Estimated dietary vitamin D intake and major vitamin D food sources of Koreans: based on the Korea National Health and Nutrition Examination Survey 2016-2019.

BACKGROUND/OBJECTIVES: The purpose of this study was to establish a database (DB) of foods containing vitamin D that were investigated in the Korea National Health and Nutrition Examination Survey (KNHANES), to estimate the dietary vitamin D intake, to evaluate the dietary adequacy of this intake, and to identify the major food sources of Koreans that contain vitamin D. SUBJECTS/METHODS: This study used data from the KNHANES 2016-2019. Individuals aged ≥ 1 year who participated in the nutrition survey (n = 28,418) were included. The dietary intake was assessed by the 24-h dietary recall method and individual dietary vitamin D intake was estimated using a newly established vitamin D DB. Dietary adequacy was evaluated by comparing the dietary intake of the participants with adequate intake (AI) as defined by Dietary Reference Intakes for Koreans (KDRIs) 2020. RESULTS: The average dietary vitamin D intake for all the subjects was 3.13 µg/d, which was 33.1% of AI. Dietary vitamin D intake was lower in rural residents, the elderly, and those with low income. The major food groups that contributed to the total dietary vitamin D intake were fish and shellfish (61.59%), eggs (17.75%), meat (8.03%), milk (4.25%), legumes (3.93%), and grains (3.84%). The top 10 individual food items that contributed to the total vitamin D intake were eggs (17.44%), squid (8.5%), eels (7.44%), salmon (5.35%), mackerel (5.27%), anchovies (4.65%), yellow croakers (4.58%), pork meat (4.47%), soymilk (4.46%), and skipjack tuna (3.80%). CONCLUSION: These results show that the mean dietary vitamin D intake of Koreans is lower than the reference AI level. Nutritional policies need to be put in place to increase the vitamin D intake of Koreans in the future. In addition, comprehensive research on all the sources of vitamin D, including intake of supplements and biosynthesis in the skin, is required.

Dietary zinc intake and sources among Koreans: findings from the Korea National Health and Nutrition Examination Survey 2016-2019.

BACKGROUND/OBJECTIVES: Zinc is an essential trace mineral which is important for the growth and development of the human body and immunological and neurological functions. Inadequate zinc intake may cause zinc deficiency with its adverse consequences. In this study, we aimed to estimate the dietary zinc intake levels and sources among Koreans. SUBJECTS/METHODS: For this secondary analysis, we obtained data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2019. Individuals aged ≥ 1 yr who had completed a 24-h recall were included. The dietary zinc intake of each individual was calculated by applying data from a newly developed zinc content database to the KNHANES raw data. We also compared the extracted data with the sex-, age-specific reference values suggested in the Korean Dietary Reference Intakes 2020. The prevalence of adequate zinc intake was then evaluated by the proportion of the individuals who met the estimated average requirement (EAR). RESULTS: The mean zinc intake of Koreans aged ≥ 1 yr and adults aged ≥ 19 yrs were 10.2 and 10.4 mg/day, equivalent to 147.4% and 140.8% of the EAR, respectively. Approximately 2 in 3 Koreans met the EAR for zinc, but the zinc intake differed slightly among the different age and sex groups. In children aged 1-2 yrs, 2 out of 5 exceeded the upper level of intake, and nearly half of the younger adults (19-29 yrs) and the elders (≥ 75 yrs) did not meet the EAR. The major contributing food groups were grains (38.9%), meats (20.4%), and vegetables (11.1%). The top 5 food contributors to zinc intake were rice, beef, pork, egg, and baechu kimchi, which accounted for half of the dietary intake. CONCLUSION: The mean zinc intake among Koreans was above the recommended level, but 1 in 3 Koreans had inadequate zinc intake and some children were at risk of excessive zinc intake. Our study included zinc intake from diet only, thus to better understand zinc status, further research to include intake from dietary supplements is needed.

Magnesium intake and dietary sources among Koreans: findings from the Korea National Health and Nutrition Examination Survey 2016-2019.

