The 10 foods highest in vitamin B12, ranked by µg per 100g

Daily vitamin B12 requirements

Compared to other vitamins, daily B12 needs are tiny — measured in micrograms (µg), not milligrams. The U.S. RDA is 2.4 µg/day for adults, rising slightly to 2.6 µg in pregnancy and 2.8 µg while breastfeeding. A single 100g portion of clams or beef liver covers a month's worth in one meal. The problem isn't getting enough B12 — it's making sure animal foods (or fortified equivalents) are in your diet at all.

B12 content per serving: what real portions actually deliver

Below is what each food delivers in a realistic serving, as a percentage of the daily B12 target. The bars all max out at 100% visually because every portion exceeds daily needs — often many times over. The percentages in the value column show exactly how much.

The 10 highest-B12 foods (per 100g)

All values are per 100g, sourced from USDA FoodData Central. The daily RDA for adults is 2.4 µg — almost any normal serving below exceeds it many times over.

1. 1Clams98.9 µg
   The undisputed B12 champion. A single 100g serving (about one small drained can) delivers over 40× the daily RDA — and because B12 is stored in your liver, that one meal contributes for weeks. Daily intakeJust ~2g — about one large clam — covers the entire 2.4 µg daily target! A standard 100g portion delivers a full month's worth of B12 in a single sitting. Also exceptional for iron and selenium.
2. 2Beef liver83.1 µg
   A nutrient-density legend: B12, vitamin A, copper, riboflavin, choline — all packed into one ingredient. Daily intake~3g — a single bite — covers daily needs. A normal 80g slice gives ~66 µg, which is over a month's RDA. Just one beef liver meal per week is enough to keep B12 reserves topped up indefinitely.
3. 3Cod liver43.0 µg
   Most commonly consumed as cod liver oil — which preserves the B12 and packs significant vitamin D and omega-3 alongside. Daily intake~6g for 2.4 µg. A standard tablespoon of cod liver oil (~10g) delivers ~4.3 µg — about 180% of daily needs — plus a hefty dose of vitamin D and EPA/DHA. It is one of the most efficient B12 + vitamin D combinations you can take.
4. 4Octopus20.0 µg
   High in B12 and protein, low in fat — a Mediterranean and East Asian staple. A 100g grilled portion delivers about 8× the daily RDA, plus selenium and copper. Daily intake~12g (a few small bites) for 2.4 µg. A typical 100g restaurant portion covers 8× daily needs. A note on cholesterol: octopus is moderate-to-high in dietary cholesterol (~96 mg/100g, more than beef or chicken). For most people this is fine — the 2015 US Dietary Guidelines removed the strict daily cholesterol limit because dietary cholesterol has less impact on blood lipids than once thought — but if you have familial hypercholesterolemia or are on a low-cholesterol diet, keep portions modest. Heavy metals: good news here — octopus isn't a top predator and the FDA classifies it as a "Best Choice" with low mercury (~0.080 ppm, well below the action level), so you can eat it freely from a contamination standpoint.
5. 5Pork liver18.7 µg
   More common in European cooking than beef liver (in form of pâtés, terrines). Very high in B12 and iron and milder in flavour than beef liver for liver-newcomers. Daily intake~13g for 2.4 µg. A standard 80g slice gives ~15 µg — over 6× daily needs. Pâté on toast (~30g spread) still delivers around 2× the RDA.
6. 6Oysters17.5 µg
   Famous for zinc, but also exceptional for B12. Six raw oysters cover daily B12 needs many times over. Daily intake~14g (under one medium oyster) for 2.4 µg. A typical serving of 6 oysters (~80g) delivers ~14 µg — about 580% of daily needs, with a side of record-breaking zinc.
7. 7Chicken liver16.6 µg
   More accessible than beef liver — milder flavour, easier to find, and the top iron source as well. Daily intake~14g (a single bite) for 2.4 µg. An 80g pâté serving delivers ~13 µg — over 550% of daily needs — and doubles as a top-tier iron source.
8. 8Mussels12.0 µg
   Affordable, sustainable seafood with excellent B12, selenium, and iron content. Often the best-value B12 source per dollar! Daily intake~20g (a few mussels) for 2.4 µg. A standard 100g portion (one cup cooked, ~20 mussels) delivers 12 µg — 500% of daily needs. A bowl of moules-frites covers more than a week's B12!
9. 9Sardines8.9 µg
   Canned sardines (skin-on, bones in) are one of the best-value B12 sources on the planet. Also rich in vitamin D, omega-3, and calcium (from the soft bones). Daily intake~27g — half a small tin — covers 2.4 µg. A whole 100g tin (one regular can) delivers ~9 µg, nearly 4× daily needs. Don't worry about canned: unlike most processed foods, canned sardines are nutritionally excellent — the canning process actually softens the bones (a huge calcium boost) and preserves the omega-3 well. Heavy metals: sardines are small fish low on the food chain, so they accumulate far less mercury than tuna, swordfish, or king mackerel — average ~0.013 ppm, among the lowest of any seafood. FDA classifies them as a "Best Choice" for pregnant women and children. The most cost-effective B12 + vitamin D + omega-3 combo at the supermarket, full stop.
10. 10Mackerel8.7 µg
    A 100g portion delivers nearly 4× daily B12 needs, plus high-quality protein and omega-3 — and unlike larger predator fish, mackerel is low in mercury. Daily intake~28g for 2.4 µg. A standard 150g fillet delivers ~13 µg — over 540% of daily needs. A great twice-weekly addition to your meals for B12, omega-3, and protein in one.

