
05/26/2025
Mixing formula and human milk in the same bottle is not recommended, and here’s why:
🧪 Different storage rules:
Formula must be discarded right after a feed, but human milk can be safely stored for 1–2 hours. Mixing the two could lead to wasting your milk if the bottle isn’t finished.
🛡️ Loss of protective properties:
Mixing formula with human milk can reduce lysozyme activity, an enzyme that helps protect against harmful bacteria like E. coli.
⚖️ Nutrient interference:
Added components in formula, like iron, may bind to the nutrients in your milk, reducing their absorbability.
💡 Best practice?
Offer human milk and formula separately to preserve the unique benefits of your milk.
For personalized support and ideas, reach out to a La Leche League Canada Leader.
🔗 Learn more: lllc.ca/should-you-mix-human-milk-formula