Nutrition reviews最新文献

Context: There are various therapeutic approaches available to reduce homocysteine (Hcy) levels. However, it remains unclear which intervention is more effective for healthy adults.

Objectives: A systematic review and network meta-analysis (NMA) were conducted to comprehensively investigate the efficacy of different nutritional supplements in reducing Hcy levels in healthy adults.

Data sources: The PubMed, Embase, Cochrane Library, and Web of Science databases were searched from inception to July 2023.

Data extraction: The lead author, year of publication, sample size, population characteristics, intervention measures, duration, and mean difference of Hcy levels from baseline to endline were extracted.

Data analysis: Data were pooled using a random-effects model. Network meta-analysis was conducted by integrating direct and indirect evidence. A total of 16 studies were included in this analysis. The nutritional supplement combination that achieved the highest ranking (surface under the cumulative ranking curve [SUCRA] = 75.8) was superior compared with a single supplement. Among similar or closely dosed folic acid (FA) supplements, 800 μg FA (SUCRA = 93.7) was the most effective option. When comparing various doses of different supplements, 1 mg of FA plus 7.2 mg of vitamin B6 (B6) plus 20 μg of vitamin B12 (B12; SUCRA = 83.9) ranked first and 800 μg of FA (SUCRA = 78.3) ranked second. In comparison with placebo or no-treatment control groups, interventions such as 1 mg of FA plus 7.2 mg of B6 plus 20 μg of B12 (mean difference [MD] = -1.03; 95% CI -1.71 to -0.36), 400 μg of FA plus 400 μg of B12 (MD = -0.87; 95% CI -1.46 to -0.27), and 800 μg of FA (MD =  -0.84; 95% CI -1.12 to -0.56) were more effective in reducing Hcy levels. The random-effects summary MD for all interventions compared with placebo was -0.59 (95% CI -0.71 to -0.48; P < .0001).

Conclusions: The NMA demonstrated that the combination of FA with other vitamins is more effective in reducing Hcy levels, particularly when the dose of FA is close to 800 μg. The combination of 1 mg of FA, 7.2 mg of B6, and 20 μg of B12 is considered the most favorable option.

Systematic review registration: PROSPERO registration no. CRD42023453123.

Developing dietary guidelines for lactating women presents significant challenges, due to limited evidence being available on their specific nutrient needs and the biological impacts of various dietary dimensions. Current dietary recommendations often rely on data from nonlactating women, leading to potential inaccuracies. The relationship between diet and health outcomes in lactating women remains underexplored, particularly across different dietary dimensions, such as nutrients, food groups, dietary patterns, and other specific dietary variables. The aims of this scoping review were to map the diverse methodologies employed in research into maternal diet during lactation, to identify the current gaps, and to suggest areas for future investigation. The review focused on the dietary variables studied in relation to breastfeeding outcomes, and offers insights into the current state of lactation nutrition research. A comprehensive search was conducted in the CINAHL, MEDLINE, and Embase databases up to December 13, 2022. The included studies encompassed original quantitative research on dietary intake among lactating women and any associated outcomes. Data extracted included study characteristics, dietary variables, and outcome measures, and they were analyzed using descriptive statistics and pivot tables. Of the 1666 relevant studies identified, 231 met the inclusion criteria. Most research was conducted in high-income and upper-middle-income countries. Studies mainly focused on relatively short lactation durations, nutrient-based dietary dimensions, and maternal outcomes, particularly breast milk composition. Maternal metabolic status and child outcomes, such as infant micronutrient status and longitudinal growth, were underexplored. Specific dietary variables included meal frequency and nutrient intake from various food sources. Commonly adjusted covariates were maternal age and socio-economic status, while contraceptive use and sanitation were often overlooked. Many areas of research concerning the diet-health relationship in lactating women remain unexplored. Filling these gaps will gather evidence to inform the development of dietary guidelines for this population.

Objectives: This systematic review (SR) highlights principles for nutrient clinical trials and explore the diverse physiological functions of vitamin D beyond its traditional role in the musculoskeletal system related to clinical study designs.

Background: Thousands of published research articles have investigated the benefits of vitamin D (a nutrient example taken in this SR) beyond the musculoskeletal system, including the immune, pulmonary, and cardiovascular systems; pregnancy; autoimmune disorders; and cancer. They illustrated vitamin D's molecular mechanisms, interactions, and genomic and nongenomic actions.

