A rich source of vitamin K2 is purified fish meal. Milk and eggs also contain vitamin K1 and K2 in small amounts. Microorganisms such as microbacteria, molds and yeast are said to be the best sources of vitamin K2.
Daily requirement: It is difficult to estimate the daily requirement of vitamin K because the intestinal flora provides the vitaipins in the amounts required.
Vitamin K deficiency or avitaminosis:
A deficiency of vitamin K may cause a deficiency of prothrombin in the circulating blood, a condition known as hypoprothrombinemia.
In the absence of prothrombin blood fails to clot and results in profuse bleeding (for example, from the gums) and haemorrhages (into joints and retina, etc.).
Recent studies indicated that vitamin K has a genetic action in including RNA formation for the synthesis of blood-clotting proteins (Olsen and Phillips).
Vitamin K toxicity or hypervitaminosis:
Over doses of vitamin K are toxic, due to which malfunction of any body organ may occur.
The coenzymes-Q group has been classed as vitamins because these compounds are capable to cure or protect against vitamin E deficiency in several species of animals. Some of the coenzymes are also active in electron transport and for oxidative phosphorylation.
Stigmasterol has been called as antistiffness factor. It is a plant sterol with a formula quite similar to that of ergosterol.
Its absence causes stiffness of the wrists and elbows of guinea pigs. The muscles atrophy and become streaked with bundles of fine white lines of calcium deposits.
Stigmasterol occurs in fresh kale or alfalfa and in fresh cream.