I’m afraid of sounding like a real ignorant person, but how do mammals turn the food that they eat into milk? We were never taught anything like that in school. We learned that mammals have mammary glands that make milk and that was it.
I have been wondering this for 18 months ever since my daughter became allergic to the dairy products that I was eating and ending up in my milk.
The mammary gland arises from the same stem tissues that form sweat glands. The human breast is mostly adipose tissue (fat) and is not functional in the production of milk. The actual glandular tissue and the network of ducts that bring the milk to the nipple are only a small portion of the tissue, except in actively lactating women. The breast gland absorbs nutrients, (chiefly glucose) from the blood, and use them as building blocks for lactose, and the many proteins found in milk. The milk of different mammals varies a great deal in content, including fats, and sugar levels and other elements. Seals, for instance have a milk which is nearly half fat, to allow the young seal to gain weight and insulation rapidly. Human milk is rather low in fat, comparatively, and very high in sugars, and proteins. The specific chemistry of the changes from blood elements to milk elements is exceptionally complex. The study of it is a very rapidly growing area of genomics from which we might gain easily reproducible vaccines, replacement hormones, and other complex chemicals produced by genetically altered mammals.)
Mammalian females are at some risk, nutritionally, when lactating. The priority of the body for needed materials is definitely weighted in favor of the offspring, and the mother’s bones, teeth, and other body parts will be stripped of needed elements to provide the essential nutrition in the milk. Survival of the mother is not a benefit in the cold equation of species survival. (In mammals, the father is most often an evolutionary liability after conception, so he doesn’t figure into this part of the equation.)
As you have noticed, some elements of the mother’s diet are transmitted directly into the milk. Dairy farmers are well aware of this as well, certain types of natural forage alter the taste of Cow’s milk and are carefully removed form the possible forage range of dairy animals. The value of such taste transmission might be that it helps young mammals recognize edible foods, early in their lives. The proteins transmitted in milk include many chemicals that assist the immune response of infant mammals. These are among the most beneficial of the characteristics that increase the survival of mammalian species.
<p align=“center”>Tris</p>
Just wanted to add that the nutrients in the milk will also vary over the period of lactation. For example cow’s milk will have a higher amount of fat at the beginning of the cow’s lactation, immediately after the birth of the offspring. In fact the closer to time of birth, the milk will contain more nutrients of all types.
I’ve been wondering something. I have three kids who all breast fed different lengths of time. The milk kept a comin’ as long as they were feeding, and stopped shortly thereafter. This was true for my youngest who breastfed for about three months to my oldest who breastfed to almost two years. What is the feedback mechanism by which the mammary glands know to stop producing?
A quick answer is that the suckling of the infant stimulates milk secretion; remove the stimulus and you don’t (need to) secrete milk. Sensory nerves in the nipple go to the brain and trigger the hormone response that induces milk secretion.
I guess I should add that the breasts are “primed” for lactation by pregnancy, in case anyone wonders why they don’t get milk while fooling around with their not-pregnant female partner.
The value of such taste transmission might be that it helps young mammals recognize edible foods, early in their lives. _____________________________________________________________________
Thank you, Tris. That’s similar to what I tell people when they want to know some of the benefits of breastfeeding. I say because nursed babies aren’t afraid to try new foods. They are much less picky as toddlers.(Along with all of the other wonderful things)
funneefarmer: And immunities go up after one year in human’s. This only makes sense because that’s when infants become mobile and go trying to put everything in the mouths. Also usually infants are eating more solid foods than breastmilk at this age so they would need the immunities to be more concentrated. Isn’t nature wonderful?
My ex-wife used to love shrimp de jong (sp?).
When she ate it while lactating, my son’s breath smelled strongly of garlic the next day. The odor migrated to uh… other places as well.
So breasts are highly evolved sweat glands, eh. That, as we say in Texas, will put me off my feed for awhile.