What liver actually contains
A 100g serving of beef liver contains more vitamin A than any other food on earth, more B12 than almost any other food, meaningful amounts of every B vitamin, more iron per gram than spinach and at a form your body absorbs at ten times the rate, CoQ10 in concentrations that exceed supplemental doses, choline at levels that rival eggs, copper at levels that exceed requirements, and complete protein with an amino acid profile that includes carnosine — the di-peptide that buffers muscle acidosis and has emerging evidence for anti-ageing effects in neural tissue. All of this in roughly 175 calories.
The word "superfood" gets applied to blueberries and spirulina and acai berries. These are fine foods. None of them come close to liver on any meaningful nutrient density metric. Liver is not a superfood in the marketing sense. It is a superfood in the literal sense — a food that delivers a supraphysiological nutrient payload relative to its caloric and volume cost.
Nutrient 01
Retinol (Vitamin A)
~6,500 µg per 100g beef liver
Preformed vitamin A — no conversion required. Directly usable by every cell in the body for immune function, skin integrity, vision, and gene expression. Not beta-carotene. Not a provitamin that requires conversion by BCMO1 enzymes that 45% of people carry variants in that reduce conversion efficiency by 30–70%.
vs. carrots: 835 µg beta-carotene — needs conversion, conversion varies by individual
Nutrient 02
Vitamin B12
~70 µg per 100g — over 2,800% RDA
As methylcobalamin and adenosylcobalamin — the active forms. No conversion from cyanocobalamin required. Direct substrate for the methylation cycle, myelin synthesis, and neurological function. B12 deficiency produces neurological symptoms that are frequently missed because serum B12 appears normal while functional B12 at cellular level is insufficient.
vs. most plant foods: zero. vs. beef muscle: ~2.5 µg per 100g
Nutrient 03
Haem Iron
~6.5 mg per 100g at 15–35% absorption
Haem iron is absorbed at 15–35% efficiency. Non-haem iron (spinach, lentils, fortified cereals) absorbs at 2–20% and is significantly reduced by phytates, oxalates, calcium, and polyphenols. The iron deficiency without anaemia picture — ferritin low, haemoglobin still normal — responds to haem iron sources far faster than supplemental non-haem iron.
vs. spinach: 2.7mg non-haem iron at 2–10% absorption
Nutrient 04
CoQ10 (Ubiquinol)
~3–4 mg per 100g
Mitochondrial electron transport chain cofactor. The same compound prescribed at 100–200mg doses in supplement form. Liver is the highest dietary source. Declines with age and is actively depleted by statin medication. Food-source CoQ10 comes packaged with the lipid matrix that enhances absorption — unlike many supplements.
vs. beef muscle: ~2.5mg per 100g · vs. most supplements: food matrix enhances bioavailability
Nutrient 05
Choline
~330 mg per 100g
Essential for cell membrane synthesis, acetylcholine neurotransmitter production, fat transport from the liver, and methylation (choline is a methyl donor). Deficiency is extremely common — estimated 90% of the UK population consume less than adequate intake. The brain requires choline for synaptic plasticity and cognitive function throughout life, not just in foetal development.
vs. eggs (the next best source): 147mg per 100g · vs. broccoli: 40mg per 100g
Nutrient 06
Folate (natural)
~290 µg per 100g as 5-MTHF
As naturally occurring 5-methyltetrahydrofolate — the active form that MTHFR variants do not need to convert. Unlike the synthetic folic acid now being added to UK flour, food-source folate from liver is directly usable by people with C677T or A1298C MTHFR polymorphisms without accumulating as unmetabolised folic acid.
vs. fortified bread: synthetic folic acid requiring conversion that MTHFR carriers may not complete
Nutrient 07
Copper
~10 mg per 100g
Copper deficiency is underdiagnosed and produces symptoms including fatigue, anaemia, and neurological problems that can be mistaken for other conditions. Copper is required for iron metabolism (ceruloplasmin), collagen synthesis, superoxide dismutase (antioxidant enzyme), and dopamine-beta-hydroxylase — the enzyme that converts dopamine to noradrenaline.
vs. nuts (reasonable source): 1–2mg per 100g
Nutrient 08
Carnosine
Present in significant amounts
A di-peptide of beta-alanine and histidine found almost exclusively in animal tissue. Buffers muscle acid during high-intensity exercise, chelates heavy metals, acts as an antioxidant in neural tissue, and has emerging evidence for anti-glycation effects — reducing the protein cross-linking that accelerates biological ageing. Not available from plant sources.
vs. plant foods: absent. Requires animal source or beta-alanine supplementation for partial conversion.
