Leah Murray, of Auckland, asks :-
Why does a breast feeding mother who eats a strongly pigmented food like beetroot have her breast milk stay white but the baby's poop go pink?
Andrew Day, a paediatric gastroenterology at the University of Otago (Christchurch campus), responded.
I understand that the pigment that makes beetroot red is betanin (also known as betacyanin, an anti-oxidant). Some of us are able to absorb this in the gut (various factors can make this more or less likely), and in that instance the red colour can end up in the urine as well.
Many of the foods that we eat can end up in the breast milk - sometimes as flavours, sometimes as whole proteins. This includes common things like coffee, but also individual highly flavoured foods (e.g. aniseed).
Mostly breast milk is white. However, the initial milk just after birth (colostrum) tends to be yellow coloured. Subsequently the foremilk tends to be more clear (more watery) than the hind milk, which is creamier and whiter (more calorie dense). This colour range reflects the main components in breast milk, especially the fat content.
Sometimes, however, individual foods can lead to the breast milk being more coloured. Lots of green foods or green dyes, can lead to a green tinge to the milk. And some people eating beets can have a red or pink tinge to the milk afterwards.
So, mostly ingestion of beetroot won't change the breast milk colour as not much absorbed and only small amounts present in circulation. However, in a person who absorbs more of the compound, and who has lots to eat, then their breast milk could have a slightly change in colour.