The Case Against Menadione in Dog Food

When you’re looking for the best food for your dog, it can be tough to wade through all of the ingredients on the label.

One ingredient that you may have heard of, but don’t know much about, is Menadione. Along with other ingredients such as corn, soybean, wheat, canola meal, menadione is among the 24 problematic dog food ingredients.

So, what is Menadione Sodium Bisulfite in Dog Food?

Menadione is a synthetic form of Vitamin K. It is often used in cheaper brands of dog food as a way to add vitamins and minerals to the food without having to use more expensive, natural ingredients.

Vitamin K is an important nutrient for dogs. It helps with blood clotting and bone health. However, the synthetic form of Vitamin K (menadione) can be toxic to dogs in large amounts.

As a man-made Vitamin K, menadione is not as easily absorbed by the body as the natural form of Vitamin K. This can lead to a build-up of toxins in the liver and kidneys, which can be harmful or even fatal to dogs.

Vitamin K3 , or menadione, has been linked to liver toxicity, hemolytic anemia (destruction of red blood cells), and birth defects in dogs. Read more about vitamin K toxicity here.

There are five versions of Vitamin K and Vitamin K3 is just one of them. The others are;

  • Vitamin K1 – found in green leafy vegetables
  • Vitamin K2 – a type of vitamin produced by bacteria that exist in a dog’s digestive system.
  • Vitamin K3 – a man-made synthetic version

Vitamins K1 and K2 are classified as natural and fat-soluble. They’re chemically ready to be used by the body as soon as they’re produced.

On the other hand, Vitamin K3 has to go through a process of alkylation. Alkylation is a process where chemicals are added to make a new compound. This makes Vitamin K3 water-soluble, so it can be easily added to foods as an inexpensive way of supplementing them with Vitamin K.

Types of Menadione:

There are two forms of Menadione – Menadione Sodium Bisulfite Complex (MSB) and Menadione Dimethylpyrimidinol Bisulfite (DMPB).

MSB is the form most often used in dog food. It is a water-soluble vitamin that is easily absorbed by the body.

DMPB, on the other hand, is not water-soluble and is not as easily absorbed. This form is more likely to build up in the liver and cause toxicity.

What’s the importance of Vitamin K?

Vitamin K plays an important role in many of the body’s functions. It helps with blood clotting, bone health, and the prevention of heart disease.

Clotting factors: Vitamin K helps the body to make clotting factors. These are proteins that help the blood to clot.

Bone health: Vitamin K is important for bone health. It helps the body to absorb calcium and phosphorus, which are two minerals that are essential for healthy bones.

Heart health: Vitamin K also plays a role in heart health. It helps to prevent the hardening of the arteries, which can lead to heart disease.

How much vitamin K does a dog need?

The National Research Council of the National Academy of Sciences specify that your dog only needs a very small amount of Vitamin K. To put that in perspective, a single green bean contains more than enough Vitamin K to meet your dog’s daily requirements.

The recommended amount of Vitamin K for dogs is 1,000 micrograms per 10 pounds of body weight. If your dog has Vitamin K deficiency, you can get supplements. If your dog is 50 pounds, you would give him or her 250 mcg 3 times a day (750 mcg total).

AAFCO has not listed menadione or Vitamin K as essential ingredients in dog food.

Most dogs will get the necessary amount of Vitamin K from their food.

Those in favor of menadione in dog food claim that;

  1. The shelf life of menadione is longer than that of natural vitamin K.
  2. It doesn’t lose its potency during processing
  3. Some dogs with intestinal disease prevent gut bacteria from making the vitamin
  4. Some dog food manufacturers do not include green leafy ingredients and may be lacking in some dog food.

Those opposed to having menadione in dog food claim that;

  • Vitamin K is easily obtained from other sources and does not need to be supplemented.
  • Menadione is a man-made synthetic vitamin and not as easily absorbed by the body.
  • It can build up in the liver and cause toxicity.
  • It promotes allergic reactions
  • It weakens the immune system

Menadione supplements have been banned by the FDA because of their high toxicity.

So, what’s the bottom line? Is Menadione safe for dogs?

In large amounts, menadione is toxic to dogs but studies suggest that it is safe in small doses.

If you’re concerned about feeding your dog Menadione, there are other sources of Vitamin K that you can use. These include; green leafy vegetables, liver, and egg yolks. You can also get supplements that do not contain Menadione.

Ultimately, the decision of whether or not to use Menadione is up to you. You should weigh the pros and cons and make a decision based on what you feel is best for your dog.

Does AAFCO Recommend Vitamin K as an essential ingredient in dog food?

No, the AAFCO does not recommend Vitamin K as an essential ingredient in dog food. Most dogs will get the necessary amount of Vitamin K from their food.

In the AAFCO rule book, Menadione sodium bisulfite is ONLY approved for use in feed for poultry.

Federal regulation 21 CFR 573.620

The FDA through 21 CFR regulations, has set out detailed guidelines on food additives in dog food including menadione dimethylpyrimidinol bisulfite or menadione nicotinamide bisulfite.

In dogs, food additives must be used within the limitations specified in FDA’s regulations to avoid potential hazard to the animal.

The FDA has not established a maximum level for menadione sodium bisulfite in dog food.

Some states have their own restrictions on menadione use in animal feed. For example, California prohibits the use of menadione sodium bisulfite in poultry feed.

Which are the best dog food without menadione?

There are many brands of dog food that do not use Menadione. Some examples include Acana, Blue Buffalo, Canidae, Merrick, Natural Balance, Orijen, Wellness, and Zignature.

These brands of dog food typically use other sources of Vitamin K such as green leafy vegetables or liver.

You can also find supplements that do not contain Menadione.

When trying to avoid Menadione, always check the ingredients list to make sure it is not included.


What are Menadione’s side effects in dogs?

While Menadione is considered safe for dogs in small doses, it can be toxic in large amounts.

Some of the side effects of menadione toxicity in dogs include; vomiting, diarrhea, liver damage, and kidney damage.

If you think your dog has ingested too much Menadione, contact your veterinarian immediately.

What are some sources of menadione in dog food?

Menadione is typically found in dog food as a vitamin supplement.

It can also be found in some Flea and Tick products as well as some dewormers.

Always check the ingredients list to make sure Menadione is not included if you are trying to avoid it.