Scientists say smelling fatty foods such as bacon when pregnant can have a knock-on effect on the unborn child’s life
Many mums-to-be find themselves eating a whole range of foods they might otherwise limit when they are pregnant. As hormones rage, some people will choose healthier options while others can enjoy tucking into fatty foods such as bacon.
However, researchers have now found that the smell of fatty foods during pregnancy increases the risk of children being overweight or obese. And this was the case even in slim and healthy mothers.
The findings have turned current thinking on its head. Sophie Steculorum, who led the study, said: “What we discovered changes how we think a mother’s diet can influence the health of her children.
“Until now, the focus has mostly been on maternal health and the negative effects of eating a high-fat diet, such as the risk of gaining too much weight. But our results suggest that the smells fetuses and newborns are exposed to could influence their health later in life independently of their mother’s health.”
The research
Researchers at the Max Planck Institute for Metabolism Research fed pregnant mice a healthy diet low in fat but containing fatty smells, such as the smell of bacon. The mothers themselves did not change their metabolism, but their offspring reacted more strongly to a high-fat diet and developed more pronounced obesity and insulin resistance, a sign of type 2 diabetes.
The team also found that the brains of the offspring had changed. The dopaminergic system, which plays an important role in motivation and reward, and the AgRP neurons, which control hunger and whole-body metabolism, reacted differently to high-fat food.
Laura Casanueva Reimon, co-first author of the study, said: “The brains of the offspring resembled those of obese mice, simply because their mothers had eaten a healthy food that smelled like fatty food.”
The researchers found that fetuses are exposed to the smells of unhealthy foods while still in the womb and as newborns during breastfeeding through their mother’s milk. Artificial activation of neural circuits associated with the smell of fatty foods during the neonatal period was sufficient to trigger obesity in adulthood.
How does this affect humans?
It is known that children of overweight mothers have an increased risk of becoming overweight themselves. The study suggests that simply smelling fatty food during development can increase the risk of overweight and obesity later in life, even in lean and healthy mothers.
However, it is important to emphasise that in these experiments the mothers needed to ingest the food containing the fatty odours, as mere exposure to the smell alone did not lead to obesity in the offspring.
Flavourings
The researchers used various flavouring agents to create the diets used for their investigations and found that these often contained the same ingredients that are used as food additives. One of these additives alone was able to trigger the same effects in the offspring.
Sophie Steculorum. added: “The findings point to the need for more research to understand how consuming these substances during pregnancy or breastfeeding could affect babies’ development and metabolic health later in life.”
