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

Global Prevalence of Adolescent Use of Nonprescription Weight-Loss Products: A Systematic Review and Meta-Analysis

Importance

Use of nonprescribed weight-loss products in adolescents is a public health concern that is associated with negative physical and psychological consequences. However, the prevalence of nonprescribed weight-loss product use in adolescents is unknown.

Objective

To determine the global prevalence of nonprescription weight-loss product use in children and adolescents.

Data Sources

Four databases, including MEDLINE, PsycINFO, CINAHL (Cumulative Index of Nursing and Allied Health), and EMBASE, were searched for quantitative studies that reported prevalence data on use of nonprescription weight-loss products with no restrictions on publication date. The search was performed December 1, 2020, and updated March 6, 2023.

Study Selection

Studies were included in the meta-analysis if they reported the prevalence of weight-loss product use, were published in English, and included individuals 18 years or younger.

Data Extraction and Synthesis

Data extraction was completed by 2 independent reviewers. Data analysis determined the overall pooled proportion of weight-loss product use in total and during the past week, past 30 days, past year, or lifetime. Inverse variance heterogeneity effect models were used.

Main Outcomes and Measures

The main outcome measure was the prevalence of nonprescription weight-loss product use in adolescents for all included studies and over the past week, past month, past year, or lifetime. Subgroup analysis included separation of groups by sex, specific weight-loss product types, geographical location, and study publication time.

Results

A total of 90 articles (604 552 unique participants) were included in the meta-analysis. Of these, 50 studies (56%) were from North America. The reported prevalence of weight-loss product use in adolescents was 5.5% (96% CI, 5.5%-5.6%) overall. When identifying use of weight-loss products in the general population, prevalence was 2.0% (95% CI, 1.9%-2.1%) in the past week, 4.4% (95% CI, 4.3%-4.5%) in the past month, 6.2% (95% CI, 6.1%-6.3%) in the past year, and 8.9% (95% CI, 8.6%-9.2%) in their lifetime. Use of weight-loss products was higher among girls than boys.

Conclusions and Relevance

This meta-analysis found that use of weight-loss products occurs at high levels in adolescents, especially girls. These findings suggest that, given the ineffectiveness of these products for weight loss coupled with their harmful long-term health consequences, interventions are required to reduce use of weight-loss products in this group.

Coleus forskohlii Extract Attenuated the Beneficial Effect of Diet-Treatment on NASH in Mouse Model

Obesity is one of the main causes of non-alcoholic steatohepatitis (NASH), which is associated with impaired liver functions including drug metabolism. Coleus forskohlii extract (CFE) is a popular ingredient of weight loss dietary supplements in Japan. In this study, we examined the effect of CFE on the treatment of NASH. C57BL/6 mice (male, 10-wk-old) were fed a NASH diet (high-fat, low-methionine, and choline-deficient diet) for 12 wk to establish NASH. Then, we examined the effect of 0.5% (w/w) CFE in diet during diet-treatment (change to control diet) and/or treadmill-exercise (45 min at 20 m/min, 5 d/wk) to improve NASH for 3 wk. After experimental period, lipids profiles and liver functional markers in the blood, and hepatic lipid content and major CYP subtype mRNA expression and activity in liver were measured. Diet-treatment, but not exercise decreased liver weight and hepatic lipid contents in NASH induced mice. CFE attenuated the effects of diet-treatment which reduced liver weight, even though body weight and adipose tissue weight were reduced. Further, CFE significantly increased liver microsomal CYP1A1, CYP1A2, CYP2C, and CYP3A activities in each condition, and CYP inductions were greater in diet-treatment group compared to those in exercise group. These results suggest that taking CFE should be avoided during diet-treatment of NASH, especially in patients under medication.

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.

Internet Use, eHealth Literacy, and Dietary Supplement Use Among Young Adults in Pakistan: Cross-Sectional Study

Background

Increased access to the internet has facilitated widespread availability of health information. Thus, electronic health (eHealth) literacy—the ability to seek, find, understand, and appraise health information from electronic resources and apply that knowledge in making a health-related decision—is a crucial skill. Despite the increasing use of the internet as a source of health information in developing countries, only a few studies have examined the eHealth literacy of young adults, who frequently use the internet to access health information in these developing countries.

Objective

The aim of this study was to assess the patterns of internet use and eHealth literacy levels among university students pursuing a non–health-related degree in Pakistan. We also examined the association of the eHealth literacy levels of these young adults with their physical activity levels and dietary supplement intake.

Methods

Students from 2 leading engineering universities in Pakistan were invited to participate in a cross-sectional anonymous web-based survey in order to collect data on their internet use, eHealth literacy, and dietary supplement intake. Of the 900 eligible university students who were invited to participate, 505 (56.1%) students who completed the questionnaire were included in the analysis. The findings were converted to median values and frequency analyses were performed. The associations between the variables were determined using the chi-square test; P≤.05 was considered significant.

Results

In this study, the median eHealth literacy scale (eHEALS) score was 29, which did not vary across gender. The most common type of health-related information that was searched by the participants was that related to maintaining a healthy lifestyle (305/505, 60.4%). Participants with high eHEALS scores were those who used the internet frequently for finding people with similar health issues (P<.001). The use of specific social media platforms was not associated with the perceived eHealth literacy levels. Neither the frequency of physical activity nor the dietary supplement use was associated with the eHealth literacy of the participants.

Conclusions

University students in non–health-related disciplines in Pakistan expressed high confidence in their skills to find health-related information on the internet, as indicated by the aggregate eHEALS scores. However, the findings of our study show that the perceived eHealth literacy was not associated with health behaviors such as physical activity and dietary supplement intake. Further research is necessary to investigate the extent to which eHealth literacy can be considered as a panacea for solving public health challenges in developing countries.

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.