Japanese fermented soybean food as the major determinant of the large geographic difference in circulating levels of vitamin K2: possible implications for hip-fracture risk

Increasing evidence indicates a significant role for vitamin K in bone metabolism and osteoporosis. In this study, we found a large geographic difference in serum vitamin K2 (menaquinone-7; MK-7) levels in postmenopausal women. Serum MK-7 concentrations were 5.26 +/- 6.13 ng/mL (mean +/- SD) in Japanese women in Tokyo, 1.22 +/- 1.85 in Japanese women in Hiroshima, and 0.37 +/- 0.20 in British women. We investigated the effect of Japanese fermented soybean food, natto, on serum vitamin K levels. Natto contains a large amount of MK-7 and is eaten frequently in eastern (Tokyo) but seldom in western (Hiroshima) Japan. Serum concentrations of MK-7 were significantly higher in frequent natto eaters, and natto intake resulted in a marked, sustained increase in serum MK-7 concentration. We analyzed the relation between the regional difference in natto intake and fracture incidence. A statistically significant inverse correlation was found between incidence of hip fractures in women and natto consumption in each prefecture throughout Japan. These findings indicate that the large geographic difference in MK-7 levels may be ascribed, at least in part, to natto intake and suggest the possibility that higher MK-7 level resulting from natto consumption may contribute to the relatively lower fracture risk in Japanese women.     

Nutritional effects of gamma-glutamyl carboxylase gene polymorphism on the correlation between the vitamin K status and gamma-carboxylation of osteocalcin in young males

Vitamin K is a cofactor for gamma-glutamyl carboxylase (GGCX), which is an essential enzyme for the gamma-carboxylation of vitamin K-dependent proteins such as osteocalcin (OC). Associations among dietary vitamin K intake, vitamin K status, and bone metabolism have not been thoroughly investigated. Recently, it has been reported that single nucleotide polymorphisms of GGCX (R325Q, 974G>A) were associated with age-related bone loss and the kinetic affinity for the substrate. In the present study, we investigated the associations among dietary vitamin K intake, the level of serum vitamin K, and the ratio of undercarboxylated OC (ucOC) to intact OC. The subjects were 60 healthy young male volunteers (mean age, 22.6 y; standard deviation, 1.6). Dietary nutrient intake was assessed by consecutive individual 3-d food records taken before the day of blood examinations. Serum concentrations of vitamin K (phylloquinone: PK, menaquinone 4: MK-4, and menaquinone 7: MK-7), ucOC, and intact OC were measured. All subjects were genotyped for polymorphism (R325Q) presence. Dietary vitamin K intake from vegetables was significantly correlated with the level of serum PK, and vitamin K intake from fermented beans, natto, was also significantly correlated with the level of serum MK-7. The ratio of ucOC to intact OC showed a negative association with the total vitamin K intake (r=-0.331, p=0.010) and serum MK-7 (r=-0.394, p=0.002). Interestingly, grouped by the GGCX genotype, a significant interaction between the ratio of ucOC to intact OC with serum MK-7 was observed in 325R homozygotes (r=-0.572, p=0.003), but not in heterozygotes, nor in 325Q homozygotes. This is the first report to suggest the effects of the single nucleotide polymorphism R325Q in the GGCX gene on the correlation between the level of serum MK-7 and gamma-carboxylation of serum OC.     

Influence of vitamin K on anticoagulant therapy depends on vitamin K status and the source and chemical forms of vitamin K

Warfarin therapy requires close monitoring to avoid excessive bleeding and to maintain the effective therapeutic concentration assessed with the internationalized ratio (INR). High vitamin K intake can decrease the therapeutic effectiveness of warfarin, while poor vitamin K status appears to increase the sensitivity to small changes in vitamin K intake, especially from supplements. Very large amounts of vitamin K from a single meal with vegetables (400 g of vegetables with 700 to 1500 microg of vitamin K1) can measurably change INR, but occasional typical servings (<100 g) would probably have little lasting impact on INR. Warfarin requirements may change in those altering their intake of dark-green vegetables. The 2005 Dietary Guidelines for Americans recommends 3 cups/week of dark-green vegetables, which contain about 100 to 570 microg/serving of vitamin K1. Less well-known sources and chemical forms of vitamin K, such as MK-7 in natto (a fermented Japanese product), also measurably influence INR. Additional research is needed in warfarin-treated patients to fully quantify the interactions among various sources and chemical forms of vitamin K, age, genotype, and other factors.     

