Loss of triglycerides and carotenoids in human milk after processing

Karien J M Tacken ¹, Annelies Vogelsang ^1*, Richard A van Lingen ¹, Janine Slootstra ², Bert D Dikkeschei ² and Diny van Zoeren-Grobben ¹

¹ Princess Amalia Department of Paediatrics, Division of Neonatology, Isala klinieken Zwolle, Netherlands
² Department of Clinical Chemistry, Isala klinieken Zwolle, Netherlands

^* To whom correspondence should be addressed. E-mail: a.vogelsang{at}isala.nl.

Accepted 20 April 2009

Abstract

Objective: Human milk (HM) is considered to be the best nutrition for preterm infants. However storage, heating or tube feeding can cause a decline in essential nutrients, which can lead to the loss of antioxidant vitamins, resulting in an increased risk for oxygen radical diseases. Recently we found that carotenoids, present in human milk, can play a role in the antioxidant protection of preterm infants. In this study we evaluated the effect of processing HM and infant formula (IF) on the triglycerides and carotenoid concentrations.

Design: The triglyceride, - and -carotene, lutein and lycopene concentrations of 30 samples of mature HM of mothers who delivered a term infant and 10 samples of IF were measured after refrigeration, freezing, microwave heating and tube feeding with and without exposure to normal light and phototherapy, imitating the clinical feeding routine in the NICU.

Results: After tube feeding triglyceride, lutein and -carotene concentrations decreased with 33 %, 35 % and 26 % respectively. The decrease in triglycerides in HM accounts for 16% of the total caloric intake of neonates. Triglyceride and carotenoid concentrations in HM remained stable after refrigeration, freezing or low temperature microwave heating, except for lutein which decreased after refrigeration and freezing. In IF no differences were found.

Conclusions: Mature human milk can be stored safely in a freezer and heated by microwave oven without loss of fat or carotenoids. The clinically important loss of fat during tube feeding is probably the most important contributing factor to the decrease in lutein and -carotene in tube feeding, with only a small role for peroxidation during light-exposure.