Correlations among vitamin K intake, body fat, lipid profile and glucose homeostasis in adults and the elderly

ABSTRACT Objective Recent research has investigated the possible inverse relationship between vitamin K intake and body fat. In addition, an increasing number of studies are supporting a key role for this vitamin in improving lipid profile and insulin sensitivity and reducing the risk of type 2 diabetes mellitus, but little is known about what mechanisms would be involved. Thus, the objective of this study was to investigate the relationship between vitamin K intake (in the form of phylloquinone - PK), body fat, lipid profile and markers of glucose homeostasis in adults and the elderly. Subjects and methods A cross-sectional study with 298 participants (46% men) in the São Paulo Health Survey 2014-2015. Spearman correlations were performed to evaluate the associations between vitamin K intake and the biochemical and body composition measures. Results Among normal-weight male adults (n = 15), PK intake presented a positive correlation with the quantitative insulin sensitivity check index (QUICKI) (r = 0.525; p = 0.045). Among men with high fat mass index (FMI) (n = 101), PK intake had a negative correlation with homeostasis model assessment estimate for β-cell function (HOMA-β) (r = −0.227; p = 0.022). In women with high FMI (n = 122), PK intake had a negative correlation with HOMA-β (r = −0.199, p = 0.032) and insulin (r = −0.207, p = 0.026). No correlations were found between PK intake and lipid profile. Conclusions Our findings support a potential relationship among PK intake, body fat and markers of glucose homeostasis in adults and the elderly.

Warfarin drug interaction with vitamin K and other foodstuffs / Interacción de la droga warfarina con la vitamina K y otros productos alimenticios

Vitamin K is found in higher concentrations in dark green plant and in vegetable oils. The adequate intake of vitamin K is 90 and 120ug/day for adult elderly men and women, respectively. The main function of vitamin K is to act as an enzymatic cofactor for hepatic prothrombin synthesis, blood coagulation factors, and anticoagulant proteins. Prominent among the many available anticoagulants is warfarin, an antagonist of vitamin K, which exerts its anticoagulant effects by inhibiting the synthesis of vitamin K1 and vitamin KH2. From the beginning of the therapy it is necessary that the patients carry out the monitoring through the prothrombin time and the international normalized ratio. However, it is known that very low intake and/or fluctuations in vitamin K intake are as harmful as high consumption. In addition, other foods can interact with warfarin, despite their content of vitamin K. The aim of this study was to gather information on the drug interaction of warfarin with vitamin K and with dietary supplements and other foods.

La vitamina K se encuentra en concentraciones más altas en plantas de color verde oscuro y en aceites vegetales. La ingesta adecuada de vitamina K es de 90 y 120 ug/día para hombres y mujeres adultos mayores, respectivamente. La función principal de la vitamina K es actuar como un cofactor enzimático para la síntesis de protrombina hepática, factores de coagulación de la sangre y proteínas anticoagulantes. Entre los muchos anticoagulantes disponibles destaca la warfarina, un antagonista de la vitamina K, que ejerce sus efectos anticoagulantes al inhibir la síntesis de la vitamina K1 y la vitamina KH2. Desde el inicio de la terapia, es necesario que los pacientes realicen el monitoreo a través del tiempo de protrombina y la proporción normalizada internacional. Sin embargo, se sabe que una ingesta muy baja y/o fluctuaciones en la ingesta de vitamina K son tan dañinas como un consumo alto. Además, otros alimentos pueden interactuar con la warfarina, a pesar de su contenido de vitamina K. El objetivo de este estudio fue recopilar información sobre la interacción de los medicamentos de la warfarina con la vitamina K y con los suplementos dietéticos y otros alimentos.

