• Korean Journal of Community Nutrition
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• v.20 no.2
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• pp.120-128
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• 2015

Objectives: The purpose of this study was to examine the relative impact of seasonal differences and age on dietary vitamin D intakes, outdoor activity time and serum vitamin D status among Korean postmenopausal women. Methods: A cross-sectional study was conducted with 164 free-living postmenopausal women (mean age=55.4 years) in Daegu, Korea. Dietary intake, daily physical activity patterns and fasting blood samples were collected during summer and winter. We compared the results from 75 women during summer and 89 women during winter. Dietary intake of vitamin D was assessed by 24-hour recall method. Daily outdoor activity time was derived from physical activity diary. Results: The average dietary intake of vitamin D of the participants was $3.7{\mu}g$ during summer, $3.3{\mu}g$ during winter, showing no significant difference between the two seasons. The average time spent on outdoor activities was not significantly different between summer ($=35.1{\pm}75.0min/d$) and winter ($=48.5{\pm}76.8min/d$). The average serum 25-(OH) vitamin D concentrations of participants was $17.5{\pm}7.5ng/mL$ in the summer and $13.4{\pm}4.3ng/mL$ in the winter, showing no significant differences by season. Dietary intake of vitamin D was not related to age. When total subjects were divided into two groups by age, the average serum 25-(OH) vitamin D concentration was significantly higher in older group (p=0.047) and time spent on outdoor activities was also (p=0.018) significantly higher in the older group. Conclusions: In order to improve the current vitamin D status of Korean postmenopausal women, nutrition education programs should focus more on adequate intake of vitamin D, while maintaining enough outdoor activities over the season.

• Nutrition Research and Practice
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• v.16 no.sup1
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• pp.57-69
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• 2022

BACKGROUND/OBJECTIVES: Vitamin D is produced in the skin during sun exposure and is also ingested from foods. The role of vitamin D needs to be considered in the prevention and management of various diseases. Moreover, since the majority of Koreans spend their days indoors, becoming susceptible to the risk of vitamin D deficiency. The current study aims to prepare a basis for determining dietary reference intake of vitamin D in Korea, by reviewing the evidence against various diseases and risks. MATERIALS/METHODS: Literature published in Korea and other countries between 2014 and 2018 was prioritized based on their study design and other criteria, and evaluated using the RoB 2.0 assessment form and United States Department of Agriculture Nutrition Evidence Library Conclusion Statement Evaluation Criteria. RESULTS: Of the 1,709 studies, 128 studies were included in the final systematic analysis after screening. To set the dietary reference intakes of vitamin D based on the selected articles, blood 25(OH)D levels and indicators of bone health were used collectively. Blood vitamin D levels and ultraviolet (UV) exposure time derived from the Korean National Health and Nutrition Examination Survey were analyzed to establish the dietary reference intakes of vitamin D for each stage of the life cycle. The adequate intake levels of vitamin D, according to age and gender, were determined to be in the range of 5-15 ㎍/day, and the tolerable upper intake level was established at 25-100 ㎍/day. CONCLUSIONS: The most important variable for vitamin D nutrition is lifestyle. A balanced diet comprising foods with high contents of vitamin D is important, as is vitamin D synthesis after UV exposure. The adequate intake level of vitamin D mentioned in the 2015 Dietary Reference Intakes for Korean (KDRI) remained unchanged in the 2020 KDRI for the management of vitamin D nutrition in Koreans.

• Nutrition Research and Practice
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• v.15 no.4
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• pp.492-503
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• 2021

BACKGROUND/OBJECTIVES: Recently, the recommended nutrient intakes (RNI) for vitamin D for Malaysian aged 1-70 yrs has been revised from 5 ㎍/day to 15 ㎍/day. This study is aimed to assess the adequacy of vitamin D intake based on revised RNI and to recommend several dietary strategies to increase total vitamin D intake. SUBJECTS/METHODS: Vitamin D intake from both food and supplement of 217 pregnant women was assessed using a validated food frequency questionnaire. Hypothetical effect of expanded supplementation and food fortifications strategies were modelled using the consumption data. RESULTS: The results revealed that more than half (67.7%) of pregnant women had inadequate vitamin D intake (RNI < 15 ㎍/day). The modelling results demonstrated the potential of universal provision of 10 ㎍/day of multivitamins supplements in increasing vitamin D intake. Moreover, mandatory fortification of both milk and malted drink at single level of 5 ㎍/serving would lead to increase in vitamin D intake of Malaysians, particularly pregnant women. CONCLUSIONS: The outcome of this study can be used as a reference for public health professionals to re-evaluate the existing Malaysian food fortification policies and supplementation recommendation for vitamin D for pregnant women.

