Multiple Vitamin K Forms Exist in Dairy Foods

Abstract

Background: The plant-based form of vitamin K (phylloquinone, vitamin K-1) has been well quantified in the US diet. Menaquinones (vitamin K-2) are another class of vitamin K compounds that differ from phylloquinone in the length and saturation of their side chain, but they have not been well characterized in foods. Objectives: The objectives of this study were to 1) quantify phylloquinone and the different forms of menaquinones [menaquinone (MK) 4–MK13] in milk, yogurt, Greek yogurt, creams, and cheeses and 2) compare the menaquinone contents of full-fat, reduced-fat, and nonfat dairy products. Methods: All dairy samples were either obtained from the USDA National Food and Nutrient Analysis Program or purchased from retail outlets. Phylloquinone and menaquinone concentrations in these dairy products were quantified by mass spectrometry technology. Results: Full-fat dairy products contained appreciable amounts of menaquinones, primarily in the forms of MK9, MK10, and MK11. We also measured modest amounts of phylloquinone, MK4, MK8, and MK12 in these products. In contrast, there was little MK5–7 or MK13 detected in the majority of dairy products. The total vitamin K contents of soft cheese, blue cheese, semi-soft cheese, and hard cheese were (means ± SEMs): 506 ± 63, 440 ± 41, 289 ± 38, and 282 ± 5.0 µg/100 g, respectively. Nonfermented cheeses, such as processed cheese, contained lower amounts of vitamin K (98 ± 11 µg/100 g). Reduced-fat or fat-free dairy products contained ∼5–22% of the vitamin K found in full-fat equivalents. For example, total vitamin K contents of full-fat milk (4% fat), 2%-fat milk, 1%-fat milk, and nonfat milk were 38.1 ± 8.6, 19.4 ± 7.7, 12.9 ± 2.0, and 7.7 ± 2.9 µg/100 g, respectively. Conclusions: To the best of our knowledge, this is the first report of menaquinone contents of US dairy products. Findings indicate that the amount of vitamin K contents in dairy products is high and proportional to the fat content of the product.

Menaquinone Content of Cheese

“…Remarkably, the menaquinone content of typical Dutch hard cheeses (Gouda, Edam) was relatively high compared to most soft cheeses as produced in Mediterranean countries. This is in contrast to a recent study from the USA [ 22 ], in which soft cheeses were found to contain on average about twice as much menaquinones as hard cheeses. This demonstrates the necessity of having national databases for menaquinone content of food.…”

Dairy Fats and Cardiovascular Disease: Do We Really Need to Be Concerned?

“…Vitamin K 2 includes a range of vitamin K isoforms that differ structurally from vitamin K 1 also known as phylloquinones, which are mainly found in leafy green vegetables. Vitamin K 2 is the most biologically active form of vitamin K and it has a longer half-life than vitamin K 1 [ 36 , 218 , 219 ]. A growing body of evidence suggests that vitamin K has beneficial effects on cardiovascular health [ 220 , 221 , 222 , 223 ].…”

“…In comparison to other foods, fermented dairy and other animal products have a high content of vitamin K 2 . Fermented dairy products, in particular cheese, yoghurt and kefir contain vitamin K 2 [ 219 , 225 ], thus consumption of fermented dairy products may be beneficial for human cardiovascular health. Randomised trials have provided some evidence to support the beneficial effects of vitamin K 2 on bone health and some intervention trials that assessed vitamin K in conjunction with vitamin D have demonstrated positive results on cardiovascular-related outcomes [ 36 ].…”

Association of dietary vitamin K and risk of coronary heart disease in middle-age adults: the Hordaland Health Study Cohort

“…100 g, and that reduced-fat products contained 5%-22% of the vitamin K found in full-fat equivalents. 30 K2 in cheese originates from bacterial processes present at the start of the cheese-making process. 26 As different lactic acid bacteria are used in cheese making, a large variability in K2 content is found.…”

“…25 However, these recommendations may not be sufficient to attain complete carboxylation of extrahepatic vitamin K-dependent proteins. 26 27 Given the limited number of epidemiological studies, [18][19][20][21][22][23][24] and the fact that dietary vitamin K sources and content differ between countries, [28][29][30][31] further research is warranted. The purpose of the current study was to evaluate the association between intake of both K1 and K2 and subsequent CHD events among community-living middle-age adults in Norway.…”