Predators eat the organs first. Always. The liver, heart, and kidneys before the muscle meat. This is not random behaviour — it is nutritional intelligence encoded over millions of years of evolution. The muscle is calorically dense. The organs are nutritionally dense. Our ancestors knew the difference. Somewhere between the industrial food system and modern squeamishness, we forgot it.
The vitamin A question — and why once a week is the right frequency
On vitamin A and frequency
Liver is extraordinarily rich in retinol — which is why the dose and the frequency both matter
The upper tolerable intake for preformed vitamin A (retinol) is approximately 3,000 µg per day for adults. A 100g serving of beef liver provides around 6,500 µg — more than twice the upper limit in a single serving. This does not mean liver is toxic in normal dietary amounts. It means it is a concentrated source that warrants some thought about frequency. Once a week is the well-established guideline for most adults eating normal portion sizes (around 100g). Pregnant women are advised to avoid liver due to the risk of vitamin A teratogenicity at high intakes — this is a real and important contraindication. For everyone else, one serving per week of beef or lamb liver, or two servings of chicken liver (which is somewhat lower in retinol at approximately 4,300 µg per 100g), sits comfortably within a safe and beneficial intake range. Daily consumption of large portions over extended periods is the scenario that warrants caution — not occasional weekly inclusion.
On vitamin A and retinol testing
If you eat liver regularly and want to know your retinol status, serum retinol is measurable on comprehensive blood panels. The functional optimal range is 1.5–3.0 µmol/L. Values above 3.5 µmol/L alongside regular high-dose liver consumption warrant reducing frequency. In practice, toxicity from dietary liver consumption is extremely rare in the absence of simultaneous high-dose retinol supplementation — the body has regulatory mechanisms for retinol storage and release that supplement forms bypass.
The practical guide — how to actually eat liver, including if you think you hate it
The taste objection is real. Liver has a strong, mineral, metallic quality that is genuinely unfamiliar to anyone raised on muscle meat and processed food. The key insight is that there is an enormous range between beef liver eaten plain and a chicken liver pâté on sourdough — and somewhere in that range, almost everyone finds an entry point.
Entry Level · Most Accessible
Desiccated Liver Capsules
For people who want the nutritional benefit without the taste, smell, or texture of actual liver, freeze-dried desiccated liver in capsule form is the cleanest solution. The quality of the source matters significantly — grass-fed, pasture-raised, from traceable farms. Ancestral Supplements and Hunter & Gather Foods are the two brands I recommend in the UK. Ancestral Supplements use New Zealand grass-fed beef liver, freeze-dried at low temperature to preserve heat-sensitive nutrients including CoQ10 and methylcobalamin. Hunter & Gather use UK and Irish grass-fed sources. Dose: typically 6 capsules = approximately 3g dried liver = roughly equivalent to 15g fresh liver, so you'd need a meaningful quantity for the full nutrient load — but it's a legitimate entry point for the taste-averse and useful for travel or convenience.
Look for: freeze-dried (not heat-dried), grass-fed source stated clearly, no fillers or flow agents.
Accessible · Most Widely Tolerated
Chicken Liver Pâté
Chicken liver has a milder, creamier flavour than beef or lamb liver — the fat content of chicken liver and the cooking method (gentle sauté with butter and aromatics, blended smooth) produces something that most people who "don't like liver" will eat happily and enjoy. Good chicken liver pâté is broadly available in UK supermarkets and delis, and trivial to make at home. Chicken liver pâté is also approximately 4,300 µg retinol per 100g of fresh liver — still extremely rich, but slightly lower than beef, which makes it more manageable at slightly higher frequency if desired. Spread on sourdough toast with good butter and a small amount of something sharp — cornichons, a little wholegrain mustard — and it bears no resemblance in the eating experience to a piece of liver fried in a pan.
Also worth trying: duck liver pâté — richer and more complex than chicken, but still milder than beef. Often available in French delis and better supermarkets.
Mid-Level · Classic Preparation
Liver with Bacon, Onions, or Mushrooms
The classic British and Irish preparation — and classic for a reason. Caramelised onions provide sweetness that counterbalances liver's mineral bitterness. Bacon provides salt, fat, and umami that complement and mask the strongest liver notes. Mushrooms — particularly darker varieties — add earthiness and additional umami that sit harmoniously with liver's flavour profile. The key technique is not to overcook: liver that is pink in the centre is tender and mild. Well-done liver becomes grainy, dry, and significantly more assertive in flavour. Lamb liver is milder than beef in this preparation and worth trying before beef if you've had a bad experience with school dinners.
Fresh liver from a butcher is significantly better than supermarket liver — the quality difference is noticeable. Ask for it sliced thinly (around 5mm) for the best texture and quickest cooking.