• Nutritional Sciences
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• v.7 no.2
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• pp.98-106
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• 2004

The dietary vitamin $B_6$ intake of 185 Korean children aged 7-12 years (y), who showed no health problems, in the Seoul area and its sources were estimated using a modified Korean vitamin $B_6$ database. The age and sex of each subject was classified according to the classifications in the Korean Recommended Dietary Allowance (RDA). Dietary vitamin $B_6$ intake and food sources were estimated using the three-day recall method with the help of a trained interviewer. Food portion sizes were estimated by using standard household measures and published average portion sizes. The average daily vitamin $B_6$ intake was 1.69$\pm$0.50 mg/d in children aged 7-9 y, 1.86$\pm$0.44 mg/d in male children aged 10-12 y and 1.77$\pm$0.62 mg/d in female children aged 10-12 y. Less than 5% of the subjects consumed less than the Korean RDA of vitamin $B_6$. The average ratio of vitamin $B_6$intake to daily protein intake was 0.028$\pm$0.006 mg/g in children aged 7-9 y, 0.028$\pm$0.004 mg/g in male children aged 10-12 y and 0.029$\pm$0.007 mg/g in female children aged 10-12 y. The intake of vitamin $B_6$ was significantly (p<.01) positively correlated to the intake of all other nutrients. Foods from animal and plant sources provided 37% and 73% respectively, of total vitamin $B_6$. Major dietary sources of vitamin $B_6$ in children in the Seoul area were rice, soybean sprouts, pork, beef, cereal, kimchi, milk, onions, and potatoes. As for major dietary sources of vitamin $B_6$, the top 20 foods provided nearly 73-75% of the total vitamin $B_6$ consumed by Korean children.

• Journal of Dairy Science and Biotechnology
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• v.27 no.2
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• pp.17-23
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• 2009

In the light of the increasing concern over the prevalence of osteoporosis, hypertension, diabetes mellitus, we performed this study to review the correlation between the dietary calcium and vitamin D intake and these diseases. To this end, we investigated the effects of dietary calcium and vitamin D on these diseases. We observed that the intake of dietary calcium and vitamin D had a negative correlation with the incidences of osteoporosis, hypertension, and diabetes mellitus. Further, the intake of these two nutrients is expected to improve related mechanisms such as the renin-angiotensin system. Therefore, we suggest that dietary calcium and vitamin D have a beneficial effect on these diseases.

• Korean Journal of Community Nutrition
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• v.19 no.3
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• pp.231-240
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• 2014

Objectives: This study was intended to examine the seasonal differences in outdoor activity times and dietary vitamin D intakes, and explicates their relative impact on improving serum 25-(OH) vitamin D status among Korean young women. Methods: A cross-sectional study was conducted with 135 free-living women aged 19-39 years in Daegu-Kyungbook, Korea. We compared the results from 52 women for the summer and 83 women for the winter. Dietary intake of vitamin D was assessed by 24 hour recall method for non-consecutive three days as well as by food frequency method. Daily outdoor activity times were derived from 24 hour physical activity diary. Results: The average dietary intake of vitamin D of the participants by 24 hour recall method was 3.1 ${\mu}g$ during the summer, 3.3 ${\mu}g$ during the winter, showing no significant difference between the two seasons. Times spent on outdoor activities (p < 0.01) in the summer (= $23.8{\pm}23.6$ min) were much longer than that in the winter (= $10.8{\pm}13.4$ min). The serum 25-(OH) vitamin D levels of participants were $17.5{\pm}7.5$ ng/mL in the summer and $13.4{\pm}4.3$ ng/mL in the winter, showing that the latter was significantly lower than that of the former (p<0.001). The serum 25-(OH) vitamin D levels of subjects were positively related to outdoor activities (r=0.315, p<0.05) during the summer, while related to dietary intake (r=0.252, p<0.05) during the winter. Conclusions: In order to improve the current vitamin D status of Korean young women, nutrition education programs should focus on increasing more dietary intake especially during the winter, and performing more outdoor activities in other seasons.

• Preventive Nutrition and Food Science
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• v.9 no.1
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• pp.85-91
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• 2004

Dietary intakes and sources of vitamin B$_{6}$ in 72 healthy Korean elderly subjects (29 men,43 women, $\geq$57 years of age) living in the Seoul area were estimated using a modified Korean vitamin B$_{6}$ database. The dietary vitamin B$_{6}$ intake and food sources were estimated by the three day recall method with the help of a trained interviewer. Food portion sizes were estimated using standard household measures and published average portion sizes. The average daily vitamin B$_{6}$ intake was 2.06$\pm$0.46 mg/d in elderly men, and 1.94$\pm$ 0.47 mg/d in elderly women. Less than 5% of elderly men and 15% of elderly women consumed less than the Korean Recommended Dietary Allowance (RDA) of vitamin B$_{6}$. The average ratios of vitamin Be intake to daily protein intake were 0.03 $\pm$ 0.01 mg/g in both elderly men and women. The intake of vitamin B$_{6}$ was significantly (p <0.01 ∼ p<0.001) and positively correlated to intakes of all other nutrients in elderly women, but was not significantly correlated to intakes of several nutrients in elderly men. Foods from animal and plant sources provided 24% and 76%, respectively, of the total vitamin B$_{6}$. Major dietary sources of vitamin B$_{6}$ in Korean elderly were rice, soybean sprout, kimchi, pork, beef, potatoes, garlic, onion, anchovy and kochujang. The major sources accounted for most of the vitamin B$_{6}$ intake with the top 20 foods providing nearly 75∼76% of the total vitamin B$_{6}$ in Korean elderly./ in Korean elderly.

