USTAGISOTC34-N2123-DTR23304

DUE: NOVEMBER 10, 2020

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ISO/DTR 23304:2020(E)

4.5 Vitamin K

Vitamin K is as a fat-soluble vitamin. Vitamin K can be found as vitamin K 1 in vegetables (spinach, lettuce, broccoli, Brussels sprouts) and as vitamin K 1 and vitamin K 2 in meat and liver.

Food regulations of many countries authorize the fortification of different kind of food products with molecules having a vitamin K activity. The names of the authorized molecular forms to add in is generally linked to the type of food product. Table 7 gives an example of vitamin K compounds allowed to use for food fortification according to European regulation depending the product type.

Table 7 – Example of authorized vitamin K compounds for food fortification in the EU according to products concerned

Product type

Molecular form

Molecular mass (g/mol)

Examples of regulations

Phylloquinone (phytomenadione

450,7

–

Food with a specific nutritional purpose

Regulation (EU) n° 609/2013

vitamin K 1 )

Menaquinone (vitamin K 2 )

444,6 450,7

Phylloquinone (phytomenadione

–

vitamin K 1 )

Supplemented food

Regulation(EC) n° 1925/2006

Menaquinone (vitamin K 2 )

444,6

Phylloquinone (phytomenadione

450,7

–

Food supplements products

vitamin K 1 )

Directive n°2002/46/EC

Menaquinone (vitamin K 2 )

444,6

There are three main vitamers of vitamin K. The major form is vitamin K 1 (phylloquinone or phytomenadione or phytonadione) There is also vitamin K 2 (menaquinone) and vitamin K 3 (menadione).

In general, the unit of measurement for vitamin K is µg vitamin K 1 (phylloquinone) or vitamin K 2 (menaquinone).

Menaquinone (vitamin K 2 ) can also be added to different kinds of food in different molecular forms (Table 7). The difference in molecular form is linked to the length of the isoprenoid chain. The number of isoprenoid groups gives the name of the menaquinone. With 4 isoprenoid group the name is vitamin K 2 - MK4 and with 7 isoprenoid group the name is vitamin K 2 -MK7.

To conclude, the vitamin K content can be calculated as:

Vitamin K (µg/100g) = vitamin K 1 (µg/100g), or vitamin K 2 (µg/100g).

It should be noted that a significant level of cis isomer can be found in synthetic vitamin K 1 . Cis-vitamin K 1 is considered less bioavailable. However, food regulations do not distinguish between cis- and trans vitamin K 1 . From a food composition perspective it can be more relevant to quantify trans-vitamin K 1 , whereas from regulatory/food labelling perspective total vitamin K 1 should be considered.

Most of the methods quantify total vitamin K 1 , but the recent standard ISO 21446 [16] enables to quantify separately the cis and the trans isomers.

© ISO 2020 – All rights reserved ISO/TC 34 N 2123 and ISO/DTR 23304:2020

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