Re: Where the heck does the 6-week dairy figure come from
So, here's the science:
From Estep and Kulczicki (2000) (from my Breastfeeding and Human Lactation Textbook). Bovine IgG antibodies(the antibody that causes the allergic reaction) has a long half life and takes a long time to clear the blood, approximately 2-4 weeks (depending on the persons weight and intake). So it will take 2-4 weeks to clear the blood of the mother. Until the mother's blood is clear, the baby is still ingesting Bovine IgG and therefore cannot clear it from their own bodies. Another 2-4 weeks to clear the blood of the baby and a simple "average" is 6 weeks total with a range of 4-8 weeks depending on whether the mother completely eliminated all dairy (including "hidden dairy") and previous quantities eaten.
That said, I have had a baby that had a dairy sensitivity (she has since outgrown it). Very small amounts of dairy would leave her fussy for 2-3 days. That said, I couldn't possibly see what was going on inside her body to know how long it took to completely clear her system.
Another thing, having had 3 nurslings all with food allergies, I have found they didn't all have the same food sensitivities. My first 2 were fine with dairy. All 3 have had problems with corn, soy and beef. The first 2 had problems with strawberries, raspberries, etc but the 3rd was fine from birth. The 2nd has problems with stone fruit, but the others don't. The list goes on and on. Personally, I eat whatever I want when pregnant. I follow my body's signals and eat what it tells me to because I believe my body knows what is best for me (assuming I ignore the signs to eat a gallon of chocolate ice cream). I always go into each birth hoping that this baby won't cause me problems, that they won't care what I eat. So far it hasn't worked. Perhaps with the next one i will limit some of my foods. That said, unless you only drink water, there's a chance that the food you love will be on the "list" of things your baby hates. There are no "safe" allergy free foods.