Hepcidin and inflammation associated with iron deficiency in childhood obesity - A systematic review

Association of iron deficiency and anemia with obesity among children: A systematic review and meta-analysis

INTRODUCTION

Obesity is a potential risk factor for anemia in children. This systematic review (SR) was undertaken to estimate the association of obesity with iron deficiency (ID) and ID anemia (IDA), in children.

METHODS

A systematic literature search for observational studies was done in PubMed, EMBASE, Scopus, and the Cochrane library, with additional hand-searching. Two reviewers independently screened the search output, included eligible studies, extracted data, and assessed study quality using the National Institutes of Health tool. The main outcomes were association of obesity with anemia (IDA), and ID. Secondary outcomes were hemoglobin level, serum iron, ferritin, transferrin receptor saturation, and hepcidin. Meta-analysis was done using a random-effects model. Comparisons were expressed through pooled OR with 95% CI.

RESULTS

Forty-two studies comprising one cohort, 29 cross-sectional, and 12 case-control studies comparing 16,633 children living with obesity and 32,573 children without obesity were included. The pooled OR (95% CI) for ID was 1.64 (1.22, 2.21), 16 studies, 20,949 children; and 0.78 (0.43, 1.43), 17 studies, 40,022 children, for IDA. The pooled prevalence of ID was 20.07% (14.98, 25.16) among children living with obesity (16 studies, 3147 children), compared to 16.1% (11.82, 20.38) in children without obesity. Children living with obesity had significantly lower levels of hemoglobin, iron, % transferrin saturation, and higher levels of ferritin and hepcidin than children without obesity.

CONCLUSION

There is a significant association between iron deficiency and obesity in children.

Effect of dietary protein on serum hepcidin and iron in adults with obesity and insulin resistance: A randomized single blind clinical trial

BACKGROUND AND AIMS

Both obesity and iron deficiency are public health problems. The association between the two problems could be explained by chronic low-grade inflammation in obesity, which could stimulate hepcidin expression and modify iron concentration that the consumption of high-protein diets could prevent. Thus, this study aimed to compare the effects of high-protein diets with a predominance of animal or vegetable protein on serum hepcidin and iron concentrations in adults with obesity.

METHODS AND RESULTS

This randomized clinical trial involved adults with obesity and insulin resistance, who were assigned to either a high animal protein (AP) group or a high vegetable protein (VP) group for a one-month intervention. Both groups followed a calorie-restricted diet, reducing energy intake by 750 kcal/day. Baseline and final measurements included serum concentrations of hepcidin and iron, biochemical parameters, anthropometric data, and body composition. A total of 33 participants (63 % female) were included in the study. Significant weight loss was observed in both groups after the intervention. Adjusted for weight loss percentage, the AP group showed a significant increase in hepcidin concentration (from 22.3 ± 14.7 to 27.5 ± 19.5 ng/mL) compared to the VP group (from 17.9 ± 15.1 to 17.2 ± 10.1 ng/mL) (p < 0.01), with no changes in serum iron concentration. Additionally, the VP diet significantly reduced serum adiponectin (p = 0.04) and C-reactive protein (p = 0.03) levels.

CONCLUSIONS

In adults with obesity following the AP diet for one month, hepcidin levels increased without affecting serum iron concentrations.

TRIAL REGISTRATION

NCT03627104.

Ferritin as an Inflammatory Marker in Pediatric Metabolic Syndrome: Links to Obesity and Liver Ultrasound Alterations

This study analyzed the relationship between obesity, metabolic syndrome (MetS) and its individual components, iron metabolism, and hepatic alterations in a pediatric group of patients. We mostly concentrated on the role of serum ferritin as a marker of inflammation. We conducted a retrospective study, in which we determined the presence of MetS and hepatic ultrasound changes in a cohort of 68 pediatric patients and examined the changes in serum iron and ferritin levels. MetS prevalence was significantly higher in obese children (64%) compared to those with average weight (11.1%). Abdominal circumference, triglycerides, and high-density lipoprotein cholesterol were the most relevant MetS criteria. Serum iron levels were significantly lower, while ferritin levels increased proportionally with MetS number of components. Liver ultrasound findings confirmed a strong association between hepatic steatosis and MetS, with advanced ultrasonographic scores correlating with increased ferritin and serum iron deficiency. These results reinforce the interplay between iron metabolism and inflammation in pediatric MetS. Given this study's unicentric design and limited ethnic diversity, further large-scale, longitudinal studies are needed to confirm these findings and improve early screening strategies for pediatric metabolic complications.

