Dietary protein is a crucial macronutrient for systemic homeostasis, and the global interest in protein supplements has surged because of their roles in muscle synthesis, immune function, and sarcopenia prevention. In South Korea, the proportion of energy derived from protein has increased steadily over the past decade, reflecting a significant shift in dietary patterns toward greater reliance on protein. Concurrently, a wide range of protein- and amino acidbased processed foods and dietary supplements has been developed and actively consumed.Nevertheless, comprehensive data on the prevalence of protein supplement users, their characteristics across different life stages, and the contribution of supplements to total daily protein requirements are lacking. Unlike other macronutrients, the human body lacks a dedicated reservoir for protein storage, necessitating a continuous dietary supply to support protein turnover, particularly for older adults facing anabolic resistance and individuals with high physical demands. Although clinical evidence highlights that protein supplementation, particularly when combined with resistance exercise, effectively improves muscle mass and physical performance, the magnitude of these benefits remains inconsistent across different life stages and protein sources. Conversely, emerging concerns about the potential metabolic risks from chronic overconsumption suggest that the validity and safety of protein supplementation are unclear, highlighting the need for a precision nutrition approach. Thus, this review evaluates the status of protein supplement intake among Koreans, synthesizes evidence on its physiological benefits and drawbacks and examines international trends and regulatory frameworks. Developed as part of the technical assessment for the 2025 revision of the Dietary Reference Intakes for Koreans, this review addresses the current lack of longterm safety data on chronic protein overconsumption. It provides a foundational framework for evidence-based dietary guidelines and serves as a critical scientific basis for establishing future tolerable upper intake levels and nutrition policies for protein supplement use in Korea.

Background: Despite various therapeutic modalities for keloids have been introduced; however, their therapeutic effects are limited. Therefore, the development of a new approach for inhibiting collagen production by scar fibroblasts is needed. Objective: To investigate the effect of electrical stimulation using a low-frequency and low-intensity alternating current on collagen and MMP-1 levels in human dermal fibroblasts. Methods: Low-frequency (20 kHz) and low-intensity (1 V/cm) electrical stimulations were applied to primary dermal fibroblasts. The production of type I procollagen and expression of matrix metalloproteinase-1 were evaluated. Transcriptomic analyses were conducted to explore the possible modes of action of electrical stimulation. Results: Electrical stimulation effectively suppressed type I procollagen production and increased MMP-1 expression. In addition, transcriptomic analyses revealed that electrical stimulation altered the gene expression associated with membrane permeability and the structure of cellular membranes. Validation using real-time polymerase chain reaction revealed that electrical stimulation significantly altered the expression of mechanosensitive ion channels (PIEZO2) and membrane-bound protein organizing caveolae (CAVIN2). Conclusion Electrical stimulation using low-frequency and low-intensity alternating currents effectively modulates extracellular matrix homeostasis by altering the cellular membrane structure and function. Our findings suggest a promising therapeutic approach for the management of keloids and hypertrophic scars.

Background: Observational studies have suggested associations between dietary polyunsaturated fatty acids (PUFAs) and cancer risk; however, causal inference regarding skin cancer remains limited due to potential recall bias, confounding, and reverse causation. Objective: This study aimed to evaluate the causal association between genetically predicted circulating PUFA levels and the risk of skin cancers, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. Methods: We conducted a 2-sample Mendelian randomization (MR) study using genome-wide association study summary statistics from the UK Biobank (PUFAs, n=115,006) and the FinnGen consortium (BCC, n=26,272; SCC, n=4,663; melanoma, n=5,753). Genetic instruments were derived for omega-3, docosahexaenoic acid, omega-6, linoleic acid, and the omega-6:3 ratio.Multiple MR methods—including inverse-variance weighted, MR-Egger, weighted median, weighted mode, and MR-PRESSO—were applied to test for consistency and assess pleiotropy and heterogeneity. Results: A higher genetically predicted linoleic acid to total fatty acid ratio was associated with a significantly lower risk of BCC and SCC. Conversely, higher genetically proxied serum omega-3 levels were associated with increased risks of BCC, SCC, and melanoma. The risk effect on SCC was attenuated upon exclusion of rs174528, a variant in the fatty acid desaturase 1 (FADS1) gene, suggesting a role for endogenous PUFA metabolism in carcinogenesis. Conclusion This MR analysis supports a causal role of circulating PUFAs in skin cancer development and highlights the importance of FADS-mediated endogenous PUFA metabolism. These findings provide novel insights into the genetic and metabolic underpinnings of skin cancer susceptibility.

Antiviral therapy is an essential treatment for chronic hepatitis B (CHB) infection. Although hypophosphatemia is an important adverse effect of antiviral agents, its clinical significance remains unclear. We investigated the incidence and clinical consequences of hypophosphatemia in a large cohort of CHB patients. Methods: This retrospective cohort study included CHB patients who started antiviral therapy between 2005 and 2015 and continued it for at least 1 year. Patients with decompensated liver cirrhosis, diabetes mellitus, hypertension, concomitant diuretic administration, and end-stage renal disease were excluded. The primary outcome was a change in renal function. Secondary outcomes included the incidence of infection and changes in serum potassium, uric acid, and total carbon dioxide (tCO2). Results: Among the 4,335 patients, hypophosphatemia developed in 75 (1.7%). During the median 2-year follow-up period, patients with hypophosphatemia showed a lower estimated glomerular filtration rate than those in the control group. The incidence of infection and changes in serum potassium, uric acid, and tCO2 were similar between groups. Conclusion: Hypophosphatemia was associated with a renal function decline in patients with CHB receiving antiviral therapy.

