Nutrition Research and Practice最新文献

Background/objectives: Fatigue is closely associated with an impaired mitochondrial function, oxidative stress, and inefficient energy metabolism, all contributing to reduced physical performance. Nutritional strategies targeting mitochondrial biogenesis and antioxidant defense may help alleviate fatigue and enhance endurance. This study examined the anti-fatigue and antioxidant effects of an amino acid (AA)-epigallocatechin gallate (EGCG) mixture comprised of 3 AAs (cysteine [Cys], glutamine [Gln], and leucine [Leu]) and EGCG on mitochondrial biogenesis, oxidative stress mitigation, and physical performance enhancement.

Materials/methods: C2C12 myoblasts were treated to assess mitochondrial biogenesis-related gene expression and oxidative stress markers. Animal studies measured the swimming endurance, glycogen, adenosine triphosphate (ATP), and serum parameters. A pilot clinical trial evaluated the blood glucose, lactate, and serum enzyme levels post-exercise.

Results: In cellular experiments, a 1:1:3 ratio of the AA mixture (Cys, Gln, and Leu) with EGCG enhanced mitochondrial biogenesis-related gene expression (AMP-activated protein kinase, sirtuin 1, and peroxisome proliferator-activated receptor gamma coactivator 1α [PGC-1α]) and reduced the oxidative stress markers (reactive oxygen species and malondialdehyde [MDA]). Animal studies revealed significant increases in swimming endurance, elevated glycogen and ATP levels, and reduced serum fatigue markers (creatine phosphokinase, lactate dehydrogenase, and blood nitrogen). Furthermore, nuclear factor erythroid 2-related factor 2 (NRF2) and PGC-1α expression was significantly upregulated in the gastrocnemius muscle, supporting enhanced mitochondrial function. In addition, the antioxidant effects were observed with reduced MDA levels in liver tissue. Clinical trial data showed improved blood lactate clearance and higher post-exercise blood glucose levels in the AA-EGCG group compared to the placebo group.

Conclusion: The AA-EGCG mixture enhances mitochondrial biogenesis and antioxidant capacity by activating the NRF2 and PGC-1α pathways, improving physical performance and reducing fatigue. This study highlights its potential as a supplement for managing fatigue and enhancing endurance.

Background/objectives: Iodine is an essential mineral that is critical for humans, as inadequate and excessive intake can lead to adverse health outcomes. Data on dietary iodine intake and adequacy among Koreans remain limited. This study aimed to estimate the dietary iodine intake of Koreans, assess the adequacy of intake, and examine the primary dietary sources of iodine in the Korean population.

Subjects/methods: This study analyzed data from 18,895 participants aged ≥ 1 yr obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) 2019-2021. Dietary iodine intake was calculated using a newly constructed iodine database applied to KNHANES data. Intake levels were compared against the sex- and age-specific reference values outlined in the Korean Dietary Reference Intakes 2020. Insufficient intake was below the estimated average requirement (EAR), while excessive intake was above the tolerable upper intake level (UL).

Results: The median iodine intake of Koreans aged ≥ 1 yr was 114 µg/d, corresponding to 123% of the EAR. Approximately 4 in 10 Koreans did not meet the EAR, one exceeded the UL, and only 5 had adequate iodine intake. Excessive intake was most prevalent among children under 12 yrs of age. Two-thirds of iodine intake came from plant-based foods, with seaweed, eggs, fish, milk, and grains identified as the major dietary contributors.

Conclusion: Koreans' median dietary iodine intake appears adequate; however, a significant proportion exhibit insufficient or excessive intake. Further research is needed to estimate usual iodine intake and develop strategies for addressing problematic iodine intake.

Background/objectives: Atherosclerosis is a chronic inflammatory disease characterized by the buildup of low-density lipoprotein (LDL) within arterial walls, triggering inflammation and vascular constriction. Vitamin D has been shown to suppress T cell proliferation, reduce inflammatory responses, and promote the development of regulatory T cells (Tregs). However, its role in modulating T cell function in atherosclerotic models is not fully understood. This study examined the effects of vitamin D supplementation on T cell activation and Treg development in Ldlr ^-/- mice.

