5 Nutrition Myths in Neonatology

It seems we may live in a day of alternate truths, myths, and misconceptions. I thought it would be interesting to review a few myths in nutrition (some of which are perhaps more pet peeves of mine).

Because there are so many details involved in nutrition management, it can be easy to hit a snag or travel down a rabbit hole. Let’s take a look at these together.

I hope these stir up discussions along the way.

1. Propping your syringe feeding upright or vertically ensures that ALL the nutrients get delivered to babies.

Yes, it is true that continuous feeding and inverted (downward facing) syringes will leave a good portion of fat behind in the tubing and syringe respectively. But the reality is that human milk is not a consistent aqueous solution, and delivery of its full contents through tubing is challenging.

The fat globules in human milk are difficult to emulsify, even with fortifiers that contain emulsifiers. Unlike human milk, formula has had its plant-based fats blended back in very small emulsified particles. Therefore, in our present methods of feeding delivery, we invariably leave some fat behind, particularly with mothers’ milk.

Our best attempts with bolus feeding, upright position of syringes, and purging of lines after feeds all help, but do not completely resolve the problem of fat loss. We also tend to lose fat with every step that milk touches, such as a new container or surface. So even if a mother’s milk is textbook 20 kcal/oz, what her infant may end up seeing may fall short of the textbook answer.

That is why it is important for neonatal providers not to trust the validity of calories a baby is receiving since the variability in caloric content in mother’s milk is high and the presence of loss throughout handling, processing and feeding may further compromise the caloric content. In the face of an infant who is not growing to your expectations, alternative strategies must be invoked early to help provide more calories, protein, minerals, etc.

2. Human milk fortification to 24 kcal can grow most preterm infants. 

I wish this were true.

This is not valid for most of our NICUs that have difficulties reaching above 160 mL/kg/day. Even with the boost in protein (over 20% compared with prior powder fortifiers), we still see infants in our unit who require more calories and protein to make them grow on their appropriate growth z-line.

This is most true for the micropreemies who we are managing more and more that range from 400g to 1000g. Some have managed to improve growth by increasing the fluid intake to 180 or 200 mL/kg/day, yet I have not seen a physical way to do this with many infants who have significant lung disease of prematurity and are quite fluid sensitive.

Furthermore, I think that for some, higher volume input may push their gut too close to their maximal capacity given their poor motility and dysbiotic microbiome. Given the limitations mentioned in point 1, I still see a need to individualize the nutrition targets for optimal growth.

3. Weight is the most important measurement to follow for growth.

It is well known that head circumference is a strong predictor of neurodevelopmental impairment, and this we measure quite well and plot reliably in our electronic medical records. However, if we were to choose which of our two other anthropomorphic measurements, weight or length, carry the most value in supporting our objective of getting the best neurodevelopmental outcomes for our infants, it would be length and not weight that we should value.

Length is more predictive of neurodevelopmental outcome than weight. Most growth restricted infants who have a higher risk for neurodevelopmental consequences also are short in length. Unfortunately, when I review how our length data looks in most of our units, we see that this is the weakest one we measure. Getting reliable accurate length data is more important for us to know to best understand the nutritional consequences of our actions. So I reach out to all of you to use proper length boards, and make an effort to standardize this measurement in your NICU.

4. At hospital discharge, a very preterm graduate can go home on plain mother’s milk.

 Infants who are being discharged less than term age will be at higher risk of not being able to meet their energy, protein, and mineral demands at discharge. This is because the nutritional demands even at the late preterm stages (34-36 weeks) are higher than at 40 weeks.

Many preterm infants also carry forward deficits in growth, protein, minerals, and vitamins that require some catchup still before they can compete with their term counterparts. Unfortunately there is very little preterm data to support what is best in the way of fortification for mother’s milk fed infants.

Nevertheless, there is a need to treat this area carefully as the consequences of undernutrition may be lifelong. A minimum approach that we adopted based on the one favorable positive Canadian study was to supplement of discharged infants’ diets for at least 12 weeks after discharge.¹ We do this consistently across the board and provide supportive information for the primary care providers to follow. While we cannot be assured that this has any impact on long term neurodevelopmental outcomes, we do know that for many we will better achieve overall growth and bone development closer to their healthy peers.

The one caveat is that there may be some older preterm infants who may attain adequate intake at term age and if it is clear that they have not carried forward any deficits in growth, protein, or minerals they may be fine without supplementation from that point forward.

5. Formula is a safe substitute to human milk.

I really hope this myth goes away soon. For the preterm neonate there is irrefutable evidence that formula is less protective against morbidities such as NEC and sepsis and that there is a greater mortality associated with formula. It is not just about being an inferior choice. This is not about whether one starts a high frequency oscillator versus a Jet ventilator. There is a clear difference between the two.

Furthermore, formula has intact bovine elements that are highly associated with causing harm, although admittedly there is less certainty about how this harm is being done. Is it breakdown of the barrier, alterations of the gut immune system, change in the microbiome, etc.?

So why are we not adamant of human milk feeding? The answer is that we don’t have enough of mother’s own milk and the solution to this requires a reconfiguration in priorities to emphasize and fund more maternal lactation support and equipment. Also, the gap to fill when mother’s own milk is not available is donor human milk, but we do not have a national system whereby donor milk is available to all NICUs and can be covered financially. I think this represents the single most powerful nutritional impact we could have on our preemies today if we want it, and that is to humanize all of our premature infants’ early diets to ward them off from the morbidities we fear the most.

 

What did you think of these 5 nutrition “lies”? Do you have more to add? Let us know in the comments below!

 

References:

1. Aimone A, Rovet J, Ward W, Jefferies A, Campbell DM, Asztalos E, Feldman M,
   Vaughan J, Westall C, Whyte H, O’Connor DL; Post-Discharge Feeding Study Group.
   Growth and body composition of human milk-fed premature infants provided with
   extra energy and nutrients early after hospital discharge: 1-year follow-up. J
   Pediatr Gastroenterol Nutr. 2009 Oct;49(4):456-66. doi:
   1097/MPG.0b013e31819bc94b. PubMed PMID: 19633578.

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, spinprogram.ucsd.edu). He is the co-author of the book, Best Medicine: Human Milk in the NICU. Dr. Kim is a clinical consultant with Medela, Inc.