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Nutrition News Bites: Vitamin D for Lung Health,
Omega-3s for Healthier Hearts
Vitamin D for Stronger Lungs
Research continues to uncover new benefits
of vitamin D, which has been linked to everything from bone strength
to reductions in the risk of prostate and colon cancers. A study
now reports that higher blood levels of this vitamin support better
lung function (1).
Using data collected from over 14,000 adults
who took part in a US National Health and Nutrition Examination
Survey, investigators divided the participants into 5 groups based
on their blood levels of vitamin D. They then compared how well
the groups had done on tests of lung function. FEV (forced expiratory
volume) measures how much air you can exhale in a second, while
forced vital capacity (FVC) determines the amount of air you can
rapidly blow out after taking a deep breath.
People with the highest vitamin D levels
had considerably stronger FEV scores and better FEC rates, even
after adjusting for factors such as smoking and exercise. The
study also found more vitamin D naturally occurring in men than
in women, and that the older and more obese a person was, the
less vitamin D was present. The researchers think that vitamin
D may be helping the remodeling of tissues in the lung.
While the study showed a "definite relationship
between vitamin D and lung function", the study's lead author
cautioned that it isn't clear whether increases in vitamin D can
favorably affect lung function in people who already have chronic
respiratory diseases.
The body's capacity to produce vitamin D
from sunlight exposure declines with age, and many experts believe
that older adults need even higher levels of this vitamin than
the currently recommended daily dose of 400 IU for those over
50 and 600 IU for those 70 years and older.
Omega-3s and Healthier Heart Rates
Many epidemiologic and clinical trials have
documented the heart-protective effects of the omega-3 fatty acids
found in cold-water fish.
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In recent years, studies have found that
consuming more omega-3s reduces the risk for sudden death in people
with coronary heart disease. Sudden death occurs when the heart
stops abruptly, a condition also known as cardiac arrest. Most
cardiac arrest occurs when electrical impulses in the heart become
rapid and/or chaotic. The omega-3 fats are believed to fight against
sudden death by regulating the heartbeat and preventing irregular
rhythms.
A new study designed to explore the possible
mechanisms in which fish oil protects against the risk of sudden
death has shown that supplementation with omega-3 fatty acids
significantly decreases heart rate while at rest, and accelerates
its return to normal after exercise (2).
In this well-controlled but small study,
men with a history of heart attack took omega-3 fatty-acid supplements
(about 800 mg daily) or placebo for 4 months, then switched to
the alternate treatment for another 4 months. Resting heart rate
significantly decreased with the omega-3 supplement, and heart
rate returned to normal much faster after the men completed a
stress test. The decrease in heart rate at 1 minute post-exercise
was 19% greater with omega-3s.
"This decrease in heart rate could help
explain the decreased risk in sudden death with omega-3 fatty
acids", noted the lead author, "because there is a relationship
between resting heart rate and the risk of sudden death: The higher
the rate, the higher the risk."
| While this study focused
on people who had already experienced a heart attack, the
omega-3s may help others too. In 2003, researchers reported
that healthy men who regularly ate fish had lower average
heart rates - a sign of a much healthier heart. |
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