Phylloquinone (vitamin K1) intakes and food sources in 18-64-year-old Irish adults

Dietary vitamin K1 (phylloquinone) levels that are sufficient to maintain normal blood coagulation may be sub-optimal for bone, and habitual low dietary intakes of vitamin K may have an adverse effect on bone health. The objective of the present study was to measure the intake and adequacy of phylloquinone intake and the contribution of foods to phylloquinone intake in a nationally representative sample of Irish adults. The North/South Ireland Food Consumption Survey database was used, which contains data collected using a 7 d food diary in a randomly selected sample of Irish adults aged 18-64 years (n 1379; 662 men and 717 women). Phylloquinone intakes were estimated using recently compiled food composition data for phylloquinone. The mean daily intake of phylloquinone from food sources was 79 (SD 44) microg. Intakes were significantly higher (P<0.001) in men than in women at levels of 84 and 75 microg/d. The main contributors to phylloquinone intakes were vegetables (48 %), particularly green vegetables (26 %). Potatoes (including chipped and fried potatoes), dairy products and fat spreads contributed 10 % each and meat contributed 8 %. In men, social class and smoking status influenced phylloquinone intakes. Of the population, 52 % had phylloquinone intakes below 1 microg/kg body weight and only 17 % of men and 27 % of women met the US adequate intakes of 120 and 90 microg/d, respectively. The present study shows that habitual phylloquinone intakes in Irish adults are low, which may have implications for bone health.     

Intake and sources of phylloquinone (vitamin K1): variation with socio-demographic and lifestyle factors in a national sample of British elderly people

Intake and sources of phylloquinone (vitamin K1) were examined according to socio-demographic and lifestyle factors in free-living British people aged 65 years and over, from the 1994-5 National Diet and Nutrition Survey. Complete 4-d weighed dietary records were obtained from 1152 participants living in private households. Using newly-available, mainly UK-specific food content data, the weighted geometric mean intake of phylloquinone was estimated at 65 (95 % CI 62, 67) microg/d for all participants, with higher intakes in men than in women (70 v. 61 microg/d respectively, P<0.01). The mean nutrient densities of phylloquinone intake were 9.3 and 10.5 microg/MJ for men and women respectively (P<0.01), after adjusting for age group, region and smoking status. Of all the participants, 59 % had phylloquinone intakes below the current guideline for adequacy of 1 microg/kg body weight per d. Participants aged 85 years and over, formerly in manual occupations, or living in Scotland or in northern England reported lower phylloquinone intakes than their comparative groups. Overall, vegetables contributed 60 % of total phylloquinone intake, with cooked green vegetables providing around 28 % of the total. Dietary supplements contributed less than 0.5 % of phylloquinone intake. Participants living in northern England or in Scotland, in particular, derived less phylloquinone from vegetables than those living in southern England.     

Deficient dietary vitamin K intake among elderly nursing home residents in Hong Kong

There is strong evidence supporting the importance of vitamin K in bone health and the aetiological role of vitamin K deficiency in osteoporosis. In view of the common occurrence of osteoporosis among older subjects in Hong Kong, we have studied the dietary vitamin K intakes in 100 residents of a nursing home (43 men, 57 women; median age 81.0 years) and 88 free-living subjects attending a day care centre (13 men, 75 women; median age 71.5 years). The subjects were interviewed and the average vitamin K intake in the preceding week was estimated, using a diet recall questionnaire modified from our previous surveys of dietary patterns in local Chinese people. The median vitamin K intake was much lower in nursing home residents than in free-living subjects (4.50 vs 488.09 microg/day or 0.13 vs 8.74 microg/kg/day, P<0.001). An intake that was below the recommended daily intake was far more common among nursing home residents (86.0 vs 11.4%, P < 0.001). Among nursing home residents, there was a negative correlation between age and vitamin K intake (r = -0.217, P = 0.030), but there was a positive correlation between body weight and vitamin K intake (r = 0.244, P = 0.015). No such relationship was seen among free-living subjects. Elderly nursing home residents in this study generally had a poor dietary vitamin K intake and might therefore be predisposed to osteoporosis. The importance of green leafy vegetables as a rich source of vitamin K should be emphasised.     

