The study, published in Food Chemistry, identified eight novel peptides that may contribute some of the benefits of human milk, through their antioxidant activity. The researchers reported two peptides in particular (YGYTGA and ISELGW) had strong antioxidant activity, signaling that the peptides could be artificially synthesized for use in infant formula.
“Further testing of these peptides may allow their inclusion in infant formulas to reduce the incidence of oxidative stress-mediated diseases in newborns,” wrote the researchers, led by Dr Apollinaire Tsopmo, Assistant Professor of Food Science and Nutrition at Carleton University, Canada.
The team of Canadian researchers said that many health conditions among preterm infants are linked to oxidative stress, include bronchopulmonary dysplasia, periventricular leukomalacia, intraventricular hemorrhage, and renal failure – all of which can lead to subsequent long-term complications in the physical and neurological development of children.
They said that premature infants are often exposed to supplemental oxygen concentrations as high as 95 percent, which can often result in the over-production of reactive oxygen species (ROS).
ROS generation in vivo is controlled by the action of antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase and the presence of non-enzymatic antioxidants, such as vitamins C and E and other bioactive agents
Previous research has shown human milk contains many bioactive components, which potentially contribute to the health benefits associated with breastfeeding.
The authors said that numerous protective mechanisms associated with mother milk constituents have been shown to stimulate the immune system, support the growth of healthy microflora, and aid the development of endogenous defense mechanisms, meaning that human milk offers greater protection against neonatal diseases compared to infants fed formulae.
Tsopmo and co-workers noted that some of the benefits of breastfeeding have been ascribed to the antioxidant activity of human milk. However, they said that there is relatively little information on the contribution of antioxidant peptides derived from the digestion of proteins present in human milk.
The authors said that recent research identified a peptide fraction (PF-23) from digested human milk protein that showed “exceptionally high peroxyl radical scavenging activity.”
The new study identified the peptides present in PF-23 and determined their antioxidant properties.
Human milk pepsin and pancreatin digests were separated and the resulting fractions were screened for antioxidant activity using ORAC assay. The researchers reported the resulting peptide fraction (the PF-23 fraction) to have high antioxidant activity.
From this fraction, the researchers identified twenty peptides, of which eight were found to be low molecular weight novel peptides. The eight novel peptides (all between four and six amino acids long) were then synthesized and screened for their antioxidant properties and linolenic acid emulsion.
Antioxidant screening of the eight peptides revealed that two (YGYTGA and ISELGW) were the most active.
“Further studies (e.g. animal model) are necessary to show the effects of these peptides in vivo after which they might be considered for inclusion in infant formulas with the aim of reducing oxidative stress mediated disease early in life,” wrote the researchers.
Source: Food Chemistry
Published online ahead of print, doi: 10.1016/j.foodchem.2010.11.146
“Novel anti-oxidative peptides from enzymatic digestion of human milk”
Authors: A. Tsopmo, A. Romanowski, L. Banda, J.C. Lavoie, H. Jenssen, J.K. Friel