The Prevalence of Dietary Supplement Use Among Elementary, Junior High, and High School Students: A Nationwide Survey in Japan

Dietary supplements increase the risk of excessive micronutrient intakes in Danish children

PURPOSE

Dietary supplement use is common in Northern Europe. Many dietary supplements contain 100% of nutrient reference values (NRV) of micronutrients. This study investigates the contribution of dietary supplements to micronutrient intake, the prevalence of excess intake of micronutrients, and parental characteristics of dietary supplement use in Danish children.

METHODS

Data on 499 4-10-year-old children from the Danish National Survey of Diet and Physical Activity 2011-2013 were analysed using non-parametric statistics to compare micronutrient intake from the diet and dietary supplements to the reference intake (RI), and to the tolerable Upper Intake Level (UL) for users and non-users of dietary supplements. Furthermore, characteristics of the parents of users and non-users of dietary supplements were examined by logistic regression analysis.

RESULTS

Sixty-four percent of the children were dietary supplement users. Multivitamin-mineral supplements were the most frequently used type of supplement (60%). Children of never-smokers were more likely to use supplements than children of smokers. Users had significantly higher total intakes of 15 micronutrients compared to non-users. Intakes of vitamin A, zinc, and iodine from the diet alone exceeded ULs in 12-30% of the children. Use of dietary supplements gave rise to 21-73% of children in exceedance of the aforementioned three ULs as well as the UL for iron (6-45%).

CONCLUSION

Dietary supplement use was common among 4-10-year-old Danish children and resulted in a considerable proportion of users exceeding the ULs for vitamin A, zinc, iodine, and iron. The long-term health consequences of exceeding these ULs for children are unknown.

Prevalence of Essential Nutrient Supplement Use and Assessment of the Knowledge and Attitudes of Lebanese Mothers towards Dietary Supplement Practices in Maternal, Infancy and Preschool Ages: Findings of a National Representative Cross-Sectional Study

Mothers are understandably concerned about protecting the well-being of their offspring in every way possible, including providing oral dietary supplements (DSs). Up to now, there has been limited data on maternal knowledge and attitudes toward concomitant maternal-child DSs practices in Lebanon. This study evaluated the maternal knowledge and attitudes toward DSs and documented the DS-related practices in mothers and their under-5 children with their correlates. This cross-sectional study involved a representative stratified cluster random sample of 511 mother-child dyads (mothers: mean age ± SD = 30.25 ± 4.98 years; children: mean age ± SD = 18.7 ± 15.5 months, girls: 55.0%). A self-administered questionnaire was used to meet study aims. Most mothers lack awareness and hold unfavorable attitudes regarding DS use. Among all mothers, 47% were DS users, with the majority using vitamin D (82%). Almost 64% of mothers provide DSs for their children, with a predominant use of multivitamin drops (61.0%). "To keep the child healthy" was the reported reason by 60.0% of mothers to provide DSs for their children. Physicians were the primary information source about DSs for most mothers (64.0%). The usage of DSs among mothers was influenced by their pregnancy status, child's age, number of children per household, and their awareness and attitudes towards DSs. DS usage among children was correlated with maternal DS use and their mothers' attitudes towards DSs. DS usage among Lebanese mother-child dyads is common. Mothers should be the focus of education sessions regarding DS use.

The Perception of Minerals and Their Prevalence in Fortified Foods and Supplements in Japan

People’s intake of some minerals does not meet the nutrient reference values even in high-income countries. Recently, the deficiency of zinc and/or selenium has been considered to cause greater risk of COVID-19 infection and severity. To investigate consumer awareness, we conducted a cross-sectional questionnaire online survey among Japanese people (7500 males and 7500 females) concerning their perceptions of each mineral and the prevalence of mineral-fortified foods and/or mineral supplements. People’s perception of each mineral varied: the highest was for calcium (91.8%) and the lowest was for selenium (44.7%). In addition, only a portion of participants believed that they consumed a sufficient amount of each mineral; the highest was sodium (23.7%), and the lowest was manganese (5.2%). In addition, 18.2% of them felt that they could not consume enough sodium, even though most of the Japanese’s intake is excessive. Among mineral-fortified-food and/or mineral-supplement users, the purposes for these products were to maintain health (80.6%), supplement nutrients (48.0%), and prevent infectious diseases (23.2%). Only 18.4% of participants knew what amount they took. In conclusion, education is needed to prevent not only the insufficiency/deficiency of each mineral but also an excess intake of sodium.

