Dr. Mehmet Oz FEEL YOUR BEST
How Excess
Vitamins
Can Harm
As a longtime champion
of the multivitamin, I’m in-
trigued by two new studies
that suggest certain vita-
mins found in a multi might
do more harm than good.
The first study, in Iowa,
found that older women
who used multivitamins
and other supplements had
a slight overall increased
risk of dying. A second
study suggested that men
who took high doses of
vitamin E had a 17 percent
increased risk of prostate
cancer after seven years.
Both studies provide
valuable lessons but invite
appropriate criticism, too.
A previous study found
none of the multivitamin
risks cited in the Iowa
study. Most important,
though, is that much of the
death risk in the Iowa study
was specifically linked to
iron supplementation.
Iron is one of those tricky
multivitamin components.
If you’re a premenopausal
woman, it can help offset
iron loss caused by men-
struation. After menopause,
however, excess iron can
These are the
recommended daily
amounts of common
vitamins for adults.
VI TAMINS:
HERE’S
WHAT YOU
NEED
Vitamin A
Men, 3,000 IU
Women, 2,310 IU
Vitamin C
Men, 90 mg
Women, 75 mg
Vitamin D
600 IU
Vitamin E
22. 4 IU
Vitamin K
Men, 120 mcg
Women, 90 mcg
become dangerous. Iron is
an oxidant, which means it
can trigger cellular damage.
In the prostate cancer
study, the participants in
the vitamin E group were
taking 400 international
units (IU) a day for several
years, even though the
recommended daily allow-
ance of vitamin E is just
22 IU a day. That said, a
separate group of men in
the study who took both
selenium and vitamin E
showed no significantly
increased risk for pros-
tate cancer. Some argue
this difference shows the
importance of examining
vitamins together, not in
isolation, because they may
work synergistically to
confer health benefits.
So, yes, I still recommend
a multivitamin for most
people, but read the labels.
Look for a multi with no
more than 3,500 IU of vi-
tamin A and no more than
30 IU of vitamin E. Medical
research supports these
values as safe doses that
can compensate for dietary
insufficiency.
I’ve never been a fan of
megadose multivitamins—
those vitamin tablets that
contain well in excess of
100 percent of the daily
value. So stay away from
those. And remember, I
recommend iron in a multi-
vitamin only for premeno-
pausal women; otherwise,
make sure you choose one
without iron.
Finally, maximize the
benefits of your multi-
vitamin: Take half in the
morning and half at night
to ensure your body gets
a steady supply of these
healthful nutrients. ;
Thiamine
Men, 1. 2 mg
Women, 1. 1 mg
Riboflavin
Men, 1. 3 mg
Women, 1. 1 mg
Niacin
Men, 16 mg
Women, 14 mg
Vitamin B6 Men, 1. 7 mg
Women, 1. 5 mg
Folate
400 mcg
Vitamin B12
2. 4 mcg
Biotin
30 mcg
Pantothenic acid
5 mg
Choline
Men, 550 mg
Women, 425 mg
