Does YOUR Pet’s Food Contain This Toxic Synthetic Vitamin?

Menadione is one of those mystery ingredients you may have noticed if you read pet food labels. Menadione is called vitamin K3, which is a synthetic version of vitamin K that is widely used in pet foods, presumably to replace naturally occurring vitamin K.

There’s a great deal of controversy and growing concern around the use of menadione in pet food, and also some human foods.

Many people know that vitamin K comes from certain foods, for example, green leafy vegetables and liver. Vitamin K is an important factor in blood clotting. It also drives minerals to certain organs of the body like the teeth and bones, to help them heal and to support connective tissue.

As with many questionable ingredients in the food supply, there is an ongoing debate over whether or not menadione is safe. The concern in the holistic community is primarily about the long-term effects of menadione.

The holistic perspective, of course, is that it’s much healthier and safer to get nutrients, especially vitamins and minerals, from food rather than supplements.

Menadione Is Toxic to the Liver and Other Organs

Menadione is a synthetic analog, which means it’s man-made. Natural vitamin K is a fat-soluble vitamin that is absorbed through fat metabolism. Menadione is a water-soluble form of vitamin K that works very differently. It is presumably absorbed by bacteria in the gut and converted to forms of vitamin K the body can use.

There are very significant limitations to menadione vs. natural vitamin K. For example, it doesn’t support blood clotting. So there are important properties of natural vitamin K that synthetic vitamin K lacks.

Another significant and growing concern about menadione is that it may cause liver toxicity. There are studies from other countries that show that menadione causes toxicity to liver cells and red blood cells. There are material safety data sheets (MSDS) that list menadione as a substance that is toxic to the liver, kidneys, lungs, mucous membranes, and other tissues. Obviously, it’s a concern when a toxin is being added to foods that pets are eating every day.

Why Pet Food Manufacturers Use Menadione

Defenders of the use of menadione in pet food say that it’s inexpensive and stable. Those are the two main reasons given for using menadione so extensively in pet food. Other manufacturers claim they’re using menadione at very low levels. Another argument is that it has been used in livestock and poultry feeds for years, and hasn’t caused any problems.

Veterinarians  see many different conditions related to the liver, and they're concerned that even tiny amounts of toxins given over a long period of time might cause or contribute to the diseases we see.

Pet food companies are using it rather than natural food-based forms of vitamin K, because it’s much cheaper to make synthetic vitamin K3 in a laboratory. Cost is a primary driver in pet food manufacturing. The other reason is that menadione is very stable. Unlike natural vitamins, it isn’t affected by heat, sunlight, storage, dehydration or other factors.

Using whole food ingredients in pet food in a way that keeps them stable is a more involved process. Plus whole food ingredients tend to be more expensive.

Types of Pet Foods Containing Menadione

Synthetic vitamin K is in every type of pet food – canned, dry, raw – all of them. But its use is especially prevalent in dry and canned foods. AAFCO has determined that menadione should be the recommended vitamin K supplement added to pet foods, so the majority of manufacturers use it.

It's shocking to discover menadione is used in some commercial raw pet foods. Most people who advocate raw diets are proponents of whole food ingredients because they understand that consuming food in its natural form and freshly prepared is optimally healthy. 

Finding it in raw diets tells me that some companies aren’t investigating the ingredients they use. They’re placing their trust in their formulators without actually evaluating each individual ingredient in their food, which concerns me.

So for all of you out there who haven’t read the fine print on your pet food label – even if you’re buying an excellent quality raw pet diet – make sure to examine the list of vitamins and minerals closely. If you see menadione or vitamin K3 on the list, you know the food contains a potentially toxic ingredient.

How Whole Food Nutrients Differ from Synthetic Nutrients

K3 is just one of five known versions of vitamin K. The three most common ones found in dog food are:
  • Vitamin K1 – naturally found in green leafy vegetables
  • Vitamin K2 – produced by bacteria living inside a dog’s gut
  • Vitamin K3 – menadione, the man-made synthetic version
Vitamins K1 and K2 are considered natural and fat soluble. So, they’re chemically ready to be used by the body just as they are.

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

Our bodies and those of our pets have evolved over millions of years eating whole foods. In other words, animal bodies (including ours) are designed to process nutrients from whole food. There are very specific receptors in the body designed to make perfect use of the nutrients contained in real food.

But when we start breaking whole foods apart to reproduce their nutrients in the laboratory, we run into lots of limitations. When a synthetic nutrient is created in a lab, the finished product has a different structure from the natural form of the nutrient. The man-made nutrient doesn’t fit well into the receptor in the body that is designed for it.

The result is that not all components of the synthetic nutrient can be used by the body. It’s therefore less efficient, it doesn’t have the same metabolic effect as the real thing, and our bodies must process the unusable portion as a xenobiotic (waste) product. It takes energy to get rid of the waste, which is a drain on the body’s resources.

The Value of Long-Term Use of Synthetic Vitamins Has Been Overstated

There are human studies that show long-term use of synthetic vitamins does not have the health benefits we expect. Menadione is an excellent example of a synthetic vitamin that is represented as vitamin K, but without many of the important benefits of whole food vitamin K. 

When it comes to synthetic vitamin K in pet food, manufacturers have done a good job of convincing consumers of its value. Also, we’re accustomed to reading the top half of pet food ingredient labels, but not the bottom half that contains the vitamins and minerals. Not only are those ingredients confusing and impossible to pronounce for most people, but there’s also no way to know where they’ve been sourced from.

I want to encourage all of you who feed a commercial diet to your pets to check the bag, can or container for the presence of menadione.

Not only does menadione lack many of the important properties of natural vitamin K (derived from whole foods), it has also been identified as a liver toxin. Even in very small amounts, ingestion of menadione on a daily basis over a dog’s or cat’s lifetime is cause for concern.