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The 7 wonders of breast milk


Learn what makes breastfeeding worthwhile

Breast milk is incredible, multifaceted, and fascinating. It’s been inspiring our research for 40 years. And as we’re able to discover more and more about its composition, more unexpected and amazing properties are being revealed.

 7 wonderful facts that might surprise you:

Number 1

Your breast milk is totally unique to you

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Your breast milk is totally unique to you

 It's composition is determined by factors including your diet, hormones, genetics, enviromental influences, and the needs of you and your baby.

Your baby recognises the smell of your breast milk1

The scent of your breast milk prompts your newborn to show searching behaviours2. And, amazingly, they can sense and process information contained in your milk3.

Number 3

Your breast milk can help your baby sleep

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Your breast milk can help your baby sleep

As your hormone levels change throughout the day, so do the levels in your breast milk. This means, for example, that in the evening your milk will pass on sleep inducing hormones to your baby.
Number 4

Breastfeeding makes your ‘love hormones’ rise

The skin-to-skin contact of breastfeeding is thought to help with bonding, but scientists have also discovered that your oxytocin levels go up while you breastfeed. This is thought to help increase your feelings of love towards your child5.

Breast milk helps your baby have a healthier future

Breast milk is filled with germ-fighting antibodies6. It can reduce the risk of developing eczema, asthma, allergies and obesity in later life7,8, while prolonged breastfeeding helps reduce the lifelong risk of heart disease9.
Find out more about the health benefits of breastfeeding.

Prolonged breastfeeding helps reduce the lifelong risk of heart disease

Number 6

Breast milk can help your baby become a lifelong healthy eater

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Breast milk can help your baby become a lifelong healthy eater

 Your diet can directly influence the composition of your breast milk10-13. And the foods you eat while breastfeeding could influence the tastes your baby enjoys throughout weaning and beyond14,15.

Number 7

Breast milk is different for sons and daughters

Did you know that boys consume more of their mother’s milk than girls16,17? And amazingly, the breast milk produced for boys contains 25% more calories than for girls18,19.

Learn more about breast milk composition.

Breast milk produced for boys contains 25% more calories

We still don't know how milk becomes naturally tailored to each baby's needs20. In fact, we're only just beginning to understand the subtleties and complexities of breast milk. There's much more research needed, but there is no doubt that breast milk is wonderful.

Worried about breastfeeding?

It's completely normal to find breastfeeding a little tricky at first, but our breastfeeding guide is full of tips and advice to help you succeed.

View references

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 1. Nishitani S et al. The calming effect of a maternal breast milk odor on the human newborn infant. Neurosci Res 2009;63:66-71.

2. Porter RH, Winberg J. Unique salience of maternal breast odors for newborn infants. Neurosci Biobehav Rev 1999;23(3):439-49.

3. Schaal B et al. Olfactory cognition at the start of life: the perinatal shaping of selective odor responsiveness. In: Schaal B (ed). Olfaction, Taste, and Cognition. West Nyack, NY (U.S.A.): Cambridge University Press, 2002.

4. Sánchez CL et al. The possible role of human milk nucleotides as sleep inducers. Nutr Neurosci 2009;12(1):2-8.

5. Uvnäs-Moberg K et al. Oxytocin and Prolactin Levels in Breast-Feeding Women. Correlation with milk Yield and Duration of Breast-feeding. Acta Obstet Gynecol Scand 1990;69:301-6.

6. Chirico G et al. Antiinfective properties of human milk. J Nutr 2008;138(9):S1801-6.

7. Unicef [Online]. Available at: [Accessed: November 2015].

8. Unicef. Diabetes [Online]. Available at: [Accessed: November 2015].

9. Schwarz EB et al. Duration of lactation and risk factors for maternal cardiovascular disease. Obstet Gynecol 2009 May;113(5):974-82.

10. Valentine CJ et al. Docosahexaenoic acid and amino acid content in pasteurized donor milk are low for preterm infants. J Pediatr 2010;157(6):906-10.

11. Saarela T et al. Macronutrient and anergy contents of human milk fractions during the first six months of lactation. Acta Paediatr 2005;94(9):1176-81.

12. Kent JC et al. Volume and frequency of breastfeeding and fat content of breast milk through the day. Pediatrics 2006;117(3):e387-95.

13. Hollis BW et al. Vitamin D compounds in human and bovine milk. Advances Nut Res 1982;4:49-75.

14. Beauchamp GK, Mennella JA. Flavor Perception in Human Infants: Development and Functional Significance. Digestion 2011;83(Suppl 1):1-6.

15. Mennella JA et al. Prenatal and postnatal flavor learning by human infants. Pediatrics 2001;107(6):E88.

16. Michaelsen KF et al. Nutrition and Growth: breast-milk intake, human milk macronutrient content, and influencing factors. Am J Clin Nutr 1994;59:600-11.

17. Butte NF et al. Infant feeding mode affects early growth and body composition. Pediatrics 2000;106(6):1355-66.

18. Thakkar SK et al. Dynamics of human milk nutrient composition of women from Singapore with a special focus on lipids. Am J Hum Biol 2013;25:770-9.

19. Powe CE et al. Infant sex predicts breast milk energy content. Am J Hum Biol 2010;22(1):50-4.

20. Hassiotou F et al. Maternal and infant infections stimulate a rapid leukocyte response in breast milk. Clin Trans Immunol 2013;2:e3.
Last reviewed: 10th March 2016

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