Assessment of Dietary Intake of Vitamin K and Maximum Limits for Vitamin K in Food Supplements

The Norwegian Scientific Committee for Food and Environment (Vitenskapskomiteen for mat og miljø, VKM) has, at the request of the Norwegian Food Safety Authority (Mattilsynet; NFSA), evaluated the intake of vitamin K in the diet. VKM has also assessed the consequences of establishing maximum limits for vitamin K in food supplements at 100, 200, 300, 600 or 800 µg/day. The former maximum limit for vitamin K of 200 µg/day in food supplements was repealed 30 May 2017. Vitamin K is a fat-soluble vitamin required for the carboxylation of glutamic acid residues in proteins that regulate blood coagulation and bone metabolism. The naturally occurring forms of vitamin K present in food and supplements are phylloquinone (vitamin K1) mainly produced by plants, and a range of menaquinones (vitamin K2) mainly produced by bacteria. The chemical structure of vitamin K is characterised by a methylated naphtoquinone ring structure assumed to be responsible for its function, in addition to a side chain which differs in length and degree of saturation. Due to the varying side chains, the different forms of vitamin K are thought to behave differently with regard to absorption, metabolism, bioavailability and thereby also toxic potential. Dark green leafy vegetables are rich sources of phylloquinone. Meat and liver products provide menaquinone-4, the most common menaquinone in Western diets, while other menaquinones are found in fermented foods and cheese. An Adequate Intake (AI) of phylloquinone of 1 µg/kg body weight per day was set by the Scientific Committee on Food (SCF) in 1993 and maintained by the European Food Safety Authority (EFSA) in 2017. No dietary reference values (DRVs) have been established for menaquinones due to insufficient evidence. Furthermore, no tolerable upper intake levels (ULs) have been established for any form of vitamin K due to insufficient evidence, but previous reports stated that no adverse effects associated with vitamin K consumption from food or supplements had been reported in humans or animals. In 2003, the UK Expert Group on Vitamins and Minerals (EVM) proposed a guidance level (GL) for safe upper intake of supplemental phylloquinone of 1 mg/day in adults. The GL was set by applying an uncertainty factor of 10 for inter-individual variation to the supplemental dose of 10 mg/day that had been consumed by eight female athletes (age 20-44) for 30 days with no reported adverse effects. The UK expert group emphasised that GLs had been derived from limited data and were less secure than safe upper levels. This GL was supported by a double-blind randomised study cited in the Nordic Nutrition Recommendations (2012), in which 440 postmenopausal women with osteopenia received a daily supplement of 5 mg phylloquinone or placebo for up to four years with no difference in adverse events between the randomised groups. Corresponding GLs for children and adolescents have been derived by adjusting for reference body weights0.75 by Rasmussen et al. (2006). The distribution of intakes of vitamin K across age groups in Norway is not known, since food composition data is not available. However, habitual intakes in a representative sample of middle-aged and older adults in Western Norway were assessed in the population-based Hordaland Health Study 1997-2000, and revealed higher intakes than those estimated from dietary surveys in the other Nordic countries. Due to lack of representative estimates of vitamin K intakes in the Norwegian population, information on vitamin K intakes from other Nordic countries is included in the current opinion. This includes the distribution of vitamin K intakes in Sweden and Finland reported by EFSA, and the distribution of vitamin K intakes in Denmark, assessed by the Technical University of Denmark (DTU). In middle-aged and older Western Norwegians participating in the Hordaland Health Study 1997-2000, estimated mean intakes of total vitamin K (denoting the sum of K1+K2) ranged from 109 to 148 µg/day in four groups based on age and gender, while the 95-percentiles ranged from 261 to 329 µg/day. Average intakes of total vitamin K in the other Nordic countries are in the magnitude of 100 µg/day in adults, while 95-percentiles in adults are in the magnitude of 200 µg/day. To illustrate the consequences of establishing maximum limits for vitamin K at 100, 200, 300, 600 or 800 µg/day in food supplements, VKM has compared these levels to the age-specific GLs for supplemental phylloquinone proposed by EVM (2003). The GLs are: 1000 µg/day for adults, 870 µg/day at age 15-17 years, 670 µg/day at age 11-14 years, 500 µg/day at age 710 years, 370 µg/day at age 4-6 years and 270 µg/day at age 1-3 years. VKM concludes that: In adults and adolescents 15-17 years old, maximum limits of 100, 200, 300, 600 and 800 µg/day are below GL. In adolescents 11-14 years old, maximum limits of 100, 200, 300 and 600 µg/day are below GL while the maximum limit of 800 µg exceeds GL. In children 4-10 years old, maximum limits of 100, 200 and 300 µg/day are below GL while maximum limits of 600 µg/day and 800 µg/day exceeds GL. In children 1-3 years old, maximum limits of 100 µg/day and 200 µg/day are below GL while maximum limits of 300, 600 and 800 µg/day exceeds GL. VKM notes that the current conclusions apply to phylloquinone (vitamin K1) only, while there is insufficient evidence to appraise potential health consequences of maximum limits of menaquinones (vitamin K2). VKM emphasises that the current assessment of maximum limits for vitamin K in food supplements is merely based on published reports concerning upper levels from the IOM (2001, USA), SCF (2003, EU), EVM (2003, UK) and NNR (2012, Nordic countries). VKM has not conducted any systematic review of the literature for the current opinion, as this was outside the scope of the terms of reference from NFSA.