Vitamin B12 content comparison — per 100g

The pattern: B12 only comes from animals (and bacteria)

Vitamin B12 is the only vitamin that's not made by plants or animals — it's produced by bacteria. Animals accumulate B12 either by eating it (cows from soil microbes, fish from plankton) or by hosting B12-producing bacteria in their gut. Plants don't accumulate it at all unless they're contaminated.

This is why every food in the top 10 is an animal product, and why vegans have to think about B12 explicitly. There's no plant equivalent to liver or clams.

Everyday foods that contribute B12 (for reference)

The top-10 above are the B12 powerhouses, but most people don't eat clams or liver every day. The list below covers the everyday animal foods that contribute B12 in real meal-sized portions — added here for reference and comparison so you can see how your typical diet stacks up against the heavy hitters.

Note: these foods all have much less B12 per gram than the top 10, but you eat them in larger quantities and more often. A single egg won't move the needle, but eggs plus milk plus cheese plus a beef serving across a week add up to a solid B12 intake — especially compared to relying on supplements alone.

Clams vs beef liver: the top-2 face-off

Both are off-the-charts B12 sources, but they have different strengths.

Clams are easier to eat regularly — canned versions are cheap, shelf-stable, and mild. Beef liver requires more cooking skill and an acquired taste for many people, but rewards with a wider nutrient profile.

Can vegans get B12 from plant foods?

Not reliably. A few plant foods claim B12 content, but the picture is more complicated than it looks on a label.

1. Nori (dried seaweed) contains real B12, but the amount varies wildly between batches and species. Some studies show useful absorption; others show the B12 is in an inactive analog form.
2. Tempeh and other fermented foods can contain trace B12 from fermentation bacteria, but quantities are too small and variable to rely on.
3. Mushrooms grown on B12-enriched substrate can contain small amounts, but typical mushrooms have essentially none.
4. "B12 analogs" in spirulina and chlorella are inactive in humans — they may even block real B12 absorption.

Nori, nutritional yeast, fortified foods: what works

If you're avoiding meat and fish, here's the realistic picture of plant-friendly B12 sources:

1. Fortified nutritional yeast — 1 tablespoon typically provides 2-4 µg of B12 (a full daily dose). Look for "B12-fortified" on the label; non-fortified nutritional yeast has none.
2. Fortified plant milks (almond, oat, soy) — many brands add 1-1.2 µg per cup. Check the label; not all are fortified.
3. Fortified breakfast cereals — often contain 1.5-6 µg per serving. Combine with fortified milk for 2-7 µg in one breakfast.
4. Nori (dried seaweed) — possibly useful, but variable. Don't rely on it alone.
5. B12 supplement — 25-100 µg daily covers all needs. Cheap and reliable.

Why B12 deficiency is so common today

Here's the paradox: B12 is everywhere in animal foods, the daily requirement is microscopic (2.4 µg), the body stores 1–2 years' worth in the liver — and yet somewhere between 6% and 20% of adults are deficient depending on the population studied. The deficiency rate climbs above 40% in adults over 60. It's not just a vegan problem. Even people on full omnivore or carnivore diets get deficient, because B12 has a uniquely fragile absorption pipeline.

