Evidence and suggestions for establishing vitamin D intake standards in Koreans for the prevention of chronic diseases

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 μg/day, and the tolerable upper intake level was established at 25–100 μg/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.

Consumption of Weight-control or Health Functional Foods, Dietary Habits, and Weight Perceptions According to the Body Mass Index of Adult Women in the Chungcheong Area / 대한지역사회영양학회지

Objectives@#This study was conducted to investigate the experience and perception among adult women regarding weight control and the consumption of weight-control foods or health functional foods based on their body mass index (BMI). @*Methods@#The subjects were 634 adult women from the Chungcheong province, Korea, and data were collected through a self-administered questionnaire from July 2021 through September 2021. The subjects were divided into four groups based on their BMI status: underweight (< 18.5 kg/㎡ , 7.6%), normal weight (18.5 ~ 22.9 kg/㎡ , 53.3%), overweight (23 ~ 24.9 kg/㎡ , 19.7%), and obese ( ≥ 25 kg/㎡ , 19.4%). @*Results@#Over the past 3 years, almost two-thirds (68.6%) of the adult women had tried weight control measures, despite the fact that a significant proportion of them were normal or underweight. More importantly, 57.6% of subjects reported the consumption of weightcontrol foods, with a lower proportion in the underweight (35.4%) group compared to the normal (56.2%), overweight (62.4%), and obese (65.0%) groups. The food items used for weight control were mostly salads, chicken breasts, low fat (soy) milk, slimming tea, protein shakes, low-calorie cereals, and energy/protein bars among others. In addition, one-third (31.1%) of the subjects reported the use of health functional foods containing ingredients for fat reduction. A significantly higher proportion of these was from the overweight (36.0%) and obese (38.2%) groups compared to the underweight (20.8%) and normal weight (28.1%) groups. Products containing Garcinia cambogia extract, green tea, or Cissus extract, were popular among users. Subjects who were obese had a poorer perception of their health and body. Most subjects felt the need for correct information regarding weight control, but this number was significantly more in the higher BMI groups. @*Conclusions@#Our results suggest that the use of weight-control foods or health functional foods is popular among adult women, especially those who are obese. Thus, nutrition education courses covering facts about weight control and practice need to be developed and provided based on the BMI status of subjects.

Use of Weight-control or Health Functional Foods, Associated Weight-control Behavior and Perception among University Students in Cheongju / 대한지역사회영양학회지

Objectives@#This study sought to assess the prevalence and duration of weight-control or health functional food use, associated weight-control behavior, perception, and knowledge among university students. @*Methods@#The subjects were 442 university students in Cheonju, Korea, and data was collected by a self-administered questionnaire. Both X2 and t-tests were conducted for categorical and mean comparisons. @*Results@#An estimated 62.7% (female 69.0%, male 54.8%) had ever attempted weightcontrol. Among these, an estimated 59.2% of females and 38.9% of males had used weight-control or health functional foods with significant gender difference. The weightcontrol foods commonly used included chicken breast, protein powder, low-fat milk and soymilk, and meal replacement drinks, while garcinia cambogia extract and green tea extract were frequently used as health functional foods. One of 10 (10.3%) consumers of weight-control foods reported ≥ 7 months use, with less frequent long-term consumption of health functional foods (4.2%). The average degree of satisfaction was 3.24 ± 0.92 for weight-control foods and 2.72 ± 0.97 for health functional foods on a 5-point scale, meaning ‘slightly satisfied’ and ‘slightly dissatisfied’, respectively. Females or students with an experience of weight-control reported poorer perceptions of their health and body image as well as a higher need for weight control. Besides, both male and female subjects felt a high need for correct information regarding weight-control methods. @*Conclusions@#Our results provide a better understanding of the characteristics associated with the use of weight-control or health functional foods among university students and will be useful in developing a nutrition education program by incorporating correct body image, knowledge, and practical yet desirable practices for weight control.

Use of Weight-control or Health Functional Foods, Associated Weight-control Behavior and Perception among University Students in Cheongju / 대한지역사회영양학회지

Objectives@#This study sought to assess the prevalence and duration of weight-control or health functional food use, associated weight-control behavior, perception, and knowledge among university students. @*Methods@#The subjects were 442 university students in Cheonju, Korea, and data was collected by a self-administered questionnaire. Both X2 and t-tests were conducted for categorical and mean comparisons. @*Results@#An estimated 62.7% (female 69.0%, male 54.8%) had ever attempted weightcontrol. Among these, an estimated 59.2% of females and 38.9% of males had used weight-control or health functional foods with significant gender difference. The weightcontrol foods commonly used included chicken breast, protein powder, low-fat milk and soymilk, and meal replacement drinks, while garcinia cambogia extract and green tea extract were frequently used as health functional foods. One of 10 (10.3%) consumers of weight-control foods reported ≥ 7 months use, with less frequent long-term consumption of health functional foods (4.2%). The average degree of satisfaction was 3.24 ± 0.92 for weight-control foods and 2.72 ± 0.97 for health functional foods on a 5-point scale, meaning ‘slightly satisfied’ and ‘slightly dissatisfied’, respectively. Females or students with an experience of weight-control reported poorer perceptions of their health and body image as well as a higher need for weight control. Besides, both male and female subjects felt a high need for correct information regarding weight-control methods. @*Conclusions@#Our results provide a better understanding of the characteristics associated with the use of weight-control or health functional foods among university students and will be useful in developing a nutrition education program by incorporating correct body image, knowledge, and practical yet desirable practices for weight control.