BACKGROUND/OBJECTIVES: Magnesium is an essential nutrient for human health. However, inadequate intake is commonly reported worldwide. Along with reduced consumption of vegetables and fruits and increased consumption of refined or processed foods, inadequate magnesium intake is increasingly reported as a serious problem. This study aimed to assess magnesium intake, its dietary sources, and the adequacy of magnesium intake in Korean populations. SUBJECTS/METHODS: Data was obtained from the Korea National Health and Nutrition Examination Survey 2016-2019 and included individuals aged ≥1 yr who had participated in a nutrition survey (n=28,418). Dietary intake was assessed by 24-h recall, and dietary magnesium intake was estimated using a newly established magnesium database. Diet adequacy was evaluated by comparing dietary intake with the estimated average requirement (EAR) suggested in the Korean Dietary Reference Intakes 2020. RESULTS: The mean dietary magnesium intake of Koreans aged ≥1 yr was 300.4 mg/d, which was equivalent to 119.8% of the EAR. The prevalence of individuals whose magnesium intake met the EAR was 56.8%. Inadequate intake was observed more in females, adolescents and young adults aged 12-29 yrs, elders aged ≥65 yrs, and individuals with low income. About four-fifths of the daily magnesium came from plant-based foods, and the major food groups contributing to magnesium intake were grains (28.3%), vegetables (17.6%), and meats (8.4%). The top 5 individual foods that contributed to magnesium intake were rice, Baechu (Korean cabbage) kimchi, tofu, pork, and milk. However, the contribution of plant foods and individual contributing food items differed slightly by sex and age groups. CONCLUSIONS: This study found that the mean dietary magnesium intake among Koreans was above the recommended intake, whereas nearly one in 2 Koreans had inadequate magnesium intake. To better understand the status of magnesium intake, further research is required, which includes the intake of dietary supplements.

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

BACKGROUND/OBJECTIVES: Vitamin 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/METHODS: This 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. RESULTS: For 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-, ß-, 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. CONCLUSIONS: This 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.

Association between kimchi intake and asthma in Korean adults: the fourth and fifth Korea National Health and Nutrition Examination Survey (2007-2011).

This study was performed to investigate the relationship between dietary factors and asthma in a representative population-based sample of 19,659 men and women, aged 19-64 years, using data from the fourth and fifth Korean National Health and Nutrition Examination Survey (KNHANES), 2007-2011. The presence of asthma was based on self-reported physician diagnosis of asthma in the Health Interview Surveys. Food intake was estimated by trained interviewers using a 24-h recall method. The prevalence of asthma in Korean adults was 2.4%. Adults with asthma consumed fewer amounts of kimchi (P=.0444) and fish (P=.0175) but had a higher cereal intake than those without asthma (P=.0056). Multiple logistic regression analysis after controlling for confounding factors showed a significant inverse relationship between kimchi consumption and the prevalence of asthma [odds ratio (95% confidence interval) for subjects consuming 1 to <2 servings (40-79.9 g), 2 to <3 servings (80-119.9 g), and ≥3 servings (≥120 g), relative to those consuming <1 serving (<40 g): 0.726 (0.534-0.987), 0.506 (0.348-0.736), and 0.678 (0.502-0.916), respectively; P for trend=0.0131]. These results warrant future studies to explore the mechanisms responsible for the association between kimchi consumption and asthma.

Comparison of dietary food and nutrient intakes by supplement use in pregnant and lactating women in Seoul.

This study was performed to compare the dietary food and nutrient intakes according to supplement use in pregnant and lactating women in Seoul. The subjects were composed of 201 pregnant and 104 lactating women, and their dietary food intake was assessed using the 24-h recall method. General information on demographic and socioeconomic factors, as well as health-related behaviors, including the use of dietary supplements, were collected. About 88% and 60% of the pregnant and lactating women took dietary supplements, respectively. The proportion of dietary supplements used was higher in pregnant women with a higher level of education. After adjusting for potential confounders, among the pregnant women, supplement users were found to consume 45% more vegetables, and those among the lactating women were found to consume 96% more beans and 58% more vegetables. The intakes of dietary fiber and ß-carotene among supplement users were higher than those of non-users, by 23% and 39%, respectively. Among pregnant women, the proportion of women with an intake of vitamin C (from diet alone) below the estimated average requirements (EAR) was lower among supplement users [users (44%) vs. non-users (68%)], and the proportion of lactating women with intakes of iron (from diet alone) below the EAR was lower among supplement users [usesr (17%) vs. non-users (38%)]. These results suggest that among pregnant and lactating women, those who do not use dietary supplements tend to have a lower intake of healthy foods, such as beans and vegetables, as well as a lower intake of dietary fiber and ß-carotene, which are abundant in these foods, and non-users are more likely than users to have inadequate intake of micro-nutrient such as vitamin C and iron.