Dietary intake and major source foods of vitamin E among Koreans: findings of the Korea National Health and Nutrition Examination Survey 2016–2019

BACKGROUND/OBJECTIVESVitamin E is essential for health, and although vitamin E deficiency seems rare in humans, studies on estimates of dietary intake are lacking. This study aimed to estimate dietary vitamin E intake, evaluate dietary adequacy of vitamin E, and detail major food sources of vitamin E in the Korean population.SUBJECTS/METHODSThis study used data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016–2019. Individuals aged ≥ 1 year that participated in a nutrition survey (n = 28,418) were included. Dietary intake was assessed by 24-h recall and individual dietary vitamin E intake was estimated using a newly established vitamin E database. Dietary adequacy was evaluated by comparing dietary intake with adequate intake (AI) as defined by Korean Dietary Reference Intakes 2020.RESULTSFor all study subjects, mean daily total vitamin E intake was 7.00 mg α-tocopherol equivalents, which was 61.6% of AI. The proportion of individuals that consumed vitamin E at above the AI was 12.9%. Inadequate intake was observed more in females, older individuals, rural residents, and those with a low income. Mean daily intakes of tocopherol (α-, β-, γ-, and δ-forms) and tocotrienol were 6.02, 0.30, 6.19, 1.63, and 1.61 mg, respectively. The major food groups that contributed to total dietary vitamin E intake were grains (22.3%), seasonings (17.0%), vegetables (15.3%), and fish, and shellfish (7.4%). The top 5 individual food items that contributed to total vitamin E intake were baechu kimchi, red pepper powder, eggs, soybean oil, and rice.CONCLUSIONSThis study shows that mean dietary vitamin E intake by Koreans did not meet the reference adequate intake value. To better understand the status of vitamin E intake, further research is needed that considers intake from dietary supplements.     

Comparative dietary intake and sources of phylloquinone (vitamin K1) among British adults in 1986-7 and 2000-1

Using data from 7 d weighed dietary records, dietary intake and sources of phylloquinone (vitamin K1) were examined by socio-demographic and lifestyle factors in 1916 participants aged 16-64 years from the 1986-7 Dietary and Nutritional Survey of British Adults, and 1423 participants aged 19-64 years from the 2000-1 National Diet and Nutrition Survey. Using UK-specific food content data, geometric mean phylloquinone intakes were estimated as 72 (95% CI 70, 74) and 67 (95% CI 65, 69) microg/d in 1986-7 and 2000-1 respectively (P<0.001). In 1986-7, 47% of participants had phylloquinone intakes below the UK guideline for adequacy (> or =1 microg/kg body weight per d), compared with 59% in 2000-1 (P<0.001). In both surveys, daily phylloquinone intake was higher among men than women and increased significantly with age. Participants of manual occupational social class, or who were smokers, had lower phylloquinone intake than their counterparts. Participants living in Scotland and northern England had lower phylloquinone intake than those living elsewhere in mainland Britain, particularly in 1986-7 when the contribution from vegetables was also lower than elsewhere. However, by 2000-1 this regional difference was no longer significant. Overall, vegetables contributed 63% of phylloquinone intake in 1986-7 and 60% in 2000-1, with cooked leafy green vegetables (LGV) providing 23 and 19% respectively. In both surveys, the contribution of vegetables (cooked LGV in particular) was directly associated with age. These data show a decrease in phylloquinone intake from 1986-7 to 2000-1, mainly owing to lower consumption of cooked LGV.     

Age and dietary form of vitamin K affect menaquinone-4 concentrations in male Fischer 344 rats