Materials/methods: C57BL/6J mice (CON) were fed a control diet (10% kcal fat), while B6.129S7-Ldlr^tm1Her /J mice (ATH) were fed a Western diet (40% kcal fat + 0.15% w/w cholesterol). Both diets contained 1,000 or 10,000 IU vitamin D/kg diet (vDC or vDS, respectively) for 16 weeks. Purified T cells were stimulated using plate-bound anti-CD3ε/soluble anti-CD28, then cultured for 48 h. Immune cell populations in the spleen, cytokine production by T cells, and the expression of key genes and proteins involved in Treg function, T cell receptor (TCR) signaling, and hypoxia were assessed.

Results: The expression of TCR signaling genes (Lck and Zap70) and the Treg transcription factor forkhead box P3 (Foxp3) were significantly higher in ATH compared to CON. Additionally, interleukin (IL)-10 levels were higher in ATH than in CON, while IL-17 and IL-2 levels did not show significant differences between the groups. Expression of hypoxia-inducible factor (Hif1a) was also higher in ATH compared to CON. Overall, vitamin D supplementation had a notable effect on Zap70 expression, which was lower in vDS compared to vDC.

Conclusion: The higher Foxp3 expression and IL-10 production observed in the ATH suggest the activation of compensatory mechanisms to counteract inflammation. Enhanced TCR signaling in the ATH, likely associated with oxygen depletion due to heightened energy demand, may have contributed to the elevated Hif1a expression. The lower Zap70 expression in the vDS suggests that vitamin D supplementation suppresses T cell activation.

Background/objectives: The association between coffee and tea consumption and the risk of hyperuricemia and gout remains controversial. This meta-analysis of observational studies evaluated this association.

Materials/methods: We conducted a literature review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched the PubMed, Embase, and the Cochrane Library databases through December 2024 using related keywords. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model.

Results: We included 13 observational studies, 10 cross-sectional studies, and 3 cohort studies involving 27,740 hyperuricemia and gout cases among 936,827 participants. While coffee consumption was significantly associated with a decreased risk of hyperuricemia and gout (OR, 0.73; 95% CI, 0.63-0.85; I² = 77.5%), tea consumption was not (OR, 1.02; 95% CI, 0.84-1.24; I² = 84.2%). In the subgroup analyses, coffee consumption was significantly associated with decreased risk of hyperuricemia and gout in cohort (OR, 0.51; 95% CI, 0.40-0.66; I² = 26.9%; n = 3) and cross-sectional (OR, 0.87; 95% CI, 0.79-0.96; I² = 49.1%; n = 6) studies. Tea consumption was significantly associated with an increased risk of hyperuricemia and gout in both male (OR, 1.18; 95% CI, 1.00-1.41; I² = 56.5%; n = 5) and female (OR, 1.19; 95% CI, 1.03-1.39; I² = 0.0%; n = 5).

Conclusion: The results of this meta-analysis suggest that dietary coffee, but not tea, consumption reduces the risk of hyperuricemia and gout. However, further prospective cohort studies are needed to confirm the confounding factors of the association between coffee and tea consumption and hyperuricemia and gout.

Background/objectives: Although dietary protein intake has received significant attention recently, research on dietary amino acid (AA) intake remains limited. Thus, this study aimed to estimate AA intake and food sources among Korean adults between 2010 and 2022.

Subjects/methods: Based on the Korea National Health and Nutrition Examination Survey data, 69,664 adults aged 19 yrs or older were included. Essential AA (EAA), branched-chain AA (BCAA), and nonessential AA (NEAA) intakes were estimated.

Results: The average total AA intake over the past 13 yrs was 62.1 g/day, consisting of 24.8 g/day of EAAs (11.8 g/day of BCAAs) and 37.3 g/day of NEAAs. Leucine was the most commonly consumed EAA, while glutamic acid was the most consumed NEAA. Over the study period, total AA intake remained stable. However, total AA intake relative to body weight significantly decreased, whereas intake relative to total energy and protein intake significantly increased. Similar trends were observed for EAAs, BCAAs, and NEAAs (P for trend < 0.0001 for all). Meat and grains were the primary food sources of AAs, and the contribution of meat consistently increased (P for trend < 0.0001).

