Developing Brain 101
Since the decoding of DNA and the human genome, it has been clear that genes alone cannot explain how human beings develop in the womb and in childhood. We now know that development is a complex, life-long dance between genes and many other factors. For example, poverty, stress and starvation during pregnancy have all been shown to have a negative impact on the development of the child’s brain. Exposure to chemicals can also be damaging, as was tragically shown in the 1950s and 1960s, when thousands of babies were born with severe defects because their mothers were given the morning sickness drug thalidomide. Recreational drugs, including alcohol, and the chemicals ingested during smoking, have also been linked to poorer development, as have environmental pollutants like lead and mercury.
If chemicals can affect how babies develop, could the food consumed during pregnancy, and later by the child itself, also affect them? Poor nutrition is linked not only to diseases like cancer and type two diabetes, but to poorer brain function in adults and adolescents. Might it also be relevant to the developing infant, in childhood and even in the womb?
Research has linked adequate nutrition, and in particular dietary levels of omega-3 fatty acids such as DHA, to various aspects of healthy brain development. These include visual function, the growth of connections between brain cells, and the flexibility of neurons’ cell membranes (which in turn affects how efficiently those neurons can communicate and adapt to their environment). Deficits or delays in these crucial aspects of brain growth might plausibly underlie the behavioural deficits which have also been observed in children with low fatty acid consumption. A large-scale study of UK children, for instance, found that those who were eating more junk food at age 4½ tended to be more hyperactive at age 7. Meanwhile, epidemiological studies from two quite different populations (the US and the Seychelles) suggest that greater consumption of omega-3 fatty acids in early life is associated with long-lasting positive effects on cognition, especially in girls.