You Don’t Have High Lipase Milk (Here’s What’s Actually Going On)
Do you think you have high lipase breast milk?
I’ve got to break it to you…
You don’t.
I know—you’ve Googled it. You’ve read the forums. You’ve smelled the milk.
You’re seeing all the signs:
That “off,” rancid, metallic, or soapy smell.
Your baby refuses the milk you worked so hard to stash (honestly… rude).
And listen—you're not imagining it.
Your nose is right. Your baby is right.
But lipase isn’t the problem.
Let’s clear this up 👇
There is no evidence that some parents produce more lipase than others.
And there is no evidence that lipase causes breast milk to smell or taste bad.
First… what is lipase?
Lipase is a naturally occurring enzyme.
It breaks down fat so your baby can actually digest and use it. In other words: we need lipase in breast milk.
Where did this myth even come from?
This part is wild.
Back in the 90s, at a lactation conference, a parent asked why their baby was rejecting pumped milk. A very well-respected lactation consultant theorized that high lipase might be the cause.
That theory spread—and stuck. Despite the fact that no evidence has ever supported it.
If it’s not lipase… what is causing the smell?
The most likely culprit is oxidation.
(Stay with me—quick science moment.)
When breast milk is exposed to:
light
air
warmth
…nutrients start to break down.
One of the first is riboflavin. If vitamin C levels are low, this process creates free radicals, which further break things down.
The result? Changes in smell and taste—and sometimes a less appealing bottle for your baby.
What can you do if your baby is rejecting frozen milk?
First—I'm so sorry. That stash represents so much work.
But before you dump it, try this:
👉 Mix frozen milk with fresh milk. Start with more fresh than frozen, then adjust the ratio. Warming the milk may also help.
Many babies will accept it this way.
If that doesn’t work, consider adding a drop or two of alcohol-free vanilla extract to each bottle to mask the taste.
How to prevent this going forward
⏱️ Nutrient breakdown can start in as little as 20 minutes! But a few small changes can make a big difference:
1. Chill milk quickly after pumping
Get it into the fridge or freezer ASAP
A cooler bag with an ice pack also works great
2. Protect it from light + air
Cap it right away
Store in opaque containers or a cooler bag
Support your milk with nutrition
Vitamin C helps reduce oxidation, so try adding more of these into your diet:
Kiwis
Strawberries
Bell peppers
Citrus
Broccoli
Brussels sprouts
Tomatoes
A vitamin C supplement may also help, and a dietitian can give personalized guidance (this is often covered by insurance).
The bottom line
Your milk isn’t “bad.”
Your body isn’t doing anything wrong.
This isn’t a lipase issue—it’s a storage and oxidation issue.
And the good news is you have control over this and it won’t take a lot to make meaningful changes.
💬 If this changed how you think about “high lipase”…
Share it with another parent. Because we can do better than repeating a 30-year-old theory that was never proven.
Credit to Dr. Jimi Francis interviewed by Margaret Salty on the Behind the Latch podcast.
