One of the most interesting and dramatic aspects of nutrition today is nutrition role in brain development and children behavior. The evidence clearly indicates a close association between severe protein-calorie malnutrition and impaired brain and behavioral development, but the degree to which malnutrition alone is the cause of depressed cognitive development has not been clearly defined.
The brain and central nervous system grow rapidly during fetal life and early infancy, and by approximately 10 months of age, the total number of cells in the brain has reached its maximum. Different regions of the brain, each made up of their characteristics cell types and each controlling different functions, show their own specific cell division growth patterns. This followed by myelination of nerve fibers and the establishment of synaptic connections which extend into the third year of life. By the time a child is four years old, some 90 percent of the brain has been formed. The formation and functioning of the brain and nerve fibers and the laying down of the myelin sheaths demand that adequate nutrients of the right type be available at this critical period. Therefore, nutrition plays a good role in brain development and children behavior.
During the early formative years as the brain acquires each new specific function it integrates the process into its total pattern of performance and experience. Experimental evidence suggests that the timing of this overall procedure is of utmost importance. Each new function seems to make its appearance chronologically at a critical period of development. Therefore, any disruption of the normal sequence may result in a limitation of the capacity of the brain in some specific ability.
Three different effects of malnutrition on brain growth depending on when it occurs:
1. Marked reduce in brain cell number when fetal malnutrition (low-birth-weight infants) and severe malnutrition during the first year of life occur.
2. A moderate reduction in brain cell numbers as a result of severe malnutrition during the first year in normal-birth-weight infants.
3. No reduction in brain cell numbers when malnutrition occurs after the first year, but a possible reduction in cell size.
The significance of the various brain abnormalities and their effects on brain function are not clearly understood.
• Abnormalities of morphologic, biochemical, and physiological characteristics may so alter normal brain function as to reduce learning ability.
• The developmental process may be impaired by decreased exposure and responsiveness to environmental stimuli during critical periods when essential sequences of experience must be acquired to provide for continued orderly development.
• The learning process may be disruptive by adverse changes in personality, emotionality, and behavior of the child. These changes may interfere with the interpersonal relationships that are necessary for learning experiences.
• Malnutrition among the persons in social contact with the child may militate against their providing an adequate learning experience.
Thus, the relationship between malnutrition and mental development is extremely complicated because the environment of poverty in which we find severe malnutrition is almost always lacking in those other characteristics, which are also important for an individual to reach full mental potential. The disadvantaged child is therefore at high risk not only in terms of limited physical growth but also in regard to psychosocial and cognitive development.