Nearly all studies on the benefits of breastfeeding are meaningless

meaningless, word written in letterpress type blocks

Nearly all studies on the purported benefits of breastfeeding are meaningless.

Why?

Because the choice of the comparison groups is beset by a crippling flaw.

Nearly all breastfeeding studies compare two groups of infants, those that have been exclusively breastfed and those that have not. The researchers inevitably fail to include an important group: those infants whose did not get adequate nutrition when breastfeeding exclusively.

To understand why that is a problem so large as to render breastfeeding studies meaningless, it helps to consider another example.

Suppose we are trying to determine the benefits of ICUs (intensive care units). What happens if we compare hospital survival rates of patients who spend time in the ICU and those who don’t? I bet it won’t surprise you to find that the survival rate of patients who spend time in the ICU is lower than that of patients who are never treated in the ICU.

[pullquote align=”right” color=”#922a3e”]Many babies DON’T thrive on exclusive breastfeeding and mothers switch to formula in order to save their lives, promote their growth and preserve their brain function.[/pullquote]

Does this mean that ICUs are harmful and we should abolish them? Of course not. We recognize that those patients who are treated in the ICU differ in fundamental ways from those who are not. Specifically, those who are treated in ICUs are far more ill than those who never spend time in the ICU, so it’s hardly surprising that they are less likely to survive. The difference in level of illness between the two groups is known as a confounding variable. Any study that does not address confounding variables produces results that are invalid.

But there’s an additional factor beyond confounding variables that renders the comparison meaningless; a key group is missing. If we want to know if ICUs are beneficial, we must compare very sick patients cared for in the ICU to very sick patients who are not cared for in the ICU. That produces a radically different conclusion; very sick patients treated in the ICU have better survival rates than very sick patients who are not treated in the ICU. In order to reach a valid conclusion, we must make a valid comparison.

How does that apply to breastfeeding studies?

Most breastfeeding studies compare babies who are exclusively breastfed with babies who are not exclusively breastfed. Even when you correct for confounding variables (mother’s socio-economic status and education level), you are still left with the wrong comparison. If we want to know the benefits of breastfeeding we need to add a third group: babies who are exclusively breastfed but are not thriving.

In order for an infant to thrive, the food it receives must meet three criteria:

1. It should contains all the nutrients and other factors that an infant needs.

2. It must be available in sufficient quantity to promote vigorous growth of the infant.

3. The infant must be able to access it easily.

Breastmilk contains the nutrients and other factors that an infant needs. But many women (up to 5%) do not produce enough breastmilk to fully support infant growth and development, and some babies are not capable of efficiently extracting milk from the breast. Some babies just can’t do it for anatomical reasons, because of weak muscle tone, or because they simply never get the hang of it.

If we want to know the difference between babies who are exclusively breastfed and those who are formula fed, we MUST include the babies who are being exclusively breastfed and failing to thrive.

Technically speaking, babies who are exclusively breastfeeding at 3 months or 6 months or any other arbitrary length of time represent only a subset of breastfed babies. That subset is babies who are thriving on exclusive breastfeeding. Comparing babies who are thriving on exclusive breastfeeding with those who are formula fed won’t tell us anything about the benefits of breastfeeding as compared to formula; we must include babies who are failing on exclusive breastfeeding. Of course, that would be a very difficult study to do because we live in a society with easy access to infant formula. We’d have to do that study in a society that lacks access to infant formula.

We’d need to create 3 groups:

  1. infants who are exclusively breastfed and are thriving
  2. infants who are exclusively breastfed, are failing and lack access to formula
  3. infants who are exclusively breastfed, are failing and are given formula supplements

To my knowledge, that study hasn’t been done for ethical reasons. But if we could conduct such a study, I suspect that we would find that infant formula has dramatic benefits as compared to exclusive breastfeeding. I’d be willing to bet that the death rate for exclusively breastfed infants would exceed by a wide margin the death rate of formula fed babies.

This point is critically important and the reason that it is routinely ignored reflects the lactivist bias that is pervasive in breastfeeding science. The bias is the lactivist lies that all women make enough breastmilk and all babies can easily access that breastmilk. The assumption, completely unjustified and not supported by scientific evidence, is that the only difference between formula fed infants and breastfed infants is that the mothers of formula fed infants couldn’t be bothered to breastfeed. The truth, which would smack any breastfeeding researcher in the face if he or she bothered to look, is that many babies DON’T thrive on exclusive breastfeeding and mothers switch to formula in order to save their lives, promote their growth and preserve their brain function.

Sure, successful exclusive breastfeeding might be beneficial compared to formula feeding, but that’s something entirely different than claiming that breastfeeding is better than formula feeding. The truth may be the opposite: that when compared to exclusive breastfeeding (successful AND unsuccessful) formula feeding is not merely beneficial, it is life saving. And, therefore, many mothers who are formula feeding are doing so because of the extraordinary benefits of infant formula.

Those formula feeding mothers deserve our support and our praise, not the sneering derision of lactivists.