Early exposure to cow's milk has benefits (breastfeeding, method, breast milk)

[sparksharp]

NEW YORK (Reuters Health) – A taste of cow's
milk during the first two weeks of life may protect a child from later developing an allergy to the milk's protein, a new study suggests.

But what his team found next most intrigued him. Infants who were first fed cow's milk at the age of 15 days or more had 19 times the risk of developing cow's milk allergy relative to those exposed earlier -- during the first two weeks of life.
Due to common difficulties in digesting the sugar content of cow's milk, some pediatricians have discouraged its introduction until a certain age, Dr. Kari Nadeau of Stanford University in California, who was not involved in the study, told Reuters Health.
Now, it seems there might also be benefits to an earlier start. "It's nice to know that if you do give small amounts of cow's milk to children at an early age," Nadeau said, "it could help prevent their immune system from later viewing this milk protein as a foreign substance and reacting unnaturally to it."

Katz added that the findings should not be interpreted as discouraging breastfeeding. Rather, he recommends simply complementing it with cow's milk early on.

"Let
Dad enjoy some midnight infant bonding," he said, "while he delivers a dose or two of cow's milk protein."

Source (http://news.yahoo.com/s/nm/20100625/hl_nm/us_early_exposure_cows_milk_benefits_study - broken link)

Well, this is interesting news!

[StarryEyedSurprise]

First of all, that's hardly surprising. Unless a breastfeeding mother has stricken all dairy from her diet prior to giving birth, her baby has some exposure to cow's milk protein. Same deal with baby formula. A minuscule amount, but I wonder if that was even factored into this study.

Here are some known risks when babies drink cow's milk that young:

Iron Deficiency Anemia in Infants and Children: How to Prevent It -- familydoctor.org

Iron deficiency anemia can cause your infant or toddler to have mental, motor or behavior problems. These problems can be long lasting even after treatment fixes the anemia.

Infants who drink cow's milk in the first year of life are at risk for iron deficiency anemia. Cow’s milk does not have enough of the iron infants need to grow and develop, and.it is the most common dietary cause of iron deficiency in infants. Do not give cow's milk to your infant in the first year of life.

Of course there's also the studies (which are much further along than the OP's referenced study, since they have NOT tracked these babies into even toddler ages) that show that early exposure to cow's milk greatly increases the risk for Type 1 diabetes, a life-long disease.

[Dorthy]

Originally Posted by StarryEyedSurprise

First of all, that's hardly surprising. Unless a breastfeeding mother has stricken all dairy from her diet prior to giving birth, her baby has some exposure to cow's milk protein. Same deal with baby formula. A minuscule amount, but I wonder if that was even factored into this study.

Yes. That is exactly what I was going to say. If a mother is feeding dairy based formula the baby will be exposed to cow's milk. If the mother is breastfeeding the baby will be exposed to cow's milk, unless the mother does not eat any dairy at all. My dd is intolerant to cow's milk and soy. She reacted to the dairy and soy in my breast milk. It wasn't until I cut all dairy and soy out of my diet did her symptoms go away. That included hidden sources in things like bread, cookies, oil, etc. So in the vast majority of cases, babies will be exposed to cow's milk within a half hour of being born.

[Hopes]

My children were allergic to cows milk the minute they were born.

They were projectile vomiting across the room the very first day. By the end of their first week, they had bloody diapers.

The pediatrician then put them on soy for a year. At a year, they went back onto milk because a soy allergy can develop if they stay on it too long.

[ADVentive]

This is not a study that I'd seen before, but I do find it interesting from an immunological perspective. The study essentially goes to tolerance. Basically, your immune cells need to learn "self" vs "non-self", and tolerance is used to tell them not to attack "self". Sometimes this gets messed up, and you end up with an autoimmune condition - essentially, your immune cells attacking some part of "self" that it should have had tolerance to. There are also plenty of "non-self" things though, that you don't want the immune system to attack - food, pollen, a fetus... The body should therefore also be able to tell "danger" from "non-danger". When the immune system mounts an attack on something that we consider "non-danger", that's typically what we call an allergy. It's a tricky business for the immune system to learn what it should and should not attack, and immunologists are very interested in learning how it works, which is still not fully understood. If we could manipulate this system, it could lead to many medical breakthroughs in autoimmune disease, allergies, transplant medicine, and the like.

