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Re: An Answer to my own Question
From: =?iso-8859-2?q?Zalányi Sámuel?= (anonymous@obgyn.net)
Wed, 31 Jan 2001 22:26:46 +0100 (MET DST)
Hi Samina,
I am sorry to have to take up the continuous medical education of US obstetricians. But if need to be... the situation is as folows.
To have a healthy diet during pregnancy is common sense. Adding vitamins is another thing. The first birth defect to be linked to vitamin deficiency was the complex called neural tube defects (NTD) comprising anencephaly and open vertrabral column (spina bifida). In the 1960 NTDs were observed at higher than average rate in Wales (This proved to be due to a metabolic anomaly in welsh population). Later on it turned out that folic acid deficiency may cause the increased prevalence of NTDs and this theory was proven in two studies (Lancet 1991:2:132-7 and N Engl J Med 1992:327:1832-35.) and the minimum amount necessary to reduce NTD risk was 800 mcg/day. No other components in the latter study (other vitamins, minerals) proved to be effective i.e. they are superfluous. This is one point of the argumant. The other is, that vitamin A IS TERATOGENOUS in large amounts, but there is no safe lower limit of its intake, i.e. it may be dangerous even in small amounts (c.f. Vitamin A and birth defects N Engl J Med 1995:333 1414-15. Maternal vitamin A supplementation in relation to selected birth defects Teratology 1990:42:497-503) some doctors went so far as to suggest limited intake of liver (rich in vitA, Eur.J Ob Gyn 1996 66:17-21). All these infomrations refer to women taking usual Western diet and pregnant before W12. After W12 intake of further vitamins (A,D) and minerals is justified. But taking extra vit A before the 12th week may be dangerous.
The problem is, that most (or every) prenatal supplement contains some amounts of vitamin A, thus they should not be recommended in the first trimester of pregnancy (not even by your obstetrician). In this period and prenatally only folic acid seems to be justified as it is proven to decrease the risk of NTDs and is harmless.
Looking forward to your reflection (on to those of your Ob)
Sam (Ob/Gyn, RE)
> Hi Sam,
>
> I had read one of the mails on this list that Vit A in the prenatals causes
> some abnormalities. I mentioned this to my doc the other day and she said
> she had heard of no such thing and asked me to continue the prenat. Could
> you please let us know what studies show that so we can show that to our
> respect . REs.
>
> Thanks
>
> Samina
>
> >Hi Jenny,
> >I am a (Hungarian ) Ob/Gyn, I have a Ph.D. in reproductive endocrinology,
> >besides I haven't forgotten what I have learned about vitamins. Thereforre
> >I copy for you two earlier letters on the same topic. You should also show
> >it to the pathologist.
> >1)
> >Glucophage is suspected to decrease the absorption of folic acid (a member
> >of the vitamin B group). I see no reason in taking B12 orally because it is
>
> >not absorbed from the gastrointestinal tract.
> >I hope this helps
> >2)
> >Congratulations to your explanation of IR and PCOS, but don't mess up with
> >vitamins and supplements.
> >I have read references on metformin blocking the absorption of folic acif,
> >all right (though I would like to see the original publication). But
> >confusing folic acid with B12 is a mistake. B12 is not absorbed from the
> >gastrointestinal system, so there is no use of taking it as a pill (you had
>
> >it INJECTED earlier).
> >Prenatal viamtins are a big delusion and a dangerous one at that. The only
> >vitamin proven to reduce the risk of certain birth defects is folic acid
> >(800 mcg/day is enough to supplement the habitual western diet).
> >Unfortunately most prenatal vitamins also contain vitamin A which is KNOWN
> >TO CAUSE certain abnormalities if taken before W12 of pregnancy. Therefore
> >I strongly advise my patients against taking vitamin complexes before W12.
> >Folic has to be taken srtictly after conception (or prophylactically
> >before). Combining more products is definitely harmful.
> >3) New: vitamin A is necessary for the heatlhy development of skin and its
> >appendages (nails, hair, sebaceous glands etc), also for ther normal
> >functioning of the retina (its lack causes twilight blindness). Vitamin E
> >can also help maintaining skin and accessories.
> >I hope this clarifies the misunderstanding
> >Sam (Ob/Gyn, RE)
> >
> > > I don't know who you are, but I'll take the info from a doctor I know,
> > > even if she is a pathologist, and the info from the bottles of hair and
> > > nail vitamins that B's are necessary for hair and nails.
> > >
> > > At Thu, 25 Jan 2001, =?iso-8859-2?q?Zalányi wrote:
> > > >
> > > >Hi JEnny,
> > > >I think I have answered this. Vitamin B has NOTHING to do with nails,
> >hair
> > > and the skin. It is for the neural system plus incorporating iron into
> >red
> > > blood cells.
> > > >Check up my earlier posting
> > > >Sam
> > > >
> > > >> I posted asking if there was a connection between metformin and my
> >nails
> > > >> breaking, splitting, and peeling. I asked everyone I could think of.
> > > >> The pharmacist said it was probably the birth control pills. I don't
> > > >> think so, I was on a stronger dose for 20 years with no prob. My GP
> > > >> didn't know, but suggested I take pre-natal vitamins. The chief
> > > >> pathologist where I work said that it was likely that the metformin
> > > >> could cause this because of the vitamin B deficiency. She said B's
> >are
> > > >> used for hair and nails.
> > > >>
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