High lipase refers to elevated lipase enzyme activity in breastmilk that breaks down fats during storage, causing expressed milk to develop a soapy or metallic taste.
Lipase is an enzyme naturally present in breastmilk that helps babies digest fats. In some parents, lipase activity is higher than average, causing expressed milk to break down fats more rapidly during storage. La Leche League GB explains that "sometimes milk smells or tastes soapy after a short time in the fridge or freezer because of an enzyme (lipase) that breaks down fats in milk."
Is high-lipase breastmilk safe?
La Leche League GB states clearly that high-lipase milk is safe: "The milk is completely safe and most babies will drink it." The soapy or metallic smell and taste result from fat breakdown and do not indicate spoilage or contamination. Some babies accept it without issue, while others may refuse it.
How can the soapy taste be prevented?
La Leche League GB describes scalding as the method to prevent lipase from breaking down fats during storage: "heat freshly-expressed milk to scalding (bubbling around the edges, but not boiling) and then quickly cool and freeze it." Scalding deactivates the lipase enzyme before it can alter the milk's taste. La Leche League GB acknowledges a trade-off: "Scalding reduces some of the immune factors, but may be the only option for some families."
What other approaches may help?
La Leche League GB notes that "some babies will accept smelly milk mixed with fresh milk." Because the change in taste is related to storage time, freshly expressed milk used immediately is not affected. Scalding is described as appropriate when a baby is refusing stored expressed milk; it is not necessary for every parent who expresses.
If your stored milk smells soapy or metallic, it's probably high lipase. Why it happens, how to prevent it, and how to use what you've already pumped.
Read the articleDefinitions only get you so far. Let's talk about your baby.
A complimentary 15-minute discovery call. No commitment, no script — just tell me what's going on and I'll tell you whether I can help.