Conclusion: While the total absolute AA intake has remained stable over the past 13 yrs, AA density relative to protein and energy intake has increased, accompanied by changes in individual AA intake over the past decade. These findings may inform future revisions of AA intake recommendations for Koreans and facilitate further research on the association between dietary AAs and various diseases.

Background/objectives: Shift work, defined as employment outside standard working hours, is becoming increasingly common in industrialized countries. This study examined the differences in eating behaviors, home meal replacement (HMR) consumption, and nutrition quotient (NQ) between male shift and non-shift workers.

Subjects/methods: A total of 392 male workers (193 shift workers and 199 non-shift workers) in the Chungcheong region of Korea participated between May and July 2024. Data were collected using a self-administered questionnaire that assessed the general characteristics, eating behaviors, frequency of HMR consumption, perceived importance and satisfaction with the HMR attributes, and NQ. Statistical analyses were conducted using SPSS version 28.0, with χ² tests, independent t-tests, and analysis of covariance.

Results: Shift workers were significantly more likely to have lower education levels, lower monthly household income, and to be employed in manufacturing-related jobs than non-shift workers. They also showed more irregular meal timing, frequent late-night eating, higher smoking rates, less frequent physical activity, and poorer perceived sleep quality. Shift workers reported significantly more frequent consumption of specific HMR products, including gimbap/lunchboxes (0.51 vs. 0.37), sandwiches/burgers (0.43 vs. 0.36), microwavable snack foods (0.33 vs. 0.19), and frozen fried rice (0.21 vs. 0.12), based on a frequency score where 1 indicated once per week. No significant differences in the importance or satisfaction with HMR attributes were observed between the groups. In contrast, shift workers exhibited significantly lower total NQ scores (48.75 vs. 51.03), particularly in the balance and moderation domains.

Conclusion: Shift workers had less favorable eating behaviors, more frequent consumption of certain HMR products, and lower NQ scores than their non-shift counterparts, underscoring the urgent need for targeted public health strategies tailored to work schedules.

Background/objectives: Healthy eating supports mental clarity, physical development, and focus in the classroom. However, government policy, cultural customs, education, family income, and food access, influence children's nutrition, which in turn affects school-age children's growth, development, and academic achievement. This study aimed to explore the barriers and facilitators influencing the nutritional and dietary intake of school-age children in urban low-income settings in Addis Ababa, Ethiopia.

Subjects/methods: A total of 10 schools (6 public and 4 private) from 2 subcities in Addis Ababa participated in a qualitative phenomenological study conducted in May 2024. Focus group discussions, key informant interviews (KIIs), and in-depth interviews (IDIs) with 92 participants were used to gather data. A total of 77 participants (41 male, 36 female) participated in 6 focus groups, 10 IDIs, and 5 KIIs from the Ministry of Agriculture, Ministry of Education, Save the Children, Water, Sanitation and Hygiene (WASH), and Ethiopian Public Health Institute (EPHI). Using MAXQDA software, native language data were transcribed, translated, and then thematically analyzed.

Results: Two major themes emerged from the study's findings. The fisrt one is barriers to healthy nutrition and dietary intake in school-aged children, including lack of awareness, inadequate and unhealthy dietary practices, financial hardship and time constraints within households, parental lack of awareness, food accessibility issues, poor infrastructure, and inconsistent policies. These factors were described as potential contributors to challenges in children's nutrition. The second one is facilitators, which include school meal programs, community engagement, family support, physical activity, and policy support for healthy eating, all of which are seen as promoting healthier dietary behaviors and possibly improving children's focus and participation in school activities.

Conclusion: Several factors influence children's diet and nutrition. Improving children's nutritional and general well-being requires focused nutrition education, policy interventions, and the utilization of coordinators.

Background/objectives: Spinal cord injury (SCI) is a severe trauma in the central nervous system (CNS) that not only affects human health but also imposes a significant burden on families. Several herbal extracts have been ascertained to regulate SCI progression. Cistanche deserticola polysaccharide (CDP), extracted from C. deserticola, exhibits beneficial effects in a variety of diseases. However, the regulatory roles and associated pathways of CDP in the SCI progression remains unclear.

