Each organ meat concentrates a specific set of nutrients that muscle meat barely contains. Liver leads in vitamin A, B12, and copper. Heart is the richest dietary source of CoQ10. Kidney packs selenium and riboflavin. Spleen is unmatched for heme iron and zinc. Together, they cover gaps no chicken breast ever will.
"2016-03-07 0890n bison (28051155086)" by Laura Blanchard from Philadelphia, USA is licensed under CC BY-SA 2.0. To view a copy of this license, visit https://creativecommons.org/l
Why Muscle Meat Alone Leaves Nutritional Gaps
For most of human history, men ate the whole animal. Not just the steak. The liver, heart, kidneys, spleen, tongue -- all of it. That's not nostalgia. It's nutritional strategy, and it worked.
Modern grocery shopping has narrowed most people down to muscle meat: chicken breast, ground beef, pork loin. These are decent protein sources. But muscle meat is surprisingly thin on a handful of nutrients that organs concentrate in meaningful amounts -- things like fat-soluble vitamins, CoQ10, heme iron, and trace minerals that support energy metabolism and normal hormonal function.
This article is a plain breakdown of what each major organ actually contains and what those compounds do in the body. No mythology. Just the nutritional data and the physiology behind it.
Liver: The Nutrient Density Benchmark
Liver is the most nutrient-dense whole food you can eat, by a substantial margin. That's not marketing copy -- it's what the USDA data shows when you run a comparison by calorie.
A 100-gram serving of beef liver delivers roughly:
- Vitamin B12: 70 mcg -- about 2,900% of the daily value. B12 supports normal red blood cell formation and helps maintain nerve function already within a normal range.
- Vitamin A (retinol): 4,900 mcg RAE. This is preformed vitamin A -- immediately usable by the body, not the beta-carotene precursor found in plants that requires conversion. Retinol supports normal immune function and cell differentiation.
- Copper: 9.8 mg -- nearly 1,100% DV. Copper plays a role in iron metabolism and the function of several enzymes involved in energy production.
- Folate: 290 mcg. Folate contributes to normal DNA synthesis and amino acid metabolism.
- Riboflavin (B2): 2.8 mg -- 215% DV. Riboflavin is essential to the mitochondrial electron transport chain.
The one caution worth stating: liver is high in preformed vitamin A, and very large daily servings over time can push retinol intake above the tolerable upper limit. Two to three servings per week is a common recommendation for most adults. Pregnant women should consult a physician.
Bison liver carries the same nutritional profile as beef liver with a slightly leaner fat composition, which is why we use it as a base in our formula alongside other whole-organ sources.
Heart: Where CoQ10 Actually Comes From
Heart muscle is still muscle, but it's a different category than the skeletal muscle cuts you grill. The heart works continuously, without rest, for an entire lifetime. That demands an extraordinary concentration of mitochondria and the compounds that keep them running.
The standout here is coenzyme Q10 (CoQ10). Beef heart contains roughly 110-130 mg of CoQ10 per 100 grams -- far higher than any other food. By comparison, beef steak contains about 3 mg per 100 grams. Pork heart is similar in density. Bison heart falls in the same range.
CoQ10 is a fat-soluble compound involved in the mitochondrial production of ATP. The body synthesizes some on its own, but output tends to decline with age. Many men over 45 get essentially none from diet because they've cut out organ meats entirely.
Heart also supplies:
- Zinc: About 5-6 mg per 100g. Zinc supports normal testosterone production and helps maintain immune function already within a normal range.
- Iron (heme): 4-5 mg per 100g in a form that absorbs at roughly 25-30%, versus the 5-10% absorption rate of non-heme iron from plants.
- B vitamins: Thiamine, B6, and B12 in quantities that support normal energy metabolism.
Kidney: Selenium and the Glutathione Connection
Kidney is the most overlooked of the four organs here. That's a mistake nutritionally. It's the richest dietary source of selenium, and selenium is a mineral that doesn't show up in most men's diets in adequate amounts.
Beef kidney contains roughly 140-160 mcg of selenium per 100 grams -- well above the 55 mcg daily value, though still below the 400 mcg tolerable upper limit. Selenium is a required cofactor for glutathione peroxidase, one of the body's primary antioxidant enzymes. It also supports normal thyroid hormone metabolism already within a normal range.
Beyond selenium, kidney delivers:
- Riboflavin (B2): 2.0-2.5 mg per 100g -- similar to liver. Critical for FAD and FMN, the two active coenzyme forms that feed the mitochondrial electron transport chain.
- B12: Around 19 mcg per 100g, roughly 800% DV.
- Iron: 4 mg per 100g heme iron.
The kidneys are filtration organs, which sometimes triggers concern about toxin accumulation. The scientific consensus is clear: properly sourced kidneys from healthy, pasture-raised animals are safe to eat and do not concentrate heavy metals in any meaningful way. The NIH Office of Dietary Supplements covers selenium's roles in detail, with full citations to primary literature.
