Breastmilk naturally contains an enzyme called lipase, which plays a role in breaking down fats. Sometimes, this enzyme can be more active in expressed milk, leading to changes in its smell or taste over time. This phenomenon is commonly referred to as “high lipase breastmilk.” While it can be a surprising discovery for parents, understanding its nature and how to address it can help ensure babies continue to receive the benefits of breastmilk.
Understanding Lipase and Its Function
Lipase is an enzyme in breastmilk that aids infant digestion. It breaks down fats in the milk, making them more easily digestible for the baby. By breaking down triglycerides into smaller fatty acids, lipase supports the baby’s digestive system and helps with the absorption of fat-soluble nutrients. Lipase activity is a normal and beneficial aspect of breastmilk.
Identifying High Lipase Breastmilk
High lipase breastmilk is often identified by changes in its smell and taste after being expressed and stored. The milk may develop an odor described as soapy, metallic, or even rancid. This altered smell and taste typically become noticeable after the milk has been refrigerated for about 12 to 24 hours, or after it has been frozen and then thawed. A baby might react by refusing to drink the expressed milk due to the unfamiliar taste, even if they readily accept freshly expressed milk. To test for high lipase, compare the taste and smell of freshly expressed milk with a sample stored in the refrigerator for 24 hours or frozen and then thawed.
Safety of High Lipase Breastmilk
A common concern among parents is whether breastmilk with high lipase activity is safe for their baby. This milk remains completely safe and retains all its nutritional value, even if its taste or smell has changed. The changes are due to the breakdown of fats by the enzyme, which is a quality issue rather than a safety one. Babies can still digest this milk without any issues, as it is the same milk they would receive directly from the breast.
Managing High Lipase Breastmilk
Scalding
One effective method is scalding the milk immediately after pumping, before it is chilled or frozen. This process involves heating the milk to about 180°F (82°C) until small bubbles appear around the edges, then rapidly cooling it in an ice bath. Scalding deactivates the lipase enzyme, preventing the rapid breakdown of fats that causes the taste changes.
Other Strategies
Another approach is to mix stored high lipase milk with freshly expressed milk, which can help dilute the soapy or metallic taste and make it more palatable for the baby. Starting with a small proportion of stored milk and gradually increasing it can help a baby adjust. Using expressed milk within a shorter timeframe, such as within 24 hours in the refrigerator, can also reduce the extent of taste changes. If a baby consistently refuses the milk, it can be used in other ways, such as mixing it into purees or oatmeal for older infants.