Vitamin K and Menadione

Menadione.  If you buy any sort of fortified pellet or seed mix, you’ve probably offered this ingredient to your parrots.  Nearly all pellets– Roudybush, Zupreem, Lafeber’s, Pretty Bird, etc.– all contain this ingredient.  If you own a dog or a cat, it’s probably in his or her food as well.  It is a widely used ingredient that appears under a multitude of long and scientific-sounding names: menadione sodium bisulfite/bisulfate complex, menadione dimethylprimidinol bisulfite/sulfite/sulfate, dimethylprimidinol bisulfite/sulfite/sulfate, or simply “Vitamin K supplement” or “a source of Vitamin K activity.”  Phew– it’s just a vitamin!  Carry on.  Right?  Wrong.

To understand what menadione is, we have to understand a bit about Vitamin K first.  Vitamin K, a fat soluble vitamin, is named as such because it comes from the German word “koagulation,” and, appropriately, it is necessary to the body for blood coagulation (clotting) among other processes.  It comes in various forms: Vitamin K1 (phylloquinone, phytomenadione, or phytonadione), Vitamin K2 (menaquinone or menatetrenone), and Vitamin K3 (menadione).  (There are actually five forms of Vitamin K, two more synthetic forms K4 and K5, but for our purposes, we will only be discussing these three.)  But there are a few crucial differences between these different types of Vitamin K.

Vitamin K1, as the prefixes “phyllo” and “phyto” indicate, is a naturally occuring vitamin that is produced in a variety of leafy green vegetables.  Raw swiss chard, collard greens, kale, broccoli, and spinach, for example, are all excellent sources of Vitamin K, and aid in the production of prothombin in the liver, necessary for proper blood coagulation.  Vitamin K2, like Vitamin K1, is also a naturally occuring vitamin, and is produced in the body by bacteria in the large intestine.  Vitamin K2 is vital to calcium use, aiding in bone growth and strength, as well as cardiovascular health.

Vitamin K3, on the other hand, is a synthetic form of vitamin K, meaning that it does not occur in nature but rather is a man-made chemical form of the vitamin.  Synthetic vitamins, although they can have some very healthful uses, all have one common flaw: although they are designed to mimic the effects of a single, naturally occuring vitamin, they cannot mimic all of the actions or the pathways that these vitamins take in the body.  Many vitamins, as you may have noticed, are part of vitamin families.  Vitamins B, C, and E, for example, are part of vitamin “complexes,” which act synergistically in accordance with each other.  So, in an isolated setting (like a controlled laboratory), a single vitamin may appear to perfectly mimic the effects of the natural one.  But, when put in an actual body, which works synergistically as a whole and complex unit (and not like a lab with a single experiment happening at once), it can act very differently.  One of the most common differences is that whereas we cannot “overdose” on most natural vitamins, synthetic vitamins are not expelled from the body in the same way, and instead build up, eventually causing vitamin toxicity (too much of one vitamin stored in the body).  This is the reason why so many pellet manufacturers call their products a “complete diet” and warn against feeding both a pelleted diet and any sort of vitamin supplementation.

Despite the possibility of vitamin toxicity, many people still take vitamin supplements and do just fine on them.  In fact, many doctors recommend a multivitamin.  So Vitamin K3 is just fine then, right?  No.  Unlike many other synthetic vitamins, Vitamin K3 poses more than just vitamin toxicity: it is linked to a whole set of different types of toxicities.  In fact, the US Food and Drug Administration found all of its effects in the body so alarming that it banned the use of menadione from all human grade foods under the Kefauver Harris Amendment to the Federal Food, Drug, and Cosmetic Act of 1962.  Studies show that menadione can interfere with the function of glutathione, a natural antioxidant in the body, resulting in damage to cell membranes, especially over time.  Menadione also causes toxic reactions in liver cells, weakens the immune system, may cause allergic reactions, causes the abnormal breakdown of red blood sells, as well as results in cytotoxicity (the death of a cell) in yeast cells in various studies.  Some people argue that there is probably such a small amount of menadione in pellets and fortified foods that it cannot be doing that much damage.  But please understand that all of these effects occur as a result of exposure– in some studies, even minimal exposure– over time.  One chemical manufacturer even warns that menadione is “toxic to kidneys, lungs, liver, muscuous membranes.  Repeated or prolonged exposure to the substance can produce target organ damage.”  Clearly, the effects of menadione are alarming and have been banned from human grade foods for several good reasons.

Why, then, is menadione still so widely used in the pet food industry?  Well, unfortunately, the FDA does not regulate its use in pet grade foods, only in human grade foods.  And because menadione is such an inexpensvie way of supplementing foods with Vitamin K, it is highly favored over other alternatives.  The pet food industry bets that despite the fact that this long and scientific-sounding name appears on its ingredients lists, consumers will be comforted by the fact that it says “source of Vitamin K” afterward and won’t bother to look up this additive and its effects.  Sadly, they are very correct in many cases.  We cannot simply trust that the pet food industry will put out good quality products– there are so many cases of pet food recalls all the time because of the low level of regulation in this industry, especially among parrot foods.  In order to see change, we must demand it– we as consumers must refuse to buy foods that use this toxic ingredient and demand better quality products.

The truth is, there are far better alternatives that are readily available and provide great sources of natural Vitamin K.  The most commonly used one in parrot foods, for example, is alfalfa, a wonderful source of phylloquinone (K1).  Totally Organics Pellets, Harrison’s, and Goldenfeast Goldn’obles all use alfalfa.  (Goldenfeast’s Goldn’obles also uses parsley, another excellent source of Vitamin K1.)  At the time of writing, these are the only three brands on the market that produce pellets without menadione.  If these companies can produce better quality products on a large scale, there is no reason that other parrot food companies should not follow suit and stop using the toxic, synthetic additive menadione.

[The links provided in this post aim to link you to primary sources and studies dealing with menadione.  There is, however, an entire body of information available on the web in the form of secondary sources, in particular in relation to dog food.  The Dog Food Project, for example, has an excellent page on menadione that I highly recommend for anybody interested in more information on the topic.]

[This entry has been imported, with some edits, from my previous blog.]