Nutrition reviews最新文献

This narrative review aimed to review plausible mechanisms for the role of vitamin C (ascorbic acid [AA]) in the maintenance of healthy weight and energy metabolism; examine the evidence for inadequate vitamin C (plasma AA <50 µmol/L), hypovitaminosis C (≤23 µmol/L), and vitamin C deficiency (≤11.4 µmol/L) in the disrupted homeostasis of obesity and metabolic syndrome; and ascertain whether vitamin C supplementation or dietary intervention could potentially treat obesity and the associated features of metabolic syndrome. Vitamin C hypovitaminosis and deficiency are prevalent in developed countries, despite the widespread availability of vitamin C-containing fruit and vegetables and vitamin supplements. Western diets are characterized by highly processed, macronutrient-rich foods, which are deficient in dietary fiber and micronutrients. This contributes to postprandial oxidative stress and gut dysbiosis, leading to profound effects on insulin sensitivity, hyperglycemia, levels of endotoxemia, fatty acid oxidation, adipocyte hypertrophy, and regulation of metabolism and energy balance. The existing in vitro and in vivo preclinical data demonstrate the effectiveness of vitamin C as both a prophylactic and a therapeutic intervention for obesity and metabolic syndrome. The outcomes in human intervention studies are more modest, with improvements in insulin sensitivity, lipid profile, metabolic inflammation, weight, hypertension, gut permeability, and hepatic steatosis. Some clinical studies are limited by the lack of baseline plasma AA concentrations, or the inability to optimize plasma AA in participants with hypovitaminosis C or metabolic syndrome. The addition of vitamin C to physical activity and dietary interventions may improve the efficacy of treatments for obesity and metabolic dysfunction. However, more data are required to understand the synergism between vitamin C supplementation, medical nutrition therapy, adequate exercise, and pharmacological intervention in weight control and metabolic syndrome management.

Adherence to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 statement has not been explored in the nutrition field. The objectives of this meta-research were to assess the reporting completeness of systematic reviews with meta-analysis (SRs-MA) of nutrition- and diet-related randomized controlled trials (RCTs), and to identify their main reporting limitations, and potential factors associated with adherence to PRISMA. We analyzed a random sample of 100 SRs-MA of nutrition- and diet-related RCTs published in journals indexed on PubMed between July 2021 and July 2022. Pairs of reviewers read the full texts to independently extract the data. One reviewer collected data on the journal's endorsement of PRISMA guidelines. A reporting completeness (RC) score was created using the data from the evaluations regarding whether each fragmented item of PRISMA 2020, PRISMA 2020 Abstracts, PRISMA-Search, and TIDieR checklists (a total of 114 sub-items) was reported in the SRs-MA and compared the RCs between studies grouped according to predefined characteristics. SRs were published in 63 different journals; most (54%) endorsed the PRISMA guidelines. Most SRs-MA (86%) mentioned the PRISMA, and 21 attached the PRISMA checklist. The mean (±SD) RC score was 53.2 ± 7.1%. None of the PRISMA items were completely reported in all SRs-MA. Only 13 items were completely reported in more than 75% of the SRs-MA. Protocol registration (beta = 3.61; 95% CI 1.22-5.99), self-reporting of PRISMA adherence (beta = 4.21; 95% CI 0.72-7.70), and evaluation of the certainty of the body of evidence (beta = 4.99; 95% CI = 2.42-7.55) were associated with RC. The poor RC in SRs-MA of nutrition- and diet-related interventions demonstrates that research in this field requires improvements. Indicators of research integrity and transparency, such as protocol registration, self-reported adherence to PRISMA, and evaluation of the certainty of the body of evidence, were positively associated with RC.

Context: Nutrition plays a fundamental role in the growth and healthy upbringing of children. While substantial evidence highlights the significance of nutrition during early life, the understanding of its impact on brain development and function, cognition, behavior, and learning throughout childhood and beyond is limited.

Objective: In this systematic review we addressed this knowledge gap by assessing the existing evidence on how nutrition influences brain structure and function, cognitive abilities, behavior, and learning skills in school-aged children (ages 5-18 years).