Phylloquinone, the primary dietary form of vitamin K, is converted to menaquinone-4 (MK-4) in certain tissues. MK-4 may have tissue-specific roles independent of those traditionally identified with vitamin K. Fischer 344 male rats of different ages (2, 12, and 24 mo, n = 20 per age group) were used to compare the conversion of phylloquinone to MK-4 with an equivalent dose of another dietary form of vitamin K, 2',3'-dihydrophylloquinone. Rats were age- and diet-group pair-fed phylloquinone (198 +/- 9.0 microg/kg diet) or dihydrophylloquinone (172 +/- 13.0 microg/kg diet) for 28 d. MK-4 was the primary form of vitamin K in serum, spleen, kidney, testes, bone marrow, and brain myelin fractions, regardless of age group. MK-4 concentrations were significantly lower in kidney, heart, testes, cortex (myelin), and striatum (myelin) in the dihydrophylloquinone diet group compared with the phylloquinone diet group (P < 0.05). The MK-4 concentrations in 2-mo-old rats were lower in liver, spleen, kidney, heart, and cortex (myelin) but higher in testes compared with 24-mo-old rats (P < 0.05). However, there were no age-specific differences in MK-4 concentrations among the rats fed the 2 diets. These data suggest that dihydrophylloquinone, which differs from phylloquinone in its side phytyl chain, is absorbed but its intake results in less MK-4 in certain tissues. Dihydrophylloquinone may be used in models for the study of tissue-specific vitamin K deficiency.     

Difference in the metabolism of vitamin K between liver and bone in vitamin K-deficient rats

The difference between vitamin K metabolism in the liver and that in the bone of vitamin K-deficient rats was examined. After 17 d administration of vitamin K-deficient food, vitamin K in the liver was almost depleted, and prothrombin time (PT) was prolonged. Serum total osteocalcin level was slightly decreased by vitamin K deficiency, whereas serum undercarboxylated osteocalcin level did not change. The level of menaquinone (MK)-4 as well as that of phylloquinone was decreased, but approximately 40 % of the initial level still existed in the femur after the 17 d period. A single-dose administration of vitamin K (250 nmol/kg body weight) markedly increased vitamin K level in the liver but not in the femur. These results suggest that the turnover of vitamin K in the bone is slower than that in the liver, and bone metabolism may be little affected by the short period of intake of vitamin K-deficient food. However, intake of a larger amount of vitamin K is required for its accumulation in the bone than in the liver. Furthermore, the counteracting effect of MK-7 on prolonged PT in vitamin K-deficient rats was found to be higher than phylloquinone or MK-4.     

Food and nutrient intake in East and West Germany, 8 years after the reunification--The German Nutrition Survey 1998

OBJECTIVE: To explore differences in food and nutrient intake as well as cardiovascular risk factors between the eastern and western parts of Germany in 1998 and to compare food consumption information between 1991 and 1998. DESIGN AND SUBJECTS: In all, 4030 people, aged 18-79 y, sampled from the East and West parts of Germany participated in the German Nutrition Survey (1998) by completing dietary histories and being assessed for cardiovascular risk factors. In a separate analysis, two food frequency data sets were compared from National Health Surveys conducted in 1991 (n = 7466) and in 1998 (n = 4556). RESULTS: In 1998, East Germans consumed more bread, fruit, fish, sausage, offal, and men additionally more cakes/cookies, beer and soft drinks than West Germans. They consumed less cereals, pasta, sweets, leafy vegetables, tea and drinking water, and men less vegetables and wine and women less pastry/crackers, potatoes and animal fat compared with their counterparts in West Germany. East Germans had a higher intake of total vitamin A, retinol, vitamin D, vitamin B12 and chloride, and in addition men of alcohol, and women of monosaccharides. They had a lower intake of total water, vitamin K, calcium, magnesium and manganese, and men of linoleic acid, and women of vitamin E than their West German counterparts. In East Germany, higher mean systolic blood pressure, and total and high-density lipoprotein cholesterol concentrations were found in men, and a lower mean total serum cholesterol concentration found in women compared with West Germany. CONCLUSION: Differences in food intake between the eastern and western parts of Germany still existed in 1998, although these differences were smaller than those observed 1 y after the reunification.     