Spleen: The Overlooked Iron and Zinc Organ
Most people have never eaten spleen. That's a relatively recent development. Spleen has been a regular food across dozens of cultures for centuries, and the nutritional case for it is strong.
Spleen has the highest iron concentration of any organ meat, typically running 30-45 mg per 100 grams in heme form. That's not a typo. For reference, beef steak contains about 2-3 mg of iron per 100 grams. The difference is roughly 10 to 20 times.
Customers often ask us why we include spleen specifically. The answer is simple: no other whole food delivers iron in that density. Heme iron from spleen absorbs efficiently, unlike the iron in spinach or fortified cereals.
Spleen is also a meaningful source of:
- Zinc: 3-4 mg per 100g, supporting normal immune function and reproductive hormone maintenance already within a normal range.
- Protein: About 17-18 grams per 100g, with a complete amino acid profile.
- Vitamin C: Small but notable -- uncommon in animal foods.
The flavor of spleen is mild, slightly metallic. Most people eating it as a dried whole-food supplement don't taste it at all.
How These Four Organs Work as a Nutritional System
Each organ concentrates what it needs to function. Liver processes everything the body absorbs, so it holds the fat-soluble vitamins and copper needed for detoxification enzymes. Heart runs on ATP, so it's packed with CoQ10 and B vitamins. Kidney filters minerals, so it accumulates selenium. Spleen manages red blood cells, so it stores iron.
That's not coincidence. It's physiology. And it's exactly why traditional diets that included the whole animal rarely showed deficiencies in these specific micronutrients.
The men who use a nose-to-tail bison organ complex are generally not sick. They're guys in their 40s and 50s who eat reasonably well but know that muscle meat alone doesn't cover everything. The goal is filling the gaps -- specifically in B12, CoQ10, selenium, iron, and zinc -- without adding complexity to daily eating.
One serving of a whole-organ complex provides a meaningful amount of each compound listed above. It doesn't replace real food. But for most men eating the modern Western diet, it covers ground that whole-organ meals two or three times a week used to cover.
For further reading on the micronutrient profiles of organ meats, the NIH Office of Dietary Supplements maintains fact sheets on each nutrient mentioned here, with full citations to primary literature.
What to Look for in an Organ Supplement
Not all organ supplements are the same. A few things worth checking before you buy:
- Source: Grass-fed, pasture-raised animals carry a cleaner nutritional profile. Bison in particular is almost always raised on pasture -- the species doesn't adapt well to feedlot conditions, which is why bison products tend to be higher quality by default.
- Processing temperature: High-heat rendering destroys heat-sensitive compounds like CoQ10, riboflavin, and B12. Cold-processing or freeze-drying preserves them. Look for freeze-dried or low-temp desiccated on the label.
- Which organs are included: A product that contains only liver is not a complete organ supplement. Liver is excellent, but heart, kidney, and spleen each bring compounds liver doesn't concentrate in the same amounts.
- Additives: A good organ supplement has one ingredient: the organ. Maybe a gelatin capsule. Nothing else. Check the label.
Wild American Bison uses freeze-dried bison liver, heart, kidney, and spleen from pasture-raised animals. No fillers, no flow agents, no artificial anything. That's the whole formulation.
Frequently asked questions
Is it safe to eat organ meats every day?
For most organs, yes -- with one exception. Liver is high in preformed vitamin A (retinol), and very large daily servings over time can push intake above the tolerable upper limit of 3,000 mcg RAE per day. Two to three liver servings per week is a common recommendation. Heart, kidney, and spleen carry no similar concern at normal serving sizes.
Do organ meats support testosterone levels?
Organ meats are concentrated sources of zinc and selenium, two minerals that play a role in maintaining normal testosterone production already within a normal range. They also supply cholesterol, which is the direct precursor to all steroid hormones including testosterone. A diet chronically low in these nutrients may make it harder for the body to maintain normal hormonal balance.
What is CoQ10 and why does it matter for men over 45?
Coenzyme Q10 is a fat-soluble compound used by every cell that produces energy via mitochondria. The body synthesizes CoQ10, but output tends to decline with age. Beef and bison heart are the only meaningful whole-food sources, containing roughly 110-130 mg per 100 grams. CoQ10 contributes to normal mitochondrial function and helps maintain energy metabolism already within a normal range.
How does heme iron in organ meats compare to plant iron?
Heme iron from animal sources absorbs at roughly 25-30%. Non-heme iron from plants and fortified foods absorbs at 5-10%, and absorption is further reduced by phytates, calcium, and polyphenols in the same meal. Spleen in particular has 30-45 mg of heme iron per 100 grams -- a density no plant food comes close to matching.
Can I get the same nutrients from a standard multivitamin?
Most multivitamins supply synthetic isolated forms of vitamins and minerals. Organ meats supply those same nutrients alongside the co-factors, enzymes, and binding proteins found in whole food. For example, B12 in liver comes packaged with binding proteins; copper comes alongside the ceruloplasmin naturally present in the tissue. Whether that matrix matters in practice depends on your absorption capacity and baseline diet.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Written by The Wildhorn Desk, Men's Health Editor.