Methods: This SR was designed to identify shortcomings in clinical study designs, statistical methods, and data interpretation that led to inconsistent findings in vitamin D-related publications. SR also highlights examples and insights into avoiding study design errors in future clinical studies, including randomized controlled clinical trials (RCTs). The SR adheres to the latest PRISMA statement, guidelines, and the PICOS process.

Results: Inappropriate or flawed study designs were frequent in clinical trials. Major failures discussed here include too short clinical study duration, inadequate or infrequent doses, insufficient statistical power, failure to measure baseline and achieved levels, and recruiting vitamin D-sufficient participants. These design errors have led to misleading interpretations. Thus, conclusions from such studies should not be generalized or used in guidelines, recommendations, or policymaking.

Conclusion: Adequately powered epidemiological studies and RCTs with sufficient vitamin D and duration in individuals with vitamin D deficiency reported favorable clinical outcomes, enriching the literature, enabling to understand its physiology and mechanisms. Proper study designs with rigorous methodologies and cautious interpretation of outcomes are crucial in advancing the nutrient field. The principles discussed apply not only to vitamin D, but also other micro-nutrients and nutraceutical research. Adhering to them enhances the credibility and reliability of clinical trials, SRs, and meta-analysis outcomes. The study emphasizes the importance of focused, hypothesis-driven, well-designed, statistically powered RCTs to explore the diverse benefits of nutrients, conducted in index nutrient deficient participants, and avoidance of study design errors. Findings from such studies should be incorporated into clinical practice, policymaking, and public health guidelines, improving the health of the nation and reducing healthcare costs.

Nonalcoholic fatty liver disease (NAFLD) is a prevalent liver disease, mainly associated with excessive accumulation of fat in the liver. It has become a global health concern. The diagnosis of NAFLD is often done through liver biopsy; however, noninvasive methods have their own advantages. Dietary intervention, especially increased dietary protein alongside managing overall body weight, have been shown to be a promising strategy to lessen the impact of NAFLD. Dietary protein has been shown to reduce fat accumulation in the liver by increasing liver metabolism, eliciting satiety, improving insulin sensitivity, and enhancing muscle mass retention, collectively aiding in weight management. Both animal and plant proteins have benefits; however, plant proteins have demonstrated more metabolic advantages, while animal proteins have more downsides. Bridging the protein gap is critical, particularly in areas with limited availability to high-quality protein or in populations where dietary protein intake is inadequate. This commentary highlights the importance of obtaining sufficient protein from readily available and sustainable food sources. Furthermore, diets high in protein, like the Mediterranean diet, have proven to delay the advancement and likelihood of NAFLD. In conclusion, adequate dietary protein plays a crucial part in diminishing the risk of NAFLD, and efforts in public health should concentrate on addressing protein deficiency to decrease the growing burden of liver disease.

Context: Early dietary habits play a crucial role in shaping long-term health outcomes. Understanding the effects of different carbohydrate types on physiological markers is essential for developing evidence-based nutritional guidelines for toddlers.

Objective: The aim was to systematically evaluate the impact of both digestible and nondigestible carbohydrate intake during early childhood (1-4 years of age) on various health outcomes, including growth patterns, metabolic parameters, and the development of risk of cardiovascular diseases.

Data sources: PubMed, Embase, and CENTRAL databases were searched up to April 2022 to identify studies investigating carbohydrate consumption in toddlers.

Data extraction: The types of carbohydrates consumed, their sources, and their associations with growth parameters and metabolic markers were extracted. Thirty-one publications, including 18 cohort studies and 2 randomized controlled trials, were included.

Data analysis: The risk of bias was assessed using the Mixed Methods Appraisal Tool. A narrative synthesis was performed, with a visual summary table of the direction of effects.

Conclusion: In toddlers, the negative impact on health risks later in life is more pronounced for digestible dietary carbohydrate intake in liquid forms, such as sugar-sweetened beverages and fruit juice, compared with solid forms. Higher nondigestible carbohydrate (dietary fiber) intake during early childhood showed a beneficial trend on later lipid profile. Further studies are required to comprehensively assess the effect of digestible and nondigestible carbohydrate intake in toddlers on cognitive and psychomotor development, infections, bowel function, and gut microbiota.

Context: COVID-19 remains globally pandemic, and although several meta-analyses have explored the association between vitamin D and COVID-19 relative to clinical outcomes, a unified view has not yet emerged.

Objective: To summarize the evidence for associations between vitamin D levels and COVID-19-related clinical outcomes and to assess the strength and validity of these associations.

