Diet in pregnancy

If you are pregnant or know someone who is, then you may have heard that maternal health and wellbeing is important as your baby grows and develops your womb. Over the last thirty years scientists and medical researchers have come to understand the importance of the in utero environment on the developing baby. Our national dietary guidelines tell us that a healthy diet during pregnancy is important for the baby’s physical development. We are now beginning to see evidence that the maternal diet might also be relevant to the developing brain, and the future mental health of children.

Pregnancy is an important period where the main hormonal, immune and brain systems are being developed. During this time, the foundations of life-long physical and mental health are being laid, and adequate nutrition is central to healthy stress and emotion-regulation systems. Diet during pregnancy – and even well before conception – is an important target for promoting both future physical and mental health.

What do we know?

Animal studies have looked at the relationship between maternal diet and offspring behaviour. Feeding animals a high fat diet during pregnancy disrupts the mood-regulation systems in offspring. Offspring of mothers that ate a high fat diet also are more likely to show anxiety or depression-like behaviours than the offspring of mothers who ate normally. Data from mice show that a high fat diet during pregnancy can result in autism-like behaviours in the offspring.

There have been similar findings seen in human studies: a large study of over 20,000 mothers and their children led by Prof Felice Jacka and colleagues that showed that the children of mothers who ate an unhealthier diet during pregnancy had higher levels of behaviours – such as aggression, hyperactivity or conduct problems – that are linked to mental disorders. These findings have been replicated in studies in the UK and Europe. Jacka’s Norwegian study also showed that the children’s diets were important too. Young children who ate a diet low in nutrient-dense foods and/or higher in discretionary foods during the first years of life had higher levels of emotional dysregulation, including anxiety, sadness and worry.

A good quality diet during pregnancy is made up of a variety of nutrient rich foods such as fruits, vegetables, wholegrains, fish, lean meat and healthy fats coming from nuts, seeds and extra virgin olive oil. A lower-quality diet consists of more ultra-processed foods, foods high in added sugar and processed meats.

Early life nutrition – from pre-conception through childhood – is important in influencing the risk for mental health problems in children as they grow. This is very important to understand if we want to think about preventing mental disorders in the first place. Of course, if you have a mental disorder, it’s important to understand that maternal nutrition during pregnancy may only be one small factor influencing a child’s mental health, as genetics, environmental factors and illnesses can contribute to mental health. We think diet is important though, and if you are planning a baby, and have control over your diet, then a healthy diet will likely benefit everyone’s health (and you’ve got nothing to lose), that goes for Dads too!

What do we need to do now?

In Australia, national surveys tell us that only a very small proportion of women meet the dietary recommendations during pregnancy. Given this is such an important period for preventing poor health outcomes in children, it is important that we finds ways to best help women to make good dietary choices during pregnancy. We also need to understand better the impact of parents’ diets on the future health of children.

In summary