• Nutritional Sciences
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• v.5 no.1
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• pp.20-25
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• 2002

The vitamin $B_{6}$ status of 49 healthy college student (women, aged 20-26 y) was estimated for evaluation of vitamin $B_{6}$ status and the Korean Recommended Dietary Allowance (RDA) for vitamin $B_{6}$. The average daily vitamin $B_{6}$ intake of the subjects was 0.86 $\pm$ 0.289 mg/d or 61.43 $\pm$ 24.10% of Korean RDA. The average ratio of vitamin $B_{6}$ intake to daily protein intake was 0.014 $\pm$ 0.003 mg/g protein. Foods from animal and plaint sources provided 34.25 $\pm$ 18.62% and 65.78 $\pm$ 18.72%, respectively, of total vitamin $B_{6}$. Plasma pyridoxal 5'-phosphate (PLP) concentration was significantly (p<.01 - p<.001) positively correlated to intakes of all other nutrients except vitamin C. However, no significant correlation was found between plasma PLP and nutrient intake. Vitamin $B_{6}$ intake only tended to have a positive correlation with plasma PLP concentration. Plasma total cholesterol was correlated to plasma PLP concentration (p<.05). Plasma PLP had no correlation with levels of glucose, triglyceride, and albumin. These results confirm that the present Korea RDA for vitamin $B_{6}$ of 1.4mg/d based on 0.02 mg/g protein is adequate.

• Nutrition Research and Practice
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• v.16 no.6
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• pp.775-788
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• 2022

BACKGROUND/OBJECTIVES: The prevalence of vitamin D deficiency in Koreans is quite high; however, until recently, Korean National Health and Nutrition Survey (KNHANES) had not analyzed the vitamin D intake among Koreans. Additionally, the Korean Dietary Reference Intake for vitamin D was established based on insufficient evidence. Therefore, we investigated vitamin D intake and its relationship with bone mineral density (BMD) in Korean adults using the combined data from the 2009-2011 KNHANES. MATERIALS AND METHODS: This study was conducted in 11,949 healthy adults. Vitamin D intake was assessed using a 24-h recall method, and the BMD was measured using dual-energy X-ray absorptiometry. RESULTS: The prevalence of vitamin D deficiency (< 20 ng/mL) was 64% in men and 77% in women. In women aged ≥ 50 yrs and men aged < 50 yrs, there was a significant positive correlation between vitamin D intake and serum 25-hydroxyvitamin D level after sun exposure adjustment. The BMD of postmenopausal women aged ≥ 50 yrs with a vitamin D intake of 5 ㎍/day or more was significantly higher than that of women with intake less than 5 ㎍/day. After adjusting for age, energy, and calcium intake, the vitamin D intake of the osteoporotic group was significantly lower than that of the osteopenia group in women. CONCLUSIONS: Since the relationship between vitamin D intake and BMD was observed in women aged ≥ 50 yrs, further research is needed to clarify these findings using cohort or randomized controlled trials.

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.981-990
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• 1996

To define the risk facots of subclinical vitamin D deficiency in postmenopausal women, circulating serum 25-hydroxyvitamin D levels, known to be the indicator of vitamin D status, were measured and risk faxtors affecting it were investigated in 27 women with low 25-hydoxyvitamin d level(ie, the study group : serum 25-hydroxyvitamin D<10ng/ml) by comparing to 55 age-matched control(the control group) were analyzed. The serum level of 25-hydorxyvitamin D was analyzed by HPLC(High Pressure Liquid Chor-matography) and analyzed biochemical parameter. The following information was obtained by interviews : sociodemographic charateristics, the intake of food containing vitamin D, proxy measure of sunlight exposure(time spent outdoors), and reprocuctive histpry of the subjects. The study group had significantly lower levels of serum calcium, increased levels of iPTH and alkaline phosphatase, Among the dietary determents, energy, protein, fat, calcium, phophorus, and vitamin D intakes were lower in the study group than the normal group. The time spent outdoors in a day was not significantly different between the two groups. However, during the day, a specific time of time spent out doors between 12:00 and 14:00 was significantly lower in the study group. Logistic analysis revealed that vitamin D and calcium intake were more important affecting factors than the time spent outdoors in post menopausal women.