Vitamin K intake and bone mineral density in women and men

BACKGROUND: Low dietary vitamin K intake has been associated with an increased risk of hip fracture in men and women. Few data exist on the association between dietary vitamin K intake and bone mineral density (BMD). OBJECTIVE: We studied cross-sectional associations between self-reported dietary vitamin K intake and BMD of the hip and spine in men and women aged 29-86 y. DESIGN: BMD was measured at the hip and spine in 1112 men and 1479 women (macro x +/- SD age: 59 +/- 9 y) who participated in the Framingham Heart Study (1996-2000). Dietary and supplemental intakes of vitamin K were assessed with the use of a food-frequency questionnaire. Additional covariates included age, body mass index, smoking status, alcohol use, physical activity score, and menopause status and current estrogen use among the women. RESULTS: Women in the lowest quartile of vitamin K intake (macro x: 70.2 microg/d) had significantly (P < or = 0.005) lower mean (+/- SEM) BMD at the femoral neck (0.854 +/- 0.006 g/cm(2)) and spine (1.140 +/- 0.010 g/cm(2)) than did those in the highest quartile of vitamin K intake (macro x: 309 microg/d): 0.888 +/- 0.006 and 1.190 +/- 0.010 g/cm(2), respectively. These associations remained after potential confounders were controlled for and after stratification by age or supplement use. No significant association was found between dietary vitamin K intake and BMD in men. CONCLUSIONS: Low dietary vitamin K intake was associated with low BMD in women, consistent with previous reports that low dietary vitamin K intake is associated with an increased risk of hip fracture. In contrast, there was no association between dietary vitamin K intake and BMD in men.     

Vitamin K supplementation does not prevent bone loss in ovariectomized Norway rats

Background

Despite plausible biological mechanisms, the differential abilities of phylloquinone (PK) and menaquinones (MKn) to prevent bone loss remain controversial. The objective of the current study was to compare the effects of PK, menaquinone-4 (MK-4) and menaquinone-7 (MK-7) on the rate of bone loss in ovariectomized (OVX) Norway rats. A secondary aim was to compare the effects of vitamin K with those of bisphosphonates (BP) on bone loss.

Methods

Rats (n = 96) were randomized to 6 dosing groups [n = 16/group; Sham; OVX; OVX + BP (100 ??g/kg/100 ??g/mL saline sc); OVX + PK; OVX + MK-4; and OVX + MK-7] for 6 wk. Equimolar daily doses of 107 mg PK/kg, 147 mg MK-4/kg, and 201 mg MK-7/kg diet were provided.

Results

BP significantly increased bone strength and bone mineral density (BMD) vs. OVX (P < 0.05). However, PK, MK-4 or MK-7 did not change bone strength or BMD compared to the OVX group. Whereas supplementation of PK, MK-4 and MK-7 increased serum and tibia concentrations of each respective form, PK concentrations were consistently higher despite equimolar intakes.

Conclusion

PK, MK-4, and MK-7 do not appear to prevent bone loss in OVX rats when administered concurrent with adequate intake of other nutrients.     

Development of a self-assessment instrument to determine daily intake and variability of dietary vitamin K

OBJECTIVE: To develop and validate a brief, self-assessment instrument (K-Card) to determine daily variations in dietary vitamin K1 (phylloquinone) intake for use in patients receiving oral warfarin anticoagulant therapy. METHODS: The K-Card was designed to include a checklist of selected common foods and beverages providing > or = 5 microg vitamin K per serving in American diets and items with lower vitamin K content typically consumed in quantities which contribute significantly to total vitamin K intake. The K-Card was validated against records of weighed food intake from thirty-six healthy volunteers, 20 to 40 and 60 to 80 years of age, whose phylloquinone intakes and plasma concentrations had been previously measured by the Metabolic Research Unit, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA USA. Future use of the K-Card by patients was simulated by a single investigator using 108 one-day weighed food records to estimate phylloquinone intakes. Dietary phylloquinone calculated from the K-Card was compared to the values of phylloquinone intake from the diet records collected on the same days, and to fasting plasma phylloquinone concentrations obtained from the same individuals on the following day. RESULTS: The mean dietary phylloquinone intake (+/- SEM) was 138.8 +/- 15.7 microg for the K-Cards compared to 136.0 +/- 15.8 microg for the diet records (p = 0.067). Bland-Altman limits of agreement between quantities of dietary phylloquinone calculated from the K-Card and values obtained from the weighed food records were +/- 38 microg. CONCLUSION: In this simulation, the K-Card provided an accurate estimate of dietary phylloquinone intake and therefore deserves further testing for use by patients receiving coumarin-based anticoagulant therapy to determine whether variability in dietary patterns contributes to disruptions in anticoagulant drug efficacy and safety.     

