As both a canine nutritionist and a certified holistic nutritionist for humans, I spend a lot of time thinking about how the foods we eat support health: not just for our dogs, but for us, too. One food that consistently stands out in both worlds is liver.
Inside the body, the liver is a biological wonder, performing more than 500 essential functions: generating glucose to keep blood sugar stable, storing vitamins and minerals in reserve, detoxifying the blood and even protecting cells from oxidative damage. And when eaten as food, it becomes one of the most concentrated sources of vitamins and minerals available.
In canine nutrition, liver is never treated as just another source of protein. Instead, it’s used as a natural supplement, delivering hard-to-source micronutrients in the balance that only nature provides – packaged together with the cofactors and synergistic compounds that help the body use them most effectively. In human nutrition, liver often flies under the radar as an under-hyped superfood: a potent and affordable source of vitamins and minerals that’s too often overlooked.
Liver in Canine Nutrition: Precision Matters
As a canine nutrition practitioner, I treat liver with the respect it deserves. It’s never simply “meat in the bowl.” While it does contain protein, its primary role in recipes is to supply essential vitamins and minerals. Because it’s so nutrient-dense, just a small amount is enough to meet needs while too much can quickly tip the balance into excess.
Copper illustrates this fine balance perfectly. Dogs require copper in their diets and liver is one of the richest natural sources. But because liver is so concentrated (especially beef liver), overfeeding it can lead to copper accumulating to unsafe levels. This is why relying on guesswork or vague rules of thumb is risky. And it’s where the value of canine nutritionists becomes clear. Instead of relying on “vibes,” we calculate how much liver a dog needs relative to their metabolic body weight: a non-linear formula that more accurately reflects nutrient needs than body weight alone. We use that figure to determine the recommended allowance for copper and then identify the safe amount of liver to feed, based on the copper content of the specific type being used.
These may sound like small details, but they’re critical to a dog’s long-term nutritional health. Take my own dog Boone, for example. He’s a big boy at 48kg (~106lbs). Based on his metabolic body weight, his daily copper requirement is 3.6mg, according to the recommended allowances established by the NRC (National Research Council), which publishes the scientific reference standards used by canine nutritionists to guide safe and balanced feeding. If I were to meet that need with beef liver alone, I’d feed him 25g (0.9oz) of cooked beef liver, which is about the size of a large walnut. That amount would actually decrease if the liver was fed as part of a recipe containing other meats, since they also contribute copper. It’s worth asking yourself: how much liver are you actually feeding your dog?
How much liver is appropriate depends a great deal on the type of liver being fed. Lamb liver, for instance, is much lower in copper: Boone would need about 51g (1.8oz), roughly the size of a large chicken egg) to meet his requirement. To get the same amount from turkey liver would take 340g (12oz), and from chicken liver, 730g (1.6lbs).
Most dog owners understand that liver is nutrient-dense, but far fewer realize how quickly overfeeding can tip a diet into imbalance, or even lead to copper toxicity over time. This is exactly why careful formulation matters and why working with a nutritionist is one of the most important investments you can make in your dog’s long-term health.
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💡 Nerd Corner: How Nutritionists Calculate Liver Amounts
Curious how this works?:
- Nutritionists calculate a dog’s metabolic body weight (MBW): body weight in kilograms raised to the power of 0.75 (BW^0.75). This accounts for the non-linear way metabolism scales with size. A Great Dane doesn’t need ten times more copper than a terrier, even if it weighs ten times as much.
- From there, we match MBW to the dog’s recommended allowance for copper and check the nutrient data for the type of liver being used.
This is why “rules of thumb” online can be misleading. It’s easy to overshoot and risk toxicity — and just as easy to cause deficiencies if you skip liver altogether.
👉 For curious readers, free databases like myfooddata.com are a great way to explore nutrient content in foods. But applying that data correctly in a balanced diet is where professional training makes all the difference.
