Does obesity increase risk of iron deficiency?

The study was published in the journal BMJ Global Health.

Deficiencies in micronutrients contribute to impaired immune function, poor growth and physical development, and increased morbidity and mortality in children. Among the micronutrients, deficiencies in iron, zinc, and vitamin A (VA) remain particularly prevalent and causally associated with adverse health outcomes for children. Iron deficiency (ID) and ID anemia (IDA) are major global health challenges affecting more than 1.2 billion people worldwide.

In the study, Researchers from the School of Food Science and Nutrition examined thousands of medical studies from 44 countries involving people under the age of 25 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).

The researchers found that iron deficiency was associated with both underweight and overweight children and adolescents. By contrast, zinc and vitamin A deficiencies were only observed in children who were undernourished, which concluded that iron deficiency in overweight children is likely due to inflammation disrupting the mechanisms that regulate iron absorption.

The findings revealed that iron, zinc deficiencies were commonly associated with undernutrition in children and young people. Overnutrition increased the risk of ID, but not zinc deficiency, with an inverted U-shaped relationship observed between iron status and body weight.

“The relationship between undernutrition and critical micronutrients for childhood growth and development is well established, but less is known about the risk of deficiencies in iron and zinc in children and adolescents who are overweight or obese, making this a hidden form of malnutrition. Our research is hugely important given the high prevalence of obesity in children. We hope it will lead to increased recognition of the problem by healthcare practitioners and improvements in clinical practice and care,” said Xiaomian Tan, a Doctoral Researcher in the University of Leeds' School of Food Science and Nutrition and lead author of the study.

Reference: Xiaomian Tan, Pui Yee Tan, Yun Yun Gong, Bernadette Moore; 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; Journal: BMJ Global Health; DOI: 10.1136/bmjgh-2024-015135