Microwaves action on milk for infants

David Fell daf at bms.brookes.ac.uk
Wed Jan 11 11:47:16 EST 1995

In article <3ekm7b$ch1 at rc1.vub.ac.be>, scorteel at resulb.ulb.ac.be (Stephane 
Corteel) says:
>As a young father (my baby now is 7 weeks old) I read a lot...
>I've read (and some people also told me) that warwing up a feeding
>bottle using a microwave oven is not recommended because the microwaves
>cause molecular changes in some proteins of the milk.
>But, at this time, nobody could confirm that or give me an more
>scientific explanation.
>If someone could provide me a answer that an engineer like me can
>accept, it would be very nice.
>Thank you very much for any information

Contrary to what other respondents have stated,
 there is some theory behind this concern.  Amino acids,
which are the building blocks of proteins in all living organisms,
occur in two spatial configurations that are often referred to as
D and L.  However, the form used with very few exceptions in
organisms is the L form; that is the form that occurs in milk
as a nutrient.

However, microwaves can "racemize" amino acids, that is, interconvert
the D and L forms.  I do not know the theoretcial basis of this
as I'd have expected the microwave energy to be too low to do this,
but I've seen reports of it being done and it has been proposed as the
basis of an industrial method for interconversion.  Indeed, I did get
a student of mine to check it out a few years ago, and she did
manage to get it to occur.

To get back to the milk, I did see a letter to Lancet a few years back
reporting that D amino acids could be detected in microwaved milk.
Right at this moment I can't find the reference.  Of course, what
you want to know is how important is this.  The loss of nutrient
quality is probably small; the D amino acids formed from essential
amino acids will be unavailable for use in making proteins in the baby.
Normally, we destroy any D amino acids we encounter.  The only concern
is that babies almost certainly have a more limited ability to cope
with D amino acids, and one of them, D - proline is somewhat
neurotoxic. The risk might be entirely hypothetical, but there is
a potential mechanism for it.  Why microwave the milk anyway? It's easy
to warm the amounts required for a baby by standing it in hot water.

David Fell


David Fell,
School of Biological & Molecular Sciences,
Oxford Brookes University,
Oxford OX3 0BP,           Tel. +44 (0)1865 483247
UK                        FAX  +44 (0)1865 484017

daf at bms.brookes.ac.uk

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