Association of hip fracture incidence and intake of calcium,magnesium, vitamin D,and vitamin K

Objective To analyze the association between hip fracture incidence in 12 regional blocks within Japan and dietary intake of four key nutrients: calcium, magnesium, vitamin D, and vitamin K. Design An ecological study. Methods Using data from the 2002 national survey on the incidence of hip fracture and the National Nutritional Survey of Japan, a standardized incidence ratio of hip fracture was calculated, and the association between the standardized incidence ratio and each nutritional intake was assessed for each region using Pearson’s correlation coefficient and partial correlation analysis. Results There were significant correlations between the standardized incidence ratio by region and magnesium, vitamin D, and vitamin K in both men and women, and calcium in women. The strongest inverse correlations were found in vitamin K in both men and women (r = −0.844, P = 0.001, and r = −0.834, P = 0.001, respectively). After adjusting for calcium, magnesium, and vitamin D, the partial correlation between the standardized incidence ratio by regional block and vitamin K was strongest in both men and women (partial correlation coefficient, pcc = −0.673, P = 0.04; pcc = −0.575, P = 0.106, respectively). Conclusions The significant correlation between hip fracture incidence and vitamin K intake, and also regional variations in food patterns, suggest that increasing intake of vegetables and legumes might lead to a decrease in hip fracture incidence in the future. Further, this study suggests that a review of the dietary reference value of vitamin K from the perspective of osteoporosis would be useful.     

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.     

Vitamin intake in Japanese women college students

The Standard Food Tables of Japanese Foods was newly revised in 2000, and contains information on all of the vitamins except biotin. Thus, we carried out a survey of vitamin intake in Japanese women who were university seniors majoring a dietitian course. The subjects (n = 33) consumed self-selected foods, and food intake was recorded by the weight method. We calculated the vitamin intake except for biotin from the food records using the Standard Food Tables of Japanese Foods. In terms of daily intake, vitamin A was 705+/-435 microg (mean+/-SD), vitamin D 6+/-8 microg, vitamin E 7.7+/-3.0 mg, vitamin K 191+/-156 microg, vitamin B1 0.7+/-0.3 mg (0.43+/-0.15 mg/1,000 kcal), vitamin B2 1.1+/-0.4 mg (0.65+/-0.18 mg/1,000 kcal), vitamin B6 0.9+/-0.4 mg (0.017+/-0.005 mg/g protein), vitamin B12 4.4+/-4.1 microg, niacin equivalent 23+/-7 mg (14.4+/-4.9 mg/1,000 kcal), pantothenic acid 4.6+/-1.4 mg, folic acid 267+/-115 microg, and vitamin C 73+/-38 mg. All of these averages were around the Japanese Recommended Dietary Allowance (RDA) for level "III (preferable)" of physical activity. Major vitamin A resources were vegetables; vitamin D resources, fish; vitamin E resources, fats and oils and vegetables; vitamin K resources, vegetables; vitamin B1 resources, cereals and animal meats; vitamin B2 resources, various foods; vitamin B6 resources, cereals, vegetables, fish, and animal meats; vitamin B12 resources, fish; niacin equivalent resources, fish, animal meats, and cereals; pantothenic acid resources, various foods; folic acid resources, vegetables; and vitamin C resources, vegetables and potatoes. From this survey, it was found that Japanese women college students consumed many kinds of food, and therefore, their vitamin nutrition was good as compared to the RDA values for level III of physical activity; however, their energy intake (1,622+/-377 kcal) was lower than the RDA for level III (2,050 kcal/d). Their strength of physical activity would be level I. Therefore, in consideration of their lifestyle, their energy intakes is considered adequate. In conclusion, a problem for student lifestyle is a shortage of food intake due to lack of exercise.     

Phylloquinone (vitamin K1) intakes and serum undercarboxylated osteocalcin levels in Irish postmenopausal women