Food and nutrient intake in dietary supplement users: a nationwide school-based study in Japan

Dietary supplements can be used to compensate for an inadequate diet. However, some studies indicate that supplement users consume healthier diets than non-users, although such data are lacking in Japanese children. The aim of the present study was to investigate the food and nutrient intake of dietary supplement users among school-aged children in Japan. A nationwide school dietary survey was conducted at fourteen elementary schools and thirteen junior high schools in twelve prefectures in Japan. Three-day non-consecutive semi-weighed dietary records were obtained on two weekdays and one weekend day. Analysis of covariance was performed to investigate differences in food and nutrient intake from meals consumed at school and outside of school between dietary supplement users and non-users, adjusted for socio-demographic and health-related characteristics. Of the 910 children included in this analysis, 80 (8⋅8 %) reported supplement use. Based on 3-d dietary records, dietary supplement users consumed higher mean amounts of oils and lower amounts of fruits and vegetables than non-users. In school lunches, users consumed significantly higher amounts of oils and lower amounts of protein than non-users. In meals consumed outside of school, dietary supplement users consumed significantly higher amounts of confectioneries and lower amounts of fruits and vegetables, folate, vitamin C and dietary fibre than non-users. Collectively, our findings indicate that dietary supplement users consumed less healthy diets than non-users. Additional studies are warranted to confirm these results and identify factors contributing to poorer dietary habits in supplement users.

[Consultation and Information Source of Interaction between Drugs and Health Foods among Pharmacists and Dietitians]

The prevalence of health food use is increasing not only among healthy individuals but also among patients. Many patients consume drugs and health foods concomitantly, and most of them use more than one drug and one health food. In this regard, the interactions between drugs and health foods should be addressed. However, it is not clear where healthcare professionals can get sufficient information about the interactions between drugs and health foods. To address this issue, we conducted an online questionnaire about the consultation and attitude concerning and information source of interactions between drugs and health foods among pharmacists and dietitians. Only 29.7% of pharmacists and 14.0% of dietitians always confirmed the use of health foods among their patients, even though they work at pharmacies or hospitals. Regarding concomitant use, 79.2% of pharmacists and 60.2% of dietitians allowed their patients to continue concomitant use, and less than 20% of them advised their patients to avoid concomitant use. Most of them checked the manufacturer's website and could not obtain sufficient information about the interactions between drugs and health foods. However, they utilized the "Information system on safety and effectiveness for health foods (HFNet)," which is the website of the National Institutes of Biomedical Innovation, Health and Nutrition, to obtain information, if they were aware of this. In conclusion, pharmacists and dietitians need more information about the interactions between drugs and health foods, and HFNet may play an important role as information source.

Determination of the Awareness about and Need for Health Support Pharmacies as the Provider of Consultation Service about Nutrition Education and Diet-Related Health Promotion by Health Professionals in Japan

Health support pharmacies (HSPs) have been established as a new category of pharmacies in Japan. In addition to prescriptions, HSPs provide several health services, including consultations on diet/nutrition, health foods, and nursing care. Therefore, not only individuals receiving medications but also community residents should have access to HSPs. However, it is unclear whether people are aware of HSPs. Thus, the purpose of this study was to assess the awareness about HSPs and determine the need for their services. To this end, we conducted an online cross-sectional questionnaire survey in 10,000 Japanese adults. Approximately 60.2% of the participants were aware of family pharmacies/pharmacists, and 21.8% of these participants had a family pharmacy/pharmacist. Meanwhile, 2.6% of the participants were aware of HSPs, while 9.2% of the participants had only heard of HSPs. Awareness of HSPs was higher among men and younger individuals than among women and older generations. In addition, only 7.2% of the participants were aware of the location of the HSP in their area of residence. At the time at which this survey was conducted, only 3.5% of the participants were using HSP services, and half of them did not perceive the merits of using these services. However, 44.4% of the participants wished to avail themselves of HSP services in the future, and this desire increased with age. Half of the participants wished to use services that were associated with drugs, and the need for other services, such as consultations on diet/nutrition or health foods, was low. In conclusion, there was low awareness about HSPs among the survey participants. However, from our findings, we gathered that if individuals are aware of HSPs, they will wish to use HSP services. To improve healthy life expectancy, it is important to increase awareness about HSPs and their number.