Maternal iron intake at mid-pregnancy is associated with reduced fetal growth: results from Mothers and Children's Environmental Health (MOCEH) study.

BACKGROUND: Iron supplementation is a common recommendation for pregnant women to prevent iron deficiency during pregnancy. There is an increasing concern about excessive iron consumption as a general iron prophylaxis by pregnant women without any due consideration about their dietary iron intake or iron status. Our present study investigated the association between total iron intake from diet and supplements and fetal growth in 337 pregnant women at mid-pregnancy in South Korea. METHODS: Iron intake from diet and supplements was examined by a 24-hour recall method. Subjects were divided into three groups based on tertiles of total iron intake levels. Fetal biometry was assessed by ultrasonography at mid-pregnancy. RESULTS: About 99% of the non-supplement users had iron intake below the recommended nutrient intake (RNI) for pregnant women (24 mg), whereas 64.9% of supplement users had iron intake above the upper level (UL) (45 mg). In the babies of mothers in the third tertile of iron intake (>17.04 mg), biparietal diameter, abdominal circumference, and femur length were lower by 0.41 cm (P =0.019), 0.41 cm (P = 0.027), and 0.07 cm (P = 0.051), respectively, than the babies of mothers in the second tertile of iron intake (11.49 ~ 17.04 mg). CONCLUSION: These results suggest that excessive maternal iron intake at mid-pregnancy is associated with reduced fetal growth. Iron supplementation for pregnant women should be individualized according to their iron status. Appropriate diet education is needed for pregnant women so that they can consume adequate amounts of iron from food and supplements.

Relationship between milk and calcium intake and lipid metabolism in female patients with type 2 diabetes.

PURPOSE: This study was conducted to determine the association between intake of milk and dairy products as well as calcium and biomarkers related to lipid metabolism in Korean female patients with type 2 diabetes. MATERIALS AND METHODS: A cohort of 509 female subjects (mean age: 59.0 years; range: 35-80 years) was recruited from Huh's Diabetes Clinic in Seoul between 2005 and 2010. Dietary intake was assessed using a validated food-frequency questionnaire. Subjects were divided into three groups on the basis of their daily intake of milk and dairy products [<50 g/day (0<50 g/day), 50-200 g/day, and >200 g/day (>200-1201 g/day)] and then further divided into two groups according to their daily calcium intake: below and above the estimated average requirement (EAR). RESULTS: After adjustment for age, body mass index, energy intake, exercise, use of nutritional supplements and cholesterol medication, the level of serum high-density lipoprotein (HDL)-cholesterol was significantly higher in subjects with milk and dairy products consumption of >200 g/day than in subjects in the other two groups. Those subjects with a milk and dairy products consumption of >200 g/day had significantly higher levels of apolipoprotein A-1 and a significantly lower atherogenic index than the other two groups. Patients with a calcium intake above the EAR exhibited a significantly greater serum HDL-cholesterol level than those with a calcium intake below the EAR. CONCLUSION: Milk and dairy products, good sources of calcium, play a positive role in lipid profiles in female patients with type 2 diabetes.

Relationship between maternal sodium intake and blood lead concentration during pregnancy.

Pb is released from bone stores during pregnancy, which constitutes a period of increased bone resorption. A high Na intake has been found to be negatively associated with Ca and adversely associated with bone metabolism. It is possible that a high Na intake during pregnancy increases the blood Pb concentration; however, no previous study has reported on the relationship between Na intake and blood Pb concentration. We thus have investigated this relationship between Na intake and blood Pb concentrations, and examined whether this relationship differs with Ca intake in pregnant Korean women. Blood Pb concentrations were analysed in 1090 pregnant women at mid-pregnancy. Dietary intakes during mid-pregnancy were estimated by a 24 h recall method covering the use of dietary supplements. Blood Pb concentrations in whole-blood samples were analysed using graphite furnace atomic absorption spectrophotometry. Multiple regression analysis performed after adjustment for covariates revealed that maternal Na intake was positively associated with blood Pb concentration during pregnancy, but only when Ca intake was below the estimated average requirement for pregnant Korean women (P= 0·001). The findings of the present study suggest that blood Pb concentration during pregnancy could be minimised by dietary recommendations that include decreased Na and increased Ca intakes.

Effects of paternal folate deficiency on the expression of insulin-like growth factor-2 and global DNA methylation in the fetal brain.

