{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,30]],"date-time":"2026-08-30T22:29:06Z","timestamp":1788128946483,"version":"build-2803163510"},"reference-count":30,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T00:00:00Z","timestamp":1778716800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Aim: To assess abnormalities in red blood cell parameters, iron metabolism, and vitamin B12 status in children with obesity, and to evaluate the influence of dietary intake and obesity-related complications on these variables. Methods: A retrospective analysis was conducted in 152 children with obesity. Anthropometric, biochemical, and hematological parameters were assessed. Dietary intake was evaluated in a subgroup of 33 participants using 3-day food records. Results: No cases of low hemoglobin levels were identified. However, elevated TIBC and occasional low ferritin levels suggested disturbances in iron metabolism. BMI Z-score was positively associated with red blood cell count and selected iron metabolism markers, whereas higher body fat percentage was negatively associated with hemoglobin and hematocrit. Dietary analysis indicated that protein and vitamin B12 intake were associated with erythrocyte parameters, while no associations were found for iron or folate intake. Elevated liver enzymes were associated with higher hemoglobin, hematocrit, and MCV values. Conclusions: Pediatric obesity was not associated with low hemoglobin levels but may be linked to early, subclinical disturbances in iron metabolism. These findings should be confirmed using more comprehensive biomarkers. Dietary factors, particularly vitamin B12 intake, may contribute to variability in erythrocyte parameters; however, these associations should be interpreted with caution. The observed relationship between liver function and erythrocyte indices warrants further investigation.<\/jats:p>","DOI":"10.3390\/nu18101566","type":"journal-article","created":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T16:27:56Z","timestamp":1778776076000},"page":"1566","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Red Blood Cell Parameters, Iron Metabolism and Vitamin B12 Status in Children with Obesity: Associations with Diet and Obesity-Related Complications"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-2848-6903","authenticated-orcid":false,"given":"Ewelina","family":"Cichocka-Mroczek","sequence":"first","affiliation":[{"name":"Laboratory of Pediatric Dietetics, Department of Pediatrics, Gastroenterology and Nutrition, Jagiellonian University Medical College, 30-663 Cracow, Poland"},{"name":"Doctoral School of Medical and Health Sciences, Jagiellonian University Medical College, 30-663 Cracow, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Iwa\u0144ska","sequence":"additional","affiliation":[{"name":"Doctoral School of Medical and Health Sciences, Jagiellonian University Medical College, 30-663 Cracow, Poland"},{"name":"Department of Pediatric and Adolescent Endocrinology, Chair of Pediatrics, Pediatric Institute, Jagiellonian University, 30-663 Cracow, Poland"},{"name":"Interclinical Center for the Treatment of Childhood Obesity, University Children\u2019s Hospital in Krak\u00f3w, ul. Wielicka 265, 30-663 Cracow, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dawid","family":"Goncerz","sequence":"additional","affiliation":[{"name":"Doctoral School of Medical and Health Sciences, Jagiellonian University Medical College, 30-663 Cracow, Poland"},{"name":"Department of Pediatric and Adolescent Endocrinology, Chair of Pediatrics, Pediatric Institute, Jagiellonian University, 30-663 Cracow, Poland"},{"name":"Interclinical Center for the Treatment of Childhood Obesity, University Children\u2019s Hospital in Krak\u00f3w, ul. Wielicka 265, 30-663 Cracow, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dorota","family":"\u0141ukasik","sequence":"additional","affiliation":[{"name":"Students\u2019 Scientific Group, Department of Paediatric and Adolescents Endocrinology, Chair of Paediatrics, Paediatric Institute, Jagiellonian University Medical College, 30-663 Cracow, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-2226-0392","authenticated-orcid":false,"given":"Aleksandra","family":"Molek","sequence":"additional","affiliation":[{"name":"Students\u2019 Scientific Group, Department of Paediatric and Adolescents Endocrinology, Chair of Paediatrics, Paediatric Institute, Jagiellonian University Medical College, 30-663 Cracow, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3889-1913","authenticated-orcid":false,"given":"Ma\u0142gorzata","family":"W\u00f3jcik","sequence":"additional","affiliation":[{"name":"Department of Pediatric and Adolescent Endocrinology, Chair of Pediatrics, Pediatric Institute, Jagiellonian University, 30-663 Cracow, Poland"},{"name":"Interclinical Center for the Treatment of Childhood Obesity, University Children\u2019s Hospital in Krak\u00f3w, ul. 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