Antioxidant Supplementation in Childhood Obesity: A Path to Improved Metabolic Health?

Childhood obesity is linked to heightened oxidative stress, a key driver of endothelial dysfunction, inflammation, and metabolic complications. Antioxidants, including Vitamins C and E, are vital in neutralizing free radicals and mitigating oxidative damage. This non-systematic review examines the potential advantages of antioxidant supplementation in pediatric obesity, focusing on its effects on vascular health, insulin sensitivity, and inflammatory processes. Emerging data suggest that antioxidants may improve endothelial function, reduce blood pressure, and enhance metabolic homeostasis in obese children. However, the long-term efficacy and safety of antioxidant supplementation remain uncertain, necessitating further rigorous randomized controlled trials. A deeper understanding of antioxidants' role in pediatric obesity could unlock novel therapeutic approaches for managing obesity-related complications and improving children's overall health outcomes.

Impact of inflammation on anemia in children: a cross-sectional study

INTRODUCTION

The association of inflammation and iron deficiency could be related to up to 40% of anemia in young children.

OBJECTIVE

To describe the anemia and iron deficiency in children and verify possible associations with dietary practices, nutritional status and inflammatory markers.

METHODS

This cross-sectional study was conducted with one hundred and twelve children aged between 6 months and 3 years in Early Childhood Education Centers in Minas Gerais, Brazil. Nutritional status regarding iron and inflammatory markers was assessed using the reference values proposed by the World Health Organization.

RESULTS

Anemia and iron deficiency were observed in 58 (51.8%) and 89 (79.5%), respectively, of children evaluated. Hemoglobin values were directly associated with the z-score of height for age after adjusting for high-sensitivity C-reactive protein values (β-adjusted = 0.375; 95% CI 0.088 to 0.662; p = 0.011). The values of high-sensitivity C-reactive protein correlated directly with RDW (r = 0.202; p = 0.033), ferritin (r = 0.425; p < 0.001) and soluble transferrin receptor (r = 0.446; p < 0.001), and inversely with hemoglobin (r = -0.287; p = 0.002), serum iron (r = -0.580; p < 0.001) and transferrin saturation index (r = -0.528; p < 0.001). The ROC curve shows that RDW (AUC = 0.708; CI 95% 0.612 to 0.803) and soluble transferrin receptor (AUC = 0.588; 95% CI 0.481 to 0.694) were the variables that showed the better level of discrimination of anemia.

CONCLUSIONS

The prevalence of anemia was higher than in national studies, and there was a correlation between inflammatory markers and biomarkers of iron nutritional status.

Deletion of hepcidin disrupts iron homeostasis and hematopoiesis in zebrafish embryogenesis

Iron is essential for cell growth and hematopoiesis, which is regulated by hepcidin (hamp). However, the role of hamp in zebrafish hematopoiesis remains unclear. Here, we have created a stable hamp knockout zebrafish model using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 system (CRISPR/Cas9 system). Our study revealed that hamp deletion led to maternal iron overload in embryos, significantly downregulating hemoglobin genes and reducing hemoglobin content. Single-cell RNA sequencing identified abnormal expression patterns in blood progenitor cells, with a specific progenitor subtype showing increased ferroptosis and delayed development. By crossing hamp knockout zebrafish with a gata1+ line (blood cells labeled fish line), we confirmed ferroptosis in blood progenitor cells. These findings underscore the crucial role of hamp in iron regulation and hematopoiesis, offering novel insights into developmental biology and potential therapeutic targets for blood disorders.

The Interplay Between Iron Metabolism and Insulin Resistance: A Key Factor in Optimizing Obesity Management in Children and Adolescents

Iron plays a vital role in insulin signaling, regulating molecular mechanisms that influence cellular insulin responses. This review explores the link between iron metabolism and insulin resistance (IR) in children and adolescents with obesity. A connection between iron metabolism, iron deficiency (ID), and IR is well-documented, but further longitudinal studies are needed to better understand how iron metabolism influences insulin resistance during childhood and adolescence. This connection warrants attention due to its significant public health implications, as optimizing obesity management could help prevent both ID and metabolic complications in children. Current evidence does not suggest that dietary factors are primary contributors to ID in children. However, there is scientific evidence that weight reduction can restore iron homeostasis in people with obesity. Therefore, efforts should focus on improving dietary habits, increasing awareness of iron's importance, and implementing strategies to address both ID and obesity.

