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Your breastmilk knows when your baby is sick

Your breastmilk knows when your baby is sick

You probably hear the same mantra over and over ‘breast is best’, a topic that can often mount excessive pressure on new mothers when feeling vulnerable. Right now, since the coronavirus pandemic hit, many new parents are more worried than ever about how they can protect their newborn baby from this invisible enemy. Well, you don’t need to look much further than the magical substance your body produces. Breast milk has many fantastic benefits, from nutrition to bonding, to forming the baby’s microbiome for life. However one important benefit, now more than ever, is breast milk’s incredible properties at protecting babies from infections.

Your breast milk is so responsive, not only does the amount produced increase and decrease in response to your baby’s hunger and growth spurts, but it also reacts very quickly to your baby’s short-term needs when you or your baby become unwell.

 

How does breastmilk protect your baby from infections?

 Breast feeding has so many incredible properties, the most impressive of which is something that can’t be replicated in any formulas. This milk can help protect your baby from infections in a number of ways; it contains antibodies and immune cells that you make whenever your body encounters a new infection such as a bacteria or virus. This means that you can pass the immunity to your baby, so that if they encounter the same thing, their body is already equipped with the tools to fight it off.

This means that even in the longer term, it can reduce the likelihood your baby gets common infections in infancy such as colds and flu-like illnesses, ear and respiratory infections.

So, when you get unwell, it’s not only safe to continue to breastfeed, but you will likely pass on your own antibodies to your baby and protect them from catching the same illness!


How does breastmilk respond when your baby becomes unwell?

One of the most fascinating features of breastmilk is that not only does it change when the mother gets unwell, but it can also work in the other direction. This means when your baby is suffering from an infection, the breastmilk can change its composition to respond to baby’s needs and tailor it’s properties to help fight the microbes.

When your baby latches to the breast and begins feeding, this creates a mini vacuum. Scientists now suggest that the most likely way your body is able to respond to your baby feeding is because some of the saliva from your baby’s mouth can be transferred back towards the breast and mix with the milk inside. This is known as ‘retrograde milk flow’.

 One theory for this is that as the milk is ejected, the pressure in the milk duct increases, milk ducts dilate and milk flows toward the nipple/baby's mouth. As the oxytocin that you release as the baby feeds wears off, the pressure in the ducts decrease again, causing the milk ducts to reduce in size and allowing milk to flow backwards, likely together with saliva from the baby's mouth. This is a time when it is possible that microorganisms from the infant could be transferred back into the breast, most likely during a pause in suckling, stimulating an infection-fighting response in the milk.

Your mammary glands are then filled with cells from your immune system such as white blood cells to help to fight infection and these cells can pass across to your baby and help them mount a response to the infection they are fighting.


Your breast milk is dynamic and responsive in so many ways; if you are expressing, you may notice its colour and consistency changes at different times. Some of the ways it may change include:

- Time from last feed – depending on when you last fed, the milk fat content will be affected as well as the volume of milk and how diluted it is

- Time of day – the fat content of the milk may be higher in the morning

- Baby’s weight and growth spurts – your baby may feed more frequently at times of growth which can change the nutrient compositions depending on what is required