Food and Behaviour Research

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14 Jan 2016 - Eurekalert - Why fish intake by pregnant women improves the growth of a child's brain

Researchers at Tohoku University's School of Medicine have found an explanation for the correlation between eating fish during pregnancy, and the health of the baby's brain.

FAB RESEARCH COMMENT:

This study reveals a clear mechanism to explain why and how maternal diets rich in omega-6 fats and low in omega-3 (i.e. typical modern, western-type diets) can permanently impair their offspring's brain development, leading to abnormal levels of anxiety in adulthood.

For details of this research, see:
The findings provide yet another example of 'nutritional programming' - whereby environmental factors operating in early life can have lifeling effects on development and functioning of the offspring.  In this case, maternal diets with a typical high omega-3/omega-6 ratio actually change the way the developing brain is formed (altering the ratio of neurons to glia, and leading to measurable changes in some areas of the brain in later life). These changes also lead to anxiety in adulthood - despite the offspring being fed a well-balanced diet from birth onwards.

As the authors emphasise in their conclusion: "These data raise important concerns regarding the increased consumption of such a modern diet during pregnancy."

Researchers at Tohoku University's School of Medicine have found an explanation for the correlation between eating fish during pregnancy, and the health of the baby's brain.

Dietary lipid contains fatty acids such as omega-6 and omega-3, which are essential nutrients for many animals and humans. The research group, led by Professor Noriko Osumi, found that a balanced intake of lipids by pregnant women is necessary for the normal brain formation of the unborn child.

In an animal study, the researchers noticed that when female mice were fed an omega-6-rich/omega-3-poor diet, their offsprings were born with a smaller brain and showed abnormal emotional behavior in adulthood.

This is significant because people in many countries these days have similarly poor dietary patterns and tend to consume more seed oils that are rich in omega-6 fatty acids and less fish rich in omega-3 fatty acids.

According to Professor Osumi, the brain abnormality found in the offsprings of mice used in the study, was caused by a premature aging of fetal neural stem cells that produce brain cells. The premature aging was promoted by an imbalance of oxides of omega-6 and omega-3 fatty acids. The offsprings also showed higher anxiety levels, even though they were raised on nutritionally optimized diets from an early lactation period.

A diet that contains a good balance of omega-6 and omega-3 fatty acids is known to improve the development of brain functions; this is based on earlier researches that evaluated the effects of maternal intake of an omega-3-poor diet on brain function in children.

The new study took this premise further and focused on the effects of dietary lipids on the brain formation. The results reveal why omega-6 and omega-3 balance is important for future brain function, and reinforces earlier suggestions that more fish intake by women during pregnancy can advantageously affect the child's health.