Materials/methods: The SCI animal model was successfully established. The Basso-Beattie-Bresnahan scores were determined through locomotion recovery assessment. Histopathological changes in spinal cord tissues were confirmed through hematoxylin eosin staining, while the number of Nissl bodies in ventral horn of spinal cord was verified through Nissl staining. The levels of malondialdehyde, superoxide dismutase, glutathione peroxidase, and catalase were quantified using commercial assay kits. The expression of ionized calcium-binding adapter molecule 1 (Iba-1) or nuclear factor erythroid 2-related factor 2 (Nrf2) was evaluated through immunofluorescence assay, and the protein expressions were inspected through western blot analysis.

Results: CDP treatment significantly improved the histopathological damage of spinal cord tissues following SCI. Additionally, CDP alleviated oxidative stress in spinal cord tissue. It also alleviated microglia activation by reducing Iba-1 expression. Mechanistically, CDP triggered the Nrf2 signaling pathway, which in turn suppressed NLR family pyrin domain containing 3 (NLRP3) inflammasome activation, as proved through rescue assays.

Conclusion: CDP alleviates SCI in mice by inhibiting NLRP3 inflammasome activation via the Nrf2 pathway. This finding suggested that CDP may serve as a promising drug for ameliorating SCI.

Background/objectives: Chronotype and ultra-processed food (UPF) intake are individually associated with metabolic risk, but their combined effect remains unclear. This study examined the interaction between chronotype and UPF intake in relation to insulin resistance, assessed by the triglyceride-glucose (TyG) index.

Subjects/methods: Data were obtained from 542 adults in the Gangwon Obesity and Metabolic Syndrome (GOMS) Study. Chronotypes were classified into morning, intermediate, and evening types using Morningness-Eveningness Questionnaire-based clustering. UPF intake was assessed using a food frequency questionnaire and classified according to the Korean-adapted NOVA classification system. Intake was expressed as a percentage of total energy and divided into quartiles. General linear models were used to examine the interaction between chronotype and UPF intake in relation to the TyG index, with adjustments for relevant covariates. An additional analysis examined the association between TyG quartiles and diabetes prevalence.

Results: A significant interaction between UPF intake and chronotype was observed only in the evening-type group (P = 0.043). In this group, TyG values were significantly higher in Q3 and Q4 compared to Q1 (P = 0.005). The TyG index also varied significantly across chronotypes and UPF intake quartiles (P = 0.005 and P = 0.046, respectively). The odds of diabetes increased across TyG quartiles, with ORs of 3.52 (Q3) and 5.41 (Q4) compared to Q1.

Conclusion: The association between UPF intake and the TyG index varied by chronotype, with evening types showing greater vulnerability. These findings suggest that biological rhythms may modify the metabolic impact of diet, highlighting the need for personalized prevention strategies.

Background/objectives: The proliferation of appearance-centered values on social media has driven non-obese adolescents towards increasingly extreme diets and exercise programs to achieve weight loss. Despite this, the effects of concurrent diets and exercise on musculoskeletal development during adolescence are unclear. This study examined whether prolonged endurance exercise (EX) with intermittent fasting during adolescence adversely affects musculoskeletal growth.

Materials/methods: Eight-week-old male Sprague-Dawley rats were assigned to 1 of 4 groups: sedentary (SED), intermittent fasting (IF), EX (treadmill running), or a combination of IF and EX (IFEX) (n = 6 per group). The rats were treated for 8 weeks, and the food intake and body weight were measured weekly. After 8 weeks of treatment, the muscle and fat masses were measured, and the bone mineral content and mineral density were assessed using dual-energy X-ray absorptiometry. The mitochondrial and antioxidant enzymes, thiobarbituric acid reactive substances (TBARs), and factors related to protein synthesis and hydrolysis in skeletal muscle were also analyzed.

Results: The IF and EX separately reduced the body weight, but the IFEX strategy also decreased skeletal muscle weight and bone mass. The protein levels associated with mitochondrial enzymes were significantly lower in the IFEX group. Moreover, elevated levels of skeletal muscle TBARs, forkhead box protein O1 phosphorylation, and the E3 ubiquitin ligases muscle atrophy F-box and muscle ring-finger protein-1 were observed.

Conclusion: Eight weeks of IFEX treatment significantly impaired musculoskeletal development in healthy growing rats despite its intention to promote weight loss.