Menaquinone dietary sources

The vitamin K requirement is met from the diet (vitamin Ki) and microorganisms in the intestine (vitamin K2). The richest dietary source of vitamin K is green leafy vegetables but it is also present in meat and dairy produce. The structural formulae of vitamin Ki (phylloquinone) and vitamin K2 (menaquinone) are given in Figure 15.15. It was discovered in 1929 by Henrik Dam in Copenhagen, who discovered that it was necessary for the clotting... 

The K vitamins include vitamin Ki, phylloquinone or phytonadione, and vitamin K2 which is a group of compounds, the menaquinones. Menadione, vitamin K3, is a precursor of menaquinone-4. Vitamin K is present in alfalfa and fish livers. Other dietary sources include green vegetables, soybean oil and eggs. A normal diet together with the bacterial synthesis of vitamin K in the gut are usually sufficient to prevent deficiencies in healthy adults. 

The main dietary sources of the phylioquinones are green vegetables, margarines, and plant oils, whereas some menaquinones are obtained from cheese, other milk products, and eggs. ... 

Table 2 Hsts the Recommended Dietary Allowances (RDA) for vitamin K. Although manufacture by intestinal bacteria represents a significant source of plasma menaquinone concentrations, rehance on this source alone is not sufficient to maintain healthy concentrations of menaquinone. Consequendy, dietary supplementation is necessary (76).

---