Phylloquinone Intakes and Food Sources and Vitamin K Status in a Nationally Representative Sample of Irish Adults

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.

Personalized Medicine in Mitochondrial Health and Disease: Molecular Basis of Therapeutic Approaches Based on Nutritional Supplements and Their Analogs

Mitochondrial diseases (MDs) may result from mutations affecting nuclear or mitochondrial genes, encoding mitochondrial proteins, or non-protein-coding mitochondrial RNA. Despite the great variability of affected genes, in the most severe cases, a neuromuscular and neurodegenerative phenotype is observed, and no specific therapy exists for a complete recovery from the disease. The most used treatments are symptomatic and based on the administration of antioxidant cocktails combined with antiepileptic/antipsychotic drugs and supportive therapy for multiorgan involvement. Nevertheless, the real utility of antioxidant cocktail treatments for patients affected by MDs still needs to be scientifically demonstrated. Unfortunately, clinical trials for antioxidant therapies using α-tocopherol, ascorbate, glutathione, riboflavin, niacin, acetyl-carnitine and coenzyme Q have met a limited success. Indeed, it would be expected that the employed antioxidants can only be effective if they are able to target the specific mechanism, i.e., involving the central and peripheral nervous system, responsible for the clinical manifestations of the disease. Noteworthily, very often the phenotypes characterizing MD patients are associated with mutations in proteins whose function does not depend on specific cofactors. Conversely, the administration of the antioxidant cocktails might determine the suppression of endogenous oxidants resulting in deleterious effects on cell viability and/or toxicity for patients. In order to avoid toxicity effects and before administering the antioxidant therapy, it might be useful to ascertain the blood serum levels of antioxidants and cofactors to be administered in MD patients. It would be also worthwhile to check the localization of mutations affecting proteins whose function should depend (less or more directly) on the cofactors to be administered, for estimating the real need and predicting the success of the proposed cofactor/antioxidant-based therapy.

Perspective: Evidence before Enthusiasm-A Critical Review of the Potential Cardiovascular Benefits of Vitamin K

A protective role for vitamin K in cardiovascular disease (CVD), a leading cause of morbidity and mortality, has been proposed because vitamin K-dependent proteins, such as matrix Gla (γ-carboxyglutamic acid) protein (MGP), are present in vascular tissue. MGP functions as a vascular calcification inhibitor-but only when it is carboxylated, which requires vitamin K. There is more than one naturally occurring form of vitamin K. Phylloquinone (vitamin K1) is found in plant-based foods, whereas menaquinones (vitamin K2) are a class of vitamin K compounds found in animal-based and fermented foods. Phylloquinone and menaquinones are capable of carboxylating MGP and other vitamin K-dependent proteins. In rodent models, high intakes of either phylloquinone or menaquinone reduced vascular calcification. Evidence of the relative importance of phylloquinone and menaquinone to CVD in humans is limited and controversial. In some observational studies, higher dietary menaquinone intake, but not phylloquinone intake, was associated with less coronary artery calcification (a subclinical manifestation of CVD) and a lower risk for clinical CVD events. These findings have led to claims that menaquinones have unique cardiovascular health benefits compared with phylloquinone. However, this claim is not supported by the results of the limited number of intervention trials conducted to date. The purpose of this review is to evaluate the strengths and limitations of the available evidence regarding the role of vitamin K in vascular calcification, CVD, and mortality.

Ball ME, McDonald E, Hull GLJ, Danaher M, Cashman KD. Biofortification of Chicken Eggs with Vitamin K-Nutritional and Quality Improvements

National nutrition surveys have shown that over half of all adults in Ireland, the United Kingdom (UK), and the United States of America (USA) have low vitamin K intakes. Thus, dietary strategies to improve vitamin K intakes are needed, and vitamin K biofortification of food may be one food-based approach. The primary aim of our study was to establish whether increasing the vitamin K3 content of hen feed can increase the vitamin K content of eggs, and the secondary aims were to examine the effects on hen performance parameters, as well as egg and eggshell quality parameters. A 12 week hen feeding trial was conducted in which Hyline chickens were randomized into four treatment groups (n = 32/group) and fed diets containing vitamin K3 (as menadione nicotinamide bisulfite) at 3 (control), 12.9, 23.7, and 45.7 mg/kg feed. Vitamin K1, menaquinone (MK)-4, MK-7, and MK-9 were measured in raw whole eggs via a liquid chromatography tandem mass spectrometry method. MK-4 was the most abundant form of vitamin K (91-98%) found in all eggs. Increasing the vitamin K3 content of hen feed over the control level significantly (p < 0.001) enhanced the MK-4 content of eggs (mean range: 46-51 µg/100 g, representing ~42-56% of US Adequate Intake values). Vitamin K biofortification also led to significant (p < 0.05) increases in the yellowness of egg yolk and in eggshell weight and thickness, but no other changes in egg quality or hen performance parameters. In conclusion, high-quality vitamin K-biofortified eggs can be produced with at least double the total vitamin K content compared to that in commercially available eggs.

