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Breast Feeding

Mixing breastmilk and formula in a bottle



I had read an excerpt that is NOT recommended b/c the formula can change the chemical makeup of the breastmilk, therefore, possibly negatively effecting the infant`s kidneys. Is there any fact to this? We have been doing this for about 1.5mos & made our peditrician aware of this. There were no negative comments made regarding our practice.

Thank you for whatever information you might offer.


I know of no literature to this effect. This belief does not seem to be based on fact.

We advise this (mixing with formula) frequently when there is not enough breast milk for the baby, both in and out of the hospital.

No problems have been reported to my knowledge, for any organ system, including the kidneys.

If there is a chemical reaction, I cannot imagine what it could be.

The iron in the formula might bind to lactoferrin, an antiinfective agent in breast milk, but even this would have no effect on the kidneys.

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Response by:

Jeanne L Ballard, MD, FAAP, FABM Jeanne L Ballard, MD, FAAP, FABM
Professor Emeritus, Pediatrics, Obstetrics and Gynecology
College of Medicine
University of Cincinnati