To hear lactivists tell it, breastfeeding has tremendous benefits in both health outcomes and IQ. Since the breastfeeding rating has varied dramatically over the past century, we have an excellent opportunity to determine whether those purported benefits really occur across populations and over time.
Below you can find a graph of US breastfeeding initiation rates from 1910-2000.
If the claims of lactivists were true, we would expect to see a decline in both health parameters and IQ when breastfeeding declined, but we see nothing of the kind.
Let’s look at infant mortality rates:
As you can see, there has been a precipitous decline in infant mortality over the past century completely independent of breastfeeding rates.
How about long term health? Here’s a graph of life expectancy vs. breastfeeding rates.
No obvious benefit here. Life expectancy has risen steadily over the past century and breastfeeding rates appear to have had no effect.
What about IQ?
American IQ has risen 25 points in a linear fashion from 1915-2000, and breastfeeding rates appear to have had no impact.
Taken individually or together, the graphs demonstrate that the impact of breastfeeding rates on mortality, life expectancy and IQ are trivial or non-existent.
Obviously, there were other factors at work in improving health and IQ, including better medical care, better nutrition and better education. Nonetheless, the fact that there is no observable effect of breastfeeding, despite the dramatic swings in breastfeeding rates, suggests that breastfeeding has a negligible effect on health and intelligence.
And that’s just what you’d expect in looking at the breastfeeding studies show real, but very small benefits. Fewer colds, and fewer episodes of diarrheal illness in infants would not be expected to produce any discernible effect in overall measures of health. IQ variations of the same magnitude as the standard error of IQ tests would not be expected to have any discernible effect on IQ.
In other words, as I have been saying over and over and over again, the benefits of breastfeeding, while real, are trivial.
The next time lactivists are tempted to berate women who don’t breastfeed, they should take a look at these graphs. They show that breastfeeding rates have no impact on health or IQ.
And any mother who feels guilty for not breastfeeding should look long and hard at these graphs. There are still a lot of reasons for mothers to feel guilty, but whether or not they breastfeed isn’t one of them.
Life expectancy in the United States. Shrestha, Laura B. Congressional Information Service, Library of Congress, 2005.
The Resurgence of Breastfeeding at the End of the Second Millennium, Wright A, Schanler R, J. Nutr. February 1, 2001 vol. 131 no. 2 421S-425S.
Trends and differentials in breast feeding: an update. Hirschman C, Butler M. Demography. 1981 Feb;18(1):39-54.