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  • Writer's picturefranceswalker@thefoodinto

Breast milk: how quickly DAIRY protein clears

It has been well documented that allergens to pass from the maternal diet into breast milk, although the amounts are highly variable.

Intact food allergens or peptides in breast milk documented include egg protein (ovalbumin) gliadin (wheat), peanut and cow's milk proteins.

Food allergens in human milk have been reported to vary over a very wide range of concentrations from just above 0.1 to >1,000 ng/m, but low levels are probably the most realistic figures (1).

How long does it take to get improvements when first going dairy and soy free?

Impacts of dairy (and soy) exclusion from the maternal diet actually has a variable time frame in terms of bub's improvements.

Some babies respond very quickly with some very significant imporvements with common ones being: decreases in bowel motion frequency, cessation of mucous, blood, reduced reflux, reduced screaming and irritability, reduced wakenings in the night and reduciton in eczema/rashes.

Some take seemingly forever- requiring 3-4 weeks to start seeing any noticable imporvements. It is not unusual to take a while in this pphase of the dairy/soy journey.

Or there is a combination, some quick significant imporvements, then some slower imporvements over time.

At the 4-6 weeks, not withstanding potential slip ups, maximal imporvement should be achieved.

How long it takes for dairy proteins to clear from breast milk

Dairy protein can make an early first appearance in breast milk, for example, within 1 hour of ingesting, but data is limited.

This is extremely variable between women and babies, and there is not a lot of reliable data, with lots of variability in methods of detection in the different studies.

Peak concentration measurements also vary with 1 hour- 24 hours- 7 days been quoted. Not enough data to knbow except to say there appears to be a large variability.

BGL, which is major cow's milk protein has been measured and the results points to slower and faster clearance trends, withg some women being categorized as ' rapid' metabolizers so it cleared mor quickly and some women 'slower' metabolizers so a slower clearing from the breast milk (2).

With huge variation, it is very possible that comparable amounts of dairy protein in the breast milk will result in

  • different levels of dairy protien in the breast milk

  • be cleared from te breast milk in different time frames

  • elicit different symptoms (and severity) in individual babies.

With all these variables, your own baby is your study.

Going dairy free and challenging with dairy

It is a very differnet scenario comparing initially going dairy free and the time it takes to get maximal improvement and conducting well thought put dairy trials via breast milk.

Initially going dairy/soy free

In addition to clearing dairy from the milk, there is the very healing time also required from the ongoing impact of the dairy portein over a sustained period of time while dairy was in the diet.

Dairy trials

Trialing with dairy via breast milk is not superimporsed on top of a gut under duress, but a functioning gut/skin that has further developed since the dairy/soy portien exclusion.

Careful dairy choices also means that a modified ladder approach can introduce dairy portien in smaller doses so any reaction is quickly nipped in the bud.

This is a very different scenario to a baby that had been continuously reacting to dairy protein over a period of time.

Knowing Your Baby

In my experience, as improvements are achieved, it becomes very evident over time that parents become well versed in their own baby's unique pattern of: peak reaction time, types of symptoms and length of time to recover.

Most babies with dairy slip ups or trials will recover relatively quickly, and cannot be compared to the original length of time it takes to recover after eliminating dairy/soy from the maternal diet.


  1. Picariello G, De Cicco M, Nocerino R, Paparo L, Mamone G, Addeo F, Berni Canani R. Excretion of Dietary Cow's Milk Derived Peptides Into Breast Milk. Front Nutr. 2019 Mar 12;6:25. doi: 10.3389/fnut.2019.00025. PMID: 30931311; PMCID: PMC6424006.

  2. Kosmeri C, Rallis D, Kostara M, Siomou E, Tsabouri S. Characteristics of Exogenous Allergen in Breast Milk and Their Impact on Oral Tolerance Induction. Front Pediatr. 2022 Mar 4;10:830718. doi: 10.3389/fped.2022.830718. Erratum in: Front Pediatr. 2022 Apr 14;10:898795. PMID: 35311039; PMCID: PMC8931296.


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