Beef Kidney SupplementSelenium, Riboflavin & Detox Support

Selenium per 100g

140–160µg

250–290% Daily Value

Riboflavin (B2) per 100g

3.4mg

261% Daily Value

Vitamin B12 per 100g

~28µg

1,167% Daily Value

CoQ10 per 100g

~4–15mg

Mitochondrial support

Zinc per 100g

2.7mg

25% Daily Value

Iron per 100g

4.6mg

26% Daily Value

USDA FoodData Central; Rayman MP, 2012 — Lancet

Beef kidney contains 140–160µg selenium per 100g — the highest selenium density of commonly available organ meats. Selenium is a critical cofactor for glutathione peroxidase (GPx) enzymes, which neutralise reactive oxygen species. Also required for iodothyronine deiodinases, which convert T4 to active T3 thyroid hormone.

USDA FoodData Central; Powers HJ, 2003 — Am J Clin Nutr

Beef kidney contains approximately 3.4mg riboflavin per 100g — 261% of the daily value. Riboflavin is a precursor to FAD and FMN, cofactors in the electron transport chain and fatty acid beta-oxidation. B2 deficiency impairs energy metabolism and is more common in those avoiding animal products.

Dallner G, Sindelar PJ, 2000 — Free Radic Biol Med

Beef kidney contains approximately 4–15mg CoQ10 per 100g. Lower than heart (~113mg/100g) but meaningful in a multi-organ blend. CoQ10 is the primary electron carrier between mitochondrial Complexes I/II and Complex III.

Q. Why is beef kidney included in organ supplements?

Beef kidney provides a unique nutrient profile vs liver and heart: it is exceptionally high in selenium, riboflavin (B2), and CoQ10, while being lower in retinol than liver. This makes it a useful complement in a nose-to-tail multi-organ stack — adding selenium and B2 density without increasing the retinol load.

Q. Is beef kidney supplement safe?

Yes, for most healthy adults. Unlike liver, kidney does not pose a vitamin A toxicity risk. The main caution: kidney is high in purines, which are metabolised to uric acid. Those with gout or hyperuricemia should use kidney supplements cautiously. Also, kidney concentrates heavy metals (cadmium) at higher rates than liver — this makes COA documentation more important for kidney-containing products.

Q. How much selenium is in beef kidney?

Beef kidney contains approximately 140–160µg selenium per 100g — roughly 250–290% of the daily value. This is significantly higher than liver (~57µg/100g) and beef heart (~40µg/100g). The RDA for selenium is 55µg/day; the tolerable upper intake is 400µg/day. At standard organ supplement doses (containing a fraction of beef kidney), selenium intake from this source alone is unlikely to approach the upper limit.