Purpose: Recently, high-protein diets have become highly popular, and the market for protein products has steadily increased in Korea together with the development of various types of such products. However, there is limited information on the consumption of protein supplements (PS) or protein-fortified foods (PF). Thus, this study aimed to evaluate the use of PS/PF among young adults in Jeju. Methods: A total of 350 adults (140 men and 210 women) aged 19–39 years voluntarily participated in this study from June 2022 to May 2023. PS/PF use was measured using a questionnaire. Dietary intake was assessed using a 24-hour dietary recall. Results: Approximately 31.4% of the participants (n = 110) had consumed PS/PF for more than 2 weeks during the past year and 71.8% of them (n = 79) were still consuming these products (PS/PF consumers). The PS/PF consumers tended to be male and physically active (p < 0.05 for all). The most frequent reason for PS/PF use was muscle gain (59.5%), followed by protein supplementation (19.0%) and body fat loss (13.9%), and the most frequent type of PS/PF consumed was powders (70.6%), followed by drinks (17.7%) and bars (8.8%). The PS/PF consumers tended to consume a high-protein low-carbohydrate diet compared to the non-consumers. The prevalence of consuming dietary protein less than the estimated average requirement (EAR) was significantly lower in PS/PF consumers (13.9%) compared to non-consumers (25.4%; p = 0.0316). Conclusion These findings indicate that the necessity of protein supplementation should be determined based on the current dietary protein intake and individual requirements. The study also provides the basic information for establishing guidelines for appropriate protein intake.

Continuous renal replacement therapy (CRRT) has become the standard modality of renal replacement therapy (RRT) in critically ill patients. However, consensus is lacking regarding the criteria for discontinuing CRRT. Here we validated the usefulness of the prediction model for successful discontinuation of CRRT in a multicenter retrospective cohort. Methods: One temporal cohort and four external cohorts included 1,517 patients with acute kidney injury who underwent CRRT for >2 days from 2018 to 2020. The model was composed of four variables: urine output, blood urea nitrogen, serum potassium, and mean arterial pressure. Successful discontinuation of CRRT was defined as the absence of an RRT requirement for 7 days thereafter. Results: The area under the receiver operating characteristic curve (AUROC) was 0.74 (95% confidence interval, 0.71–0.76). The probabilities of successful discontinuation were approximately 17%, 35%, and 70% in the low-score, intermediate-score, and highscore groups, respectively. The model performance was good in four cohorts (AUROC, 0.73–0.75) but poor in one cohort (AUROC, 0.56). In one cohort with poor performance, attending physicians primarily controlled CRRT prescription and discontinuation, while in the other four cohorts, nephrologists determined all important steps in CRRT operation, including screening for CRRT discontinuation. Conclusion: The overall performance of our prediction model using four simple variables for successful discontinuation of CRRT was good, except for one cohort where nephrologists did not actively engage in CRRT operation. These results suggest the need for active engagement of nephrologists and protocolized management for CRRT discontinuation.

BACKGROUND/OBJECTIVES: The diet is an important route of exposure to endocrinedisrupting chemicals (EDCs). However, few studies have investigated the association between dietary intake and EDC exposure levels among Koreans. In an earlier study, we showed that the bioactivity of serum aryl hydrocarbon receptor ligands (AhRLs) could be a surrogate biomarker to indicate exposure to EDCs and that they inhibit mitochondrial function. We also found that the mitochondria-inhibiting substances (MIS) in serum ascertained by intracellular adenosine triphosphate (MIS-ATP) and reactive oxygen species (MIS-ROS) levels could be biomarkers of exposure to EDCs, as they showed a strong correlation with AhRL and the levels of EDCs in the blood. Here, we investigated the association between the consumption of specific foods and surrogate serum biomarkers for EDCs, namely AhRL, MIS-ATP, and MIS-ROS, among middle-aged Korean adults. SUBJECTS/METHODS: A total of 1,466 participants aged 45–76 yrs from the Ansung cohort of the Korean Genome and Epidemiology Study were included. Food consumption, including that of meat, fish, vegetables, and fruits, was measured using a semiquantitative food frequency questionnaire. RESULTS: Fish intake was positively associated with AhRL (β = 0.0035, P = 0.0166), whereas cruciferous vegetable intake was negatively associated with AhRL (β = −0.0007, P = 0.0488).Cruciferous vegetable intake was positively associated with the MIS-ATP levels (β = 0.0051, P = 0.0420). A higher intake of fish was significantly associated with an increased risk of high AhRL (tertile: odds ratio [OR], 1.49; 95% confidence intervals (CIs), 1.08–2.06; P for trend = 0.0305). In addition, the second-highest tertile of cruciferous vegetable intake had lower odds of high AhRL than the lowest tertile (OR, 0.73; 95% CIs, 0.54–0.97), although no significant linear trend was observed. CONCLUSION Consumption of different types of foods may be differentially associated with EDC exposure in middle-aged Korean adults.

Human nutrient intake is closely related to the conditions of their workplace.

Long working hours are associated with an increased risk of cardiovascular disease, yet the underlying mechanism(s) remain unclear. The study examines how occupational factors like working hours, shift work, and employment status correlate with dietary choices and sodium intake, impacting hypertension risk.

Human nutrient intake is closely related to the conditions of their workplace.