• Nutrition Research and Practice
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• v.9 no.2
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• pp.158-164
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• 2015

BACKGROUND/OBJECTIVES: Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS: A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and $1,25(OH)_2D$ levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml. RESULTS: Mean 25(OH)D and $1,25(OH)_2D$ levels were $13.5{\pm}5.8ng/ml$ and $20.6{\pm}11.8pg/ml$, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (${\geq}30ng/ml$) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise. CONCLUSIONS: Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.

• Nutrition Research and Practice
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• v.13 no.2
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• pp.115-125
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• 2019

BACKGROUND/OBJECTIVES: Vitamin D plays an important role in skeletal growth and maintenance and in the prevention of various diseases. We investigated the relationship between vitamin D intake and bone mineral density (BMD) in Korean adults aged ${\geq}50$ years using the 2009 Korea National Health and Nutrition Examination Survey data. SUBJECTS/METHODS: This study was conducted in 1,808 subjects aged ${\geq}50$ years with BMD data in Korea. Dietary vitamin D levels were assessed by the 24-hour recall method. BMD was measured using dual-energy X-ray absorptiometry. We investigated general characteristics and the association between these characteristics, vitamin D status, and BMD. RESULTS: Vitamin D intake was significantly lower in the osteoporosis group among women (P < 0.05). Among all subjects, the higher the serum 25(OH)D concentration, the higher the whole-body total BMD (WBT-BMD), femoral total hip BMD, and femoral neck BMD (P < 0.01). In the serum vitamin D-deficient group of both the total population and women, serum 25(OH)D concentration was associated with WBT-BMD (P < 0.05). Among women with a calcium intake < 537.74 mg/day, BMD of those with a vitamin D intake > $2.51{\mu}g/day$ (average intake of women) was higher than that of women with a vitamin D intake ${\leq}2.51{\mu}g/day$ (P < 0.001). CONCLUSIONS: Korean adults should increase their BMD by increasing serum 25(OH)D concentration. Furthermore, increasing vitamin D intake could improve BMD, especially in Korean women who consume less calcium than the estimated average requirement.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.3
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• pp.292-298
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• 2006

Modification of the diet during childhood and adolescence may be an effective strategy for maximizing the peak bone mass. Many supplementation studies have suggested a positive effect of the increased vitamin D intake on the bone mineral status in the elderly. However to date all studies have been conducted on old men and postmenopausal women. The aim of this study was to examine the effects of vitamin D supplementation on the bone mineral density and bone mineral content in growing rats. Twenty Sprague-Dawley female rats were divided into two groups; Control, and vitamin D supplementation. The bone mineral density(BMD) and bone mineral content(BMC) were measured using PIXImus in the spine and femur. Vitamin D supplementation did not affect the level of weight gain, mean food intake and food efficiency ratio. In addition, vitamin D supplementation had no added effect on the spine and femur BMD, and BMC. There were no significant differences in the spine BMD/weight and BMC/weight between the groups, but the spine BMD/weight and BMC/weight was 11 % higher in the vitamin D supplementation group. The femur BMD/weight and femur BMC/weight were significantly higher in the vitamin D supplementation group 9 weeks after the experiment. These results provide evidence of the beneficial effects of vitamin D supplementation on the BMD during the growth period.

• Clinical Nutrition Research
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• v.11 no.2
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• pp.84-97
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• 2022

As the proportion of the elderly population increases rapidly, interest in musculoskeletal health is also emerging. Here, we investigated how antioxidant vitamin intake and musculoskeletal health are related. Adults aged 50 to 80 years with a body mass index (BMI) of 18.5 to 27.0 kg/m² were included. Bone mineral density (BMD), lean mass (LM), appendicular skeletal muscle mass index (ASMI) were measured using dual-energy X-ray absorptiometry (DXA), and the grip strength and knee extension using hand dynamometer. Nutrient intakes were measured using a 24-hour recall questionnaire. A total of 153 adults (44 men and 109 women) participated in this study. A partial correlation analysis showed a significant positive relationship between vitamin E and BMD and between vitamin C and LM/Height. Participants were classified into three groups according to whether their vitamin E and C intake met the recommended intake for Dietary Reference Intakes for Koreans (KDRIs). The prevalence of having low T-score (< -1.0) and low ASMI (< 7.0 for men and < 5.4 for women) was 51.3% and 15.4% in the group with vitamins C and E intakes below KDRIs. After adjusting for sex, smoking status and energy, protein, vitamin D, and calcium intake, the group with vitamins C and E both below the KDRIs displayed a significantly lower BMD at all test sites and LM/Height compared with vitamin C and/or E intake above the KDRIs groups. We conclude that sufficient intake of vitamin E and C is important for maintaining BMD and lean mass in Korean adults over 50 years of age.

• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.570-580
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• 2014

The purpose of this study was to investigate the effect of calcium (Ca) and vitamin D (vit. D) levels on metabolism of various minerals such as Ca, P, Mg, Fe, Zn, Cu, and Cr. The comparison was made on the rats that were placed on diet containing powdered skim milk with different Ca and vit. D levels for 5 weeks. A total of 42 5-week-old Sprague-Dawley rats were divided into 7 groups as follows: Control group consisted of normal Ca and normal vit. D (0.5% Ca, 1,000 IU vit. D); Experimental groups were divided into low (0.25%) and high (1.0%) calcium levels; and vit. D group was divided into low (10 IU), normal (1,000 IU), and high (5,000 IU) subgroups. The weight gain and food efficiency ratios of the rats were not significantly different with increasing dietary Ca levels. The absorption rates of 7 minerals (Ca, P, Mg, Fe, Zn, Cu, and Cr) were significantly decreased with increasing dietary Ca levels. Also, fecal excretion of P significantly increased with increasing dietary vit. D levels (p<0.05), and urine excretion of Fe was significantly increased with increasing dietary vit. D levels (p<0.001). The result indicated that higher Ca intake affected on bioavailability of other minerals, due to interactions among minerals in the process of intestinal absorption. However, vitamin D intake had no effect on bioavailability of several minerals. Therefore, it could be suggested that adequate Ca intake is important for balance of the minerals.

• Journal of Nutrition and Health
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• v.49 no.6
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• pp.437-446
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• 2016

Purpose: The purpose of this study was to estimate dietary intake of vitamin D and the relationship between serum 25-hydroxyvitamin D (25OHD) concentration and bone mineral density (BMD) in Korean adults using the 2011 data from the Korea National Health and Nutrition Examination Survey. Methods: Daily intake of vitamin D and ratio of subjects that consumed less vitamin D than adequate intake (AI) were estimated in 4,879 Korean adults. The relationship between daily intake of vitamin D and serum 25OHD and BMD were analyzed. Results: Average daily intakes of vitamin D were $3.84{\pm}0.23{\mu}g/day$ for men and $2.22{\pm}0.11{\mu}g/day$ for women. Approximately 72~97% of men and 80~99% of women consumed less than the AI of vitamin D for Koreans. Serum 25OHD concentration increased with age, and the ratios of serum vitamin D deficiency (< 20 ng/mL) were 47.8~81.1% for men and 59.4~92.8% for women. Average intake of vitamin D was higher in subjects aged < 50 yr than in those ${\geq}50yr$, but lower in serum 25OHD concentration. In subjects aged < 50 yr, serum 25OHD was higher in subjects that consumed $10{\mu}g/day$ of vitamin D than in those that consumed less than $5{\mu}g/day$. In female subjects aged ${\geq}50yr$, average intake of vitamin D was associated with higher bone mineral density. Conclusion: It was found that dietary intake of vitamin D could increase serum 25OHD concentration in young adults and bone mineral density in old women. Therefore, nutrition policies for enriched foods with vitamin D and nutrition education to consume more vitamin D-rich foods are needed to ameliorate vitamin D status of the Korean population. Adequate intake for Korean population aged < 50 yr might be adjusted upwardly up to $10{\mu}g/day$.

• Korean Journal of Community Nutrition
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• v.24 no.3
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• pp.245-256
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• 2019

Objectives: Although the number of laboratory workers is constantly increasing every year, few studies have been conducted on the health and nutritional status of these research workers. This study determined the health status of laboratory workers by analyzing their anthropometric indices, dietary life, vitamin D status and blood clinical indices. Methods: The subjects consisted of 100 female laboratory workers. This study investigated their diet, anthropometric indices, vitamin D status and blood clinical indices. The subjects were divided into two groups according to their duration of working in a laboratory (<1 year, $${\geq}_-1year$$). Results: The average age and body mass index (BMI) of subjects were 23.18 years and $21.51kg/m^2$, respectively Those subjects with over 1 year employment ($${\geq}_-1year$$) had a significantly higher waist-hip ratio than that of the subjects with the less than 1 year employment (<1 year). The mean serum vitamin D level of all the subjects was 10.04 ng/mL, which is close to a level of vitamin D deficiency. There was a significantly higher average intake of calories in the over 1 year employment group as compared to that of the less than 1 year employment group. The frequency of eating sweet snacks was significantly higher for the over 1 year employment group. The correlation analysis showed a significant positive correlation between the serum 25-(OH)-vitamin D level and the time of exposure to sunlight, while dietary intake of vitamin D did not show correlation with the serum 25-(OH)-vitamin D level. However, the serum 25-(OH)-vitamin D level was also negatively correlated with both the percentage of body fat and visceral fat. Conclusions: Laboratory workers are a very high risk group in terms of their nutritional status of vitamin D. Therefore, they need greater time of exposure to sunlight as well as increasing their dietary consumption of vitamin D. In addition, it is important for laboratory worker to practice regular and balanced dietary habits in order to maintain a healthy life.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1082-1089
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• 2009