Pilot study of dietary supplement consumption by kindergarten and elementary school children

Introduction: The use of dietary supplements has been increasing globally, especially among children. A lot of parents are influenced by advertising. In addition, in Poland a trend to self-medication has been observed. Parents often do not distinguish dietary supplements, medicinal products and non-prescription drugs. These are the most common reasons for the increase in sales of dietary supplements in Poland. Until a few years ago, many products containing vitamins and minerals intended for children were sold as medicines. Today, a product with the same formulation is sold as a dietary supplement. However, a few studies have been conducted to assess the use of dietary supplements among Polish children.

Objective: The aim of the study was to analyse the use of dietary supplements provided by parents and the study of the awareness of the risks associated with supplements intake among preschool and elementary school students.

Methods: The study was conducted by questionnaire method among 316 parents/legal guardians of children attending elementary schools and preschools in three provinces.

Results: The questionnaire was completed by 88.3% mothers and 11.7% fathers. The age of the respondents was as follows: 64.5% aged 31–40, 18.3% aged 41–45, 9.5% aged 26–30, 7.2% above 46 years and only 0.3% younger than 25. About 80% of parents administered their children with dietary supplements in specific situations. Vitamin and mineral supplements were predominant. A statistical analysis showed the effect of the education level as well as having many children on the administration of dietary supplements.

Conclusion: The questionnaire shows that the vast majority of parents/legal guardians administer their children with dietary supplements. There is a need to educate parents/legal guardians about the use of supplements and the risks involved.

The Perception of Vitamins and Their Prevalence in Fortified Food and Supplements in Japan

Most vitamins are primarily ingested from foods. However, it has been reported that intakes of some vitamins do not meet the nutrition reference values even in high-income countries. In this case, vitamin-fortified foods and/or vitamin supplements are helpful to fix insufficient/deficient status. However, it is not clear whether consumers are aware of their nutritional status or whether they use these products efficiently. To address this issue, we conducted an online cross-sectional questionnaire survey among 14,741 Japanese adults (over 20 years old, 7489 males and 7252 females) concerning the perceptions and prevalence of vitamin-fortified food and/or vitamin supplements. Differences in distribution among groups were compared using the chi-squared test. According to dietary habits, 33.2% of the participants consumed a well-balanced diet every day, but 25.5% could not because of time (41.6%) or money (36.9%) constraints. The perception of each vitamin varied: the highest was for vitamin C (93.2%) and the lowest was for biotin (41.9%). In addition, only a portion of the participants believed that they took sufficient amounts of each vitamin; the highest was vitamin C (22.3%) and the lowest was biotin (5.2%). Despite this situation, most did not use vitamin-fortified food and/or vitamin supplements due to economic reasons. Among vitamin-fortified food and/or vitamin supplement users, the purposes for the usage of these products were varied, such as maintaining health (80.5%), supplementation of nutrients (47.8%), beauty-related purposes (27.5%), and to prevent infectious disease (23.2%). To remedy nutritional status in individuals, it is important to improve not only consumer awareness but also the environment, which can lead consumers to use acceptable vitamin products without any burden.

Effect of Vitamin K-Mediated PXR Activation on Drug-Metabolizing Gene Expression in Human Intestinal Carcinoma LS180 Cell Line

The pregnane X receptor (PXR) is the key regulator of our defense mechanism against foreign substances such as drugs, dietary nutrients, or environmental pollutants. Because of increased health consciousness, the use of dietary supplements has gradually increased, and most of them can activate PXR. Therefore, an analysis of the interaction between drugs and nutrients is important because altered levels of drug-metabolizing enzymes or transporters can remarkably affect the efficiency of a co-administered drug. In the present study, we analyzed the effect of vitamin K-mediated PXR activation on drug metabolism-related gene expression in intestine-derived LS180 cells via gene expression studies and western blotting analyses. We demonstrated that menaquinone 4 (MK-4), along with other vitamin Ks, including vitamin K₁, has the potential to induce MDR1 and CYP3A4 gene expression. We showed that PXR knockdown reversed MK-4-mediated stimulation of these genes, indicating the involvement of PXR in this effect. In addition, we showed that the expression of MDR1 and CYP3A4 genes increased synergistically after 24 h of rifampicin and MK-4 co-treatment. Our study thus elucidates the importance of drug–nutrient interaction mediated via PXR.

