By now I'm sure you have noticed that when you store your breastmilk in the fridge the milk separates and it goes to the top of your container. Also some fat tends to stick to the sides as well. There is a huge variation as to the thickness of the fat, how clear the separated milk is, how much fat there is... even the color of the milk. There is a huge range that is considered normal. So if you're seeing this for the first time, don't worry, it's supposed to do that.Now there are TONS of reputable sources that say you should NOT shake your breastmilk. From International Board Certified Lactation Consultants (IBCLCs) and Kelly Mom to Breastfeeding Place. Why is that? There are three primary reasons why expressed breastmilk should be swirled:
- Shaking denatures proteins
- Swirling helps to remove fat globules stuck to the side of the container
- Shaking damages cells.
However, I found an interesting article here that shed light on those three aspects mentioned above. It's a lot of science and a lot of math and worth the read. The bottom lines are that in regards to shaking denatures proteins: there are a lot of variable when it comes to the proteins and there are no publishes papers on this topic. Since there are no studies in human milk, water was used as a substitute. The idea that shaking denatures proteins is based on the shear force of the proteins would be exposed to during shaking.
In regards to shaking damaging cells, it is highly unlikely that the human arm is capable of generating enough force to damage the cells in the milk. Breastmilk cells are likely exposed to high shear force at multiple points during their normal life course- from milk ejection to swallowing to digesting, and may be more resistant to cell damage than previously thought.
And lastly, in regards to swirling helping to remove fat stuck to the side of the container... personally I think this is all based on preference. I know some moms who say their milk is so high in fat that they have to shake it to get all the fat off. Others like myself, have no problem with swirling to get milk off the container.
In the end, there is no published evidence to support that shaking actually damages breastmilk when compared to swirling. However this in itself isn't enough proof, at least for me, that it in fact does not damage breastmilk. Bottom line is that not enough research has been done.
Some have theories that its just another way for people to make breastfeeding seem harder than it really is. No matter what anyone says on the matter, it's up to mom to decided what she feels best for her and baby. If you wanna shake that bottle then go for it. If you wanna swirl it, then swirl to you hearts content. As mentioned before, I prefer to swirl. Not only do I find it more effective in removing milk from the container, but it also reduces the amount of air bubbles in the milk. And I prefer to be more cautious and not take chances with possibly destroying any cells. But that's just me.
