Questions parents have: What is Fore-milk and Hind-milk?
Over the next few posts I will try and answers some common questions most parents, who come to the Breastfeeding Clinic have ;-).
What is Fore-milk and Hind-milk?
You may have heard that mothers produce two kinds of milk: “fore-milk”, the thinner milk the baby gets first, which has a lower fat content; and “hind-milk”, the high-fat, creamier milk that follow? These terms can make it seem as if the breasts produce two distinct kinds of milk, which is not the case. A woman's breast really only makes one type of milk, the higher-fat milk that we typically think of as “hind-milk”.(1) When you drink milk from a glass and you look at the empty glass, can you see “milk” left behind on the sides of the glass? Well the same thing happens in the breasts.
Diana West and Lisa Marasco explain the process in their book, “The Breastfeeding Mother's Guide to Making More Milk”: The fat globules in the milk tend to stick to each other and to the walls of the alveoli (“factories” where the milk is made – looks like a cluster of grapes ;-).
Milk is made continually and between feedings, when the alveoli gets too full to hold the milk, milk starts moving down the ducts toward the nipple, leaving more and more of the fat "stuck" further back in the milk ducts. The more time between feedings, the lower the fat content of the “fore-milk” available to baby at the beginning of the feeding.
Once the let-down (or *Milk Ejection Reflex/MER) is triggered (by baby's feeding, moms pumping, etc.), the milk is squeezed out of the alveoli, down the ducts by the contracting muscles cells surrounding the alveoli. The fat globules begin to dislodge and move down the ducts. So the further into the feed, the higher the fat content of the milk, as more and more fat globules are forced out. The end result is that the milk gradually increases in fat as the feeding progresses.(2)
* Milk Ejection Reflex/MER happens when baby sucks at the breast, stimulating the very sensitive nipple/areola area, sending a nerve message to the brain, which causes the hormone oxytocin to be released into the bloodstream and this hormone causes the muscle cells around the milk glands (alveoli) to tighten and squeeze the milk out.
Diane Wiessinger (www.normalfed.com) talks about a “three course meal”. From the description above you can see baby may start with the soup (so called “fore-milk”) and as the milk “lets-down” baby goes over to the main meal and ends the feed with the high-fat “chocolate-pudding” dessert which is what satisfies baby’s hunger (and babies feed for calories, not for volume!). Now you may also begin to understand why we should rather let baby finish a feed at one breast before offering the other? No time limits per breast!
1. Diana West, BA, IBCLC & Lisa Marasco, M.A., IBCLC. (2009). The Breastfeeding Mother's Guide to Making More Milk. USA: McGraw-Hill.
2. J Mammary Gland Biol Neoplasia. (1996). Feedback control of milk secretion from milk. Peaker M, Wilde CJ. Hannah Research Institute, United Kingdom, Jul;1(3):307-15.