Unfortunately, we still don't know exactly how it does work. This study is postulating that exposure to the allergen within the first two weeks of life, seems to result in a higher rate of tolerance to that allergen (in this case, cow's milk protein). This study though, is purely observational and does not even begin to propose a mechanism for how and why this would work. Without a mechanism, one observational study is not going to be enough to influence the medical associations and public health boards to change their current recommendation of exclusive breastfeeding for at least 6 months - exclusive breastfeeding being defined as no water, juice, formula, cereal, or foods.

Some other thoughts on this study:

**The reported incidence of cow's milk allergy (CMA) is 2-5%, yet this study only found it in 0.5% of their population. They either have a skewed demographic or they have different diagnostic criteria than other clinicians. In addition, 381 cases were reported to the researchers by the parents as CMA, but the researchers diagnosed only 66 of these as actually allergic using their criteria. If parents did not report CMA, the researchers assumed CMA was not present. Only those who reported CMA were tested for it. Also of note, this study did not find any correlation of rate of CMA with other factors previously shown to affect likelihood, including gender, type of delivery, and genetic background.

**The study purports to relate first exposure of cow's milk protein with incidence of CMA, however the researchers excluded any formula that was given to newborns while still in the hospital (estimated to be ~70% of all Israeli babies) as inconsequential.

**The study also excludes babies who were not exposed to cow's milk or cow's milk formula at all within the first year. The general recommendation from medical and public health associations is to breastfeed exclusively for 6 months, followed by continued breastfeeding with the introduction of complementary foods until at least 12 months, with introduction of cow's milk after 12 months. Therefore, all babies whose parents actually followed this advice were excluded from the study and there is no data on their rate of CMA. These babies were excluded presumably because babies typically outgrow a cow's milk protein allergy after the first year anyway. Babies who were delayed introduction to cow's milk until after this time are not at a disadvantage. Cow's milk is not a necessary part of a human diet, particularly a human infant whose diet consists of human milk.

**The study found a 0.5% rate of CMA for introduction of cow's milk protein at most time-points. The publicized result was that the rate was 10 times lower when introduced at less than 14 days. However, it is also worthy to note that the incidence was 3.5 times higher when cow's milk protein was introduced between 3.5-6.5 months. And, as mentioned above, the rate for those who were not exposed to cow's milk protein until after 12 months was not given because these infants were excluded from the study.

**The study measures the first (non-hospital) exposure to cow's milk protein in days, but it does so through parental interview at two-month intervals. Recall rate down to the exact day for introduction of cow's milk protein from an interview up to two months later seems prone to inaccuracy given that parents were not asked to keep a daily diary. Though the study calls itself prospective because subjects were enrolled at birth, the methodology for data collection was retrospective.

**The study did report on dairy product consumption by the mother, however less than 1% of mothers did not consume dairy. Of note, all of the mothers who did not consume dairy had babies who did not have CMA, but the numbers were very small and there was no statistical significance.

**The study was funded by the Israel Dairy Board, a potential conflict of interest. Note that the conclusions of the study are to begin supplementing breastfeeding with formula made from cow's milk within the first two weeks of birth, which would be of financial benefit to the Dairy Board.

My personal conclusions: Benefits of introducing cow's milk formula within the first 2 weeks may include reducing the likelihood of cow's milk allergy by inducing early tolerance. Costs of introducing cow's milk formula though are loss of exclusive breastfeeding (and associated health implications) and increased likelihood of earlier weaning in general. Cow's milk allergy is typically outgrown within the first year anyway, and delay of introduction of cow's milk or cow's milk formula until after 12 months also reduces the likelihood of cow's milk allergy while also avoiding the other risks inherent in formula feeding. Introduction of cow's milk formula between 3.5-6.5 months may be the worst scenario with respect to cow's milk allergy. Even if reduced risk of cow's milk allergy was only to be achieved through early use of formula, I do not think that this would be worth risking the other health implications of not exclusively breastfeeding.