Dr. Chaney gives us so much insight into some of the latest research from Iowa Women’s Health Study. Sometimes it’s difficult to sort out the truth. If you are interested in more information on the topic of vitamins’ value, please let me know. I’d be happy to share his previous post also.
from Dr. Chaney. . .
Last week I discussed the strengths and weaknesses of
the Iowa Women’s Health Study (Mursu et al, Archives of
Internal Medicine, 171: 1625-1633, 2011) which has been
interpreted as suggesting that multivitamins and
certain individual vitamin or mineral supplements could
actually increase the risk of mortality in older women.
This week I’d like to focus on the bottom line for you,
and give you my personal recommendations.
1) As I mentioned last week the sample size for women
taking a copper-only supplement was exceedingly small
(108), so I do not have much confidence in the data
reported for copper supplement users in this study.
However, high doses of copper can be toxic and there is
no reason to be taking a stand-alone copper supplement
unless it is recommended by your physician.
On the other hand, copper is an essential nutrient, so
some copper should be included in your multivitamins. I
recommend looking for multivitamins providing around 1
mg of copper (50% of the DV) on a daily basis.
2) The potential toxicity of iron in adult men and
post-menopausal women is well documented. About 5-10%
of these population groups have an increased need for
iron that can be easily diagnosed by their physicians.
There is another 10-15% that have a genetic condition
that can lead to iron overload and premature death.
This condition is insidious and is often not diagnosed
until considerable damage has been done. For the rest
of the people in these population groups iron offers
neither a risk nor a benefit.
This is why the standard recommendation for adult men
and post-menopausal women is to avoid iron supplements
and iron-containing multivitamins unless supplemental
iron is specifically recommended by their physicians.
To be quite clear, if you are an adult man or post-
menopausal woman there is no reason to be taking an
iron-containing supplement unless it has been
recommended by your physician.
3) The potential toxicity of vitamin B6 and folic acid
as stand-alone supplements in this study was quite
small and was not seen in several previous studies.
However, as I pointed out last week there was no risk
involved in taking a B complex supplement containing
B6 and folic acid.
This reinforces a continuing theme of mine – namely
that we should be focusing on a holistic, balanced
approach to supplementation rather than relying on
supplements providing individual, high potency
4) Similarly, the potential toxicity of magnesium and
zinc was also quite small, was seen only after
considerable adjustment of the primary data, and has
not been seen in several previous studies.
My recommendation would be to get both of these
nutrients from a well-designed multivitamin supplement
where all of the essential minerals are provided in the
appropriate amounts and balance. If you do use
magnesium and zinc as stand-alone supplements my
recommendation would be to avoid very high doses of
either unless directed by your physician.
5) The very slight increase in mortality associated
with multivitamin use is not completely surprising
because some previous studies have suggested this
As last week one needs to know why the participants
were taking a multivitamin (ie, was it because they had
a medical condition) to appropriately evaluate these
However, it is also important to ask how well designed
and tested the multivitamin was. There are some
multivitamins in the marketplace that are so poorly
designed and/or manufactured that they could possibly
cause more harm than good. Here are the questions
that you should ask about the supplement that you are
– Does it represent a holistic approach to
I have already talked about the value of having all of
the B vitamins in balance rather than high dose B6 or
folic acid alone. However, both pure alpha tocopherol
alone (even all natural d-alpha tocopherol) or pure
beta- carotene alone have the potential to cause some
harm by interfering with the absorption of similar
You should look for a supplement that provides all of
the naturally occurring tocopherols and tocotrienols –
especially gamma-, beta- and delta tocopherol rather
than pure d-alpha-tocopherol alone.
You should also look for a supplement that provides all
of the major carotenoids (beta-carotene, alpha-
carotene, lycopene, lutein, and zeaxanthin) rather than
And finally, a truly holistic supplement will contain
omega-3 fatty acids, polyphenols and probiotics.
– Does the manufacturer do quality controls that
guarantee the supplement does not contain contaminants
that can harm you? Ask them how many quality controls
they perform with the product that you are using.
– Can the supplement manufacturer provide you with
clinical studies done with their product showing that
it delivers the nutrients to your bloodstream and has
the intended effect in your body? Animal and cell
culture studies don’t count.
– Are there clinical studies showing that long term use
of the supplement actually decreases disease risk? The
study should be at least as long as the Iowa Women’s
Health Study (19 years).
6) Finally, we should not ignore the “good news” part
of the study – namely that calcium supplementation
decreased mortality risk. Of course, this conclusion is
subject to the same limitations as the previous ones
and not every previous study has come to the same
The DV for calcium for women in this age range is 1,200
mg/day and some 40-60% of older women do not achieve
this from diet alone. I recommend that everyone strive
for the DV for calcium from diet plus supplementation.
Intakes slightly above 1,200 mg/day are probably safe
for older women, but I don’t recommend going above
I’ve covered a lot of ground over the past two weeks.
Let me close with a quick summary.
– The Iowa Women’s Health Study has a number of
significant design flaws and its conclusions should be
confirmed by subsequent studies before recommendations
are made to the public.
– The study’s warning against taking iron-containing
supplements and copper-alone supplements is, however,
right on. In postmenopausal women these supplements
should only be taken if prescribed by a doctor.
– Individual high dose B6 or folic acid supplements are
also probably not a good idea unless prescribed by a
physician, but a well designed B complex or
multivitamin supplement containing those nutrients
appears to be safe.
– The risk associated with individual high dose
magnesium and zinc is weak and needs to be confirmed by
additional studies. Holistic supplements containing
magnesium and zinc should not be a problem.
– The risk associated with multivitamin use was also
weak and needs to be confirmed. My take on this is that
many of the multivitamins on the market are poorly
designed and could conceivable cause more harm than
good. I recommend looking for holistic supplements
backed by strong clinical studies showing that they are
safe and effective for long term use.
– This study suggests that supplemental calcium may
decrease the risk of death. While this needs to be
confirmed by subsequent studies, it does make sense to
make sure that you are getting the DV for calcium on a
To Your Health!
Dr. Stephen G Chaney