Low vitamin C intake
is associated with worse outcomes for heart failure patients
Low levels of vitamin C were associated with
higher levels of high sensitivity C-Reactive protein (hsCRP) and
shorter intervals without major cardiac issues or death for heart
failure patients, in research presented at the American Heart Association's
Scientific Sessions 2011.
Compared to those with high vitamin C intake from food, heart failure
patients in the study who had low vitamin C intake were 2.4 times
more likely to have higher levels of hsCRP, a marker for inflammation
and a risk factor for heart disease.
The study is the first to demonstrate that low vitamin C intake
is associated with worse outcomes for heart failure patients.
Study participants with low vitamin C intake and hsCRP over 3 milligrams
per liter (mg/L) were also nearly twice as likely to die from cardiovascular
disease within one year of follow-up.
"We found that adequate intake of vitamin C was associated
with longer survival in patients with heart failure," said
Eun Kyeung Song, Ph.D., R.N., lead author of the study and assistant
professor at the Department of Nursing, College of Medicine, in
the University of Ulsan in Korea.
The average age among the 212 patients in the study was 61, and
about one-third were women. Approximately 45 percent of the participants
had moderate to severe heart failure.
Participants completed a four-day food diary verified by a registered
dietitian and a software program calculated their vitamin C intake.
Bloods tests measured hsCRP.
Researchers divided participants into one group with levels over
3 mg/L of hsCRP and another with lower levels. Patients were followed
for one year to determine the length of time to their first visit
to the emergency department due to cardiac problems or death.
Researchers found that 82 patients (39 percent) had inadequate
vitamin C intake, according to criteria set by the Institute of
Medicine. These criteria allowed the researchers to estimate the
likelihood that the patient's diet was habitually deficient in vitamin
C based on a four-day food diary. After a year follow-up, 61 patients
(29 percent) had cardiac events, which included an emergency department
visit or hospitalization due to cardiac problems, or cardiac death.
The researchers found that 98 patients (46 percent) had hsCRP over
3 mg/L, according to Song.
Inflammatory pathways in heart failure patients may be why vitamin
C deficiency contributed to poor health outcomes, the data suggests.
"Increased levels of high-sensitivity C-reactive protein means
a worsening of heart failure," Song said. "An adequate
level of vitamin C is associated with lower levels of high-sensitivity
C-reactive protein. This results in a longer cardiac event-free
survival in patients."
The use of diuretics may also play a role because vitamin C is
water-soluble and diuretics increase the amount of water excreted
from the kidneys, said Terry Lennie, Ph.D., R.N., study author and
associate dean of Ph.D. studies in the College of Nursing at the
University of Kentucky in Lexington, Kentucky.
"Diet is the best source of vitamin C," Lennie said.
"Eating the recommended five servings of fruits and vegetables
a day provides an adequate amount."
More randomized controlled trials and longitudinal prospective
studies are needed to determine the impact of other micronutrients
on survival or rehospitalization, Song said.
Other co-authors are Debra K. Moser, D.N.Sc., R.N.; Heather Payne-Emerson,
Ph.D., R.D.; Sandra B. Dunbar, D.S.N., R.N. and Susan J. Pressler,
Ph.D., R.N.
The American Heart Association, National Institutes of Health and
National Institute of Nursing Research funded the study.
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