Oxidation products of polyunsaturated fatty acids in infant formulas compared to human milk--a preliminary study

Mol Nutr Food Res. 2008 Dec;52(12):1478-85. doi: 10.1002/mnfr.200700451.

Abstract

Information about lipid oxidation in fresh and stored human milk compared with infant formulas is scarce. We aimed to assess n-6 and n-3 PUFA oxidation in these milks by measuring the 4-hydroxynonenal (4-HNE) and 4-hydroxyhexenal (4-HHE) content. Human milk samples (n = 4), obtained from volunteer mothers, were analyzed fresh and after 1 wk at 4 degrees C or 24 h at 18 degrees C. Vitamin E and malondialdehyde (MDA) were measured by HPLC and fatty acid profile by GC. The 4-HHE and 4-HNE contents were measured by GC-MS. Infant formulas (n = 10) were tested; their fat droplet size was measured by laser light scattering and observed by confocal laser scanning microscopy. Human milk samples contained 31.0 +/- 6.3 g/L of lipids and 1.14 +/- 0.26 mg/L of vitamin E. Fat droplets were smaller in infant formulas than reported in human milk. The (4-HHE/n-3 PUFA) ratio was 0.19 +/- 0.01 microg/g in fresh human milk (unchanged after storage) versus 3.6 +/- 3.1 microg/g in dissolved powder formulas and 4.3 +/- 3.8 microg/g in liquid formula. (4-HNE/n-6 PUFA) was 0.004 +/- 0.000 microg/g in fresh milk (0.03 +/- 0.01 microg/g after storage) versus 1.1 +/- 1.0 microg/g in dissolved powder formulas and 0.2 +/- 0.3 microg/g in liquid formula. Infant formulas also contained more MDA than human milk. n-3 PUFA were more prone to oxidation than n-6 PUFA. Whether threshold levels of 4-HHE and 4-HNE would be of health concern should be elucidated.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aldehydes / analysis*
  • Fatty Acids, Unsaturated / chemistry*
  • Female
  • Humans
  • Infant Formula / chemistry*
  • Lipid Peroxidation
  • Milk, Human / chemistry*
  • Oxidation-Reduction
  • Pregnancy
  • Time Factors
  • Vitamin E / analysis

Substances

  • Aldehydes
  • Fatty Acids, Unsaturated
  • 4-hydroxyhexenal
  • Vitamin E
  • 4-hydroxy-2-nonenal