“Hidden Hunger” And Iron Deficiency

“Hidden Hunger'' is more common in high-income countries where it is associated with ultra-processed foods that are high in sugar, salt, fat, and energy while in lower and middle-income countries obesity is often associated with poverty and monotonous diets with limited choices of staples such as corn, rice, wheat, and potatoes. However, many developing countries are now faced with the double burden of overnutrition alongside malnutrition due to the rapid increase in the global prevalence of obesity in recent decades, especially among children between the ages of 5 and 19 years old.

Recent research from the University of Leeds published in the journal BMJ Global Health examined thousands of studies from 44 countries that involved participants under the age of 25 years old where levels of iron, as well as other vitamins and minerals, were recorded alongside other medical history such as weight. 

The analysis revealed that iron deficiency was associated with both underweight and overweight children and adolescents. Zinc and vitamin A deficiencies were only found in those who were undernourished, suggesting that the iron deficiency among those who were overweight is likely due to inflammation disrupting the mechanisms that regulate iron absorption.

Iron deficiency can have a negative effect on brain function, including attention, memory, and concentration, it can also increase the risks for anemia as well as autism and ADHD in children. Iron deficiency is already recognized as a problem among adults with obesity, but this is thought to be the first work to look at the association in children.

"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, vitamin A and zinc in children and adolescents who are overweight or obese, making this a hidden form of malnutrition,” said lead author Xiaomian Tan, a Doctoral Researcher in the University of Leeds' School of Food Science and Nutrition. "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."

Most studies in developing nations such as Asia and Africa focus on undernutrition, while those in higher-income countries such as Europe and North America tend to focus on overnutrition. This trend is concerning as both Asia and Africa are experiencing the highest rates of the double burden of malnutrition brought on by the economic growth and transition to a Western-style high-sugar high-fat diet. 

For example, between 2000 and 2017 the number of overweight children under the age of 5 in Africa has increased by 2.1 million children (6.6 to 9.7 million), and in Asia, the number of overweight children has increased by 3.6 million children (13.9 to 17.5 million). At the same time as the increase in overweight children, Africa also experienced an increase in the number of stunted children under the age of 5 years old which grew from 50.6 to 58.7 million. 

"These stark figures underscore the fact that the investigation of micronutrient deficiencies in relation to the double burden of malnutrition remains critically important for child health,” said research supervisor Bernadette Moore, Professor of Nutritional Sciences at Leeds' School of Food Science and Nutrition. "By the age of 11 here in the UK, one in three children are living with overweight or obesity, and our data suggests that even in overweight children inflammation leading to iron deficiency can be an issue.

"Iron status may be the canary in the coalmine, but the real issue is that prolonged inflammation leads to heart disease, diabetes and fatty liver."

Previous research indicates that increasing physical activity and improving diet helps to reduce inflammation and improve the iron status in children, the researchers suggest additional research into the effectiveness of these interventions. The researchers also believe more research should be conducted into micronutrient deficiencies as well as the double burden of malnutrition and overnutrition in countries with gaps in data.