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The effect of undernutrition on young children (ages 0-8) can be devastating and enduring. It can impede behavioral and cognitive development, educability, and reproductive health, thereby undermining future work productivity. Since growth failure occurs almost exclusively during the intrauterine period and in the first two years of life, preventing stunting, anemia, or xerophthalmia, therefore calls for interventions, which focus on the very young.

Whether or not children are well-nourished during their first years of life can have a profound effect on their health status, as well as their ability to learn, communicate, think analytically, socialize effectively and adapt to new environments and people. Good nutrition is the first line of defense against numerous childhood diseases, which can leave their mark on a child for life. In the area of cognitive development, "when there isn't enough food, the body has to make a decision about how to invest the limited foodstuffs available. Survival comes first. Growth comes second. In this nutritional triage, the body seems obliged to rank learning last. Better to be stupid and alive than smart and dead" (Sagan and Druyan).

Some of the developmental problems experienced by malnourished children are caused by direct physiological crippling, such as retarded brain growth and low birth weight, where as other conditions are the result of limited and abnormal interaction and stimulation vital to healthy development. Good nutrition and good health are very closely linked throughout the lifespan, but the connection is even more striking during infancy. Over half of child mortality in low-income countries can be attributed to malnutrition.

The relationship between undernutrition and cognitive and behavioral development can be summarized by Dr. Reynaldo Martorell's answers to the following questions:

1. Does undernutrition impair behavioral development?

Poor nutrition during intrauterine life and early years leads to profound and varied effects including:
- Delayed physical growth and motor development
- General effects on cognitive development resulting in lower IQs (lower by 15 points or more in the severely malnourished)
- Greater degree of behavioral problems and deficient social skills at school age
- Decreased attention, deficient learning, and lower educational achievement.

2. Are these effects found only in the severely malnourished?

No. The effects of undernutrition on cognition occur as well in children without clinical signs of undernutrition but who are retarded in growth. Most of the food supplementation experiments in developing countries, for example, were aimed at the nonseverly malnourished children.

3. Who is more affected by undernutrition?

Undernutrition and the socioeconomic context in which it occurs appear to be related. Undernutrition has a greater effect on development in children living in poverty, whether in industrialized or in developing countries, than on children who are not poor. Some evidence suggests that nutrition interventions benefit cognition and behavior to a greater extent among the poorer segment of society.

4. Which nutrients are responsible for cognitive and behavioral impairments?

Because nutrient deficiencies tend to cluster in individuals, isolating the specific contributions of single nutrients is difficult from nonintervention studies. Iodine deficiency and iron-deficiency anemia are easier to study than micronutrient deficiencies, and relevant research has shown that both of these micronutrients are involved specifically in causing impairments. Less severe forms of iron deficiency do not appear to affect behavior. This degree of certainty is not possible in studies of protein-energy deficiency because the food supplements provide protein and energy as well as other nutrients. However, no evidence indicates that deficiencies in protein and energy are unimportant. The safest course for ensuring cognitive and behavioral development is to meet all nutrient needs with natural or fortified foods prepared appropriately for young children. The benefits of breastfeeding also must be considered in fostering growth and development.

5. When in life are nutrition interventions more likely to be effective?

Strong evidence suggests that the earlier children begin benefiting from nutrition interventions the greater the improvement on behavioral development. In the case of physical growth, nutrition interventions may be effective only during pregnancy and the fist 2-3 years of life. For behavioral development, nutrition interventions may have a benefit, although much reduced, at later ages.  

6. Are the effects of undernutrition irreversible?

Considerable evidence indicates that substantial improvements can be achieved, even in severely malnourished children, if appropriate steps are taken at a young age to satisfy nutritional and psychosocial needs. The longer the developmental delays remain uncorrected, the greater the chance of permanent effects. In developing countries, where few children live to see their situation improve, once the effects of undernutrition are established in early childhood, they typically become permanent. The intellectual potential of such children at school entry most likely is already damaged irrevocably.

7. Are the effects of improved nutrition long lasting?

Yes. Long-term studies indicate that nutrition interventions aimed at preschool children in the first few years of life lead to measurable improvements in adolescence and adulthood.

8. Do early interventions to stimulate cognitive development interact with nutrition interventions?

Early intervention programs to stimulate cognition have improved cognition and perhaps physical growth. Similar to nutrition interventions, the earlier the program is started, the better the results tend to be. Although current evidence is not conclusive regarding whether the effects of stimulation are additive or interactive, children who receive combined nutrition and stimulation programs perform better than those who receive either type of intervention alone.

The importance of early nutrition interventions and their relationship to cognitive ability in the short- and long-term is very clear. It is also clear that both nutrition and early stimulation programs work better when children benefit from them simultaneously. ECD projects can help prevent and address malnutrition by providing supplemental feeding in center-based and home-based settings and by educating parents about their children's nutritional needs. 

  • Martorell, R. 1996. "Undernutrition During Pregnancy and Early Childhood and its Consequences for Behavioral Development." Paper prepared for World Bank's conference on Early Child Development: Investing in the Future, April 8 & 9, 1996.
  • Sagan, C., A. Druyan. 1994. "Literacy -- The Path to A More Prosperous, Less Dangerous America." Parade Magazine, March 6, 1994.