Reliability of Self-Administered Questionnaire on Dietary Supplement Consumption in Malaysian Adolescents

The repeatability of most questionnaires utilized in previous studies related to the consumption of dietary supplements (DS) among youth has not been well documented. Thus, a simple and easy-to-administer questionnaire to capture the habitual use of DS in the past one year known as the dietary supplement questionnaire (DiSQ) was developed and supported with external reliability evaluation. Analyses were done based on a convenience sample of 46 secondary school students. To elicit information regarding the intake of DS, the questionnaire was partitioned into two domains. The first domain was used to identify vitamin/mineral (VM) supplements, while the second domain was utilized to identify non-vitamin/non-mineral (NVNM) supplements. Cohen’s kappa coefficient (k) was used to evaluate the test–retest reliability of the questionnaire. Questionnaire administration to the respondents was done twice whereby a retest was given two weeks after the first test. Between test and retest, the reliability of individual items ranged from moderate to almost perfect for the VM (k = 0.53–1.00) and NVNM (k = 0.63–1.00) domains. None of the items had “fair” or ”poor” agreement. Various correlation coefficients can be obtained for the DiSQ but are generally reliable over time for assessing information on the consumption of supplements among the adolescent population.

Supplement (mis)use in adolescents

PURPOSE OF REVIEW

Dietary supplement usage by adolescents has been on the rise in the last decade and is expected to continue to grow, although the evidence of their benefits in healthy individuals remains unclear. This review aims to spread awareness about the poorly regulated supplements and their effects on the health of adolescents to minimize medical hazards.

RECENT FINDINGS

In this review, we have attempted to summarize some of the commonly consumed supplements, their alleged benefits, effects and side effects, along with the motivation that drives adolescents into consuming them.

SUMMARY

The widespread use of dietary supplements among adolescents, in the background of lack of knowledge and medical guidance, predisposes adolescents to significant health risks. Although supplements may be necessary and safely consumed in certain specific situations, most healthy adolescents do not need them. The lack of regulation of supplements encourages contamination and ensures indiscriminate, easy access.

Use of nutritional supplements by elite Japanese track and field athletes

BACKGROUND

While scientific evidence supports the efficacy of only limited nutritional supplements (NS) on sports performance, the use of NS is widespread in athletes. Given the serious issues of health damage or unintended Anti-Doping Rule Violations due to ingestion of contaminated NS in sports, accurately understanding NS practices by athletes is crucial. This study therefore elucidated the use of NS by elite Japanese track and field (TF) athletes.

METHODS

The subjects were 574 Japanese TF athletes, including 275 junior athletes (under 20 years) and 299 senior athletes, who participated in international competitions from 2013 to 2018. Data on NS use were collected through pre-participation medical forms obtained from all entrants before their participation in competitions. NS users were requested to report the product names and primary components of all NS they were taking.

RESULTS

The overall prevalence of NS use was 63.9%. The mean number of NS products used per athlete was 1.4. The prevalence was significantly higher in women (69.2%) than in men (59.6%) (p = 0.018) and significantly higher in senior athletes (68.9%) than in junior athletes (58.9%) (p = 0.012). The prevalence of NS use was higher in long-distance runners (75.8%) and lower in jumpers (52.3%) and throwers (49.2%) than other disciplines (p < 0.001). The most prevalent components were amino acids (49.3%), followed by vitamins (48.3%), minerals (22.8%), and protein (17.8%).

CONCLUSIONS

Approximately two-thirds of elite Japanese TF athletes reported the use of NS, and NS practices varied by gender, age, and discipline.