Data sources: PubMed, Embase, Web of Science, Scopus, and the Cochrane Database of Systematic Reviews databases were searched from January 1, 2020, to June 15, 2024.

Data extraction: Two reviewers independently extracted data and assessed study quality.

Data analysis: Low vitamin D levels increased the risk of infection by 1.26- to 2.18-fold, the risk of severe illness by 1.50- to 5.57-fold, the risk of intensive care unit (ICU) admission by more than 2-fold, and the risk of death by 1.22- to 4.15-fold. In addition, patients with vitamin D deficiency had an average increase in length of hospital stay of 0.54 days compared with patients with high vitamin D levels. Overall, vitamin D supplementation may reduce severity (eg, ICU admissions, need for mechanical ventilation) and shorter length of hospital stay but has a nonsignificant effect on infection and mortality rates. In addition, there were significant differences in vitamin D levels between individuals testing positive for COVID-19 and those testing negative (mean difference [MD] = -3.22 ng mL-1; 95% CI, -5.18 to -1.25), those with severe cases and those with mild cases (MD = -4.60 ng mL-1; 95% CI, -5.49 to -3.71), and nonsurvivors and survivors of COVID-19 infection (MD = -6.59 ng mL-1; 95% CI: -8.94 to -4.24).

Conclusions: Low vitamin D levels are associated with higher infection rates, more severe disease, and higher mortality rates among individuals with COVID-19, whereas vitamin D supplementation may reduce patients' disease severity. The beneficial effects on infection rates and mortality remain to be further explored, however, in higher-quality, randomized controlled studies. Nonetheless, caution is warranted because the methodological quality of most meta-analyses and the level of evidence for most outcomes are very low.

Systematic review registration: PROSPERO registration No. CRD42022385036.

The edible and nonedible parts of the mango (Mangifera indica L.) contain vitamins, phytocompounds, fiber, and fatty acids. This review highlights the uses of mango by-products in the food industry and their effects on human health. The literature offers many new possibilities for the usage of mango secondary products in the food industry, such as the production of functional foods and bakery products, in addition to the potential for extraction of antioxidants and enzymes. Furthermore, due to their antioxidant and anti-inflammatory properties, the consumption of various mango by-products, in the form of peel and leaf (powder or extract), can improve glycemia, plasma lipid levels, satiety, and endothelial function, suggesting that these compounds can prevent or improve various risk factors for cardiovascular complications and metabolic syndrome. Clinical trials show that the discarded parts of mango fruits and leaves can be used to treat diabetes mellitus, obesity, and cardiovascular disorders. Moreover, mango by-products can be utilized to improve the functional characteristics of foods, may be incorporated as fat replacers, and have the potential to leverage agribusiness and reduce environmental damage resulting from the disposal of discarded materials, in addition to reducing waste and the complex chain of environmental damage. Mango by-products also have the potential to produce nutraceutical food items. The use of new technologies can bring to light the production of numerous products made from by-products, contributing to the development of industrial functional foods. In addition, products for the pharmaceutical and cosmetics industries may also be developed. Nutraceutical and pharmaceutical products could have lower prices and could, therefore, be used by low-income populations. The utilization of mango by-products meets the current trend and growing market for better and healthier products. However, more clinical trials are necessary to evaluate the effectiveness of mango by-products on human health, and new technologies can improve industrial applications.

Context: Dietary acid load (DAL) plays an important role in different aspects of human health.

Objective: The aim of this meta-analysis was to systematically synthesize the observational evidence reporting on the associations between the DAL (represented by a potential renal acid load [PRAL] and net endogenous acid production [NEAP]) and a range of health outcomes.

Data sources: A systematic search of Medline (via PubMed), EMBASE, Scopus, and Web of Science was performed to identify eligible studies.

Data extraction: Study screening and risk-of-bias assessment were conducted by 2 independent reviewers.

Data analysis: The credibility of each outcome was graded based on predefined criteria: pooled effect size with corresponding 95% CI, 95% prediction interval, heterogeneity, small-study effect, and excess significance bias. In total, 118 observational studies (case-control [n = 22], cross-sectional [n = 65], and cohort [n = 31]) on 38 outcomes were included, incorporating a total population of 1 014 081 participants. Overall, 21/37 and 20/38 of the outcomes reported statistically significant effect sizes for PRAL and NEAP, respectively. The credibility of the evidence for PRAL was rated convincing (class I) for type 2 diabetes (T2D), and as highly suggestive evidence (class II) for overall cancer and systolic blood pressure. By assessing the credibility of the evidence for NEAP, T2D and overall cancer presented convincing evidence (class I) and breast cancer presented highly suggestive evidence (class II). The remaining outcomes presented class III (suggestive) or lower evidence (weak or no association).

