November 21, 2011 (Orlando, Florida) — Heart-failure patients consuming a diet high in vitamin C are about half as likely to suffer a cardiac event within a year as patients with low vitamin-C levels, according to results of a study presented at the American Heart Association 2011 Scientific Sessions .
In the study, led by Dr Eun Kyeung Song (University of Ulsan, Korea), 212 heart-failure patients (45% with NYHA class 3 or 4) at three centers in the US completed a four-day food diary verified by a dietitian. All of the patients were tested for high-sensitivity C-reactive protein (hs-CRP) levels and followed for one year.
Based on an Institute of Medicine formula, 82 patients (39%) had an "inadequate" vitamin-C intake. One year after enrollment, 61 patients (29%) had an adverse cardiac event or died. Low vitamin-C intake was associated with higher levels of hs-CRP (odds ratio 2.4), and both low vitamin-C intake (HR 2.0) and hs-CRP >3 mg/L (HR 1.9) were associated with a shorter event-free survival after researchers controlled for age, gender, body-mass index, heart-failure class, left-ventricular ejection fraction, other comorbidities, total caloric intake, and the influence of medications.
Song said that this is the first study to demonstrate a connection between low vitamin-C intake and shorter event-free survival. She hypothesized that vitamin-C deficiency may contribute to inflammatory pathways in HF patients. Study coauthor Dr Terry Lennie (University of Kentucky, Lexington) suggested that the diuretics used by some heart-failure patients may be contributing to the loss of vitamin C because vitamin C is water soluble.
Commenting on the study, Dr Clyde Yancy (Northwestern University, Chicago, IL) told heartwire that despite the connection between vitamin-C intake and better outcomes in the study, "we have to temper our enthusiasm. There's clearly a benefit to diets high in vitamin C, but it's not clear that vitamin C [alone] is the reason." He suggested that the patients with more vitamin C in their diet have better outcomes than vitamin-C–deficient patients because their diet is higher in fruits and vegetables and lower in fat and simple carbohydrates, which contributes to heart health through a variety of mechanisms other than vitamin C.
Song said she has received grants from the National Institutes of Health and the University of Kentucky.
Heartwire from Medscape © 2011 Medscape, LLC
Cite this: Low Vitamin C Portends Worse Heart-Failure Outcomes - Medscape - Nov 22, 2011.