An educational intervention improved knowledge of dietary supplements in college students

BACKGROUND

We have previously reported on the prevalence of dietary supplements among college students; it was deduced that their intake of supplements increased according to their grade (i.e., 13.1% in the first grade to 20.5% in the sixth grade). We also reported that some students had experienced adverse events in Japan due to their intake of these supplements. However, awareness of dietary supplements among college students remains limited, even among pharmaceutical students. Being appropriately educated about them is important for pharmaceutical students, both for themselves as well as for their future careers as pharmacists.

METHODS

We conducted a lecture-based educational intervention about dietary supplements on 328 college students in Japan-184 from pharmaceutical science and 144 from environmental science or food and life science disciplines. The purpose of this study was to evaluate the effects of an educational intervention on college students' understanding of dietary supplements. The intervention involved a lecture that covered the quality of dietary supplements, how they differed from drugs, and a summary of their adverse events. The lecture was evaluated using a 14-question questionnaire. We then compared the pre- and post-intervention responses to the same questionnaire using a Wilcoxon signed-rank test. The questions were assessed using a Likert scale that ranged from "strongly agree" to "strongly disagree"; the latter being the preferred answer.

RESULTS

Before the intervention had taken place, the students' understanding of dietary supplements was shown to be deficient. Conversely, post-intervention, their knowledge levels had significantly improved, especially concerning agreement on whether "Dietary supplements are safe because they are just food items". Pre-intervention, 2.7% strongly agreed and 37.5% agreed; post-intervention, 1.2% strongly agreed and 15.6% agreed. On whether "Dietary supplements made from natural ingredients or herbs are safe", at the pre-intervention stage 2.8% strongly agreed and 44.0% agreed and post-intervention, 2.2% strongly agreed and 16.9% agreed. On whether "Dietary supplements made from food items are safe", 4.0% strongly agreed and 43.6% agreed pre-intervention and 0.9% strongly agreed and 16.6% agreed post-intervention. Despite there being a greater number of pharmaceutical students who had a correct understanding of dietary supplements before the intervention, these students still showed improvement after the lecture.

CONCLUSION

An intervention in the form of a single educational lecture has the capacity to improve college students' understanding of dietary supplements. It is important for pharmacists to be appropriately educated about dietary supplements when they consult with patients. We will evaluate the long-term effects of the intervention on the alumni (pharmacists) in a subsequent study.

Vitamin D Status in Japanese Adults: Relationship of Serum 25-Hydroxyvitamin D with Simultaneously Measured Dietary Vitamin D Intake and Ultraviolet Ray Exposure

Vitamin D insufficiency/deficiency is prevalent worldwide. We investigated the effect of vitamin D intake and ultraviolet ray (UV) exposure on serum vitamin D concentration in Japan. A total of 107 healthy adult participants were recruited from Hokkaido (43° N) and Kumamoto (33° N) prefectures. All participants undertook surveys in both summer and winter. Serum 25-hydroxyvitamin D (25(OH)D₃) was examined, and vitamin D intake was assessed with a diet history questionnaire. UV exposure was measured with a wearable UV dosimeter. Regression analysis was performed to investigate the relationship between these factors, with covariates such as sun avoidance behavior. The prevalence of vitamin D insufficiency (serum 25(OH)D₃; 12 ng/mL (30 nmol/L) ≤ and <20 ng/mL (50 nmol/L))/deficiency (<12 ng/mL) was 47.7% in summer and 82.2% in winter. UV exposure time was short in Kumamoto (the urban area), at 11.6 min in summer and 14.9 min in winter. In Hokkaido (the rural area), UV exposure time was 58.3 min in summer and 22.5 min in winter. Vitamin D intake was significantly associated with serum 25(OH)D₃, and a 1 μg/1000kcal increase in intake was necessary to increase 25(OH)D₃ by 0.88 ng/mL in summer and by 1.7 ng/mL in winter. UV exposure time was significantly associated with serum 25(OH)D₃ in summer, and a 10 min increase in UV exposure time was necessary to increase 25(OH)D₃ by 0.47 ng/mL. Although consideration of personal occupation and lifestyle is necessary, most Japanese may need to increase both vitamin D intake and UV exposure.