SCOPE: We examined the effect of paternal folate deficiency on the folate content, the percentage of 5-methycytosine (percentage of 5-mC) in the total DNA, and the protein expression of insulin-like growth factor-2 (IGF-2) in the fetal whole brain. METHODS AND RESULTS: Rats were mated after males were fed a folic acid deficient (PD) or folic acid supplemented (PS) diet for 4 weeks, and fetuses were killed on day 20 of gestation. The folate content in the fetal liver was significantly lower in the PD group than in the PS group, whereas it did not differ in the fetal whole brain. The percentage of 5-mC and the protein expression of IGF-2 in the fetal whole brain were both lower in the PD group than in the PS group. There were positive correlations between paternal liver and testis folate content and the percentage of 5-mC and IGF-2 expression in the fetal whole brain. CONCLUSION: Our results on the folate content, the percentage of 5-mC, and IGF-2 expression in the fetal whole brain show that paternal folate deficiency at mating can influence fetal brain DNA methylation and IGF-2 expression despite an adequate maternal folate status during the gestational period.

Effect of paternal folate deficiency on placental folate content and folate receptor α expression in rats.

We investigated the effect of paternal folate status on folate content and expression of the folate transporter folate receptor α (FRα) in rat placental tissues. Rats were mated after males were fed a diet containing 0 mg of folic acid/kg of diet (paternal folate-deficient, PD) or 8 mg folic acid/kg of diet (paternal folate-supplemented, PS) for 4 weeks. At 20 days of gestation, the litter size, placental weight, and fetal weight were measured, and placental folate content (n = 8/group) and expression of FRα (n = 10/group) were analyzed by microbiological assay and Western blot analysis, respectively. Although there was no difference observed in litter size or fetal weight, but significant reduction (10%) in the weight of the placenta was observed in the PD group compared to that in the PS group. In the PD group, placental folate content was significantly lower (by 35%), whereas FRα expression was higher (by 130%) compared to the PS group. Our results suggest that paternal folate status plays a critical role in regulating placental folate metabolism and transport.

Ultrasound-guided fine-needle aspiration biopsy of thyroid nodules: is it necessary to use local anesthesia for the application of one needle puncture?

OBJECTIVE: This study was designed to evaluate the difference in the degree of patient pain for an ultrasound-guided fine-needle aspiration biopsy (USFNAB) of a thyroid nodule with one needle puncture with and without local anesthesia. MATERIALS AND METHODS: A total of 50 patients participated in the study. We examined prospective patients who would undergo US-FNABs of two thyroid nodules (larger than 10 mm maximum diameter), which were located in separate thyroid lobes. For one of these thyroid nodules, US-FNAB was performed following the administration of local anesthesia; for the other nodule, no anesthesia was administered. The application of anesthesia was alternatively administered between patients (either prior to the first US-FNAB procedure or prior to the second procedure). For all patients, the degree of pain during and after each US-guided FNAB was evaluated according to a 4-category verbal rating scale (VRS), an 11-point numeric rating scale (NRS) and a 100-mm visual analogue scale (VAS). RESULTS: The mean maximum diameters of thyroid nodules examined by US-FNAB with the use of local anesthesia and with no local anesthesia were 13.6 mm and 13.0 mm, respectively. There was no significant difference in nodule size (p > 0.05) between two groups. For the VRS, there were 27 patients with a higher pain score when local anesthesia was used and four patients with a higher pain score when no local anesthesia was administered. Nineteen patients had equivalent pain score for both treatments. This finding was statistically significant (p < 0.001). For the NRS, there were 33 patients with a higher pain score when local anesthesia was used and 10 patients with a higher pain score when no local anesthesia was administered. Seven patients had an equivalent pain score for each treatment. This finding was statistically significant (p < 0.001). For the VAS, there were 35 patients with a higher pain score when local anesthesia was used and 11 patients with a higher pain score where no local anesthesia was administered. Four patients had an equivalent pain score for both treatments. This finding was also statistically significant (p = 0.001). CONCLUSION: In our study, patient pain scales were significantly lower when no local anesthesia was used prior to US-FNABs of thyroid nodules as compared to when local anesthesia was administered. Therefore, we believe that when one needle puncture is used, US-FNAB should be performed without administering local anesthesia.

Four cases of a cerebral air embolism complicating a percutaneous transthoracic needle biopsy.

