Jean wrote:
>(This is how I
>>interpret Peter Hartmann saying that we ought to discard the terms
>>foremilk and hindmilk, as during some feedings, at certain times of the
>>day, baby may get more fat as he begins to feed than he got when he fell
> >asleep at the breast earlier in the day.)
>

Denise wrote:
>Now from my readings of Peter's work that's not the way I interpret it.<snip>
>
>I'd appreciate other opinions on this research.

Denise talked about fat adhering to the walls after a feed as causing
reduction in fat concentration in the milk. This may well be
happening, but I don't think this really has anything to do with
Peter's findings and why he says that the terms foremilk and hindmilk
are of limited value. This is a challenge, but I will try to explain
what I understand about this without the benefit of a diagram. If
anyone has March 1995 J Hum Lact 11(1), page 31, this is what I am
basing it on (plus from listening to Peter on numerous occasions).

Note that fat concentration is directly related to degree of breast
'emptiness' (and therefore inversely correlated with breast volume).

Think of (or draw!) a graph, vertical axis is breast volume and
horizontal axis is time of day. (This is for each breast
individually.) As baby feeds at first feed of the day (assuming a
long time gap prior to this from previous feed, so mum quite 'full' -
2000 ml in right breast), draw a line going almost straight down
indicating that breast volume has dropped, say 300 ml (to about 1700
ml). Feed ends, and milk synthesis causes the line on the graph to
start to rise again (say 100 ml from end of first feed, ie to 1800
ml). Baby has another feed, and this time drops the breast volume 100
ml further down than at the end of the last feed (now breast volume
at 1600 ml).(Note that the emptier the breast is at the end of a
feed, the faster the synthesis rate to fill it up again, but is not
as fast as the drop from feeding in this mother with a large storage
capacity.) This zig-zag graph continues in a downward trend over the
day and at some stage the breast volume at the *start* of a feed
(much later in the day) is lower than it was at the *end* of the
first feed of the day. I think this is what Jean was alluding to.

This means that the fat concentration (as it is related to breast
'emptiness') is higher at the start of this later feed (so-called
'foremilk') than it was at the end of the first feed of the day
(so-called 'hindmilk').

Now this example was for a mother with a large storage capacity. If
you look on page 33 of this article in J Hum Lact you will see what
happens in a mother with a small storage capacity. This second mother
needed to feed frequently and regularly and her baby emptied her
breasts fairly efficiently each feed. Her synthesis rate is fairly
constant (and high) to keep up the supply. This is more 'classic' for
the meaning of foremilk and hindmilk as we usually use the terms, as
for her, it would be relatively low-fat foremilk and high-fat
hindmilk every feed.

These mothers illustrate beautifully why set 'rules' for how to
breastfeed (eg 10 minutes a side every 4 hours, etc) cannot possibly
work for *all* mothers. The first mother here with the large storage
capacity would have been OK probably, but the second would have had
'insufficient milk' very quickly on this regime.

Sorry this ended up so long. I really recommend anyone wanting good
explanations of this read Peter's and his students' (they are his PhD
students at University of Western Australia) papers. The two in the J
Hum Lact should be easy to find for many. They are both in the same
issue (March 1995). Some other papers are Exp Physiol 77: 79-87 1992;
Exp Physiol 78(6): 741-55 1993; Exp Physiol 81: 861-75 1996; Exper
Physiol 81: 1007-1020 1996, J Nutr 128: 394S-399S 1998. Also in a
book, 'Scientific Foundations of Obstetrics and Gynaecology', 4th Edn.
******************************************************************
Joy Anderson B.Sc. Dip.Ed. Grad.Dip.Med.Tech. IBCLC
Nursing Mothers' Association of Australia Breastfeeding Counsellor
Perth, Western Australia.   mailto:[log in to unmask]
******************************************************************

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