Concomitant Use of Dietary Supplements and Medicines among Preschool and School-Aged Children in Japan

Dietary supplement use is widespread amongst the general population including in children and adolescents. The ingredients in dietary supplements can interact with medicines when patients take them concomitantly. However, the prevalence of the concomitant use of dietary supplements and medicines in Japan among children remains unclear. To clarify this issue, a nationwide internet survey was administered to 55,038 mothers (25 to 60 years old) of preschool- or school-aged children in Japan. Among them, 7.6% currently provide dietary supplements and 3.2% concomitantly provide dietary supplements and prescription or over-the-counter medicines to their children. The prevalence of concomitant use increased with the children's grade. Among 1057 mothers with 1154 children who were concomitantly using dietary supplements and medicines, 69.1% provided dietary supplements without physician consultation because they considered dietary supplements as only foods and therefore safe. Although the purpose of the use and types of dietary supplement differed between boys and girls, the most popular product was probiotics in both boys and girls. Among concomitant users, 8.3% of mothers gave dietary supplements for treatment of diseases and 4.9% mothers recognized the adverse events of dietary supplements in their child. The findings of this study suggest that mothers' knowledge about the risk of using dietary supplement with medicines is insufficient. Parental education about the safety of dietary supplements and potential risk of drug-supplement interaction is needed.

Determinants of taking dietary supplements in Iranian children and adolescents: the CASPIAN-V study

Aim

Tendency for taking dietary supplements is dramatically increasing. However, limited studies exist in this regard. We aimed to assess the frequency and determinants of dietary supplement use among a nationally-representative sample of Iranian children and adolescents.

Methods

This population-based cross-sectional study (the CASPIAN V) was conducted in students aged 7 to 18 years old in 2015. Multistage, stratified cluster sampling method was used to select participants from thirty provinces in Iran. Data regarding taking vitamin and mineral supplements were collected. Demographic information, anthropometric indices, physical activity, screen time and body image were also evaluated. Multivariate logistic regression model was used for analyses.

Results

The prevalence of dietary supplements use was 34.1% and the most popular dietary supplement was Iron (12.9%). Multivariate logistic regression showed that boys (0.84, 95%CI: 0.78, 0.91) and body image perception (OR: 0.84, 95%CI: 0.75, 0.94) used less dietary supplements compared to others. Children aged 11 to 14 years (OR: 1.15, 95%CI: 1.06, 1.26) and those with moderate family socioeconomic status (OR: 1.12, 95%CI: 1.007, 1.25) used more supplement compared to other groups. Moreover, those with higher paternal educational level (OR: 0.77, 95%CI: 0.64, 0.93) used less supplements. However, living area, family size, paternal occupation, children BMI, Intended weight loss, and body image by student did not indicate any significant association.

Conclusion

Our findings indicated that about one-third of Iranian children and adolescents used dietary supplements; iron supplements were the most frequent ones. Children aged 11 to 14 years, those with higher educated mothers and moderate family socioeconomic status used more supplements compared to others. However, boys, children with excess weight and those with high-educated parents used less supplements compared to others. More studies are needed to clarify the efficacy and safety of dietary supplements in different age groups in various societies.

A Nationwide Survey of the Attitudes toward the Use of Dietary Supplements among Japanese High-School Students

We previously studied the prevalence of dietary supplement use in Japanese high-school students by conducting a study on mothers. However, there is often a discrepancy between mothers' understanding and children's attitudes. Thus, we conducted an internet survey of high-school students to clarify their attitudes toward the use of dietary supplements. An invitation to the internet survey was e-mailed to registrants of a research company aged 15 to 18 years. A total of 1031 students (276 male, 755 female) answered the questionnaire on a first come, first served basis. The participants were classified according to the purchasers of their supplements: students who purchased supplements themselves were defined as active users, and others were defined as passive users. The prevalence of dietary supplement use was 30.8% in males and 26.7% in females. Among the users, 42.4% of males and 43.8% of females were active users. Males used supplements for health regardless of active or passive use. However, in females, more active users (40.9%) used supplements for weight loss than passive users (20.4%); the corresponding prevalence was 2.3% in our previous report on mothers' understanding of their daughters. The most frequently used source of information for active users was the internet, whereas for passive users it was family. The frequency of adverse events was 9.4% in males and 14.4% in females, with gastrointestinal symptoms being the most commonly experienced events. Our results suggest that dietary education, including healthy eating and the appropriate use of dietary supplements, should be provided to high-school students.