A percutaneous transthoracic needle biopsy is a common procedure in the practice of pulmonology. An air embolism is a rare but potentially fatal complication of a percutaneous transthoracic needle biopsy. We report four cases of a cerebral air embolism that developed after a percutaneous transthoracic needle biopsy. Early diagnosis and the rapid application of hyperbaric oxygen therapy is the mainstay of therapy for an embolism. Prevention is the best course and it is essential that possible risk factors be avoided.

Antiplatelet and antithrombotic activities of Korean Red Ginseng.

The antiplatelet and antithrombotic activities of Korean Red Ginseng (KRG) were examined on rat carotid artery thrombosis in vivo, and platelet aggregation in vitro and ex vivo. Administration of KRG to rats not only prevented carotid artery thrombosis in vivo in a dose-dependent manner, but also significantly inhibited ADP- and collagen-induced platelet aggregation ex vivo, while failed to prolong coagulation times such as activated partial thromboplastin time (APTT) and prothrombin time (PT), indicating the antithrombotic effect of KRG might be due to its antiplatelet aggregation rather than anticoagulation effect. In line with the above observations, KRG inhibited U46619-, arachidonic acid-, collagen- and thrombin-induced rabbit platelet aggregation in vitro in a concentration-dependent manner, with IC50 values of 620 +/- 12, 823 +/- 22, 722 + 21 and 650 +/- 14 microg/mL, respectively. Accordingly, KRG also inhibited various agonists-induced platelet serotonin secretions as it suppressed platelet aggregation. These results suggest that KRG has a potent antithrombotic effect in vivo, which may be due to antiplatelet rather than anticoagulation activity, and KRG intake may be beneficial to the individuals with high risks of thrombotic and cardiovascular diseases.

Effect of genistein on the expression of bone metabolism genes in ovariectomized mice using a cDNA microarray.

Osteoporosis associated with estrogen deficiency is defined as an abnormal decrease in bone mass leading to an increased fracture risk. Genistein (GEN), as a phytoestrogen, is a type of soybean-derived isoflavone that possesses structural similarity to estrogen. In this study, we assessed the effect of GEN in ovariectomized (OVX) mice. To determine the effect of GEN on bone metabolism, we investigated gene expression profiles using a radioactive cDNA microarray. Eight-week-old female mice were either sham operated (SHAM) or OVX. From 1 week after the operation, OVX mice were injected daily with intraperitoneal GEN (0.1, 0.5, 1.5 and 3.0 mg/day) or 17beta-estradiol (E2, 0.03 microg/day) for 4 weeks. A cDNA microarray was used to evaluate changes in the expression of 1,152 genes. OVX mice showed bone mineral density (BMD) loss versus SHAM mice (5.8+/-0.4 vs. 6.9+/-0.6 mg/cm2). However, femur BMDs were completely restored by GEN and by E2 administration in OVX mice. Serum osteocalcin in OVX mice treated with 0.5 mg/day of GEN was 1.6-fold (44.30+/-5.73 ng/ml) higher than that in untreated mice. GEN treatment up-regulated 38 genes (e.g., mitogen-activated protein kinase 10) and down-regulated 18 (e.g., matrix metalloproteinase 13). Moreover, GEN was found to have a protective effect on bone loss caused by estrogen deficiency in OVX mice. The present study suggests that GEN modulates bone metabolism-related gene expression, including calciotropic receptor, cytokines, growth factors and bone matrix proteins.

The risk of folate and vitamin B(12) deficiencies associated with hyperhomocysteinemia among pregnant women.

The purpose of this study was to compare the folate and vitamin B (12) levels in pregnant and nonpregnant women to evaluate the risk for hyperhomocysteinemia and for folate and vitamin B (12) deficiencies during pregnancy. Healthy pregnant women (n = 92; 24 to 28 gestational weeks; 18 to 39 years old) and nonpregnant women (n = 176; 18 to 39 years old) were sampled for serum levels of folate, vitamin B (12), and homocysteine. Pregnant women were less likely to have folate deficiency (8.0% versus 12.0%) but much more likely to have vitamin B (12) deficiency (46.1% versus 0.6%) than nonpregnant women. Those with lower dietary vitamin intakes were more likely to have vitamin B (12) deficiency. Serum folate and vitamin B (12) were negatively correlated with homocysteine among pregnant women. Pregnant women with folate deficiency were more likely to have hyperhomocysteinemia than those without folate deficiency. The vitamin B (12) level associated with hyperhomocysteinemia was lower in pregnant subjects than in nonpregnant subjects in this study, indicating that pregnant women require vitamin B (12) supplementation.