Overnutrition is a risk factor for iron, but not for zinc or vitamin A deficiency in children and young people: a systematic review and meta-analysis

INTRODUCTION

Traditionally associated with undernutrition, increasing evidence suggests micronutrient deficiencies can coexist with overnutrition. Therefore, this work aimed to systematically review the associations between iron, zinc and vitamin A (VA) status and weight status (both underweight and overweight) in children and young people.

METHODS

Ovid Medline, Ovid Embase, Scopus and Cochrane databases were systematically searched for observational studies assessing micronutrient status (blood, serum or plasma levels of iron, zinc or VA biomarkers) and weight status (body mass index or other anthropometric measurement) in humans under 25 years of any ethnicity and gender. Risk of bias assessment was conducted using the American Dietetic Association Quality Criteria Checklist. Where possible, random effects restricted maximum likelihood meta-analyses were performed.

RESULTS

After screening, 83 observational studies involving 190 443 participants from 44 countries were identified, with many studies having reported on more than one micronutrient and/or weight status indicator. Iron was the most investigated micronutrient, with 46, 28 and 27 studies reporting data for iron, zinc and VA status, respectively. Synthesising 16 records of OR from seven eligible studies, overnutrition (overweight and obesity) increased odds of iron deficiency (ID) (OR (95% CI): 1.51 (1.20 to 1.82), p<0.0001, I2=40.7%). Odds appeared to be higher for children living with obesity (1.88 (1.33 to 2.43), p<0.0001, I2=20.6%) in comparison to those with overweight (1.31 (0.98 to 1.64), p<0.0001, I2=40.5%), although between group differences were not significant (p=0.08).

CONCLUSIONS

Overnutrition is associated with increased risk of ID, but not zinc or VA deficiencies, with an inverted U-shaped relationship observed between iron status and bodyweight. Our results highlight significant heterogeneity in the reporting of micronutrient biomarkers and how deficiencies were defined. Inflammation status was rarely adequately accounted for, and the burden of ID may well be under-recognised, particularly in children and young people living with overnutrition.

PROSPERO REGISTRATION NUMBER

CRD42020221523.

Associations of Ultrasound Findings with Serum Iron and Ferritin Levels in Children with Obesity

The nutritional status of children is always a concern for medical professionals. Increasingly, obesogenic factors have created a new global epidemic. Obesity is characterized by persistent inflammation, which can have detrimental effects on the growth and development of children. Iron and ferritin are both important factors to consider when evaluating these children due to their role in the pathophysiology of chronic inflammation. Recently, ultrasonographic evaluation seems to be an increasingly used method in pediatric clinical practice. In this study, we included 98 children aged 6-14 years, 72 of whom were obese and 26 had normal weight. The data obtained indicated that there was an association between low iron and increased ferritin levels, aspects of non-alcoholic fatty liver visualized by ultrasonography, and the degree of fibrosis assessed elastographically. Ultrasonography can help us identify liver damage, but the possibility of identifying an association with other paraclinical investigations such as iron and ferritin levels can be cumulative. In this way, the assessment can be more complex, as the child benefits from comprehensive evaluation and management. The results drew attention to non-invasive, easy-to-perform, and low-cost methods of assessing obese children in terms of iron metabolism and structural liver changes.

The Value of an Ecological Approach to Improve the Precision of Nutritional Assessment: Addressing Contributors and Implications of the "Multiple Burdens of Malnutrition"

Globally, children are exposed to multiple health risks associated with diet and nutrition. Rather than simply being a condition of having too much or too little food, malnutrition is more a syndrome comprising multiple burdens of coexisting and reciprocal malnutrition, infection, or other conditions. Importantly, children with such syndromes (e.g., stunting and anemia, which are neither specific nor necessarily sensitive to nutritional status) are more likely to also have irreversible functional outcomes such as poor growth, impaired immune function, or cognitive delays. The global health community has identified nutrition-related targets (e.g., Sustainable Development Goals (SDGs) and World Health Organization (WHO) Global Nutrition Targets) that, for multiple reasons, are difficult to address. Moreover, as the complexity of the global health context increases with persistent pandemics of infectious diseases and the rising prevalence of noncommunicable diseases, there is a growing appreciation that conditions selected as nutrition/health targets indeed represent syndromes for which nutritional status serves as both an input and outcome. In recognition of the impact of these combined challenges and the role of the multiple manifestations of malnutrition, we suggest an approach to nutritional assessment that is intended to improve the precision of context-specific, equitable approaches to health promotion, disease prevention, and treatment.