Vit. K & MBD?

[Katherine]

I watched a program on health issues. One of the doctors said that Vit. K is important for bone development in humans. I was wondering if anyone knows of similar research in animals & a possible link to MBD?

[Pnerissa]

From what I've learned, it needs to be natural vitamin K as the synthetic vitamin K is hazardous to rodents. I'm sure someone will be along shortly to fill in the blanks.

[Katherine]

From what I've learned, it needs to be natural vitamin K as the synthetic vitamin K is hazardous to rodents. I'm sure someone will be along shortly to fill in the blanks.

Thanks for the information. Didn't know K dangerous for rodents.

[4skwerlz]

You're both right. Formerly it was believed that the only function of vit K was to help blood to clot. Newer research has found it plays a role in bone-building, perhaps a very important role.

And yes, there is an artificial form of vit K called menadione or menadione sodium bisulfite, or by a similar name. It's not exactly a form of vit K, but rather a chemical that supposedly stimulates "vit k activity." It is banned in the US for human use because of toxicity, especially liver toxicity; there were even some deaths. It is also banned in pet foods in most developed countries. Sadly, in the US this chemical is found in ALL pet foods and animal feeds. Why? Because it's cheap of course. Real, plant-based vit K (such as phylloquinone) is very expensive because it has to be extracted from plants.

The authors of the Nutrient Requirements of Laboratory Animals went "out on a limb" on this issue--considering that you can't buy a commercial feed that doesn't contain menadione--and recommended NOT feeding menadione, but rather phylloquinone. Perhaps some of the purified diets available for laboratory animals don't contain menadione.

NRLA, pp. 43-44.
The synthetic derivative of vitamin K, menadione, lacks the isoprenoid side chain of the natural compounds with vitamin K activity, and it must be converted to menaquinone-4 in the liver to be functional (Dialameh et al., 1971). Menadione is about one-tenth as active as phylloquinone. Some of the water-soluble derivatives of menadione, such as the menadione sodium bisulfite complex, are much more readily absorbed and are about equally as active as phylloquinone (Griminger, 1966).

Because the rat actively absorbs phylloquinone and gives preference to phylloquinone metabolically, phylloquinone is the recommended form to be used in diets. Menadione and its derivatives are not recommended.

Signs of Vitamin K Toxicity Phylloquinone is essentially nontoxic when given orally. Rats given daily doses of 4,400 µmol phylloquinone/kg BW for 30 days did not show signs of toxicity, whereas 2,000 µmol menadione/kg BW was lethal (Molitor and Robinson, 1940). At 260 µmol/kg diet, menadione depressed the activity of several heme-containing enzymes in vitamin E-deficient rats (Hauswirth and Nair, 1975). This concentration is present in a popular commercial vitamin mix. At higher concentrations both menadione and menadione sodium bisulfite produce liver toxicity.

[Katherine]

You're both right. Formerly it was believed that the only function of vit K was to help blood to clot. Newer research has found it plays a role in bone-building, perhaps a very important role.

And yes, there is an artificial form of vit K called menadione or menadione sodium bisulfite, or by a similar name. It's not exactly a form of vit K, but rather a chemical that supposedly stimulates "vit k activity." It is banned in the US for human use because of toxicity, especially liver toxicity; there were even some deaths. It is also banned in pet foods in most developed countries. Sadly, in the US this chemical is found in ALL pet foods and animal feeds. Why? Because it's cheap of course. Real, plant-based vit K (such as phylloquinone) is very expensive because it has to be extracted from plants.

The authors of the Nutrient Requirements of Laboratory Animals went "out on a limb" on this issue--considering that you can't buy a commercial feed that doesn't contain menadione--and recommended NOT feeding menadione, but rather phylloquinone. Perhaps some of the purified diets available for laboratory animals don't contain menadione.

Thanks 4S. So, I am correct in saying that the vit K in pip's commercial food is of no bone-building value?

[4skwerlz]

Thanks 4S. So, I am correct in saying that the vit K in pip's commercial food is of no bone-building value?

That I don't know. Since menadione is no longer used as a supplement for humans, the current research on vit K's role in bone-building is focused on phylloquinone, not menadione. So far, three proteins in bone have been found to be vitamin-K-dependent.

[Busysqrl]

The Vit K issue and no preservatives is one reason I love 4S blocks. You know EXACTLY what's in them. Good info 4S