Modelling the impact of mandatory folic acid fortification of bread or flour in Ireland on the risk of occurrence of NTD-affected pregnancies in women of childbearing age and on risk of masking vitamin B12 deficiency in older adults

PURPOSE

The rate of neural tube defects (NTDs) in Europe has remained similar since the 1990s despite folic acid supplement recommendations (400 µg/day) for women of childbearing age. Mandatory folic acid fortification of staple foods has proved effective for reducing the prevalence of NTDs in over 80 countries. This study estimated the impact of addition of folic acid to bread or flour in the Republic of Ireland on reducing the risk of occurrence of NTD-affected pregnancies and the possible risk of masking (undiagnosed) vitamin B₁₂ deficiency in older adults.

METHODS

Analyses were based on the Irish National Adult Nutrition Survey (2008-2010). Folic acid fortification was modelled using DaDiet© software. Estimates were made of the increase in average daily folic acid intake in women (18-50 years) and the risk of exceeding the tolerable upper intake level (UL) of 1000 µg for folic acid in adults over 50 years of age.

RESULTS

The fortification scenarios examined would reduce the risk of NTD-affected pregnancies by 8-32%, corresponding to an increase of 39-152 μg in the mean daily folic acid intake of WCBA. The risk of masking anaemia associated with vitamin B₁₂ deficiency in older adults would be negligible as the probability of exceeding the UL for folic acid, even by a small amount, is very low (≤ 0.2%).

CONCLUSIONS

These levels of addition of folic acid to bread or flour would effectively reduce the risk of NTDs while allowing safe consumption of folic acid at current levels from other fortified foods and supplements.

Vitamin K Status in Women of Childbearing Years Before or After Bariatric Surgery

BACKGROUND

Vitamin K adequacy has not been widely studied before or after bariatric surgery. Reports of babies born with intracranial bleeds to women after bariatric surgery make this an important vitamin to study in women of childbearing years.

OBJECTIVES

The aim of this study was to assess the functional vitamin K status in 2 groups of women of childbearing age, 1 group seeking bariatric surgery and 1 group post Roux-en-Y gastric bypass (RYGB).

METHODS

In a cross-sectional design, 40 women [19 presurgical and 21 post-RYGB (6-18 mo following surgery)], aged 18-40 y, completed the study. Participants provided a 3-d food intake record and a list of dietary supplements routinely taken. Participants then underwent a commercially available test to measure des-γ-carboxyprothrombin (DCP) concentration as a measure of functional vitamin K status.

RESULTS

Independent-samples t tests (P < 0.05) indicated that there was no significant difference [Sig (2-tailed) 0.821] between the DCP concentrations of the presurgical group and those of the post-RYGB group (mean ± SD DCP: 0.3 ± 0.1 and 0.4 ± 0.2 ng/mL, respectively). Vitamin K intake from food (248 ± 227 and 210 ± 239 μg) and supplements (13 ± 31 and 750 ± 271 μg) showed no linear correlation to DCP (presurgical group: 0.25 and -0.15, respectively; post-RYGB group: 0.13 and 0.05, respectively). Vitamin K intakes for both groups were above the current Institute of Medicine's recommended 90 μg/d for women. Bivariate correlation was conducted on other independent variables with only current BMI for the post-RYGB group having a moderate negative correlation to DCP (-0.54, P < 0.05). No correlation with statistical significance was found between other variables and DCP.

CONCLUSIONS

Although the American Society for Metabolic and Bariatric Surgery recommends DCP as a test to determine vitamin K adequacy, no published studies in pre- or post-RYGB patients have been performed with the current commercially available test, which is not FDA approved as a vitamin K biomarker. Previous studies reporting vitamin K inadequacies based on DCP utilized a different assay than the one currently available. Due to the importance of ensuring adequate maternal concentrations of vitamin K after bariatric surgery in order to prevent intracranial bleeding in babies, more research is needed to determine suitable vitamin K measures.

