Supporting Breastfeeding

La Leche League Canada

What Is in Your Breastmilk?

on April 6, 2015

Breastmilk volume varies widely, but for fully breastfed babies around four months of age, it is often 700 to 800 ml per day. It may rise later to as much as 1000 ml or more.  The nutrients present in this milk come from the diet of the mother or from her nutrient reserves.

Human breastmilk has a fairly constant composition, and is only selectively affected by the diet of the mother. One liter of milk provides about 750 calories and contains approximately the following:

  • 70 g carbohydrate
  • 46 g fat
  • 13 g protein
  • 300 mg calcium
  • 2 mg iron
  • 480 µg vitamin A
  • 0.2 mg thiamine
  • 0.4 mg riboflavin
  • 2 mg niacin
  • 40 mg vitamin C

The fat content of breastmilk varies somewhat. The carbohydrate, protein, fat, calcium and iron contents do not change much even if the mother is short of these in her diet.  A mother whose diet is deficient in thiamine and vitamins A and C, however, produces less of these in her milk.  In general, the effect of very poor nutrition on a lactating woman is to reduce the quantity rather than the quality of breastmilk.  Very few women in Canada would have a level of nutrition so poor that it would significantly affect the quality or quantity of their breastmilk.


Nutritional data from the Food and Agriculture Organization of the United Nations: Human Nutrition in the Developing World 

If you need more information or have a breastfeeding problem or concern, you are strongly encouraged to talk directly to an accredited La Leche League Leader.  In Canada, Leaders can be located by clicking or Internationally


If you have found this article helpful, La Leche League Canada would appreciate your support in the form of a donation at so we can continue to help others breastfeed.


3 responses to “What Is in Your Breastmilk?

  1. Alissa says:

    Isn’t there another 280 or so molecules/compounds not listed here? Might be good to add?

  2. […] Something to eat: You are producing 500- 700 calories of milk a day for your baby; feeling hungry is justifiable. You may be sitting in your nursing nest for a […]

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