Liver in Human Nutrition: An Under-hyped Superfood
What nutritionists know for dogs also applies to us. Liver is one of the most concentrated sources of essential micronutrients available to humans. Just a modest serving delivers vitamin A in its active form (retinol), vitamin D3, vitamin B12, heme iron (the highly bioavailable form of iron found in animal foods, more readily absorbed than non-heme iron from plants) and a range of minerals like zinc and copper. These nutrients play critical roles in vision, energy, immunity and overall metabolic health.
This is why liver has long been valued in ancestral and, more recently, paleo diets. For traditional cultures, organ meats were not discarded; they were prized, often eaten first because of their remarkable nutrient density. The paleo approach embraces this whole-animal perspective, recognizing the value of organ meats alongside muscle meats. Eating the whole animal provides a broader and more balanced spectrum of nutrients than relying on lean cuts alone.
By contrast, the Standard American Diet (often referred to as “SAD” in holistic nutrition circles) places heavy emphasis on muscle meats and processed foods while overlooking organ meats almost entirely. This shift has left many people with nutritional gaps, especially in vitamins like A, D, and B12, as well as minerals such as iron and zinc: all of which liver provides in abundance. (Interestingly, organ meats are actually far more common in canine nutrition than in human diets, often appearing in commercial foods from large manufacturers under the label “byproducts.”)
How Human Nutrition Trends Shape Canine Nutrition
Modern nutrition science confirms what our ancestors already understood: liver is uniquely dense in nutrients compared to almost any other food. Its value lies not just in the individual vitamins and minerals it contains, but in the way nature combines them. Liver delivers these nutrients in balance, together with the cofactors that help the body absorb and use them efficiently. Reintroducing it isn’t about following a fad diet. It’s about reclaiming a practice that nourished humans for millennia and that valued organs, bones and other nutrient-rich parts of the animal alongside muscle meat.
One common concern is whether liver itself is “toxic,” since it processes medications and environmental chemicals. But the liver isn’t a simple filter that traps poisons. Instead it’s more like a processing plant, breaking down and neutralizing compounds so they can be safely excreted. If an animal’s liver were truly “toxic,” the animal itself would be sick.
Like other tissues, liver can contain trace amounts of heavy metals if animals are raised in polluted environments, but research shows these levels are generally well within safe limits for consumption. As Mark Sisson points out, if you eat meat at all, every part of the animal is exposed to the same environment. The sensible approach isn’t to avoid liver altogether, but to think about sourcing. Because liver can accumulate toxins and because its best eaten occasionally as a palm-sized portion (about 75–100g / 2.5–3.5 oz) once a week, it makes sense to seek out the highest-quality organ meats you can afford. A small amount is all you need; liver is so nutrient-dense (and filling) that a little truly goes a long way. Choosing products from farms that use organic practices, avoid pesticides and raise animals in healthier environments is a practical way to enjoy liver’s nutritional benefits while minimizing potential risks.
That’s a Wrap
For both dogs and humans, liver is more than just food: it’s a concentrated source of essential micronutrients. In canine diets, it must be calculated with care and used like a supplement to balance health without tipping into excess. In human diets, it offers an impactful but often overlooked way to boost nutrition when enjoyed in moderation.
Because I have the good fortune to work in both canine nutrition and holistic human nutrition, I’ve seen how often these two worlds overlap. The same curiosity that inspires us to eat well for ourselves often guides the way we feed our dogs. By treating liver with respect, choosing high-quality sources and using it in the right amounts, we can give our families, two- and four-legged alike, the nourishment they deserve.
The More You Know
As you can see, even with a food as nutritious as liver, canine nutrition is full of nuance. The same ingredient that’s a powerful source of micronutrients can also create imbalances if not fed appropriately. If you’re feeling uncertain about how to safely and optimally nourish your dog, that’s exactly where a canine nutritionist can help. I offer personalized nutrition consulting to take the stress and guesswork out of feeding, so you can feel confident that your dog’s diet supports their long-term health. Reach out today for a free 15-minute discovery call to see if my services might be the right fit for you and your dog.