Sleep Quality and Its Association with the Dietary Behavior and Lifestyle of University Students in Cheongju / 대한지역사회영양학회지

OBJECTIVES: This study examined the association of the sleep quality and patterns with the dietary behavior, including snack and beverage consumption, taste preferences, as well as lifestyle of university students. METHODS: The subjects were 406 university students in Cheongju, Korea, and the data were collected using a self-administered questionnaire. They were divided into two groups according to the Pittsburgh Sleep Quality Index (PSQI): good-quality sleepers (PSQI score ≤ 5) and poor-quality sleepers (PSQI score > 5). The data were analyzed using a χ2-test, independent t-test, and analysis of covariance using the SPSS 25.0 program. RESULTS: Fifty-two percent of university students were categorized as poor-quality sleepers by the PSQI. Students classified as poor-quality sleepers had delayed bedtimes, and a shorter duration in bed and total sleep hours than the good-quality sleepers did. Poor-quality sleepers were more prevalent among those who were female, having irregular mealtimes, or frequent late night meals. They also consumed fast food frequently, such as fried chicken and hamburgers, and noodles when adjusted for gender. In addition, drinks with caffeine over milk were dominant among poor-quality sleepers. Furthermore, the preferences for spicy and salty tastes and longer smartphone usage were more prevalent in those with poor-sleep quality. CONCLUSIONS: These results showed that more than 50% of university students reported disturbed sleep and poor quality sleep was associated with less desirable snack consumption and taste preference, more smartphone usage, and others. Therefore, nutrition education program along with lifestyle changes promoting sufficient sleep are encouraged to provide for university students, particularly those who have poor sleep quality.

Lifestyle, Dietary Behavior and Snack Preference of Upper-grade Elementary School Students in Cheongju according to the Usage Time of Smartphones / 대한지역사회영양학회지

OBJECTIVES: This study was conducted to examine the length of exposure to smartphone and its association with dietary behavior toward snacks, lifestyle, and nutrition knowledge in elementary school students. METHODS: Subjects were 372 5th and 6th grade schoolchildren in Cheongju, Korea, and data was collected by a self-administered questionnaire. They were divided into two groups by the time spent using smartphone: moderate (< 2 hours/day) and overexposure (≥ 2 hours/day). Data was analyzed using frequency analysis, χ²-test, and independent t-test as well as analysis of covariance when necessary. RESULTS: Approximately half of subjects (41.4%) reported spending ≥ 2 hours/day using smartphone. That habit was more frequent among students in the 6th grade, those who received more monthly allowance, and who has a working mother. 63.4% of the subjects reported that they consumed snacks while watching television, using a computer and/or a smartphone and 48.1% said that they consumed snacks while they use a smartphone. Both situations were most prevalent among those with overexposure to smartphone (≥ 2 hours/day). We also observed that a higher percentage of subjects from the overexposure group spent more money on snack foods with the preference for ice cream, fast food, and carbonated drinks. Further, those in the overexposure group consumed more ice cream, cookies, and carbonated drinks. In addition, they had less desirable dietary behavior and health-related lifestyle (sleep duration and frequency of regular exercise) compared to those with moderate smartphone usage (< 2 hours/day). However, there was no statistical difference in nutrition knowledge among children with different degrees of smartphone usage. CONCLUSIONS: Our results showed that longer smartphone use was associated with less desirable snack preference/consumption and other dietary behavior in elementary school students. Thus interest and positive attitudes towards healthy snacks and diet should be reinforced in nutrition education programs, especially for those who are prone to use smartphones.

Dietary Habits and Perception Toward Food Additives according to the Frequency of Consumption of Convenience Food at Convenience Stores among University Students in Cheongju / 대한지역사회영양학회지

OBJECTIVES: This study was performed to examine the consumption patterns of convenience food at convenience stores, dietary habits, and perception as well as knowledge of food additives among university students. METHODS: Subjects were 352 university students in Cheongju, Korea, and data was collected by a self-administered questionnaire. They were divided into three groups according to the frequency of consumption of convenience food at convenience stores: 79 rare (≤ 1 time/month), 89 moderate (2-4 times/month) and 184 frequent (≥ 2 times/week). RESULTS: More subjects from the frequent consumption group lived apart from parents (p<0.001) and possessed more pocket money (p<0.01). Frequent consumption group consumed noodles, Kimbab, and sandwich & burger significantly more often (p<0.001, respectively) than others. In addition, frequent consumption of convenience foods at convenience stores was associated with frequent breakfast skipping (p<0.05), irregular meal time (p<0.01), snacking (p<0.05), and eating late night meal (p<0.001). More from the rare consumption group had heard about food additives previously compared to the frequent consumption group (79.7% vs. 63.6%, p<0.01). Frequent consumption group showed significantly higher score than did the rare consumption group for the following questions: monosodium glutamate is harmful to your health (p<0.05), food additives are necessary for food manufacturing (p<0.005), food additives need to be labeled on products (p<0.05), there is no food additive at all if labeled as no preservatives, no coloring, and no added sugar (p<0.05). There was a significant difference in degrees of choosing products with less food additives depending on the consumption pattern. CONCLUSIONS: Our results provided a better understanding of the factors associated with frequent consumption of convenience foods at convenience stores among university students and will be useful to develop a nutrition education program for those who are more prone to consume convenience foods.