Breastmilk fortification: individualisation and use of human milk diets

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Individualised fortification

Typical practices of breastmilk fortification assume an average content of macronutrients, but data clearly show that macronutrient content varies significantly within the same mother, and more so between mothers. Therefore, a significant proportion of preterm infants will receive enteral diets of unbalanced composition. This may impact on growth rates and body composition and may explain why some infants experience postnatal growth faltering.

Potential ways to overcome the natural variation of breastmilk composition include target pooling of breastmilk, but this is logistically complex and rarely used for mother’s own milk. An alternative approach is individualised fortification. This describes the practice of changing the fortifier composition based on analysis of the specific milk used.

There are 2 main types of individualised fortification, known as “adjustable” or “targeted” fortification. The basics of each strategy are shown in the image below:

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As with many approaches in medicine, there are advantages and disadvantages to using either adjusted or targeted fortification. These are summarised in the table below:

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The application of individualised fortification is an ongoing area of research, with studies and trials assessing both adjustable and targeted fortification strategies. Studies assessing targeted fortification have had mixed results. Whilst several studies have shown targeted fortification may improve the quality and consistency of nutrient intake, clear benefits on growth or other outcomes have not yet been consistently demonstrated. However, a Cochrane analysis has provided moderate- to low-certainty evidence suggesting that individualised fortification (either adjustable or targeted) of enteral feeds in very low birthweight (VLBW) infants increases growth velocity of weight, length, and head circumference compared with standard non-individualised fortification.

Osmolality

There could be concerns about high osmolality levels when additional fortification is being provided to human milk for VLBW infants. In most studies, individualised fortification increases osmolality during the first hour, but generally levels stay below 460-480 mOsm/L during the next 12 to 24 hours which many consider acceptable.

Fortification strategies when using donor human milk

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There is no consensus surrounding whether infants primarily receiving DHM should have that milk fortified until hospital discharge, or whether this could be replaced with formula milk. In addition, because DHM is ‘mature’, protein levels may often be less than that of mother’s own milk, and some have suggested a pragmatic approach of adding extra protein (0.3-0.7 g/100mL). However, this has not been tested in prospective trials and is logistically complex as it requires access to a separate protein source, in addition to multicomponent fortifiers.

Exclusive human milk diet

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The concept of “exclusive human milk diet” uses exclusive human milk fortifier products that come as liquids (after extensive lacto-engineering) or as powder (after lyophilisation of native or partly defatted human milk). Production uses similar processes as those from bovine fortifier industry. Many hospitals (primarily those in North America) now use human milk-derived fortifiers. Observational studies and 2 small studies suggest there may be potential benefit. Earlier studies suggested there might be slower growth (although that could be improved with adjusting the composition) but also a reduction in NEC. The current evidence does not support a recommendation for routine use, and cost is also an important issue. However, costs may be offset by a lower incidence of NEC if this was conclusively shown. Further large-scale studies are needed.

Conclusions

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Recommendations

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If you wish, you can download the SDC for this step for future reference.