Dietary fiber and growth, iron status and bowel function in children 0-5 years old: a systematic review.

Jutta Dierkes, Bright I Nwaru, Alfons Ramel, Erik Kristoffer Arnesen, Birna Thorisdottir, Christel Lamberg-Allardt, Ulrike Spielau, Fredrik Söderlund, Linnea Bärebring, Agneta Åkesson

Journal: Food & nutrition research 2023;67():67

PMID: 37050923

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Plain Language Summary

Emerging evidence shows that high fibre intake has beneficial effects on bowel function, cardiometabolic risk factors and cardiometabolic risk in adults, while the benefits are less clear in children. The aim of this study was to identify, critically appraise and synthesize evidence from studies on the role of high fibre intake on growth and development, iron status and bowel function in small children living in affluent countries. This study was a systematic review of fours studies of which two were randomised controlled trials and the other two were observational studies. Results show that there are no robust associations between high intake of fibre and growth in healthy infants and preschool children. Increased dietary fibre increased stool production in the randomised controlled trials, but higher fibre intake was not associated with constipation in the observational study. Authors conclude that there is a lack of studies on high fibre intake and iron status in well-nourished infants and children. Thus, further studies are needed both to determine desirable levels of fibre intake in small children and to clarify the role of dietary fibre in infancy and childhood for normal bowel function, growth and nutritional status.

Abstract

BACKGROUND

While dietary fiber intake is low in many children, the current trend to plant-based diets is associated with higher fiber intake in children raised on these diets. As older reports indicate that diets providing high fiber intake in children 0-5 years may affect growth, iron status and bowel function, we summarized the available evidence in this systematic review.

OBJECTIVE

To identify, critically appraise, and synthesize evidence on the effect of high fiber intake on growth, iron and bowel function in children 0-5 years, with relevance to the Nordic and Baltic countries.

METHODS

Following a pre-registered protocol, we searched MEDLINE, EMBASE, Cochrane Central of Controlled Trials, and Scopus for clinical trials and prospective cohort studies published until November 2021. Two reviewers independently screened retrieved literature, extracted relevant data, and performed risk of bias assessment. Outcomes were growth, iron metabolism and bowel function in children 0-5 years. We narratively described findings from studies that met inclusion criteria.

RESULTS

From 5,644 identified records, five articles met the inclusion criteria. Two RCTs had an overall moderate risk of bias, while the three observational studies had serious risk. Overall, we found no robust association between high intake of dietary fiber and growth. In the RCTs, higher intake of fiber had a positive effect on bowel movements and constipation. No studies on fiber intake and iron status were identified.The certainty of the overall evidence was inconclusive for growth and bowel function, while no assessment was made for iron status.

CONCLUSION

We found no clear association between high intake of dietary fiber and growth or bowel function in young children living in affluent countries, albeit with only a limited number of studies. There is a lack of studies investigating health effects of high fiber intake in small children.

Address: Centre for Nutrition, Department of Clinical Medicine, University of Bergen, Bergen, Norway.; Department of Laboratory Medicine and Pathology, Haukeland University Hospital, Bergen, Norway.; Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.; Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland.; Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.; Faculty of Sociology, Anthropology and Folkloristics & Health Science Institute, University of Iceland, Reykjavik, Iceland.; Department of Food and Nutrition, University of Helsinki, Helsinki, Finland.; Department of Laboratory Medicine and Pathology, Haukeland University Hospital, Bergen, Norway.; Unit of Cardiovascular and Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.; Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.

DOI: 10.29219/fnr.v67.9011