Early brain development

Press, 8 May 1982, Page 10

Early brain development

1 /health

Professor

Don Beaven

It is now generally accepted that the first few weeks after conception and implantation of the ovum are a hazardous time for organised cell division. At this time cells of the' fertilised ovum divide extremely rapidly. It is also at this time that the organisation of the early brain is most susceptible to toxic or harmful influences. It is probably at this phase of growth that lesser degrees of malnutrition in the motner may lead to some maldevelopments in the foetus.

Timing of any? nutritional insult to the developing brain may be as important as the degree of nutrient deprivation. It has even been suggested — on not very good scientific evidence — that moderate degrees of insult in the first few weeks of - development will lead to an early abortion of the abnormal foetus. This may only be regarded as a delayed and heavy period. . Most at risk periods Professor John Dobbing, of the Department of Child Health at Oxford, suggests in his review on this topic that studies in humans can never be conclusive. If we use as an example the developing rat brain, then it seems there may be a further period of risk from mid-term in the pregnancy until the second or third week after birth. In the human, he suggests that the period is longer, as one would expect from its greater size and longer life.

Here he suggests that the. period is from mid-gestation to the second year of life. During all of this period of risk the rapidity of growth in the brain cells us not matched at other times. Intelligence Infant feeding and links with intellect is also a topic of great controversy. Because millions of children. around the world are affected by man-made malnutrition, this is an explosive political subject. In the first place, measurements of intellect are difficult. Special testing procedures may be needed for some populations and tribal groups. Even then the learning processes and education of the same ethnic or racial group may be altered by the financial and social circumstances of the parents. ’ It is perhaps only by having a big enough sample of new-born babies and following them forward — called a

prospective study — that some answers be’found. One such study is the child development study of the Academic Department of Pediatrics. here in Christchurch. Christchurch setting It is unlikely that this study, though it is yielding valuable information in a number of areas, could help to answer a question posed by our correspondent: Does a deficient protein intake endanger the brain development of a baby?” Except where the mother is a drug addict or an alcoholic there is little chance of real protein deficiency in this country. Teen-age pregnancies with a poor educational background are at risk. Psychological illness, or repetitive vomiting throughout pregnancy, are also risk factors. Even in these cases it

would need to start with a young mother already malnourished at the beginning of pregnancy. There have, however, been young malnourished babies in New Zealand admitted to hospital who show measurable vitamin deficiency and low blood proteins. These children have come from communes where strict vegetarianism of the vegan type is practiced. - Under these circumstances just enough protein can be absorbed to maintain cell turnover in the adult, but a true v-agan’s diet must be regarded as hazardous to the rapidly dividing cells of the evolving brain. In the final analysis, as Professor Dobbing says, we cannot take too much risk until we have much more knowledge about the duration. severity, nature, and above all, timing of the environmental conditions that produce damage in the developing brain which persists into adulthood.