Vitamin K: content in food consumed in São Paulo, Brazil

ABSTRACT Recent research on Vitamin K has shown its importance in maintaining vascular and bone health. Brazilian food composition tables do not show phylloquinone content in national foods. These data are needed to obtain more reliable results in nutritional status assessment studies of individuals in relation to this vitamin as studies have shown a geographical influence in food phylloquinone content. This study aims to determine phylloquinone (Vitamin K1) levels in its most important source: dark green leaved vegetables. Several varieties of vegetables were purchased directly from CEAGESP (General Warehouse Company of São Paulo) at different times. Phylloquinone was extracted using organic solvents and quantified by High Performance Liquid Chromatography - HPLC. Results show the concentrations of phylloquinone in commonly consumed foodstuffs. In general, results showed variations with data from literature on the amount of Vitamin K in the plants analysed.

Effects of Vitamin K1 Supplementation on the Risk Factors to the Stroke and on Memory in Spontaneously Hypertensive Rats Stroke Prone (SHR-sp)

A number of risk factors have been associated to the stroke and many strategies have been proposed in order to control them as well. Vitamin K has been largely found in brain, which suggests a possible function at that tissue. This study aimed to evaluate the potential of this vitamin on the prevention of risk factors to stroke and on cognitive function on SHRSP rats. Twelve SHRSP males, 15 weeks old, were divided into two groups (n= 6 each), receiving the vehicle-coconut oil (control group) or 40 μg of phylloquinone (treated group) during 28 days. Biological parameters, systolic blood pressure and lipid profile were evaluated. Both groups were submitted to the neurological tasks. The data was treated by Student's t test and ANOVA one-way test being P<0.05 considered significant. The phylloquinone supplementation showed a statistically significant reduction in the treated group of all parameters of lipid profile and systolic blood pressure when compared to the control group. Neurological evaluation indicated a statistically significant improvement in the performance of long term memory tests in the treated group, without similar findings in the evaluation of short memory. In sum, phylloquinone supplementation was shown to modulated lipid profile and protect neuronal suffering in this model.

