High Levels of
Antioxidant Alpha-Carotene from Fruits, Vegetables Found to Extend Life
Higher
alpha-carotene concentration lowers risk of dying from cardiovascular
disease or cancer and all other causes
Nov.
22, 2010 - High blood levels of the antioxidant alpha-carotene – most
often acquired from eating fruits and vegetables - appear to be
associated with a reduced risk of dying over a 14-year period, according
to a report posted online today that will be published in the March 28
print issue of Archives of Internal Medicine, one of the JAMA/Archives
journals.
Oxygen-related
damage to DNA, proteins and fats may play a role in the development of
chronic diseases like heart disease and cancer, according to background
information in the article. Carotenoids - including beta-carotene,
alpha-carotene and lycopene - are produced by plants and microorganisms
and act as antioxidants, counteracting this damage.
Carotenoids in
the human body are obtained mainly through eating fruits and vegetables
rich in the nutrients, or through antioxidant supplements.
Although studies
suggest eating more fruits and vegetables is associated with lower risk
of chronic diseases, randomized controlled trials have not shown any
benefit for beta-carotene supplements, the authors note.
"Therefore,
carotenoids other than beta-carotene may contribute to the reduction in
disease risk, and their effects on risk of disease merit investigation,"
according to the report.
Chaoyang Li,
M.D., Ph.D., of the Centers for Disease Control and Prevention, Atlanta,
and colleagues assessed the relationship between alpha-carotene and the
risk of death among 15,318 adults age 20 and older who participated in
the Third National Health and Nutrition Examination Survey Follow-up
Study.
Participants
underwent a medical examination and provided blood samples between 1988
and 1994, and were followed through 2006 to determine whether and how
they died.
Over the course
of the study, 3,810 participants died; the risk for dying was lower with
higher levels of alpha-carotene in the blood.
Compared with
individuals with blood alpha-carotene levels between 0 and 1 micrograms
per deciliter (one tenth of a liter), the risk of death during the study
period was
● 23 percent lower among who had concentrations between 2 and 3
micrograms per deciliter,
● 27 percent lower with levels between 4 and 5 micrograms per
deciliter,
● 34 percent lower with levels between 6 and 8 micrograms per
deciliter and
● 39 percent lower with levels of 9 micrograms per deciliter or
higher.
Higher
alpha-carotene concentration also appeared to be associated with lower
risk of dying from cardiovascular disease or cancer individually, and of
all other causes.
"The association
between serum alpha-carotene concentrations and risk of death from all
causes was significant in most subgroups stratified by demographic
characteristics, lifestyle habits and health risk factors," the authors
write.
Alpha-carotene
is chemically similar to beta-carotene but may be more effective at
inhibiting the growth of cancer cells in the brain, liver and skin, they
note.
"Moreover,
results from a population-based case-control study of the association
between the consumption of fruits and vegetables and risk of lung cancer
suggest that consumption of yellow-orange (carrots, sweet potatoes or
pumpkin and winter squash) and dark-green (broccoli, green beans, green
peas, spinach, turnips greens, collards and leaf lettuce) vegetables,
which have a high alpha-carotene content, was more strongly associated
with a decreased risk of lung cancer than was consumption of all other
types of vegetables," the authors write.
The results
support increasing fruit and vegetable consumption as a way of
preventing premature death, and suggest a need for clinical research
into the health benefits of alpha-carotene, they conclude.
Keep up with the latest news for senior citizens, baby
boomers
Nov.
22, 2010 - High blood levels of the antioxidant alpha-carotene – most
often acquired from eating fruits and vegetables - appear to be
associated with a reduced risk of dying over a 14-year period, according
to a report posted online today that will be published in the March 28
print issue of Archives of Internal Medicine, one of the JAMA/Archives
journals.