Corvallis, Oregon – October 29, 2008 -- Vitamin
E has been heralded for its ability to reduce the risk of blood clots,
heart attack, and sudden death. Yet in some people, vitamin E causes
bleeding. Scientists have known for more than 50 years that excess
vitamin E promotes bleeding by interfering with vitamin K, which is
essential in blood clotting. However, they haven’t been able to
pinpoint how the two vitamins interact. Nutrition researcher Maret
Traber of Oregon State University reviews studies of possible
explanations of the interaction in an article published recently in
of the most compelling studies of the benefits of vitamin E is the
Women’s Health Study, in which 40,000 healthy women, 45 and older, took
600 IU vitamin E supplements or a placebo every other day for 10 years.
Women taking the supplements had 24 percent fewer deaths from heart
disease. Vitamin E’s protective effect appeared even stronger in women
65 and older. Those taking the vitamin experienced a 26 percent
reduction in cardiovascular events and a 49 percent reduction in
a significant benefit,” Traber said. Yet, she added, “In some people
high doses of vitamin E increase the tendency to bleed. Women enrolled
in the study had an increase in nose bleeds.”
lessen the bleeding risk, the U.S.-based Food and Nutrition Board in
2000 set the upper tolerable limit for daily vitamin E intake at 1500
Traber reviewed suggests that a shared metabolic pathway in the liver
causes vitamins E and K to interact. Vitamin K in the liver appears to
diminish as vitamin E increases.
different explanations could account for the interaction between the
two vitamins,” Traber said. “We need more research to understand the
delicate balance between vitamins E and K.”
This study is published in the November 2008 issue of
Nutrition Reviews. Media wishing to receive a PDF of this article may contact [email protected].
To view the abstract for this article, please click here.
Maret Traber is affiliated with Oregon State University and can be reached for questions at [email protected].
is a highly cited journal devoted to keeping academic researchers,
students, and professionals abreast of the latest research in the field
with authoritative and critical reviews of significant developments in
all areas of nutrition science and policy.
111 River St.
Hoboken, NJ 07030