

New Study Says Breastfeeding Doesn't Prevent Obesity


Thursday, March 09, 2006

Just a few weeks ago, I wrote about a new study that claimed extended breastfeeding led to reduced rates of obesity in teens and adults. This week, a contradictory study has been released that claims breastfeeding and obesity have no ties.

From the BBC:

The American Journal of Clinical Nutrition study contradicts previous research which suggested breastfeeding could protect against later obesity.

It measured the body fatness of 313 American children aged five and found no difference between those who were breastfed and those who were not.

Lead researcher Dr Hillary Burdette at the Children's Hospital of Philadelphia said there was much interest in whether breastfeeding or the delayed introduction of complementary foods or both can reduce the risk of obesity later.

But she said many studies had conflicting results, so the team tried to devise a new technique to measure their subjects' body fatness, or adiposity, using a specially created X-ray machine.

Earlier studies had used a body mass index, which divides a person's weight in kilograms by the square of their height in metres.

The key difference in this study is the way that fat was measured...as the article points out, older studies have used BMI (body mass index) while the new study proports to more accurately measure obesity. The people that conducted the new study claim that BMI isn't an accurate measure of true body fat levels, but also made note that the study was in no way intended to minimize the other beneficial qualities of breast milk.

Critics note that the study followed children only from the age of 3-5, which doesn't really provide a long-term assessment of the impact of breastfeeding. I'd tend to agree with this camp as obesity, or weight issues, tend to show up after kids hit puberty, thus I would THINK that results would be more accurate if you were making these measurements at a later point in time.

Either way, I'll be curious to see how this plays in the news.


  1. Anonymous Anonymous | 6:42 AM |  

    Any studies on the link between giving kids juice, fruit, mainstream cereals and other "kiddie foods", and obesity?

    Love your site, Jennifer.

    Damien (married to another Jennifer, dad of a tenatious 2-yo)

  2. Blogger Jennifer | 6:48 AM |  

    Ahh...should have included that, sorry. Same study that looked at breastfeeding and obesity using the X-ray type machine also factored in when solids where started, what types of solids and when fruit and soda were started.

    They say they found no correlation from any of it.

    That's the other thing that made me suspicious about the study. I'm actually more willing to believe that breastfeeding doesn't have a huge impact on future weight than I am that the early introduction of foods, fruit juice and pop don't.

  3. Anonymous Anonymous | 9:03 AM |  

    Another one I didn't think of mentioning was the other (lesser) side of the equation: formula. Not all formulas are created equal and I wouldn't be too surprised if the top selling brands were so poorly balanced nutrition-wise that they also led to health problems.

    Why can't they just publically announce that Breast is Best and tell the neigh-sayers to go pack sand? But oh no, that wouldn't bring in sales taxes, bribes, etc.

    Damien (tired of the over-materialization of baby health)

  4. Blogger Jennifer | 9:18 AM |  

    I'm not sure who you want to "publically announce" it, because pretty much everyone already does. :) Even the formula companies. Of course they say it with a "wink, wink, nudge, nudge" and a "but NEXT to the BREAST, We're the best..."

    As for some formulas being inferior...that's a tougher one. Inferior to breast milk clearly, but inferior to each other...not so much. Infant formula is actually very carefully regulated by the FDA through the "Infant Formula Act."

    The FDA regulations require minimum amounts of 29 ingredients and maximum amounts of 9 ingredients and all formula manufacturers must pass pretty specific screening and testing on each batch that they produce. The reality is that with the obvious exception of soy verses milk, taste issues and some extra added ingredients, most formulas are actually pretty close to the same.

    For the most part, you could buy target brand formula or Enfamil or Similac or Good Start or whatever, and you're mostly getting the same stuff. It's just paying for the marketing difference with the name brand ones.

  5. Blogger Maia | 11:40 AM |  

    Coming in late on this - but doesn't it also depend on how long the children were breastfed for? IIRC, previous studies have shown that the length of bf-ing makes all the difference. Did this study take that into account? Did it compare long term bf children with non-bf children or did it say a child was breastfed even if it only had a couple of weeks' worth of bm?

  6. Blogger Jennifer | 2:10 PM |  

    I do believe that it took into account the length of breastfeeding, rather than just whether or not they ever had a drop of breast milk, but I have not read the full text of the study so I can't promise that.

    I will say that if they simply marked breastfed or not in their study and then released their data, it's going to put them up there with the study that said homebirth was dangerous because it uncluded unplanned homebirths AND miscarriages in it. :-P

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