Malnutrition or being underweight is often related to numerous risks associated with deficiencies. In a recent study, researchers identified that being overweight or obese also puts children and young adults at a significantly high risk of iron deficiency.

The findings were made by nutritional scientists at the University of Leeds, U.K. after examining thousands of medical studies from 44 countries. These studies involved participants below the age of 25 whose levels of iron and other vitamins and minerals were recorded along with their weight.

The analysis showed that iron deficiency was associated with both underweight and overweight children and adolescents. However, zinc and vitamin A deficiencies were only observed in undernourished children. The results were published in the journal BMJ Global Health.

A deficiency of iron can lead to anemia, a condition that results in inadequate healthy red blood cells. The symptoms include fatigue, weakness, pale skin, brittle nails, and poor appetite. Iron deficiency anemia can cause complications including heart problems such as irregular heartbeat, premature birth, low birth weight in pregnant women, and delayed growth and development in young children.

Earlier studies have identified iron deficiency as a problem in adults living with obesity, but the latest research is the first 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 in a news release.

"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," Tan said.

The researchers believe that iron deficiency in overweight children is probably due to inflammation-disrupting mechanisms that regulate iron absorption.

"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," said research supervisor Bernadette Moore.

"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," Moore said.

To reduce inflammation and improve iron status, researchers recommend enhancing both physical activity and diet, while they underscore the need for further studies into the effectiveness of these interventions.