Low phylloquinone (vitamin K1) intakes have been associated with low bone mineral density in older adults. Phylloquinone intakes and serum undercarboxylated osteocalcin (ucOC) levels were assessed in ninety-seven apparently healthy, free-living Irish women aged 50-75 years. Phylloquinone intakes were estimated using a detailed dietary history, which measured habitual food intakes from a typical 14 d period, and recently published food composition data for phylloquinone. Fasting serum ucOC was measured using an enzyme immunoassay. The median daily intake of phylloquinone in the group from all sources was 108.8 microg and from food sources only was 106.6 microg, indicating that approximately 99 % of the phylloquinone came from food. Vegetables and vegetable dishes contributed 67 % of the total phylloquinone intake, but further analysis showed that broccoli, cabbage and lettuce were the primary sources, making a total contribution of 44 %. Twenty per cent of the women had a phylloquinone intake below the UK recommendation of 1 microg/kg body weight per day and 34 % failed to meet the US Adequate Intake value of 90 microg/day. Mean serum ucOC levels in the women were 6.2 (SD 1.7) ng/ml and were predicted by phylloquinone intake (beta -2.20, generated from log-transformed phylloquinone intake data; P=0.04). On the basis of comparisons with both UK recommendations and US Adequate Intakes for phylloquinone, the habitual intakes of phylloquinone in a high proportion of Irish postmenopausal women may not be adequate.     

Excretion of the urinary 5C- and 7C-aglycone metabolites of vitamin K by young adults responds to changes in dietary phylloquinone and dihydrophylloquinone intakes

The physiological function and putative health roles of vitamin K-dependent proteins now extend beyond their classical role in hemostasis and include bone mineralization, arterial calcification, apoptosis, phagocytosis, growth control, chemotaxis, and signal transduction. Current assessments of vitamin K status do not reflect the variety of molecular forms of vitamin K. We assessed whether urinary excretion of 2-methyl-3-(5'-carboxy-3'-methyl-2'-pentenyl)-1,4-naphthoquinone (7C-aglycone) and 2-methyl-3-(3'-3'-carboxymethylpropyl)-1,4-naphthoquinone (5C-aglycone), vitamin K metabolites common to both phylloquinone and the menaquinone series, reflect dietary vitamin K intake. In a randomized crossover study, 9 adults resided in a metabolic unit for two 30-d periods separated by a free-living period of > or = 4 wk. During each residency, subjects consumed 3 sequential diets: a control diet (93 microg phylloquinone/d) for 5 d, a phylloquinone-restricted diet (11 microg/d) for 15 d, followed by a randomly assigned repletion diet for 10 d with either phylloquinone (206 microg/d) or dihydrophylloquinone (240 microg/d). During the second residency, the alternative repletion diet was assigned. Urinary excretion of the 5C- and 7C-aglycones was measured in sequential 24-h collections. The 5C-aglycone accounted for approximately 75% of total excretion and declined in response to phylloquinone restriction (P = 0.001) to approximately 30% of that during the control diet period. Repletion with phylloquinone and dihydrophylloquinone doubled the excretion rate of the major 5C-aglycone by 24 h (P < 0.001), and tripled excretion by 4 d. There was a linear relationship between the logarithm of total urinary excretion and dietary vitamin K intake (r = 0.699, P < 0.001). We conclude that the urinary excretion of vitamin K metabolites reflects dietary phylloquinone intake and offers the first candidate marker of global vitamin K status.     

A preliminary assessment of vitamin K1 intakes and serum undercarboxylated osteocalcin levels in 11-13 year old Irish girls

Low vitamin K1 intakes have been associated with low bone mineral density in women and reduced bone turnover in girls. No European data exist on the relationship between vitamin K1 and serum undercarboxylated osteocalcin (ucOC), an indicator of K1 status in adolescents. The aim of the current study was to assess intakes of vitamin K1 in relation to serum ucOC status in Irish girls. A detailed dietary history method, which measured habitual intakes from a typical 14-day period, was used to estimate vitamin K1 intakes in 18 girls aged 11-13 years. Recently compiled and validated food composition data for vitamin K1 were used to determine vitamin K1 intakes. An enzyme immunoassay was used to measure ucOC in fasting serum samples. The mean (+/- SD) intake of vitamin K1 in the girls was 72.4 microg/day (SD 34.4). Vegetables (particularly broccoli, composite dishes, and lettuce) contributed 53% of total vitamin K1 intakes. Thirty-Seven percent of the girls failed to meet the current U.S. adequate intake for adolescents of 60 microg/day vitamin K1. Serum ucOC levels were inversely related to body weight-adjusted vitamin K1 intakes, controlling for energy intake (partial correlation r = -0.538; p = 0.026). The data indicate that large-scale studies to examine relationships between vitamin K1 (and green vegetable) intakes and bone growth and development in adolescents are warranted.