Vitamin K (phylloquinone and menaquinones) in foods - Optimisation of extraction, clean-up and LC-ESI-MS/MS method for quantification

Vitamin K content of Australian-grown horticultural commodities

Vitamin K is a multi-function vitamin that has emerging roles in bone, brain and vascular health. Vitamin K composition data remain limited globally and Australia has lacked nationally representative data for vitamin K1 (phylloquinone) in horticultural commodities. Primary samples (n = 927) of 90 Australian-grown fruit, vegetable and nut commodities were purchased in three Australian cities. We measured vitamin K1/phylloquinone in duplicate in 95 composite samples using liquid chromatography with electrospray ionisation-tandem mass spectrometry. The greatest mean concentrations of vitamin K1/phylloquinone were found in kale (565 μg/100 g), baby spinach (255 μg/100 g) and Brussels sprouts (195 μg/100 g). The data contribute to the global collection of vitamin K food composition data. They add to the evidence that vitamin K1/phylloquinone concentrations vary markedly between geographic regions, supporting development of region-specific datasets for national food composition databases that do not yet contain data for vitamin K. Such data are needed globally.

Unveiling ferroptosis as a promising therapeutic avenue for colorectal cancer and colitis treatment

Ferroptosis is a novel type of regulated cell death (RCD) involving iron accumulation and lipid peroxidation. Since its discovery in 2012, various studies have shown that ferroptosis is associated with the pathogenesis of various diseases. Ferroptotic cell death has also been linked to intestinal dysfunction but can act as either a positive or negative regulator of intestinal disease, depending on the cell type and disease context. The continued investigation of mechanisms underlying ferroptosis provides a wealth of potential for developing novel treatments. Considering the growing prevalence of intestinal diseases, particularly colorectal cancer (CRC) and inflammatory bowel disease (IBD), this review article focuses on potential therapeutics targeting the ferroptotic pathway in relation to CRC and IBD.

Characterization of K-binding factor involved in water-soluble complex of menaquinone-7 produced by Bacillus subtilis natto

Vitamin Ks are expected to contribute bone and cardiovascular health. Especially, menaquinone-7 has a higher bioavailability and a longer half-life than other vitamin Ks in the human body. However, their low water-solubility limits their application. On the other hand, Bacillus subtilis natto produces a water-soluble complex, which comprises menaquinone-7 and peptides. The peptide named K-binding factor (KBF) has been reported as the main component of the complex. In the present, the structural characteristics of KBF were studied. Mass spectrometry showed significant peaks at m/z = 1050, while the previous PAGE suggested that molecular weight of KBF was ~ 3k. Amino acid analysis revealed that the 1k peptides were the various combinations of nine amino acids, among which Asx, Glx, Val, Leu and Met were found to be the most abundant. The peptides could serve as detergent properties. The 1k peptides could be isolated by reverse-phase high performance liquid chromatography. The bundle of three 1k detergent-like peptides would participate to the micelle structure containing menqauinone-7 inside. In conclusion, a basic unit of KBF would be the ~ 1k peptides, and the three basic unit assemble to the ~ 3k bundle, then the bundle form a water-soluble micelle including menqauinone-7 inside.

Vitamin K content of cheese, yoghurt and meat products in Australia

Vitamin K is vital for normal blood coagulation, and may influence bone, neurological and vascular health. Data on the vitamin K content of Australian foods are limited, preventing estimation of vitamin K intakes in the Australian population. We measured phylloquinone (PK) and menaquinone (MK) -4 to -10 in cheese, yoghurt and meat products (48 composite samples from 288 primary samples) by liquid chromatography with electrospray ionisation-tandem mass spectrometry. At least one K vitamer was found in every sample. The greatest mean (± standard deviation for foods sampled in multiple cities) concentrations of PK (4.9 µg/100 g), MK-4 (58 ± 9 µg/100 g) and MK-9 (8 ± 2 µg/100 g) were found in lamb liver, chicken leg meat and Cheddar cheese, respectively. Cheddar cheese (1.1 ± 0.3 µg/100 g) and cream cheese (1.0 µg/100 g) contained MK-5. MK-8 was found in Cheddar cheese only (4 ± 2 µg/100 g). As the K vitamer profile and concentrations appear to vary considerably by geographical location, Australia needs a vitamin K food composition dataset that is representative of foods consumed in Australia.

In vitro bioaccessibility of vitamin K (phylloquinone and menaquinones) in food and supplements assessed by INFOGEST 2.0 - vit K

Vitamin K describes a group of fat-soluble vitamers namely phylloquinone and menaquinones. The growing evidence for vitamin K's role beyond blood coagulation, and the possible differences between the vitamers are emerging. Knowledge of the content of menaquinones in different food matrixes and the potential differences in bioaccessibility between the vitamin K vitamers and food matrixes are limited. In this study, the bioaccessibility was assessed using the INFOGEST 2.0 static in vitro digestion model optimised by including a Danish standard meal. The presence of the standard meal was crucial to obtaining a robust and stable digestion model. The bioaccessibility of the Danish standard meal, water, vitamin K standards, vitamin K supplements, broccoli, spinach, natto, pasteurised whole egg and canola oil was assessed by three replications. The bioaccessibility was in the range 30%-102%. The lowest bioaccessibility was observed in broccoli while the highest bioaccessibility was found in egg and canola oil. No competition in the bioaccessibility between vitamin K vitamers and vitamin D was observed.

Content and Bioaccessibility of Vitamin K (Phylloquinone and Menaquinones) in Cheese

Vitamin K is a fat-soluble group of vitamers consisting of phylloquinone (PK) and menaquinones (MKs). To date, only a daily reference intake for PK is set; however, in the last decade, research studying the correlation between MKs intake and improvement of health in regards to cardiovascular diseases, bone metabolism, and chronic kidney disease has been conducted. MKs are synthesised by bacteria in the fermentation process of foods, e.g., cheeses. The content and bioaccessibility of vitamin K vitamers (PK, MK-4, MK-5, MK-6, MK-7, MK-8, MK-9, and MK-10) were assessed in eight different cheese products differing in ripening time, starter culture, fat content, and water content. The bioaccessibility was assessed using the static in vitro digestion model INFOGEST 2.0. Variation of the vitamin K content (<0.5 μg/100 g-32 μg/100 g) and of the vitamin K bioaccessibility (6.4-80%) was observed. A longer ripening time did not necessarily result in an increase of MKs. These results indicate that the vitamin K content and bioaccessibility differs significantly between different cheese products, and the ripening time, starter culture, fat content, and water content cannot explain this difference.