Vitamin D is an important fat-soluble vitamin that functions as a prohormone and affects bone mineralization and calcium homeostasis. Vitamin D deficiency causesboth musculoskeletal manifestations, including rickets, and extra-musculoskeletal symptoms. Because vitamin D is naturally present in only some foods, intake of daily foods cannot meet the dietary reference intake for vitamin D. Sunlight is the main source of vitamin D in humans therefore, the lack of sunlight can easily cause vitamin D deficiency in children and adolescents. Vitamin D deficiency can be diagnosed on the basis ofits typical clinical manifestation, laboratory tests, and radiologic findings. Detection of vitamin D deficiency in children or adolescents necessitates the simultaneous administration of vitamin D and calcium supplements. To prevent vitamin D deficiency, 200 IU of daily vitamin D intake is recommended in infants, and 400 IU of daily vitamin D intake is recommended in Korean children and adolescents.

• Nutritional Sciences
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• v.7 no.2
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• pp.107-112
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• 2004

This study investigated the interactions of bone health with several variables such as outdoor activity hours, nutritional status including habitual intake of calcium andvitamin D status in 72 high school girls aged 16-17 yearsattending day classes or night classes. The subjects consisted of 39 day-class students and 33 night-class students. Dietaty nutrient intakes were estimated using the 24-hour recall method. The daily activities of each subject were assessed using an activity questionnaire. Urinary calcium and creatinine excretion were assayed from subjects' 24-hoururine, while 25-OH-vitamin D[25-(OH)-D] and osteocalcin were measured from the subjects' fasting blood. Intake of energy, iron, vitamin A and vitamin C were worse in the night-class students. There was no significant difference in dietary calcium between the subjects in the different class types. Time spent on outdoor activities was significantly less in subjects attending night classes. Urinary calcium excretion of the night-class subjects was significantly higher than that of the day-class subjects (p<0.05). There was no significant difference in serum 25-(OH)-D level according to class type. Serum osteocalcin for night-class subjects was significantly higher than that for day-class subjects (p<0.01). It appeared that the night-class students had poorer dietary habits as well as fewer outdoor activities. Even though the estimated bone health of both groups of subjects appeared to be normal, the overall nutritional intake and duration of outdoor activities appeared to be important for maintaining bone health and lowering the future risk of osteoporosis.

• Journal of Nutrition and Health
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• v.45 no.6
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• pp.531-540
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• 2012

This study was carried out in order to investigate the status of food and nutrient intakes depending on the types of chronic disease of the elderly at welfare centers in Seoul. The total number of subjects was 299 elderly over the age of 60 (82 men and 217 women); they were grouped by the disease status: normal, cardiovascular disease (CVD), diabetes mellitus (DM) and arthritis patients groups. The dietary intakes were obtained by a 24-hour recall and analyzed by CAN-Pro 4.0; they were then compared with the dietary reference intakes for the Korean (KDRIs). In the results of anthropometric data according to chronic disease, the waist circumference of the normal group in males and females was lower than the other groups; in particular, the normal female group showed a lower level of waist-hip ratio, body mass index (BMI) and body fat % than those of the other groups. The arthritis group showed a higher intake of milk products than the other groups (p < 0.05); consequently, calcium intake was significantly higher than that of the other groups (p < 0.001). Vitamin A intake in the arthritis group was significantly higher than the intake in the normal and DM groups (p < 0.01). Normal and arthritis groups showed significantly higher intake of zinc and copper than the CVD group (p < 0.01). In general, about 80% of the subjects in this study revealed insufficient intakes of riboflavin, vitamin C, calcium, dietary fiber, vitamin D, biotin and potassium, compared with the estimated average requirement (EAR) or adequate intake (AI). However, sodium intake of all groups was higher than the AI of KDRIs. In conclusion, nutrient intake, according to the chronic disease, showed significant difference in some of the micronutrients, vitamin A, Ca, Zn and Cu. Therefore, we suggest that dietary guidelines, such as reducing the intake of salty foods and sweet drinks and increasing the intake of foods with sufficient calcium, vitamin D and vitamin C, are necessary to the improvement of eating habits for the elderly.