Heightened risk of iron deficiency in children with overweight and obesity

A comprehensive study conducted by the University of Leeds’ nutritional scientists has revealed a significant correlation between overweight and obesity in children and young people and an increased risk of iron deficiency. The research, spearheaded by the School of Food Science and Nutrition, involved a meticulous analysis of numerous medical studies across 44 countries, focusing on individuals under 25 years old. These studies assessed levels of essential vitamins and minerals, including iron, in relation to body weight.

The findings indicated that iron deficiency is prevalent among both underweight and overweight youths. Professor Bernadette Moore of the School of Food Science and Nutrition highlighted the broader implications of these findings, suggesting that “Iron status may be the canary in the coalmine, signalling deeper health issues like prolonged inflammation, which is linked to serious conditions including heart disease, diabetes, and fatty liver.”

Unlike deficiencies in zinc and vitamin A, which were primarily found in undernourished children, iron deficiency in overweight children appears to stem from inflammation that disrupts iron absorption. This research, funded by the UK Biotechnology and Biological Sciences Research Council and published in the ‘BMJ Global Health’ journal on 10 May 2024, marks a significant advancement in understanding the nutritional challenges faced by children with obesity.

The impact of iron deficiency on cognitive functions such as attention, concentration, and memory is well-documented, with potential links to conditions like autism and ADHD. This study is pioneering in its focus on the association of iron deficiency with childhood obesity, an area previously unexplored.

Xiaomian Tan, a doctoral researcher at the University, emphasised the importance of this study, stating, “While the link between undernutrition and deficiency of crucial micronutrients in children’s growth is established, the risks posed by obesity—leading to what can be described as a hidden form of malnutrition—are less understood.”

The study also addresses the broader socio-economic implications. Historically, nutrient deficiencies have been associated with hunger, especially in lower- and middle-income countries where they contribute significantly to child mortality. However, the phenomenon of ‘hidden hunger’—nutrient deficiencies in the context of an energy-dense but nutrient-poor diet—is becoming more prevalent in both affluent and developing nations. This is often linked to diets dominated by ultra-processed foods in wealthier countries and limited dietary variety in poorer regions.

The dual burden of malnutrition and overnutrition is particularly pressing in regions like Africa and Asia, which are undergoing rapid economic changes and dietary shifts towards Western high-sugar, high-fat foods. Between 2000 and 2017, the number of overweight children under five years old rose significantly in these continents, alongside an increase in stunting.

Professor Moore also pointed out the alarming trend in the UK, where one in three children by age 11 have overweight or obesity, which compounds the risk of inflammation-driven iron deficiencies. She advocates for increased physical activity and dietary improvements to mitigate these risks.

The call for further research is clear, with an emphasis on the need for more comprehensive studies that address micronutrient deficiencies within the context of the growing global epidemic of obesity, particularly in regions currently lacking detailed data.