Volume 90, Issue 5, November (2003), pp. 979-986 © The Author 2003
doi:10.1079/BJN2003979

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Infant intake of fatty acids from human milk over the first year of lactation

Leon R. Mitoulas¹, Lyle C. Gurrin², Dorota A. Doherty², Jillian L. Sherriff³, Peter E. Hartmann^1
1Biochemistry and Molecular Biology, School of Biomedical and Chemical Sciences, Faculty of Life and Physical Sciences, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
²Women and Infants Research Foundation and The University of Western Australia Department of Obstetrics and Gynaecology, King Edward Memorial Hospital, Subiaco WA 6008, Australia
³Department of Nutrition, Dietetics and Food Science, School of Public Health, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, , Australia

 (Received 14 June 2002–Revised 12 June 2003–Accepted 11 July 2003)

Despite the importance of human milk fatty acids for infant growth and development, there are few reports describing infant intakes of individual fatty acids. We have measured volume, fat content and fatty acid composition of milk from each breast at each feed over a 24 h period to determine the mean daily amounts of each fatty acid delivered to the infant from breast milk at 1, 2, 4, 6, 9 and 12 months of lactation in five women. Daily (24 h) milk production was 336·60 (sem 26·21) and 414·49 (sem 28·39) ml and milk fat content was 36·06 (sem 1·37) and 34·97 (sem 1·50) g/l for left and right breasts respectively over the course of the first year of lactation. Fatty acid composition varied over the course of the day (mean CV 14·3 (sd 7·7) %), but did not follow a circadian rhythm. The proportions (g/100 g total fatty acids) of fatty acids differed significantly between mothers (P<0·05) and over the first year of lactation (P<0·05). However, amounts (g) of most fatty acids delivered to the infant over 24 h did not differ during the first year of lactation and only the amounts of 18 : 3n-3, 22 : 5n-3 and 22 : 6n-3 delivered differed between mothers (P<0·05). Mean amounts of 18 : 2n-6, 18 : 3n-3, 20 : 4n-6 and 22 : 6n-3 delivered to the infant per 24 h over the first year of lactation were 2·380 (sd 0·980), 0·194 (sd 0·074), 0·093 (sd 0·031) and 0·049 (sd 0·021) g respectively. These results suggest that variation in proportions of fatty acids may not translate to variation in the amount delivered and that milk production and fat content need to be considered.

Keywords:
Fatty acids, Infant nutrition, Human milk lipids, Sampling protocols, Breast-feeding

Abbreviations:
FA, fatty acid