Data sources: A systematic search of MEDLINE (via PubMed, Science Direct, and Google Scholar) for published and clinical nutrition-based intervention studies was performed with the focus on effects significantly improving brain, cognition, behavior, and learning in children 5-18 years old for relevant studies published after January 2010.

Data extraction: A total of 977 studies were identified, out of which 76 studies fit the inclusion criteria and were included in the systematic analysis.

Data analysis: Included studies were systematically assessed to provide a comprehensive overview of the relationship between nutritional intake and its impact on brain structure and function, cognition, behavior, and learning skills. In addition, for intervention studies, quality assessment was performed.

Conclusions: Findings suggest that, despite the limited number of studies specifically examining brain-related benefits, nutrition plays a significant role in enhancing and supporting typical neurocognitive development during school age. Current results indicate that diet quality (eg, Mediterranean and Nordic) and the intake of specific nutrients, such as lipids, seem to have the most promising impact and are associated with positive effects. However studies' diversity (ie, intervention versus observational) and methodologies employed, limits drawing strong conclusions regarding the most effective nutritional interventions and their underlying causative mechanisms. In sum, this work provides a systematic summary of the available evidence, by identifying common findings across multiple studies, and suggesting avenues for future research in this important, yet underexplored, area.

Systematic review registration: PROSPERO registration No. 580224.

Context: Complementary feeding is a window of opportunity for optimal growth and development of eating behaviors and preferences. Social norms influence parents' complementary feeding decisions; however, we lack an understanding of what these norms are.

Objective: This mixed-methods systematic review aimed to determine the social norms surrounding complementary feeding and their development and influences in high and upper-middle income countries.

Data sources: Systematic searches were performed using 5 databases: Medline, CINAHL, PsychInfo, Scopus, and EmCare. Studies were eligible if they included caregivers of children aged 0-5 years and focused on social norms relating to complementary feeding. Records were screened in duplicate.

Data extraction: Findings were synthesized using Bayesian methods and categorized by objective.

Data analysis: The search identified 8419 articles, of which 34 articles reporting on 33 studies were included. This review found social and cultural norms around the timing of introducing complementary foods, first foods to introduce, types of foods to provide, feeding method, food preparation, family meals, infant weight, and social contexts. Social norms influenced intentions and behaviors around introducing complementary foods and were created and reinforced by various socioecological influences, including family, peers, health professionals, community, broader society, culture, religion, and education.

Conclusion: Social norms should be considered by health professionals and in public health initiatives to support families to meet nutritional recommendations, especially among migrant populations and/or those with strong family influences who might be exposed to norms that do not align with infant feeding recommendations. Longitudinal research is recommended to better understand the roles and influence of social norms throughout complementary feeding.

Systematic review registration: PROSPERO no. CRD42023424666.

Context: The global increase in the intake of ultra-processed food (UPF) parallels rising rates of early-onset colorectal cancer (CRC), raising concern about possible causal links. Although observational studies suggest that UPFs contribute to gastrointestinal inflammation, it remains unclear whether CRC risk is mediated through inflammatory pathways such as inflammatory bowel disease (IBD).

Objective: In this review we sought to evaluate, using a 2-stage mediation meta-analysis, the association between UPF consumption and CRC risk and to examine whether IBD mediates this relationship.

Data sources: We searched PubMed, Embase, Scopus, and Web of Science through September 2025.

Data extraction: Two reviewers independently extracted data using a standardized form, including study characteristics, UPF assessment method, exposure categories, follow-up, covariates, and adjusted effect estimates (hazard ratio [HR], relative risk [RR], odds ratio [OR], standardized incidence ratios [SIRs]). For UPF-CRC and UPF-IBD, the primary contrast was highest vs lowest UPF category, with per-10% increments recorded when reported. For IBD-CRC, adjusted RRs were abstracted similarly. No individual-level data were obtained.

Data analysis: Study-specific effect estimates were log transformed and pooled using random-effects models (REMLs). Heterogeneity was assessed via I2 and Cochran's Q. Associations of UPF-IBD and IBD-CRC were meta-analyzed separately and combined to estimate the indirect UPF-CRC effect via a 2-stage product-of-coefficients method, with SEs derived using the delta method.

