If you are a breastfeeding mother who stores breast milk for your baby, discovering that your breast milk has high lipase activity can be distressing. High amounts of the enzyme lipase in breast milk can alter the taste and smell of stored breast milk. This article shares information about high lipase milk and provides management strategies and tips to help your baby get as much of your precious milk as possible.
Understanding High Lipase in Breast Milk
Lipase is an enzyme that aids in fat digestion and is naturally produced in the digestive tract and present in breast milk. Although the digestive system starts producing lipase in utero, newborns may not produce enough on their own (1). Therefore, the lipase in breast milk plays an important role in helping babies break down and absorb fats from their mother’s milk.
In some mothers, the activity of the lipase in their breast milk is particularly high, causing the fat in their expressed milk to break down more rapidly (2). This increased lipase activity can lead to a soapy, metallic, or sour taste that babies may dislike, although the milk remains safe and nutritious (2). It’s important to note that this isn’t caused by having more lipase but rather by the enzyme’s heightened activity. Many nursing mothers likely have high lipase activity in their milk without even noticing because the taste change only becomes apparent in stored milk.
High lipase activity only becomes an issue if you need to store your milk, and it can be incredibly frustrating. After all the effort of pumping and storing, having your baby refuse your milk can feel discouraging. However, there are ways to manage high lipase activity, and with some adjustments, your baby can still benefit from the nourishment you’re providing.
Signs of High Lipase Activity
As mentioned above, high lipase activity in breast milk only becomes apparent when breast milk is stored and it likely goes unnoticed quite often. As such, there is little data on the prevalence of high lipase breast milk. The signs of high lipase breast milk are:
- Changes in Taste and Smell of Stored Breast Milk: Unlike milk that has soured, high lipase milk does not smell rancid but may develop a soapy or metallic taste after storage for a few hours or days. The time it takes for the flavor or smell of breast milk to begin to change depends on individual lipase activity levels and storage conditions (2).
- Infant Rejection: Babies might start to refuse previously accepted milk once it has been stored. If your baby takes a bottle of freshly expressed breast milk fine, but refuses stored milk, this is a big clue that your milk might have a high lipase content.
If you notice the above signs of high lipase breast milk, I recommend tasting your breast milk yourself! Do you notice a soapy or metallic flavor? If yes, you likely have high lipase content in your breast milk.
If your stored breast milk tastes off, it is worth taking a look at your storage practices to rule out unsafe storage and spoilage as a cause of the flavor changes in your milk. Click here to view the La Leche League safe storage guidelines.
Strategies for Managing High Lipase Milk
For parents who rely on pumped and stored milk, finding out that your baby rejects it due to a change in taste can be incredibly stressful. While it’s important to know that your milk is still safe and nutritious, this doesn’t solve the challenge of getting your baby to drink it! Below are some strategies that can help make your high lipase milk more acceptable to your baby.
1. Scald Freshly Expressed Breast Milk
Scalding deactivates the lipase enzyme, preventing the breakdown of fats that leads to taste changes. Note that scalding isn’t helpful for milk that has already changed in flavor. High lipase breast milk should be scalded as soon after expression as possible.
Scalding breast milk can reduce some beneficial enzyme activity and may slightly impact nutrient levels (2,3). However, these effects are minimal. Some parents worry that after scalding, milk without active lipase might be harder for babies to digest. Thankfully, even after scalding, high lipase breast milk generally contains enough lipase that the milk fat is already broken down enough for babies to still digest the milk easily.
How to Scald: First, prepare an ice bath. Then, heat your breast milk to about 180°F (82°C). (You should see small bubbles at the edges, but avoid bringing it to a boil). Pour your breast milk into a clean container (I recommend a small mason jar), close it tightly, and submerge it into the ice bath to cool it quickly. Store it immediately.
2. Mix Stored Milk with Fresh Milk
Combine thawed high lipase milk with freshly expressed milk. Start with a small amount of thawed milk and gradually increase the proportion over time. This helps to dilute the flavor, making it more acceptable to your baby.
3. Mix Stored Milk with Formula
If your baby is used to formula, you can try mixing thawed high lipase breast milk with formula in increasing amounts. This can help babies get accustomed to the taste of the stored milk.
4. Add Alcohol-Free Vanilla Extract
A small drop of alcohol-free vanilla extract can be added to your thawed milk to help mask the soapy or metallic taste. This method works for many babies and is considered safe, provided the extract is alcohol free, pure, and ideally organic.
5. Freeze-Dry Your Breast Milk
Freeze-drying your breast milk is a preservation method that removes moisture, but keeps many of the beneficial compounds unchanged, and turns the milk into a shelf-stable powder that can be reconstituted with water when needed — like formula. Many mothers report that this process helps mask lipase induced flavor changes. It is rather pricey, but if you have a freezer stash that your baby won’t tolerate this could be a solution!