Conclusion: The higher acid-forming potential of diet was associated with a higher risk of T2D and overall cancer. Since this meta-analysis included observational studies and some of the associations were graded as weak, caution should be exercised in interpreting these associations. Further cohort studies are required with consideration of other factors that can cause biases.

Systematic review registration: PROSPERO registration no. CRD42022336050.

Background: Mounting evidence has shown that incarceration can affect the health and well-being of individuals and increase the risk of noncommunicable diseases (NCDs). Diet quality is known to be one of the main determinants of risk of NCDs, and dietary changes are the first approach used in primary care to reduce the incidence of NCDs.

Objective: This scoping review aimed to summarize the evidence for (1) the diet quality of inmates, and (2) the effect of nutritional intervention in prison systems. In addition, we aimed to describe limitations in the current literature and to suggest potential future research areas.

Method: A systematic search was performed in 2 databases (PubMed and Web of Science) using predefined search terms and covering the period May 2023 to June 2023. Additionally, reference lists from the retrieved studies were hand-searched to identify any additional relevant publications. The identified literature was screened based on defined search strategies, criteria, and research questions defined using the PICo (population or problem, interest, and context) framework. The review was conducted referring to the PRISMA-ScR and the PICo framework.

Results: A total of 19 studies out of 63 initially identified records were included in this review (11 cross-sectional evaluations and 9 intervention-based studies). In almost all studies, assessment of the diet quality of menus showed the menus to be nutritionally adequate, except for having a higher-than-recommended intake of total energy, saturated fatty acids, sodium, cholesterol, and sugar. In addition, some studies reported a lower-than-recommended intake of fiber, magnesium, potassium, vitamins D, E, and A, and omega-3 fatty acids. Nutritional interventions were mainly planned in the form of workshops, seminars, and written material to deliver information on healthy dietary choices. Although no significant changes in inmates' dietary choices were observed in any of the studies, a high participation rate was detected.

Conclusion: Inmates might require additional prevention intervention to reduce their susceptibility to cardiometabolic diseases by virtue of their isolation from community facilities. Interventions should be tailored to the characteristics of prison settings and inmates to increase adherence to nutritional recommendations.

Context: Orthorexia nervosa (ON) is characterized by compulsive behaviors and increased concerns about healthful eating. Dietitians appear to be especially vulnerable to ON, and it is still debatable whether the disordered eating behaviors motivate individuals to enroll in nutrition programs, or whether these behaviors result from an exaggerated preoccupation with healthy eating triggered during their nutrition studies.

Objective: The aim was to provide an overview of the present state of knowledge about the prevalence, risk factors, and interventions addressing ON among dietitians and dietetics students. More specifically, it was examined whether dietitians and dietetics students differ from students attending different education programs or other health professionals with regard to the severity and risk factors of ON, and whether the extent of ON changes during the progression in the nutrition education years of study.

Data sources: MEDLINE (Ovid), PubMed, EMBASE (Ovid), PsycInfo (EBSCO), CINAHL (EBSCO), Cochrane, ProQuest Central, CABI, ProQuest Dissertations, Google Scholar, ScienceDirect, and SpringerLink were searched on May 8, 2021, and updated on November 12, 2022.

Data extraction: Records were screened for eligibility; study characteristics, methodology, and findings of included articles were extracted; and the methodological quality assessed using the AXIS tool. Each step was preceded by a calibration exercise and conducted independently and in duplicate by pairs of 2 reviewers. Any disagreements were resolved through discussions.

Data analysis: A narrative synthesis was performed, whereby the characteristics, methodologies, and results of included studies were compared.

Conclusions: Results were inconclusive; yet, a general status of the relatively "high" prevalence of ON among dietitians and dietetics students was established, stressing the need for systematic research to understand and mitigate orthorexic tendencies in this group. It is still too early to answer questions pertaining to prevalence, risk factors, interventions, and differences between dietetics students and other majors when it comes to severity and progress of ON throughout the continuing years of study, or between dietitians and other professional groups.

Systematic review registration: Open Science Framework Identifier: DOI 10.17605/OSF.IO/BY5KF.