Conclusions: Sixteen cohort studies including over 2 million participants met inclusion criteria. High UPF intake was modestly associated with increased CRC risk (RR 1.13, 95% CI, 1.06-1.20) and incident IBD (RR 1.33, 95% CI, 1.15-1.55), with stronger effects for Crohn disease. The IBD-CRC association was positive but heterogeneous (RR 1.36, 95% CI, 1.14-1.62). A 2-stage mediation model suggested a small indirect UPF to CRC effect via IBD (approximate RR 1.07). Higher UPF consumption is therefore associated with modestly increased risks of IBD and CRC, although the indirect effect through IBD appears limited.

Systematic review registration: PROSPERO registration No. CRD420251035864.

Context: Caloric restriction (CR) combined with exercise has been shown to significantly improve cardiovascular health; however, the synergistic effects of different exercise modalities with CR remain unclear.

Objective: In this network meta-analysis we aimed to compare the effects of resistance (RE), aerobic (AE), and mixed (MIX) exercise combined with CR on lipid metabolism and blood pressure to identify the most effective intervention strategy and provide evidence-based recommendations for cardiovascular health improvement.

Data sources: We systematically searched relevant studies published January 2007 to September 2024 in PubMed, Web of Science, Embase, and the Cochrane Library.

Data extraction: Randomized controlled trials (RCTs) examining CR combined with different exercise types were included in this analysis. Data were extracted on study characteristics, intervention details, and outcome indicators. The Cochrane Collaboration risk of bias tool was used to evaluate methodological quality.

Data analysis: Standardized mean differences (SMDs) with 95% CIs were calculated using a random-effects model. Subgroup analyses were performed based on study characteristics, methodological factors, and intervention duration.

Conclusions: When the intervention duration is ≤16 weeks, mixed exercise combined with CR exhibits the highest probability of yielding optimal improvements in blood lipids, cholesterol, and blood pressure. For interventions exceeding 16 weeks, aerobic exercise with CR is most likely to produce the greatest improvements in blood lipids and cholesterol. For improving blood pressure, mixed exercise combined with CR consistently shows a higher probability of being the most effective intervention compared to other approaches.

Systematic review registration: PROSPERO registration No. [CRD42025632306].

Accurate portion-size estimation is a key element of practical dietary assessment. Food atlases, visual representations of various portion sizes, have become increasingly popular estimation tools. However, their validity remains underexplored. This scoping review aims to evaluate the validity of food atlases in diverse dietary assessment contexts. A comprehensive search for relevant articles published between 2010 and February 2025 was conducted in 3 primary databases: PubMed, Scopus, and Web of Science. The inclusion criteria were original English-language studies that assessed the validity of food atlases as aids for portion-size estimation, regardless of population characteristics. Data extraction followed the PCC (Population, Concept, Context) framework and PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) guidelines. Of 241 articles identified, 27 met the eligibility criteria. Most studies (37%) were published between 2018 and 2021 and originated from 25 countries, primarily focusing on adult populations (59.3%). Both print (70.4%) and digital (22.2%) versions of food atlases were evaluated. Most studies reported acceptable validity for food atlases, although estimation accuracy varied widely between individuals. Amorphous foods and liquids exhibited lower validity. Overestimation was more frequent for smaller portions, while larger portions tended to be underestimated. Some studies reported no significant differences in estimation accuracy between printed and digital formats. Food atlases are potentially valid for estimating portion sizes at the population level; however, the accuracy at the individual level is variable. Accuracy may be improved through cultural adaptation, enhanced visual design, and complementary estimation tools. This review highlights key methodological considerations to guide future development and validation of food atlases.

Context: Type 2 diabetes mellitus (T2DM) is a global health problem characterized by chronic hyperglycemia, which disrupts the antioxidant defense system and increases reactive oxygen species (ROS). These changes contribute to the progression and complications of diabetes. As a result, therapies targeting redox balance, especially by enhancing endogenous antioxidant defenses, are being explored to prevent or reduce diabetic complications.

Objective: The present study aimed to systematically review the effects of bioactive food compounds on oxidative stress and the antioxidant defense systems in patients with T2DM.

Data sources: A comprehensive literature search was performed across multiple databases, including Medline, Embase, Web of Science, Scopus, and Cochrane CENTRAL.