To absorb B12 from food, your body needs three things working in sequence: stomach acid (HCl) to release B12 from food protein, the enzyme pepsin to free it further, and a protein called intrinsic factor (made by parietal cells in the stomach) to ferry B12 across the intestinal wall. If any one of these breaks down, dietary B12 intake doesn't translate to absorbed B12. Common reasons it breaks down:

1. Age-related decline in stomach acid (atrophic gastritis) — by age 60, an estimated 10–30% of adults produce too little stomach acid to release B12 from animal protein. They can eat all the steak in the world and still not absorb it from food. (Free B12 in supplements bypasses this problem, which is why supplementation works.)
2. Acid-blocking medications — long-term use of proton pump inhibitors (omeprazole, esomeprazole, pantoprazole) or H2 blockers (famotidine, ranitidine) directly suppresses the stomach acid needed to release B12. Studies show 2+ years of PPI use roughly doubles deficiency risk.
3. Metformin — the most common diabetes drug. Long-term use (4+ years) reduces B12 absorption in 10–30% of users. Anyone on metformin should have their B12 checked annually.
4. Pernicious anemia — an autoimmune condition where the body destroys the parietal cells that make intrinsic factor. Affects about 1–2% of older adults. Requires lifelong B12 injections or very high-dose oral supplementation, because no amount of dietary B12 can be absorbed without intrinsic factor.
5. Gastric or intestinal surgery — gastric bypass, sleeve gastrectomy, or any procedure removing parts of the stomach or terminal ileum reduces B12 absorption sites. Lifelong supplementation is standard post-op.
6. Chronic inflammation of the gut — Crohn's disease, celiac disease, ulcerative colitis, and small-intestinal bacterial overgrowth (SIBO) can all impair B12 absorption even when intake is adequate.
7. Heavy alcohol use — damages the gastric lining and impairs B12 storage in the liver.
8. Vegan and strict vegetarian diets — the obvious one. No reliable plant B12, so unless fortified foods or a supplement are part of the routine, deficiency develops over months to years.

Signs of vitamin B12 deficiency

B12 deficiency develops slowly because your liver stores 1-2 years' worth. By the time symptoms appear, levels are often well below normal. Watch for:

1. Persistent fatigue and weakness that doesn't improve with rest
2. Tingling or numbness in hands and feet ("pins and needles")
3. Balance problems — feeling unsteady or clumsy
4. Memory or concentration issues, "brain fog"
5. Sore, smooth, red tongue (glossitis)
6. Pale or yellowish skin, mild jaundice
7. Shortness of breath on mild exertion
8. Mood changes — depression, irritability

B12 deficiency can cause permanent nerve damage if it goes untreated long enough. If you have several of these symptoms, especially combined with a vegan/vegetarian diet or being over 50, request a serum B12 and methylmalonic acid blood test from your doctor.

Who needs to supplement

You should consider a B12 supplement (or strongly increase fortified food intake) if you're in any of these groups:

1. Vegans — essentially mandatory unless you eat fortified foods reliably every day
2. Vegetarians with minimal dairy/egg intake — likely insufficient
3. Adults over 50 — stomach acid declines with age, reducing B12 absorption from food
4. People on metformin (diabetes drug) — known to reduce B12 absorption over time
5. People on proton pump inhibitors (omeprazole, lansoprazole) — reduce stomach acid needed for B12 release
6. People with pernicious anemia — autoimmune condition that blocks B12 absorption; requires injections or high-dose oral supplements
7. People who've had gastric or intestinal surgery — bypassed or altered absorption sites

Frequently asked questions

Which food has the most vitamin B12 per 100g?
Clams (98.9 µg) top the list — over 40× the daily RDA. Beef liver is a close second at 83 µg.

Can vegans get B12 from plant foods?
Not reliably. Fortified foods (plant milks, cereals, nutritional yeast) or a supplement are essential.

What are the signs of B12 deficiency?
Fatigue, tingling in hands and feet, balance issues, memory problems, sore tongue. Can cause permanent nerve damage if untreated.

Who needs a B12 supplement?
Vegans, strict vegetarians, adults over 50, people on metformin or proton pump inhibitors, and anyone with low B12 levels.

Sources & references

• U.S. Department of Agriculture. FoodData Central (SR Legacy). All nutrient values per 100g.
• National Institutes of Health Office of Dietary Supplements. Vitamin B12: Health Professional Fact Sheet.
• Watanabe F. Vitamin B12 sources and bioavailability. Experimental Biology and Medicine, 2007.
• European Food Safety Authority. EFSA Dietary Reference Values for Vitamin B12.

This article is for informational purposes only and is not a substitute for professional medical advice. If you suspect B12 deficiency, consult a qualified healthcare provider for blood testing.

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