MONDAY, Nov. 22 (HealthDay News) -- Consuming high amounts of
beta-carotene's less well-known antioxidant cousin, alpha-carotene,
in fruits and vegetables can lower the risk of dying from all
causes, including heart disease and cancer, new research
Both nutrients are called carotenoids -- named after carrots --
because of the red, yellow and orange coloring they lend to a range
of produce. Once consumed, both alpha- and beta-carotene are
converted by the body to vitamin A, although that process is
believed to unfold more efficiently with beta-carotene than with
However, the new study suggests alpha-carotene may play the more
crucial role in defending cells' DNA from attack. This might
explain the nutrient's ability to limit the type of tissue damage
that can trigger fatal illness, researchers say.
In the study, a team at the U.S. Centers for Disease Control and
Prevention (CDC) found that over 14 years of follow-up, most people
-- regardless of lifestyle habits, demographics or overall health
risks -- had fewer life-limiting health troubles as their blood
concentrations of alpha-carotene rose.
The effect was dramatic, with risks falling from 23 to 39
percent as an individual's alpha-carotene levels climbed.
"This study does continue to prove the point there's a lot of things in food -- mainly in fruits and vegetables that are orange or kind of red in color -- that are good for us," said registered dietitian Lona Sandon, American Dietetic Association spokeswoman and an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas. But Sandon stressed that, right now, the study only proves an association between alpha-carotene and longer life, and can't show cause-and-effect.
The findings are to be published in the upcoming March 28 print
issue of the
Archives of Internal Medicine, with an online version of the report published Monday.
Researchers led by Dr. Chaoyang Li, from the CDC's division of
behavioral surveillance with epidemiology and laboratory services,
note that a host of yellow-orange foods such as carrots, sweet
potatoes, pumpkin and winter squash, and mango and cantaloupe are
rich in alpha-carotene, as are some dark-green foods such as
broccoli, green beans, green peas, spinach, turnip greens,
collards, kale, brussels sprouts, kiwi, spinach and leaf
These foods fall within the U.S. Department of Agriculture's
current dietary recommendations, which highlight the benefits of
consuming two to four servings of fruit and three to five servings
of vegetables daily.
Li's team focused on more than 15,000 American adults, 20 years
of age or older, who took part in the Third National Health and
Nutrition Examination Survey. All underwent a medical exam between
1988 and 1994, during which time blood samples were taken.
Participants were tracked for a 14-year period through 2006.
By that point, more than 3,800 participants had died. Blood
analyses revealed that, compared with those who had blood
alpha-carotene levels of between 0 and 1 micrograms per deciliter
(mcg/dL), those falling in the range of between 2 and 3 mcg/dL
faced a 23 percent lower risk of death from all causes.
Risk of death for those with alpha-carotene blood levels in the
range of between 4 and 5 mcg/dL, between 6 and 8 mcg/dL, and 9
mcg/dL or above dropped 27 percent, 34 percent and 39 percent,
respectively, versus those in the 0 to 1 mcg/dL range.
The team also linked higher blood alpha-carotene levels to a
lower risk for dying from the nation's two top killers:
cardiovascular disease or cancer.
Li's team said that while more research is needed, the findings
generally suggest that eating more fruits and vegetables can help
lower your risk for premature death.
Sandon agreed, but cautioned against over-interpreting the
"This is very preliminary," she said. "There haven't been many clinical trials looking into this. And it's always tricky when you're singling out a single nutrient, because components in foods may work individually or synergistically. The question is: Is alpha-carotene acting in conjunction with something else? We don't really know," Sandon explained.
"The alpha-carotene itself is probably not the cause of longer life," she added. "But we can still say that if you're getting more of these kinds of phytonutrients found in foods, this may help you live longer and healthier."
The bottom line, according to Sandon: "I certainly think it
would be wrong for people to take away from this that they should
set out to specifically consume alpha-carotene. What people should
take away from this is that they should go out and eat the
foods that have alpha-carotene in them."
And what about nutritional supplements? Li's team pointed out
antioxidant supplements currently on the market do not contain
much, if any, alpha-carotene, and the study therefore only looked
at the impact of consuming the compound via foods.
For more on alpha-carotene, visit the
U.S. National Library of Medicine.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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