Effects of phylloquinone supplementation on lipid profile in women with rheumatoid arthritis: a double blind placebo controlled study

BACKGROUND/OBJECTIVES: Rheumatoid arthritis (RA) is associated with an excess mortality from cardiovascular disease which is likely attributed to an atherogenic lipid profile. Among nutritional factors vitamin K has been recently focused as a pivotal nutrient in improvement of lipid related markers. Thus, this study was designed to determine the effects of vitamin K on lipid profile in this disease. SUBJECTS/METHODS: Fifty eight patients with definitive RA were participated in the present double blind placebo controlled study. They were randomly allocated into two groups to receive vitamin K1 as phylloquinone [10 mg/day] (n = 30) or placebo pills (n = 28), for eight weeks. In order to control the effects of probable confounders dietary intakes, anthropometric measurements including weight and height, clinical status using disease activity score-28 (DAS-28), physical activity and anxiety status were evaluated at baseline. Moreover, serum levels of lipid related markers including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) were measured at baseline and at the end of intervention. RESULTS: There were no significant differences between the two groups regarding any of the baseline characteristics. After adjusting for some relevant confounders, in comparison between two groups, we observed no significant changes in lipid related markers at the end of intervention. Also, there was no significant difference between before and after intervention values within groups (P > 0.05). CONCLUSIONS: Function of vitamin K1 in lipid profile modification remains still controversial. This study showed that vitamin K1 has no effect on lipid profile in women with rheumatoid arthritis. Further studies with a longer follow-up are required to determine the effects of vitamin K on atherogenic lipid profile.

Effects of phylloquinone supplementation on lipid profile in women with rheumatoid arthritis: a double blind placebo controlled study

BACKGROUND/OBJECTIVES: Rheumatoid arthritis (RA) is associated with an excess mortality from cardiovascular disease which is likely attributed to an atherogenic lipid profile. Among nutritional factors vitamin K has been recently focused as a pivotal nutrient in improvement of lipid related markers. Thus, this study was designed to determine the effects of vitamin K on lipid profile in this disease. SUBJECTS/METHODS: Fifty eight patients with definitive RA were participated in the present double blind placebo controlled study. They were randomly allocated into two groups to receive vitamin K1 as phylloquinone [10 mg/day] (n = 30) or placebo pills (n = 28), for eight weeks. In order to control the effects of probable confounders dietary intakes, anthropometric measurements including weight and height, clinical status using disease activity score-28 (DAS-28), physical activity and anxiety status were evaluated at baseline. Moreover, serum levels of lipid related markers including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) were measured at baseline and at the end of intervention. RESULTS: There were no significant differences between the two groups regarding any of the baseline characteristics. After adjusting for some relevant confounders, in comparison between two groups, we observed no significant changes in lipid related markers at the end of intervention. Also, there was no significant difference between before and after intervention values within groups (P > 0.05). CONCLUSIONS: Function of vitamin K1 in lipid profile modification remains still controversial. This study showed that vitamin K1 has no effect on lipid profile in women with rheumatoid arthritis. Further studies with a longer follow-up are required to determine the effects of vitamin K on atherogenic lipid profile.

Estimation of vitamin K intake in Koreans and determination of the primary vitamin K-containing food sources based on the fifth Korean National Health and Nutrition Examination Survey (2010-2011)

There is little information on dietary vitamin K intake and nutritional status of daily requirements of vitamin K in Korea. The objective of this study was to investigate the vitamin K intake and major food sources of Vitamin K in Koreans. The survey data from the 2010-2011 Korean National Health and Nutrition Examination Survey of 7,792 subjects (aged 19-64 years) were examined. Total vitamin K intake was calculated from 24-hour dietary recall using a vitamin K food database, Computer Aided Nutritional analysis Program and the United States Department of Agriculture database. The geometric mean of vitamin K was estimated as 322.40 +/- 6.33 ug/day for men and 271.20 +/- 4.92 ug/day for women. Daily vitamin K intake increased significantly with age (p for trend < 0.001). The main food source of vitamin K was vegetables (72.84%), including cabbage kimchi (19.26%), spinach (17.38%), sesame leaves (7.11%), radish leaves (6.65%), spring onions (6.28%), and laver (4.82%), followed by seaweed, seasonings, and fat and oils. We observed that the vitamin K intake of Koreans was relatively higher than that reported by other studies in Western countries and differed depending on age.