6. Use Stored Milk in Solids and Smoothies
For older babies who have started solids, high lipase milk can be incorporated into their meals. Try blending the milk into fruit smoothies or mixing it into stronger-flavored purees to mask the taste. This ensures they still benefit from your breast milk without noticing the flavor changes.
Additional Ways to Use Breast Milk
If your baby continues to reject high lipase breast milk despite these tips, you can still use it in other ways.
1. Donate to a Milk Bank
If your baby refuses high lipase breast milk and you have a significant supply, consider donating it to a milk bank. Many milk banks accept milk with high lipase content, as it remains safe and nutritious. Additionally, milk banks typically pasteurize donated milk, which can neutralize the lipase flavor. Donating can be a fulfilling way to ensure your milk is put to good use.
2. Give Baby a Milk Bath
Breast milk is incredibly nourishing for the skin and can be used in breast milk baths. A breast milk bath is a simple, natural way to nourish your baby’s skin using any extra breast milk you have on hand. If you have breast milk that your baby refuses to drink, a breast milk bath is a way to put this milk to good use. Breast milk baths are especially helpful for soothing dry skin, eczema, or diaper rash.
What You’ll Need:
- Breast Milk: Use whatever amount of breast milk you have available, whether it’s fresh, thawed, or even slightly expired milk (one day max). Anywhere from 2-10 ounces is sufficient.
- Baby Bath or Bathtub: Fill the tub with warm water, enough to bathe your baby comfortably.
Directions:
- Fill the Tub: Start by running a bath with warm water. Ensure the temperature is comfortable for your baby, ideally between 98 – 100°F (36 – 38°C).
- Add Breast Milk: Pour your breast milk into the water. The amount can vary depending on what you have on hand, and you should notice the water becoming cloudy. Stir gently to mix it evenly.
- Bathe Baby: Place your baby in the milk bath and allow them to soak for 10-15 minutes while constantly supervising.
- Pat Baby Dry: After the bath, simply pat your baby dry with a soft towel without rinsing off the milk to preserve its skin-soothing benefits.
- Moisturize Baby’s Skin: Follow up by applying a gentle, fragrance-free moisturizer to help seal in the hydration and benefits from the milk bath.
What if It’s Not High Lipase?
If your storage conditions are correct and your milk is not spoiled, but you don’t believe high lipase is the problem because your milk does not taste soapy but rather tastes/smells sour or rancid, a rare condition known as chemical oxidation could be responsible for the off-taste of your breast milk (2). There is not a lot known about chemical oxidation, but it may occur if your diet is high in polyunsaturated fats (PUFAs), which are commonly found in commercially packaged foods. Additionally, the presence of free copper or iron ions in your drinking water, often found in well water or homes with older copper piping, may contribute to this issue. If you believe that chemical oxidation may be affecting your breast milk, consider limiting your intake of PUFAs, increasing antioxidants in your diet, and drinking filtered water.
When to Seek Help
If you’ve ruled out spoilage and tried multiple strategies to make your stored breast milk more palatable, and your baby still refuses it, it might be time to consult a lactation consultant. They can offer guidance and check if there are other factors at play.
To learn more about common breastfeeding challenges, read these articles: How To Prevent & Treat Sore Nipples While Breastfeeding, Understanding Infant Thrush: Symptoms, Home Care, & When To Seek Medical Attention and Mastitis 101: Symptoms, Home Remedies, and When to Seek Medical Attention
Summary
Lipase is an enzyme naturally present in breast milk that helps babies digest fats. High levels of lipase in breast milk can cause stored milk to develop a soapy or metallic taste, which some babies may dislike. It is important to know that this milk is still safe and nutritious. Strategies to manage high lipase breast milk include scalding freshly expressed milk to deactivate the lipase or mixing stored breast milk with fresh breast milk, formula, or a small amount of vanilla extract to make the milk more palatable. If your baby continues to reject your stored milk despite these strategies, consider using the milk for baths or donating to a milk bank.
References:
- Koh, J., Victor, A. F., Howell, M. L., Yeo, J. G., Qu, Y., Selover, B., Waite-Cusic, J., & Dallas, D. C. (2020). Bile Salt-Stimulated Lipase Activity in Donor Breast Milk Influenced by Pasteurization Techniques. Frontiers in nutrition, 7, 552362. https://doi.org/10.3389/fnut.2020.552362
- La Leche League International. (2024). Llli.org. Smell of Stored Human Milk. https://llli.org/breastfeeding-info/smell-human-milk
- Zhang, J., Duley, J. A., Cowley, D. M., Shaw, P. N., Zhou, P., Koorts, P., & Bansal, N. (2023). The Results of Different Heating Temperatures on Activities of Bioactive Proteins in Human Milk. J Hum Lact. 2023 May;39(2):300-307. doi: 10.1177/08903344221124870. Epub 2022 Sep 29. PMID: 36176243.
