Shaking Breast Milk – Does It Really Damage It?

Breast milk provides all the necessary nutrients, antibodies, and growth factors needed for optimal infant development. Accordingly, it’s important to handle and store breast milk properly to ensure its quality and safety. One common question that comes up frequently among breastfeeding moms is whether shaking breast milk harms its composition. In this article, we’ll explore the effects of shaking breast milk and if it actually damages it.

Does shaking breast milk harm its composition?

Shaking breast milk doesn’t harm its composition significantly. However, it can cause some of the fat to separate from the milk and stick to the sides of the container, making it appear clumpy or lumpy. This is because breast milk contains different types of fat that vary in size and density. When the milk is shaken, the fat globules collide with each other and the sides of the container, causing them to stick together and separate from the rest of the milk.

Additionally, the American Academy of Pediatrics has noted that vigorously shaking breast milk can cause denaturation (breaking down) of the proteins contained within breast milk. However, this type of shaking is not likely to occur during typical handling and use. According to a study published in the Journal of Human Lactation, while some milk proteins may denature when shaken vigorously, the overall nutritional quality of breast milk is not significantly affected by shaking.

Related article: How to Scald Breast Milk Quickly & Properly (& Why You Need To)

So while shaking breast milk can cause the fat to separate, this does not affect the nutritional content of the milk. The fat globules contain essential fatty acids that are important for brain and eye development, and separating them from the rest of the milk does not alter their composition. In fact, some experts recommend gently swirling or shaking breast milk before feeding to redistribute the fat and ensure that the baby gets all the nutrients possible. Keep in mind, too, that a bottle warmer will also help in melting the fat and allow it to mix back in.

shaking breast milk

If gently swirling or shaking breast milk doesn’t redistribute the fat on a pump bottle, you can run the bottle or bag of breast milk under warm water.

shaking breast milk; removing fat by running under water

What is the composition of breast milk?

Breast milk is a complex and highly nutritious fluid that provides all the essential nutrients needed for a newborn baby’s growth and development. That’s why it’s often referred to as “liquid gold”. The composition of breast milk can vary depending on factors such as a mom’s diet, health, and stage of lactation, as well as the baby’s age and individual needs. It’s composed of a unique combination of proteins, fats, carbohydrates, vitamins, and minerals, along with other bioactive components (source).


Breast milk contains two types of protein: whey and casein. Whey protein is easily digestible and the predominant protein found in breast milk. Casein protein is digested more slowly and helps to provide a feeling of fullness. The protein content of breast milk varies over time, with higher levels of protein in colostrum (the first milk produced after birth) and lower levels in mature milk.

Related article: One Breast Producing Less Milk Than The Other? Mine, Too!


Breast milk contains a range of different types of fats, including saturated, monounsaturated, and polyunsaturated fats. The fats in breast milk are essential for brain development and growth. Breast milk also contains a type of fat called long-chain polyunsaturated fatty acids (LCPUFAs), which are important for cognitive development and visual acuity.


Lactose, similar to that found in cow’s milk, is the main carbohydrate in breast milk. It provides energy and helps with the absorption of calcium and other minerals.

Related article: Daycare Gave Baby Wrong Breast Milk? Here’s What To Do.

Vitamins and minerals

Breast milk contains all the vitamins and minerals that a baby needs for growth and development. It also contains immune factors such as antibodies and other bioactive compounds that help to protect the baby from infections and diseases.

Other bioactive components

Breast milk contains a range of other bioactive components that provide additional benefits to the baby. For example, it contains enzymes that aid in digestion, hormones that regulate various bodily functions, and growth factors that promote tissue growth and repair.

Related article: Does Flange Size Affect Milk Output? Yes, Here’s How.

Best practices for handling and storing breast milk

To ensure the quality and safety of breast milk, it is important to follow best practices for handling and storing it. We have an article dedicated to this topic: How to Store Breast Milk After Pumping. Here are some additional tips to keep in mind:

  1. Wash your hands before pumping or handling breast milk to avoid introducing bacteria into the milk.
  2. Use clean containers and equipment for pumping, storing, and feeding breast milk. Glass or hard plastic containers with tight-fitting lids are best for storing breast milk.
  3. Label each storage bag with the date and time the milk was expressed. Use the oldest milk first to avoid wasting any milk.
  4. Store breast milk in the refrigerator or freezer as soon as possible after expressing. See our article on How to Build a Freezer Stash of Breast Milk (With Little Effort!) for more tips.
  5. Thaw frozen breast milk in the refrigerator overnight or under warm running water. Do not use a microwave to thaw breast milk, as it can heat unevenly and destroy some of the nutrients. If you don’t use all of the breast milk you thaw, check out our article on Can You Refreeze Breast Milk? It Depends. Find Out How.
  6. Gently swirl or shake breast milk before feeding to redistribute the fat and ensure that the baby gets all the available nutrients.

Related article: Breast Pump Not Working? Here’s 5 Troubleshooting Tips to Try.

Ultimately, shaking breast milk does not harm its composition significantly. While it can cause the fat to separate and appear clumpy, this doesn’t affect the nutritional content of the milk. To ensure the quality and safety of breast milk, follow best practices for handling and storing it. By following these guidelines, breastfeeding moms can provide their babies with the best possible nutrition and ensure their healthy development. And know that it’s OK to shake up breast milk gently!

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Shannon founded Work Breastfeed Mom in 2019 during her second round of pumping at work. She was tired of googling the same pumping questions over and over again, and discouraged at the lack of websites aimed at working breastfeeding moms. So, she created one herself. Shannon lives, works, and doles out Puffs to her little people in sunny Florida. She has her MBA and works as a strategic planner for a large healthcare system. She is passionate about coffee, memoirs, paddle boarding, and skincare routines. Shannon is mom to Scarlett and Ivy, and hopes to have more babies if her career allows.