We are often asked about various vitamins and supplements and when
important information becomes available, we try to make blog posts to update
everyone. We’ve also decided to
summarize some of our thoughts about supplements and this is the result of that
effort. As always, the opinions
expressed here are general recommendations and we always encourage a
conversation with your physician before you make any changes to previously
recommended treatments.
Multivitamins
There is general agreement among physicians that a well-balanced
diet provides adequate vitamins and minerals required to maintain health and
prevent diseases. Over half of Americans report that they regularly
take dietary supplements in an effort to improve their health. Unfortunately,
no studies have documented any benefit from multivitamin supplementation in
healthy adults and safety concerns have been raised.
Specific
vitamins and supplements
We do not recommend routine supplementation
with vitamins A, C, E, folic acid or beta-carotene.
Taking antioxidant vitamins (such as vitamin C and vitamin E) has
been promoted as beneficial in prevention of colds, heart attack, stroke and
cancer. Unfortunately, none of these illnesses are prevented by taking
vitamins. And worse yet, evidence has accumulated that antioxidant vitamins can
be harmful.
A remarkable study from Norway published in the New England Journal of Medicine in 2006 rebuffed prior theories that heart attacks could be
prevented by antioxidant vitamins and was among the first to raise concerns
that these might actually increase heart attack and stroke risk.
Supplemental beta-carotene, vitamin A and vitamin E may increase risk of death according to a recent
JAMA
review.
A study
published in the Proceedings of the National Academy
of Sciences demonstrated that taking supplemental vitamin C and
vitamin E eliminated one of the major benefits of exercise in healthy men (in
this case, the body’s ability to respond to insulin). We described this study
in detail in a prior
post.
There is no evidence that
vitamin E is effective in preventing Alzheimer’s disease or other types of
dementia.
A recent review of 67 studies (involving over 230,000
participants) concluded that vitamin C (alone or in combination with other
vitamins) did not lower mortality. The same review concluded that vitamin E
supplementation (as well as supplementation with vitamin A and beta-carotene)
may increase mortality
significantly.
A recent study published in the Archives of Internal
Medicine also concluded that the “more is better” approach is not
necessarily the best. They concluded
that for adult women, multivitamins, vitamin B6, folic acid, iron,
magnesium, zinc and copper all increased
mortality in and that calcium supplementation decreased overall risk.
A study published in the Journal of the American
Medical Association this month also concluded that men who took 400 IU of vitamin
E were 17% more likely to develop prostate cancer over 7 years than were those
who did not take vitamin E. An earlier
study concluded that vitamin E supplementation increased the risk of death
in men.
Earlier studies in smokers found that beta-carotene supplements increased
lung cancer risk and the trace mineral selenium has been linked to an increased
risk of non-melanoma skin cancer in women and men.
The
exceptions
Deficiencies of vitamins B12
and D are linked to many health problems and when low levels are found in lab
testing, we often recommend supplementation.
Also, most American adults should probably take a calcium
supplement.
It is very clear that vitamin D is important for bone health (to
prevent osteoporosis). Recently, data have suggested that adequate vitamin D
levels may also decrease the risk of falling, and prevent colon polyps and
cancer and heart attack and may facilitate weight loss in those who are
overweight. We’ve reviewed this data and while it’s unlikely that vitamin D is
magic, it does seem to be important. Over-the-counter vitamin D supplementation
is reasonable for average-risk patients who have a mild vitamin D
insufficiency, but a much higher dose (prescription strength) supplement is
probably more appropriate in patients at risk for osteoporosis or those with
severe deficiency.
Low levels of vitamin B12 can cause anemia and damage to the brain and nerve
cells. Symptoms of nerve damage may be present before anemia. They can include
numbness or tingling in the fingers and toes, poor balance and coordination,
forgetfulness, depression, confusion, difficulty thinking and concentrating,
impaired judgment and poor control of impulses, a decreased ability to sense
vibration, ringing in the ears (tinnitus), and dementia, a decline in mental
abilities that is severe enough to interfere with daily life.
The Bottom Line
The Bottom Line
With the few exceptions above, vitamin
supplements are unnecessary and potentially harmful. A well-balanced diet coupled with daily
exercise is the closest thing to a magic pill for good health.
