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Study Says Supplementing Breast Milk with Formula Negates Immunity Benefits

By carolyncastiglia |

breastfeeding, formula feeding

More fuel for the breast vs. bottle debate.

Okay, calm down.  Calm down.  Yes, I know you’ve been crying all day because your baby won’t latch and your nipples are bleeding but you’re putting yourself through hell anyway because “breast is best.”  BUT – a new study shows that while “breastfeeding definitely has protective benefits for baby’s immune system… The caveat is that these benefits diminish if a baby isn’t fed breast milk exclusively for the first six months of life.”

Dear scientists behind this study: on behalf of every mother out there, I salute you.  With a giant bird.

Our own Being Pregnant blogger Rebecca Odes concluded about the study, “Babies who were fed a combination of breast milk and formula showed little immunity advantage over those who were fed just formula.”  She says the 10% of the 926 infants studied in Greece who were still being exclusively breastfed at 6 months old “had lower rates of ear, respiratory, and thrush infections than the babies who were fed formula or a combination of formula and breast milk.”

But why?  The folks at WebMD don’t say.  Are bottle-fed babies getting ear infections because they’re being put to bed with a bottle at night, and thus fluid is draining into their ears?  What’s the big deal about thrush, anyway?  It’s said to be “harmless.”  (My daughter had it as an infant and my pediatrician acted like all babies get it.)  Respiratory infections – okay – those can be a big deal.  (And an ear infection can be the result of a respiratory infection.)  My daughter was formula fed and thankfully never had one.  In fact, I think she had one cold as an infant – I swear – we were lucky.

I don’t know what to say other than I refuse to feel guilty about the fact that I had trouble breastfeeding and fed my daughter formula before she turned 6 months old – and I hope everyone out there in the same predicament or who has made the same choice does, too.  The results of this (very small) study shouldn’t make moms who wish to continue to combine breastfeeding with formula feeding feel like they might as well give up and go straight to the bottle – the baby bottle, I mean.  (Put down the vodka, Mommy – it’ll be alright.)  Do what you can and what you feel is best – your child will be fine as long as he is loved.

More on Babble

About carolyncastiglia



Carolyn Castiglia is a New York-based comedian/writer wowing audiences with her stand-up and freestyle rap. She’s appeared in TONY, The NY Post, The Idiot’s Guide to Jokes and Life & Style. You can find Carolyn’s writing elsewhere online at and The Huffington Post. Read bio and latest posts → Read Carolyn's latest posts →

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20 thoughts on “Study Says Supplementing Breast Milk with Formula Negates Immunity Benefits

  1. Linda says:

    There’s nothing “new” about this information. It was out there when my oldest was a newborn 13 years ago.

  2. nmcdny says:

    I agree, now may I have some soda and ice for my vodka?

  3. Gretchen Powers says:

    i think the Babble headline is what’s overstating things here…it’s the same as this, if you eat fruits and vegetables you’ll be healthy…if you eat fruits and vegetables as well as bacon and french fries you’ll be less healthy…it kind of makes sense…scientific results can’t be denied or diminished because they might make someone feel guilty, if you want to give ‘em the bird, just give ‘em the bird

  4. Laure68 says:

    I’m not sure why you are upset at the scientists. This was the result of the study. Were they not supposed to publish it? (In this case, the press release actually reflects the conclusion of the study. You wouldn’t believe how many times I’ve seen the press release present a different conclusion than the actual study conclusion.)

  5. laura says:

    “I salute you. With a giant bird.” – hahaha

    I had actually read studies that moms who supplemented less than 1/4 of the babies milk consumption experienced identical benefits as those who exclusively breastfed…hmm.

    To me, this just makes me feel like if breastmilk were as magical as everyone makes it out to be, why can’t it overpower a couple oz of formula from time to time? what is the take home message, if you breastfeed and can’t make enough milk at any time for any reason, you should (a) let your baby starve or (b) give up breastfeeding all together because you’re about to negate all of your efforts anyway.

  6. Gretchen Powers says:

    Again, it seems the problem is with Babble’s headline…”Negate” vs. “diminish”…the quote from the study (presumably) says “caveat is that these benefits diminish if a baby isn’t fed breast milk exclusively for the first six months of life”…they “diminish” they aren’t entirely “negated”…overall, though, it is my opinion that many of the stories of “not making enough milk” are not really because the person could not physically make enough milk, but because of other confounding factors…lack of BF support and education being among them

  7. Manjari says:

    I don’t understand the point of getting upset with study results. The results don’t hate you and want you to feel bad. Scientists are not saying that you should let your baby starve. That seems like a hysterical reaction to a study that concludes that benefits of breastfeeding are diminished by supplementing. I’m not sure why it is expected that all scientific research should produce conclusions that won’t hurt anyone’s feelings. I have read reports of studies indicating that TV watching is detrimental to children. I am not going to cry about it and get angry with the research, but I’m not going to donate the TV set either. I accept that I am not always going to conform 100% to the ideal in every area of parenting, and that my kids will survive anyway.

  8. Pepperlru says:

    Losing some immunological advantages through supplementing in no way negates the effort of breastfeeding. I haven’t seen it noted yet here that a better immune system is only one of the many benefits of nursing to six months or beyond. A very short list includes superior nutrition (bioavailable nutrients and minerals that are more easily digested), lower risk of constipation, and lowered risk of breast cancer for the mom. These benefits and more! are available to the breastfeeding mother even with the addition of some formula … not to mention the non-health-related benefits nursing provides.

  9. Radical Dad says:

    Why is the question always about guilt? You guys all remind me of my own parents with your constant obsession with feeling guilty about how you raise your children. Calm down. It will be okay. Breast feeding is clearly the best way to feed your infant, but there are a lot of best ways to do things, and we don’t always do them. If we did, we’d be divine, and there’s only one little dude who had God as a father.

