Malnutrition and cognitive problems (2-6 years)

Malnutrition affects physical and mental health

From global studies in over 150 countries, it has been reported that the two most important factors affecting the cognitive development of children under 5 years, are stunting (lack of growth due to malnutrition) and living in poverty [1]. In 2004 alone, over 200 million children in South Asia and Southern Africa fell into this category.

“Malnutrition” means a lack of all nutrients below the levels required for normal growth and development. These including macro- (bulk) and micro- (trace) nutrients. All nutrients are important for brain function and structure, and they work together as part of complete and balanced nutrition. However, some micronutrients have more critical roles in preventing cognitive development problems.


Protein is a critical macronutrient, providing a source of amino acids that are used for making neurotransmitters and developing new nerve connections in the brain.

A research study compared Egyptian children of 3-6 years of age, who had experienced from Protein-Energy Malnutrition (PEM), a lack of dietary protein. The affected children were not only shorter, but showed 13-22% lower levels of IQ, mental age and language skills, compared to children with normal nutrition [2].


In adults, the brain uses about 20% of our daily carbohydrate intake. In children, this is more like 50%, because of the dramatic increase in brain growth and activity up to 5 years [3]. Carbohydrates provide the main energy supply of the brain, as glucose, that powers the brain.

PEM, as described above, also represents a shortage of energy from carbohydrates, not just protein. Children from 2-3 years of age with PEM have been reported to have problems in how the brain uses carbohydrates, with higher lactic acid, lower blood flow and some carbohydrates converted into fats [4].

Omega-3 fatty acids

As we have discussed, omega-3 fats, such as DHA are very important in the developing brain and eye. DHA increases steadily in the infant brain up to 2 ½ years [5] , and from then on, it is required in adequate amounts in the diet as the brain increases in size up to 5 years.

In one research study, African children at 2 years of age with PEM were found to have 50% lower levels of DHA in their blood, along with lower test scores for mental development [6].

Other micronutrients

Several other micronutrients are known to important in brain development, including

  • Iron – a mineral that helps to oxygenate the brain and helps it use carbohydrates
  • Iodine – a mineral that helps in the control of brain development
  • Choline – a vitamin that helps make other fatty acids in the brain
  • Lutein, vitamin E – antioxidants that protects the brain against
  • Zinc – a mineral that helps in brain growth
  • B-vitamins – vitamins that support energy production in the brain

Two of the most important minerals that are commonly missing during malnutrition are iron and iodine.

Iron deficiency is a leading cause of anemia in children, a condition where they can’t produce enough red blood cells. These cells are critical for providing oxygen to the brain. Many studies have reported losses of cognitive and social ability with low iron in children [7], and this effect even be seen up to ten years later [8].

Iodine is critical for brain development and plays a major role in learning and intellectual achievement. Deficient children have on average 6-10 points lower IQ than children with normal levels under 5 years of age [9].

Importance of complete nutrition

Researchers still have trouble working out if cognitive problems are caused by only one specific missing from the child’s diet, because in most cases, many of them are missing. Since they all work together, a complete and balanced source of nutrients is a key approach to preventing malnutrition.

Jenny Dang
Author: Jenny Dang

Hi there! I'm Jenny, a writer at Little Étoile with three years of experience in researching and crafting stories that make a difference. I'm on a mission to help moms and their little ones live healthier and happier lives through insightful and practical content. Let's make this journey of motherhood a delightful adventure together!