Data extraction: The literature search included documents published from inception up to April 22, 2025, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only randomized controlled trials (RCTs) that evaluated the effects of food bioactive compounds on the outcomes of interest were included. Meta-analyses were performed using R. The standardized mean difference (SMD) and corresponding 95% CI were used to represent the pooled effects.

Data analysis: We included 109 human RCTs. Our meta-analysis demonstrated that both alpha-lipoic acid (ALA) and vitamin D led to significant reductions in glycosylated hemoglobin (HbA1c) levels. Additionally, the analysis indicated that curcumin and vitamin D significantly decreased malondialdehyde (MDA) levels. Amino acids like N-acetylcysteine, L-citrulline, and an amino sulfonic acid derivative (2-aminoethanesulfonic acid [taurine]), enhanced antioxidant defenses and improved glycemic control. Supplementation with zinc, selenium, and chromium was linked to better glycemic control and antioxidant status, including lower HbA1c and MDA, and higher total antioxidant capacity (TAC), glutathione (GSH), and antioxidant enzyme activity.

Conclusion: Supplementation with food bioactive compounds such as vitamin E, vitamin D, curcumin, and ALA may help to regulate HbA1c levels and enhance antioxidant defenses in patients with T2DM, indicating significant clinical potential for diabetes management. However, further research is needed to confirm their clinical efficacy and to determine optimal dosing strategies.

Systematic review registration: PROSPERO registration No. CRD42024592055.

Sarcopenic obesity (SO), a pathological interplay of muscle atrophy and excessive adiposity, poses increasing health risks in aging individuals. This review elucidates the multifactorial role of the gut microbiota (GM) in SO pathogenesis, emphasizing novel mechanisms linking GM dysbiosis to impaired muscle-lipid homeostasis. We emphasize how a Western diet and a sedentary lifestyle contribute to alterations in the GM composition, leading to changes in metabolic products, such as reduced short-chain fatty acids and increased production of lipopolysaccharides (LPS). These changes drive systemic inflammation, increased intestinal permeability, and metabolic dysfunction in adipose tissue and skeletal muscle. Emerging interventions, including next-generation probiotics, prebiotics, and glucagon-like peptide-1 receptor agonists (GLP-1RAs), demonstrate therapeutic potential. Our synthesis highlights GM as a pivotal therapeutic target, suggesting that personalized strategies combining microbiota modulation, dietary optimization, and exercise can be used to counteract SO. This work provides mechanistic insights into translational applications, offering a roadmap for innovative, microbiota-centric interventions to improve aging-related metabolic and muscle health.

Diabetes is a chronic, lifelong metabolic disorder characterized by elevated blood glucose levels. The role of diet and nutrition in the entire life cycle of metabolic diseases, particularly type 2 diabetes (T2D), is pivotal and represents the primary modifiable factors in combating the onset and progression of diabetes. The previous association between a high-sugar diet and diabetes risk has been well established. However, there is now evidence suggesting that a shift towards reduced carbohydrate intake and increased dietary fat may be linked to higher morbidity and mortality rates in patients with diabetes. This review investigated the effects of dietary fats and carbohydrates on the onset and progression of T2D and its associated complications (microvascular and macrovascular) and fatal events by reviewing several clinical studies and animal experiments. A lack of controlled trials comparing high-sugar and high-fat diets (HFDs) in clinical studies hinders us from drawing consistent conclusions. The majority of animal studies demonstrated a greater impact from HFDs compared with higher-sugar diets. There are several diets for treating diabetes that restrict fat intake below the upper limit of the dietary guidelines, and people with diabetes or abnormal glucose tolerance seem more able to tolerate low-fat, high-carbohydrate, low-calorie diets. Due to various factors, including the types of carbohydrates and fats, caloric intake, cognition, population age, and study design, it is difficult to conclusively determine which ratio of dietary components is more likely to contribute to diabetes, microvascular and macrovascular complications, or mortality events. Animal experiments may provide a systematic approach for simulating the effects of dietary fats and carbohydrates across the entire diabetes life cycle. Nevertheless, care must be taken when generalizing the findings from animal models to human contexts. Consequently, there is still a need for more high-quality, large, prospective controlled research to elucidate the role of dietary structure with different fat to carbohydrate ratios across the life cycle of diabetes. Meanwhile, studies should analyze relevant interactions, including potential effect modification factors.