For the Adventurous · Full Nutrient Density
Monkfish Liver, Frozen-Grated, Raw Heart
Monkfish liver — ankimo in Japanese cuisine — is a delicacy with a rich, creamy texture quite unlike mammalian liver. It is available from good fishmongers and Japanese food suppliers and is a legitimate gateway for people who want to explore liver without the red meat flavour. For those comfortable with the concept: freezing liver briefly (around 2 weeks at -18°C) destroys surface pathogens and makes it possible to grate frozen liver into smoothies or soups where it disappears entirely into the other flavours. This is how to deliver the full nutrient payload to someone who genuinely cannot manage any detectable liver taste. I went through a period of doing exactly this — and separately, of eating beef and venison heart raw. Heart is not liver in flavour — it is closer to dense, lean muscle meat with a slight metallic quality. It is extraordinarily rich in CoQ10, B vitamins, and carnosine.
Frozen-grated liver in a smoothie with frozen banana, cocoa powder, and full-fat milk: you will not taste it. The nutrients are fully present.
From 37 years of clinical practice
I have recommended liver to clients for most of my clinical career and encountered every version of the objection. "I tried it once and hated it." "It smells." "I can't get past the texture." The conversation I always have is this: the liver you tried was almost certainly overcooked, possibly of poor quality, and prepared without the aromatics and combinations that make it genuinely good food. Chicken liver pâté has converted more anti-liver clients than anything else I've suggested. The desiccated capsules have converted the rest. I have never found a client who, after trying two or three different preparations, could not find at least one way to include liver regularly. The nutritional return on that effort is unlike anything else a food can offer.
Desiccated Liver — UK Brands Worth Knowing
For those who want the nutrients without the kitchen
Ancestral Supplements
Grass Fed Beef Liver
New Zealand grass-fed, pasture-raised. Freeze-dried at low temperature. The benchmark product in this category. Available direct and through Amazon UK.
Hunter & Gather Foods
Beef Liver Capsules
UK and Irish grass-fed source. Freeze-dried. Good quality control, well-sourced, available in UK health stores and direct.
Important: desiccated liver capsules are a supplement, not a replacement for whole food liver. The freeze-drying process preserves most nutrients well but the food matrix that enhances absorption of whole food nutrients is partially lost. Use capsules as a practical entry point or convenience option — not as the only form you consume. And always check that the source is grass-fed and freeze-dried, not heat-processed or from feedlot cattle.
How often — a practical guide
Frequency guidance by situation
How much liver, how often, for whom
General adult population
100g beef or lamb liver once per week, or 150g chicken or duck liver once per week. This delivers the nutrient payload without approaching vitamin A upper limits over time.
Iron deficiency / low ferritin
2x per week for 6–8 weeks to drive haem iron repletion, then reduce to weekly maintenance. Combine with vitamin C at the meal to further enhance absorption.
B12 deficiency / methylation support
Weekly liver plus a methylcobalamin supplement (not cyanocobalamin) if functional B12 on testing is below optimal. Liver alone may not be sufficient for established deficiency.
Fatigue / mitochondrial support
Weekly liver for CoQ10, B2, B3, and carnitine precursors. Pair with the wider mitochondrial support picture if OAT shows Krebs cycle impairment.
Pregnant women
Avoid. The high retinol content of liver is genuinely contraindicated in pregnancy due to teratogenicity risk at elevated vitamin A intakes. This is a real clinical caution, not overcaution.
Those who won't eat it
Desiccated liver capsules (Ancestral Supplements or Hunter & Gather) at manufacturer's recommended dose. Or — try chicken liver pâté first. Most people who think they hate liver have not tried it well-prepared.
The context that makes liver make sense
Liver is not a health trend. It is not biohacking. It is the food that every traditional culture prioritised — given to pregnant women, nursing mothers, growing children, and the unwell — before the industrialisation of food reduced most of the population to muscle meat and grain. The fact that it fell out of fashion is a cultural accident, not a nutritional development.
What testing reveals is exactly why it matters individually. A client with low ferritin, borderline B12 on functional testing, low retinol, and CoQ10 insufficiency on the OAT has — in liver — a single food that addresses all four simultaneously in their active, preformed, bioavailable forms. No supplement protocol addresses all four as efficiently. No other single food comes close.
Erling Haaland eating liver weekly is not a coincidence. Elite athletes tend toward the foods that support the highest possible tissue function. The same reasoning applies whether you are a professional footballer or a 52-year-old in Edinburgh trying to maintain energy, cognitive function, and mitochondrial capacity into the decades ahead.
Know what you're actually deficient in
Retinol, functional B12, ferritin, CoQ10 markers, and omega-3 index are all measurable with functional testing. If you're going to prioritise liver as a food, knowing your baseline tells you whether the priority is right and how long to maintain it.
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