Fachblatt The Lancet
antioxydativ wirkenden Vitamine
A und E können Herzerkrankungen
doch nicht verhindern
Dr. med. Jochen Kubitschek
Die angesehene Medizin-Fachzeitung The Lancet räumt
jetzt mit einem weiteren weit verbreiteten Vorurteil auf, das
besagte, dass die antioxydativ wirkenden Vitamine A und E die
Entwicklung einer Arteriosklerose verlangsamen und so der Entstehung
vorbeugen. In der jetzt in The Lancet publizierten Untersuchung
wurden 7 Vitamin-E- und 8 Beta-Carotin (Vitamin A)- Studien analysiert,
an der in der Vergangenheit jeweils mehr als 1.000 Menschen teilgenommen
hatten. Die Teilnehmer wurden nach dem Zufallsprinzip mit den
Vitaminen bzw. einem Scheinmedikament behandelt. Der Effekt der
Tabletteneinnahme wurde in den jeweiligen Studien bis zu 12 Jahre
Arbeitsgruppe um Marc S. Penn von der Cleveland Clinic Foundation,
USA, kam jetzt zu dem für viele begeisterte Anhänger
der Einnahme von Vitaminpillen ernüchternden Schluss, dass
keine der untersuchten Großstudien den geringsten Hinweis
erbrachte, dass die Antioxydantien Vitamin A und E Herzerkrankungen
tatsächlich vorbeugen. Doch nicht nur das - es zeigte sich
sogar, dass die Einnahme des Vitamin-A-Vorläufersubstanz
Beta-Carotin mit einem leicht erhöhten Herz-Kreislaufrisiko
Marc S. Penn fordert daher die Beendigung all jener derzeit noch
laufenden Herz-Kreislauf-Studien, bei denen einige Versuchsteilnehmer
auch Beta-Carotin bzw. Vitamin A einnehmen.
Lancet 2003; 361:2017-2023
EVIDENCE THAT VITAMIN SUPPLEMENTS DO NOT PROTECT AGAINST CARDIOVASCULAR
DISEASE (p 2017)
meta-analysis of randomised trials in this week's issue of THE
LANCET provides further evidence that antioxidant vitamins are
not effective in reducing the risk of cardiovascular disease.
Supplements containing vitamin A compounds could actually contribute
to an increase in cardiovascular death and all-cause mortality.
previous studies have suggested that antioxidant vitamins could
delay the progression of atherosclerosis and thereby offer protection
against cardiovascular disease. However no such benefit has
been shown in large randomised trials.
S Penn from the Cleveland Clinic Foundation, USA, and colleagues
analysed seven randomised trials of treatment with vitamin
E and eight trials of treatment with beta carotene (a source
of vitamin A). All the trials included over 1.000 participants,
and follow-up ranged from one to twelve years.
E was not beneficial in reducing death from cardiovascular causes,
all-cause mortality, or in reducing the incidence of stroke compared
with people given control treatment. Beta carotene led to a small
(0.4%) but statistically significant increase in all-cause mortality
and a 0.3% increase in cardiovascular death.
S Penn comments: "Given the results of this meta-analysis,
the use of vitamin supplements containing beta carotene and vitamin
A, beta carotene's biologically active metabolite, should be
actively discouraged because this family of agents is associated
with a small but significant excess of all-cause mortality and
cardiovascular death. We recommend that clinical studies of beta
carotene should be discontinued because of its risks.
used as secondary prevention, vitamin E did not reduce the risk
of cardiovascular endpoints. Furthermore, given our results and
the lack of mechanistic data supporting efficacy of vitamin E
as a potent antioxidant in vivo, we do not support the continued
use of vitamin E treatment and discourage the inclusion of vitamin
E in future primary and secondary prevention trials in patients
at high risk of coronary artery disease."
Alicia Sokol, Department of Public & Media Relations, Cleveland
Clinic Foundation, W14, 9500 Euclid Avenue, Cleveland, OH 44195,
USA, T)+1 216 445 9661, F) +1 216 445 3040, E) email@example.com
Don't Cut Heart Disease Risk: Study
June 13, 2003 05:14 PM ET
By Keith Mulvihill and Karla Gale
YORK (Reuters Health) - Antioxidants such as beta carotene and
vitamin E don't cut the risk of dying from heart disease, and
beta carotene may even slightly increase the risk, according to
a new analysis of studies conducted in the past.
a result, researchers at the Cleveland Clinic Foundation said
the use of supplements containing beta carotene and vitamin A
(a beta carotene metabolite) should be actively discouraged and
that clinical studies using the antioxidant be discontinued.
addition, they also discourage similar investigations involving
vitamin E for heart disease treatment or prevention.
the conclusions of the new study sparked criticism from one expert.
conclusions are "unwarranted and very surprising," said
Dr. Jeffrey Blumberg of Tufts University in Boston, Massachusetts,
in an interview with Reuters Health.
new research has been conducted and this is why their conclusions
are so surprising," added Blumberg, who is an antioxidant
the study, Dr. Deepak P. Vivekananthan and associates reviewed
seven previously published trials of vitamin E treatment and eight
trials of beta carotene treatment, according to the report published
in the June 14th issue of The Lancet. All of the trials included
at least 1,000 patients and were trials in which patients were
randomly assigned to take the supplements or a "control"
E did not reduce the risk of stroke or dying of heart disease
and made no difference in the risk of death due to any cause.
Beta carotene users actually had a slight increase in the risk
of death due to any cause and the risk of death due to heart disease.
researchers note that the small harmful effect seen for beta carotene
was largely due to two studies that included a lot of smokers.
suggest that there is some new danger is wildly out of proportion
to the data," said Blumberg, noting that scientists have
known the potential risks beta carotene poses to smokers for some
to what the conclusions of this study state, beta carotene is
quite safe to nonsmokers," he added.
the more than 80,000 patients included in vitamin E trials, the
lack of efficacy leads the authors to say they do "not support
the continued use of vitamin E treatment."
fact, co-author Dr. Marc S. Penn told Reuters Health, one "trial
showed that vitamin E blocked the effects of otherwise established
good therapies with statins and niacin, so I think there's no
evidence they're good and there is a hint that they may be harmful."
he and his associates recommend that vitamin E be excluded in
trials of patients at high risk of coronary artery disease.
Penn pointed out that ophthalmologists recommend large doses of
vitamin supplements for the sight-robbing condition macular degeneration
and that the antioxidants are being studied as treatment for other
if there is a risk for other diseases where beta carotene has
been shown to be efficacious, they should still take those,"
"we should really be focusing on healthy diets," he
said. "The concept of vitamin supplements to overcome bad
dietary habits is not a valid thesis, at least with vitamin E
and beta carotene."
according to Blumberg, there is a biological basis for vitamin
E's potential role in heart disease prevention. He noted that
several studies have shown that vitamin E appeared to help prevent
heart disease in healthy people who took the antioxidant over
Council for Responsible Nutrition, a group the represents supplement
manufacturers and suppliers, called the analysis "irresponsible,
over-interpreted, and old news disguised as something new for
publicity purposes," in a press statement.
note that the risk of beta carotene is associated primarily with
smoking. They also said that vitamin E has potential benefits
for vision, Alzheimer's disease and cancer.
The Lancet 2003;361:2017-2023.