We know prolonged breastfeeding reduces overall cancer risk, but did you know your boobs start to eat themselves once breastfeeding is over, and it’s all related.

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We’ve just finished celebrating World Breastfeeding Week, and here at The Central App we came across some interesting research connected to breastfeeding.

When a woman stops breastfeeding, her breasts go from being full-time milk factories to regular body parts in only a matter of days. 

Now scientists have discovered something: your boobs start to eat themselves after breastfeeding is over.

And it’s good for you.

A molecular switch has been identified. It controls the breasts’ transformation from milk secretors to cellular eaters that gobble up their dying neighbours. The discovery, scientists say, could provide new insights into prevention of breast cancer.

Women’s breasts comprise a network of ducts, covered by a layer of fatty tissue. During pregnancy, hormonal signals cause cells lining those ducts to multiply until they form ball-like structures called alveoli.  These are where milk is made once the baby is born. 

However, once women stop breastfeeding, these alveoli are no longer needed and self-destruct – a process that involves massive cellular suicide, followed by the removal of all debris.

Here is the mystery that scientists began to ponder: our  immune system usually removes dead and dying cells in the body. 

However, the amount of material that is consumed once breastfeeding stops and the alveoli are no longer required is so great you’d expect immune system overload, significant inflammation, pain and tissue damage. 

 But that doesn’t typically happen when breastfeeding is over.

After lactation, it seems it’s the cells lining the ducts that eat their dead neighbours. 

Since a protein called Rac1 is essential for normal milk production, Nasreen Akhtar and her colleagues at the University of Sheffield wondered whether it might also be involved in this process of breast transformation.

Experiments with mice revealed to the team that without Rac1, dead cells and milk flooded the breasts, triggering swelling and a state of chronic inflammation, impairing the ability to regenerate tissue or produce milk in later pregnancies.

The mammary gland has a huge amount of tissue and debris that it has to get rid of quickly after lactation. Akhtar’s work showed for the first time that Rac1 is responsible for clearing everything up once breastfeeding is finished, and that this clearance of cell corpses and milk is essential for long term tissue health and function.

So, Rac1 makes the epithelial cells (cells lining the ducts) clean themselves up.

These findings could have positive consequences for understanding the development and progression of breast cancer, scientists say. 

We know prolonged breastfeeding reduces overall cancer risk. 

So, the process the body uses where excess or dead cells are removed by other cells in the breast, thereby suppressing inflammation,  is something scientists are exploring further in a push to better understand breast cancer.

Journal reference: Developmental Cell, DOI: 10.1016/j.devcel.2016.08.005

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