Vitamin K status and inflammation are associated with cognition in older Irish adults

Studies have shown associations between reduced vitamin K status and poor cognitive function. However, despite this apparent link, direct studies measuring cognitive function, vitamin K status and inflammation are lacking. In the current study, The ELDERMET cohort was investigated to identify associations between cognition, vitamin K status and inflammation. The primary aim of the ELDERMET study was to investigate the relationship between gut bacteria, diet, lifestyle and health in 500 older Irish adults. Significant differences in serum phylloquinone, dietary phylloquinone and inflammatory markers were found across varying levels of cognitive function, after controlling for sex, age, body mass index (BMI), triglycerides and blood pressure. In addition, significantly higher levels of dietary phylloquinone were found in those with better cognition compared to those with the poorest function. Higher levels of inflammatory were also associated with poor cognition. Furthermore, both dietary and serum phylloquinone were significant independent predictors of good cognitive function, after controlling for confounders. This study highlights the importance of dietary vitamin K as a potentially protective cognitive factor; it also provides evidence for the correlation between cognition and inflammation. Strategies should be devised by which elderly populations can access rich dietary sources of phylloquinone to maintain cognition.

Vegetables and Mixed Dishes Are Top Contributors to Phylloquinone Intake in US Adults: Data from the 2011-2012 NHANES

Background: Phylloquinone is the most abundant form of vitamin K in US diets. Green vegetables are considered the predominant dietary source of phylloquinone. As our food supply diversifies and expands, the food groups that contribute to phylloquinone intake are also changing, which may change absolute intakes. Thus, it is important to identify the contributors to dietary vitamin K estimates to guide recommendations on intakes and food sources.Objective: The purpose of this study was to estimate 1) the amount of phylloquinone consumed in the diet of US adults, 2) to estimate the contribution of different food groups to phylloquinone intake in individuals with a high or low vegetable intake (≥2 or <2 cups vegetables/d), and 3) to characterize the contribution of different mixed dishes to phylloquinone intake.Methods: Usual phylloquinone intake was determined from NHANES 2011-2012 (≥20 y old; 2092 men and 2214 women) and the National Cancer Institute Method by utilizing a complex, stratified, multistage probability-cluster sampling design.Results: On average, 43.0% of men and 62.5% of women met the adequate intake (120 and 90 μg/d, respectively) for phylloquinone, with the lowest self-reported intakes noted among men, especially in the older age groups (51-70 and ≥71 y). Vegetables were the highest contributor to phylloquinone intake, contributing 60.0% in the high-vegetable-intake group and 36.1% in the low-vegetable-intake group. Mixed dishes were the second-highest contributor to phylloquinone intake, contributing 16.0% in the high-vegetable-intake group and 28.0% in the low-vegetable-intake group.Conclusion: Self-reported phylloquinone intakes from updated food composition data applied to NHANES 2011-2012 reveal that fewer men than women are meeting the current adequate intake. Application of current food composition data confirms that vegetables continue to be the primary dietary source of phylloquinone in the US diet. However, mixed dishes and convenience foods have emerged as previously unrecognized but important contributors to phylloquinone intake in the United States, which challenges the assumption that phylloquinone intake is a marker of a healthy diet. These findings emphasize the need for the expansion of food composition databases that consider how mixed dishes are compiled and defined.

Dietary reference values for vitamin K

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derives dietary reference values (DRVs) for vitamin K. In this Opinion, the Panel considers vitamin K to comprise both phylloquinone and menaquinones. The Panel considers that none of the biomarkers of vitamin K intake or status is suitable by itself to derive DRVs for vitamin K. Several health outcomes possibly associated with vitamin K intake were also considered but data could not be used to establish DRVs. The Panel considers that average requirements and population reference intakes for vitamin K cannot be derived for adults, infants and children, and therefore sets adequate intakes (AIs). The Panel considers that available evidence on occurrence, absorption, function and content in the body or organs of menaquinones is insufficient, and, therefore, sets AIs for phylloquinone only. Having assessed additional evidence available since 1993 in particular related to biomarkers, intake data and the factorial approach, which all are associated with considerable uncertainties, the Panel maintains the reference value proposed by the Scientific Committee for Food (SCF) in 1993. An AI of 1 μg phylloquinone/kg body weight per day is set for all age and sex population groups. Considering the respective reference body weights, AIs for phylloquinone are set at 70 μg/day for all adults including pregnant and lactating women, at 10 μg/day for infants aged 7-11 months, and between 12 μg/day for children aged 1-3 years and 65 μg/day for children aged 15-17 years.