Formula is our best attempt at a breast milk substitute… but falls short
Breast milk is just the best! It is full of the perfect amounts and types of fat, protein, and carbohydrates for a growing baby. It also contains all kinds of other non-nutrient components that protect baby and help him develop. These include hormones, antibodies, probiotics (healthy good bacteria), and prebiotics (food for those healthy bacteria) just to name a few! There is still so much we don’t understand about exactly how breast milk does such an amazing job protecting baby. In fact, researchers (such as myself!) have built an entire career studying human milk. But this series is about formula. I could go on-and-on about breast milk but will cut myself off. If you want to read a great summary of the benefits of breast milk, American Academy of Pediatrics has a great article (3). While breast milk is the optimal choice, many parents choose to feed their infants formula for a variety of good reasons. Once parents make this choice, they should be able to feel confident picking out a formula that fits their family’s needs. The point I want to make here is that infant formula is the medical community’s best attempt at mimicking human breast milk. The problem is – there is incredible variation in what we find in breast milk! For example, the amount of fat in human milk can range anywhere from 2 to 9 g/100mL between women (4). Similarly, the amount of other vitamins, minerals, and calories in breast milk dramatically varies between women. Much of this variation can be explained by differences in maternal characteristics and behavior, but some cannot. For example, the amount of iron in breast milk does not really depend on maternal diet. However, the content of some essential fatty acids (like, docosohexanoic acid, or DHA, which is the fatty acid in fish oil that everyone goes crazy over) can differ up to ten fold depending on what country Mom is from and what type of diet she eats (4). So how do we know what to put in formula? Well, we often shoot for the average value of what is found in breast milk, or estimate what a baby needs based on what is needed to meet growth demands. In short, we guess. It is an educated guess, yes, but still a guess. There are plenty of non-nutrient components in breast milk that are so independent to Mom and Baby that we haven’t even attempted to put them in formula yet. The obvious example is antibodies (parts of our immune system that fight and kill germs). Mothers pass antibodies to their babies through their breast milk. This is incredible because it provides the infant (who can’t make his own antibodies yet) with the antibodies needed to fight off viruses, bacteria, and other germs that live in the infant’s individual environment. How amazing! But how difficult to mimic in formula! Other characteristics of milk are often “individualized” to individual babies. For example, the milk produced by mothers who deliver prematurely has more protein, calories, calcium and phosphorus than milk of mothers who deliver at term (5). This meets these little babies’ higher calorie and protein needs. All of this variation combined makes it difficult for researchers and doctors to create a perfect infant formula because the optimal diet for one infant may actually be quite different from that of another infant. Lastly, there’s one final but major challenge facing our attempt to mimic breast milk. This is: breast milk is ever-changing! The composition of breast milk changes across a feed, throughout the day, over time as the baby ages, and with special circumstances, like an illness. This is very hard to mimic! Formula fed babies (obviously) only get one food that is the same in composition and doesn’t change over time. All these points combined illustrates that there are several characteristics of breast milk that we will never be able to recreate in formula. This means that it’s that much more important to perfect the things that we can manipulate in formula. Research is continually ongoing to improve the composition of infant formulas. The next few articles in this series are designed to educate parents about what is in formula, and why it’s there, so they know how to choose what their baby needs. The more parents execute educated decisions in the market, the more demand we will generate for further improvements in infant formula. That’s our goal! I want to give a small disclaimer here before you read the rest of this series. From here on out, I will be focusing on food for generally healthy infants who were delivered at term (not prematurely). Premature infants and infants with serious health conditions have special nutritional needs that fall outside the scope of this blog series. There are also different kinds of formulas developed for these cases, and I would be happy to point parents to some resources that would be helpful for such cases. However, for the sake of time, I won’t discuss these infants’ needs here; I will focus on healthy term babies and the numerous formulas marketed to this group. In the next article, I’ll explain exactly how much/little the FDA regulates infant formula and why your doctor doesn’t know all this information. Take Home Points:
- Infant formula is the medical community’s best attempt at mimicking human breast milk.
- Regarding the amount of individual nutrients in formula, we often shoot for the average value of what is found in breast milk, or estimate what a baby needs based on what is needed to meet growth demands. In short, we guess.
- Certain components of breast milk are individual to Mom and Baby and thus cannot be duplicated.
- Breast milk is constantly changing, but we cannot mimic this in formula.
- In short, when creating infant formulas, we are forced to guess at and produce a one-size-fits-all product.
- It is critical to ensure what we can control in formula is perfect!
3. Breastfeeding and the use of human milk. (2012) Pediatrics 129, e827-e841 4. Stam, J., Sauer, P. J., and Boehm, G. (2013) Can we define an infant’s need from the composition of human milk? Am. J. Clin. Nutr. 98, 521S-528S 5. Lawrence, R. A. L., R. M. (2011) Breastfeeding – A Guide for the Medical Professional, Elsevier Mosby