  10. Susan says:

    The other issue that all these knd of posts keep raising is that breastfeeding is so hard and painful for soemwomen. I’m a lactation consultant and in so many cases, it’s just a matter of a quick change of position or a little pressure on the jaw. I have helped hundreds of woe with breastfeeding, at WIC, in the hospital, and in homes. I never see that much trauma but it’s all over the Internet! I’m good but not that good :) ! It’s like myth that keeps being perpetuated. If the15 year olds I have seen can do it, the rest of you can too.

  11. Dawn says:

    The reasons why babies given some formula are more vulnerable to infection are well established. Formula damages the lining of the intestine so it’s easier for infection to occur and makes the environment so that its easier for bad bacteria to grow and multiply. Formula retards the development of the immune system. Read more at

  12. Anna Watson says:

    Formula is still worse for baby! Several research studies have shown that it is still better to breast feed than formula feed, even when smoking. Breast feeding will protect against gastro etc and babies who are exposed to smoke but not breastfed are at a much greater risk of respiratory infections. But bearing in mind the SIDS risk, I’d suggest cutting down, not co-sleeping, and perhaps getting a monitor like a respisense.

  13. Rosana says:

    Well Duh!! Common sense!!

  14. Penn Girl says:

    I hate that this study, like many others, doesn’t seem to make any distinction on how much a person is supplementing. My daughter gets 2 ozs of formula per workday added to the 25-30 ozs of my milk she receives. I refuse to believe that those two ounces completely negate the benefits of breastfeeding. It’s preposterous. The studies should clarify how much supplementing is taking place, because it is extremely disheartening to women like me who are trying to balance a job and nursing a baby.

  15. Marj says:

    Well, I wish I’d known this before. I would have skipped trying to breastfeed entirely. I part-time breastfed my twins until my health and sanity couldn’t take it anymore (a little over 2 months). If I had known there was no medical benefit to breastfeeding in those circumstances, I would have saved my health and my sanity and skipped it.

  16. Valorie says:

    It bugs me that you wrote, “Dear scientists behind this study: on behalf of every mother out there, I salute you. With a giant bird.”

    You don’t salute them on behalf of me!

  17. Stephanie says:

    I agree that the wording of this study is a little misleading. I highly doubt that supplementing with formula negates any benefits from breastfeeding, it’s probably just the case that the more breastmilk you substitute with formula the closer your baby is to being on a formula diet hence the farther they are from recieving the benefits of breastfeeding. I exclusively breastfed until my daughter was 3 1/2 months old and now I am only giving her 6 ounces of forumla 1 or 2 days a week while I am at school, and only as a last resort if I am unable to pump enough milk beforehand (I am gone on wednesdays from 8 in the morning til 7:30 at night, so this is often hard to do). I highly doubt that by getting maybe 3% of her nutrition from formula, my baby gets NONE of the benefits of breastfeeding, which is what the title of this study implies. I send a giant bird not to the scientists, but to whoever wrote this article.

  18. Stat Girl says:

    Thank you for attacking poorly written headlines and bad reporting of results. The folks at WebMD don’t say because a) they don’t know and b) they don’t care. Enough is enough with these formula is poison types. Your post recognizes that without additional information, there is NO reason to worry about the study results. There isn’t adequate information to REALLY know anything. Remember those tests in school when the correct answer actually was , “Don’t know, don’t have enough info to answer the question?”

  19. Kelly H says:

    I realize that this is an older post but I just had to respond to Susan from October, when she said, “If the15 year olds I have seen can do it, the rest of you can too.” That completely lacks logic, as there are 15 year olds out there that can do many things I can’t do. I can do things they can’t, too. The statement also – more importantly – neglects to take into account many possible extenuating circumstances that families face. Like mine, for instance: my daughter was in the NICU for over a week after birth and had surgery (so not only was she not eating for a lot of that time, but I also couldn’t be with her 24/7, as I was also recovering from surgery (c-section). When she was finally ready to breastfeed, I had a ton of support. And I was determined. I had taken a class a few months before. I had read some book chapters and internet articles. I worked with lactation consultant after consultant (who all told me I was doing everything right and I just had to keep trying). Well, one can only go through so much, both psychologically and physically. I would have experienced post partum depression in the worst way had I kept trying. I have no doubt that my daughter benefitted from my decision to stop pushing for something that just wasn’t working.

  20. Kara says:

    To the poster who indicated that she does not believe it’s really a problem with mom’s not being able to produce enough milk, I would like to say that that is completely not true. While yes, that is something that a lot of BF mom’s might feel at times, and this might cause them to give up on BF’ing before they should (I get that), many women do actually have problems producing enough milk, while I will agree with you that the lack of support in beginning is usually the biggest issue, and I would say in creating a milk supply as well. I had to switch to exclusively pumping breast milk when my son was 4 days old b/c he was having so many problems with nursing that in 3 days he lost 12% of his birthweight. We sought out support from hospital staff a lactation consultant who came to our home, the pediatrician, and they were all really wonderful, but BF was just not going to work. I started pumping in the hospital and worked very hard at it, so my supply started getting established quickly. However my son is big and HUNGRY, and at 4 weeks he started out eating what I could produce (and trust me I’ve tried everything to increase supply). So supplementing with formula has been necessary for us. It would be a slap in the face to me if someone told me that having to give him formula in addition to my breast milk (which I work SOOOOO hard to get for him) is negating the benefits of giving him breast milk. I am not willing to starve my child (not to be dramatic). I think mom’s need to stop being made to feel guilty; this is already the hardest thing we will ever do, and any mom who does the best she can and always has her child’s best interests in mind is doing a great job!

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