farmed Atlantic salmon actually contains slightly more total omega-3 (2,147mg versus 1,840mg per 100g), driven by higher EPA levels. This is a direct result of feed composition: farmed salmon consume oil-rich pellets that elevate their overall fat content. Wild salmon is leaner (8.1g total fat versus 12.4g for farmed) and carries more iron, but loses ground on omega-3 quantity. For most people specifically eating salmon for DHA and EPA, farmed Atlantic is a legitimate choice. Tuna's low omega-3 count is the biggest surprise in this data. At 222mg DHA+EPA per 100g, canned light tuna in water is often assumed to be a solid omega-3 source, but it delivers less than a quarter of what sardines offer and barely a tenth of salmon. The lean profile of canned tuna means very little fat of any kind — which explains both its calorie advantage and its omega-3 deficit.

The Full Nutrition Picture

Sardine's Hidden Strengths

Sardines are genuinely underrated in the nutrition conversation. The calcium figure stands out most sharply: 382mg per 100g, compared to 15–18mg in salmon and tuna. That is because canned sardines are eaten with their small, softened bones, and bone is where calcium lives. A 100g serving of sardines covers roughly a third of the daily calcium requirement — comparable to a glass of milk — while also delivering meaningful omega-3, protein, and several B vitamins. Vitamin B12 in sardines is exceptional: 8.94µg per 100g is nearly 4 times the daily requirement (2.4µg) in a single serving. This makes sardines one of the most B12-dense foods available at a modest price point. B12 is essential for neurological function and red blood cell formation, and is the nutrient most commonly deficient in people who limit or avoid animal foods. Iron comes in at 2.92mg per 100g in sardines — the highest of the three fish, and meaningfully above salmon's 1.03mg and tuna's 1.67mg. This is non-heme iron (the less absorbable form found in most foods other than red meat), but the quantity is high enough to make sardines a useful dietary source, particularly combined with the vitamin C from a typical meal. The trade-offs are real. Sardines are higher in sodium (307mg per 100g) and cholesterol (142mg) than both salmon and tuna. People managing sodium intake closely — due to hypertension or kidney conditions — may want to account for this. Rinsing canned sardines before eating reduces sodium content by a modest amount. For most healthy people these figures are well within acceptable ranges as part of a varied diet. Cost is sardines' most underappreciated advantage. Quality canned sardines typically run under $2 per tin, making them one of the least expensive sources of omega-3, complete protein, calcium, and B12 available.

Which Fish Should You Eat?

• Choose salmon if omega-3 is your primary goal. Nothing in everyday grocery shopping delivers DHA and EPA as efficiently. Both wild and farmed Atlantic salmon are strong options — wild has slightly more iron and less saturated fat; farmed has marginally more total omega-3. Either is a sound choice depending on what's available and affordable.
• Choose tuna for lean protein and selenium. Canned light tuna in water is the leanest of the three at 90 kcal and 0.9g fat per 100g, making it the best fit when protein is the goal and calorie budget is tight. It also leads on selenium (67.8µg), an antioxidant mineral linked to thyroid function and immune health.
• Choose sardines for calcium, B12, and budget. If you are not drinking much dairy, sardines are one of the easiest ways to hit meaningful calcium intake from whole food sources. The B12 content is exceptional and the cost per serving is low. Eating them with crackers and mustard, or incorporated into pasta or salads, is more approachable than people expect.
• Eat a variety for the best nutritional coverage. No single fish dominates every nutrient. Rotating between salmon, sardines, and tuna across the week captures the omega-3 and vitamin D from salmon, the calcium and B12 from sardines, and the lean selenium-rich protein from tuna without over-indexing on any one food.
• Pay attention to mercury, especially with tuna. Canned light tuna contains meaningfully less mercury than albacore (white) tuna because it comes primarily from smaller skipjack tuna lower in the food chain. Salmon and sardines both accumulate far less mercury than larger fish and are generally considered safe to eat multiple times per week. The FDA advises adults to limit albacore tuna to one serving per week while allowing 2–3 servings of light tuna.
• Consider the sodium in canned fish if it matters for you. Fresh or home-cooked salmon has very low sodium (56mg per 100g). Canned tuna adds 219mg and canned sardines add 307mg — still moderate in the context of a full day's eating, but worth knowing if you are tracking intake precisely. No-salt-added canned tuna is widely available as an alternative.