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breastfeeding and increased allergies?

782 Views 14 Replies 11 Participants Last post by  jeca
I just caught the end of an interview where they talked about a new study that claims that breastfeeding increases by 3 times the risks of allergies (I don't know if it's of all allergies).
Has anyone heard about this?
I'm sure many people will listen to this an take it as an good reason not to bf.
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The media almost invariably sensationalizes these "new studies." Bfing always comes up as bad and artificial feeding as good. Go figure.

I got this:

Do you have a link to the "new study?"
Well, in my own experience, my daughter, who has a LOT of food allergies was sick depending on what I ate and I had to eliminate a lot of food groups from my diet, but it was worth it. The formula would have killed her. THAT, she was definitely allergic to. I once used it for her cereal and that was her first full-blown, run-to-the-er reaction. If you child has allergies, formula sure isn't going to help that. Soy and cow's milk are in the top ten. At least a mother can control most of what's in breast milk.
maybe this was the story?

it said this about breastfeeding:

"Babies who were breastfed for more than four months, and who received antibiotics in their first six months were three times more likely to develop allergies - although they were no more likely to develop asthma.....

The biggest risk of all - an 11-fold increase - was found among children who were prescribed a broad-spectrum antibiotic, such as penicillin, were breastfed for four months, and did not have any family pets."

It said they studied 448 children TOTAL so I wonder how many breastfed babies they based their figures on?

edited to add:
this link is a bit more detailed :
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Another link:

It's not the bf'ing that is causing the allergy increase, it's having antibiotics before six months.
(wipes brow) WHEW! Thank goodness we have two cats! Otherwise ds would be screwed for sure, between my breastfeeding and the antibiotics he got as a neonate in the NICU for four days.

This study found, among other things that "By age 7, children given at least one antibiotic in the first six months and who were breast-fed for more than four months were three times more likely to develop allergies."

The allergies they looked at were "pets, ragweed, grass and dust mites."

The study involved 448 children. 49% of whom received antibiotics within the first 6 months. There are no other useful numbers in the press
release, and this is from an unpublished study so I can't look up the publication myself and see what kind of actual numbers they find.

I know that ~70% of babies are bf at birth, but I believe the rate falls to ~30% at 4 months.

That means I guess their sample size for breastfed babies was about 134.

Say that the rate of antibiotic use was the same in bf and bottle fed babies (though we can probably safely assume it's less). That means ~66 babies got antibiotics and 4 months of breastmilk.

What is the rate of these allergies in 7 year olds? I have no clue. Let's guess it's 20% of the total population of 7 year olds.

That would mean that if bf babies were 3 times as likely as non-bf babies to get these allergies, and 30% of babies are bf for 4 months, 15% are both breastfed and get antibiotics.

From this, I gather that:

90 kids in the study had allergies, of them 31 kids were in the group of both breastfed and receiving antibiotics. Seems significant considering we're guessing 66 had both breastmilk and antibiotics. That's a rate of about 50%. Yikes! Compare the rate of allergies in bf babies overall, though, and you get 23%, marginally greater than the overall population.

But wait! Fewer breastfed babies end up on antibiotics than non-breastfed babies. I'm not sure what that rate is, but given the decrease in rate of ear infections, let's say that the rate of antibiotic use with breastfed babies is half that of non breastfed babies.

Therefore, our sample of babies with both 4 months of brestfeeding and a dose of antibiotics in the first 6 months is now only 39 kids and
something like 20 of them with allergies. Hmmm. Now our sample size is too small to say much, but let's try: This means, again, that a huge fraction of those kids both bf and with antibiotics ended up with allergies. HOWEVER, the overall rate for allergies with 4 months of breastfeeding is now 15%, less than the overall population.

From all this, I would gather that breastfeeding protects against allergies, but the protection is likely because it is associated with a lower rate of antibiotics usage.

To all this I ask: Why are they comparing apples and oranges? How many of those kids were breastfed for *only* 4 months and received their antibiotics at some time between 4-6 months? (Breastfeeding rates drop fast as women return to work. Antibiotics use climbs quickly as babies enter daycare...)
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Thanks for working out the math!

But I have no idea if 20% of US 7 yr olds have allergies to dust, pets, ragweed and "grass." Grass is a generic term anyway. But 20% seems high. So that would skew the figures.
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You're right. 20% came out of the ether. However, they way the numbers work out, it doesn't really matter what the rate is. I would find a slightly greater rate of allergies in the bf group overall assuming equal use of antibiotics, or a lower rate overall assuming a more realistic decrease in use of antibiotics. Again, all I've seen is a short press release on an unpublished study. If this ever gets published, I'll be sure to look up what the actual numbers are.

Since it really is the antibiotic use that seems to be the cause of allergies, then bf can, by extension, likely protect against allergies.
I also hate when studies assume correlation=cause. Just because most crime happens when ice cream stores are closed doesn't mean that not being able to get ice cream causes people to commit crimes.

Perhaps there is something else going on with that child that causes causes them to need antibiotics as an infant and develop allergies. So if you breastfeed and your child does need antibiotics then these are the children that are most likely to develope allergies anyway, no matter how they were fed. And since the breastfeeding is keeping all the borderline immune systems from developing in an unhelpful way- then if you have a baby who still needed antibiotics even with breastmilk then the allergies and breastmilk percentage is going to be higher. Just like if most people had babies at home then the c-section rates for hospitals would be very high just because they are only dealing with the high risk people anyway.
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I was just reading something about candida and allergies. Apparently systemic candida predisposes that person to have more allergies in general.

So, if a baby is on antibiotics in the first 4 mos and is breastfed, then i think the chances of developing thrush, which can lead to systemic yeast infections are a lot greater...

I think there's something to the theory that bf + antibiotics = allergies, but i dont think the media is giving us the full story. Go figure.

I think it should look more like bf + antibiotics = candida = a whole slew of problems if left untreated, including allergies.
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go with your heart....don't let any study change that.

one day they say something is good, and the next day they claim it will kill you.

i dont think allergy prevention should really be a factor more about doing what your heart tells you.

<--my two cents.
Mallory wrote:

So if you breastfeed and your child does need antibiotics then these are the children that are most likely to develope allergies anyway, no matter how they were fed.
Mallory, that's a really good point. I hadn't thought of that.
I didn't read through all the posts but am I crazy or is BF suppose to decrease the risk of allergies. I swear that's what I always though or was told.
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