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Controversy Over Menadione in Dog Food

Menadione is actually a vitamin. It’s the man-made version of an essential nutrient commonly known as vitamin K… more precisely, vitamin K3.

But K3 is just one of five known versions of vitamin K. The three most common ones found in dog food are…

  1. Vitamin K1 – naturally found in green leafy vegetables
  2. Vitamin K2 – produced by bacteria living inside a dog’s gut
  3. Vitamin K3 – menadione, the man-made synthetic version

Vitamins K1 and K2 are considered natural.

That’s why, in addition to being fat soluble, they’re also chemically ready to be used by the body… just as they are.

But vitamin K3 is synthetic. So, all forms of the chemical must first undergo the cellular process of alkylation before they can be used by the body.

So, What’s So Important
About Vitamin K

Vitamin K is used by the liver to produce various clotting factors… chemical compounds designed to stop or control bleeding.

So, how much vitamin K does a dog need?

Well, according to one authority, not much.  A dog needs very little Vitamin K per serving to sustain life… just one part per million.2

And the vitamin isn’t even listed as a required dog food ingredient in the nutrient profiles established by the Association of American Feed Control Officials.3

The controversy over menadione appears to center around two opposing views.

Menadione… a Nutritional Necessity?

Supporters4 see menadione as a necessary additive… an critical supplement dog food companies should feel compelled to include in their product recipes.

Defenders favor the use of menadione because…

  • Natural vitamin K may lose its potency during processing
  • Intestinal disease can prevent gut bacteria from making the vitamin
  • Not all manufacturers include green leafy vegetables in their recipes

Advocates also claim menadione should be considered safe because toxic levels are a thousand times greater than the recommended daily dose.

So, many companies routinely choose the vitamin K supplement most readily available… menadione.

Or a Dangerous Toxin?

Critics5 see menadione as only a precursor to the vitamin’s more natural versions. They cite studies that make some disturbing claims. They worry that menadione…

  1. Causes toxic reactions in liver cells
  2. Weakens the immune system
  3. Induces allergic reactions
  4. Causes abnormal break-down of red blood cells

One company selling menadione warns its human buyers that menadione is “toxic to kidneys, lungs, liver, mucous membranes. Repeated or prolonged exposure to the substance can produce target organ damage.

According to a peer-reviewed article published in 2004 by the Linus Pauling Institute at the Oregon State University: “Although allergic reaction is possible, there is no known toxicity associated with high doses of the phylloquinone (vitamin K1) or menaquinone (vitamin K2) forms of vitamin K8. The same is not true for synthetic menadione (vitamin K3) and its derivatives. Menadione can interfere with the function of glutathione, one of the body’s natural antioxidants, resulting in oxidative damage to cell membranes. Menadione given by injection has induced liver toxicity, jaundice, and hemolytic anemia (due to the rupture of red blood cells) in infants9; therefore, menadione is no longer used for treatment of vitamin K deficiency10. No tolerable upper level of intake has been established for vitamin K.”

The FDA has banned the use of menadione from over-the-counter supplements because large doses have been shown to cause these dangerous biological effects.

A Wolf in Sheep’s Clothing

Unfortunately, it can be difficult to spot menadione in a dog food recipe. That’s because manufacturers frequently list the vitamin in rather cryptic fashion.

Here are some common chemical names for menadione that can show up on a dog food ingredients list.

  • Menadione sodium bisulfate
  • Menadione sodium bisulfite
  • Menadione dimethylprimidinol sulfate
  • Menadione dimethylprimidinol sulfite
  • Menadione dimethylprimidinol bisulfite
  • Dimethylprimidinol sulfate
  • Dimethylprimidinol sulfite
  • Dimethylprimidinol bisulfate
  • Vitamin K supplement

And watch out! You might even come across menadione hiding behind innocent little phrases like one that refers to it as… “a source of vitamin K activity”.

The Bottom Line

So, what should you do when you find dog food recipes containing menadione?

Until there’s a peer-reviewed scientific study proving the safety of menadione, I’d recommend shoppers give preference to products that don’t contain this potentially dangerous ingredient.

Article by Mike Sagman * = The best place to see how your dog food rates!

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