According to Asian News International, German scientists report that blood levels of vitamin D are significantly lower in patients with chronic heart failure, supporting previous animal research.
The article quotes a study reported in Cardiology, performed by researchers from the Univeristy of Bonn and Bad Oeynhausen Heart Center.
The study also reports that the more severe the deficiency to 50% of normal levels), the worse the symptoms became.
The researchers have not yet studied the results of supplementation, but animal studies suggest supplementation may help.