Human Milk Fortification: Is Winter Coming?

Jae Kim, MD, PhD


I know, I can’t be saying that especially after the winter most of the country has just come through, and it may not be over yet and it is the middle of March! I talked about change before but I want to use this specific example of human milk fortification because it is highly topical for 2014.

Well, I don’t know what the future will hold this year in the area, but I think the conditions are ripe for a storm and I want to give some perspective to help everyone figure things out.

I was recently out in Long Island, NY and gave what I thought was a clear explanation of the benefits of human milk over infant formula. As part of this conference we were able to ask pre and post questions to the audience. My first question was to ask whether the audience believed that infant formula is now able to match all the nutritional and biologic properties of human milk. Before and even after my talk, about half the audience continued to believe that infant formula did in fact have similar properties, including biologic properties, to human milk. I fully admit that this may have been poor messaging on my part, but I can’t help wonder whether the effectiveness of a single lecture, especially during the postprandial lull after lunch may be asking for a lot in terms of embracing new knowledge and certainly one as paradigm shifting as accepting human milk as a living tissue with enormous bioactive properties distinguishing it from infant formula. In fact human leaves infant formula in the dust when we look at biologic activity. The strength of prior beliefs, great marketing by the infant formula companies in building trust with healthcare professionals, and the inertia of knowledge may also be to blame.

Given my recent experience, it is not surprising then that studies in quality improvement have demonstrated that those who just listen to lectures on a topic do not change. This is simply not enough to make practical changes happen. It reminds me of my avid reading of Golf and Golf Digest magazines and my warped belief that by reading several good article on proper stance or secrets of the short game, my real golf game will truly get better. The sad realization occurs when I go to the range to hit balls or play a round of gold and my body’s muscle memory kicks right back in and makes me play just like I have always played, like a mortal and not a tour pro.

Change requires practice, lots of it, and it is only practice that is transformative. Ask any musician or athlete and they will tell you that performance gets better when you take the time to practice and especially focus on improving your weakest link. In golf if putting is where you lose all your points that is where you should focus on.

So what confusion is coming in human milk fortification? There are several trends that are happening that are important to take note of.  I present these ones because they are all colliding into the area of human milk fortification.

The first is the move from powder to liquid. Almost 10 years ago we were told by the FDA and CDC that powdered milk products were a risk to the infant due to the inability to sterilize the powder and the reports of real Cronobacter (previously Enterobacter) sakazakii infections that occurred. Well not much happened in the NICU other than the use of ready to feed liquid formulas. Our human milk fortifiers were powders but we did not have any liquid solutions and so we did not change here. In the past 5 years, however, we have access to several liquid options including a donor human milk based HMF, several concentrated bovine based HMFs and a liquid protein module. On top of that we just completed a clinical trial using a yet to be introduced concentrated bovine HMF that like one already on the market contains hydrolyzed bovine protein.(1) Now that we have an assortment of liquid products available to us I predict change from powder to liquid will be extremely fast. Unlike adopting antenatal steroids over a 17 year period, we will likely move to liquid over only a couple of years, primarily due to the litigation risk of keeping with powder.

There is something about not Mary but bovine. Another trend that is occurring is a general fear around intact bovine protein. The exclusive human milk trial using donor human milk based HMF that we were a part of demonstrated that infants developed more NEC and surgical NEC when they received standard intact bovine fortifier compared with infants who received exclusively human product.(2) While some have argued that the study was flawed in that some babies in the control arm received preterm formula there were still more infants who only received mother’s milk as base milk and intact bovine fortifier that developed NEC compared to the exclusive human milk group. This editorial comment aside, it is very apparent that early exposure to intact bovine protein is not as safe as human milk. What mechanisms are at play here are unknown. Certainly some of this effect may be due to antigenicity of fully intact bovine proteins but at least for NEC this has not been discovered yet.

The trend for more human milk for preterm infants has increased our need for donor human milk. This an exciting development for the human milk banking industry as they were nearly decimated when HIV came out. Now that we know that the current standardized process of screening mothers and pasteurizing their donated milk makes very safe milk even for preterm infants, NICUs are converting over to using donor human milk over infant formula all over the country. There are some pitfalls here that need to be paid attention to though. The first it that donor human milk is inferior to fresh mother’s own milk. Due to the collection, processing, and storage of donor human milk the quality of donor human milk has some properties that are important to recognize. The first is that the protein content is generally lower due to the donor pool being later in lactation. The second is that the pasteurization does attenuate some bioactive properties of human milk. One key one is the loss of functional lipase. This loss of lipase does reduce the digestibility of the milk by preterm infants who have lower capacity to produce pancreatic lipases. What this all means is that if you are not careful preterm infants will not grow as well on donor milk. The best remedy we have for this is to get mother’s milk up to speed as quickly as possible. This requires a dedicated team of lactation focused healthcare providers to ensure the supply line is strong.

The human milk nutrition field is clearly undergoing some dramatic changes both with a tectonic shift to more human milk use including donor milk and with an abundant platform of products are on the market or coming to the market this year. So is winter coming? That depends. After this winter that we have been through (I know I can’t complain from where I am in San Diego), facing another storm is the last thing we want to do.

Ultimately I am a born optimist and so I firmly believe that we will make these changes to a new way of practicing human milk nutrition successfully with a net improvement in making babies better. Having just passed my American citizenship this month I am reflecting a bit on what a great country the U.S. is in having so many people who want to do good things but also who have the capacity to dream big. Change can be very difficult but seeing a better future can change our perspectives to make change more palatable. Instead let’s spring forward…


(1) Kim JH, Chan G, Schanler R, et al. Effect of an Extensively Hydrolyzed Protein Liquid Human Milk Fortifier on the Growth of Preterm Infants. J Pediatr Gastroenterol Nutr  2013;57(suppl1). Abstract 329.

(2) Sullivan, S., Schanler, R. J., Kim, J. H., Patel, A. L., Trawoger, R., Kiechl-Kohlendorfer, U., . . . Lucas, A. (2010). An exclusively human milk-based diet is associated with a lower rate of necrotizing enterocolitis than a diet of human milk and bovine milk-based products. J Pediatr, 156(4), 562-567. doi: S0022-3476(09)01085-3 [pii]


Enjoy more blog insight from Dr. Kim!
View his recent article, Breaking Bad Eating Habits in the NICU.


About the Author

Jae Kim is an academic neonatologist and pediatric gastroenterologist and nutritionist at UC San Diego Medical Center and Rady Children’s Hospital of San Diego. He has been practicing medicine for over 23 years both in Canada and the USA. He has published numerous journal articles, book chapters, and speaks nationally on a variety of neonatal topics. He is the Director for the Neonatal-Perinatal Medicine Fellowship Program at UC San Diego and the Nutrition Director of an innovative multidisciplinary program to advance premature infant nutrition called SPIN (Supporting Premature Infant Nutrition, He is the co-author of the book, Best Medicine: Human Milk in the NICU. Dr. Kim is a clinical consultant with Medela, Inc.