A daily dose of vitamin D3 can dramatically improve heart function in people with chronic heart failure, British researchers have found.
The study, funded by the Medical Research Council, involved 160 patients who were already being treated for heart failure using proven treatments and medicines. Vitamin D3 can be boosted by exposure to sunlight, but older heart failure patients are often deficient in it.
Half the participants were asked to take vitamin D3, in the form of the blackcurrant-flavoured chewable tablet, while the other half took a placebo tablet.
Dr Klaus Witte, who led the five-year University of Leeds research project, told The Independent the improvements seen in patients taking the vitamin were “nothing short of amazing,” and called his team's findings a “significant breakthrough.”
Over the course of a year, those who took the vitamin D3 experienced a great improvement in heart function compared to those who took the placebo, with the results being the best seen "in a generation", according to Dr Witte.
Researchers made ultrasound scans of participants' hearts and measured the how much blood was being pumped with each heartbeat, to get a figure called ejection fraction.
The ejection fraction of a healthy person is usually around 60 to 70 per cent, but it dropped to an average of 26 per cent among the patients enrolled in the study.
For those who took vitamin D3, the ejection fraction was improved from 26 to 34 per cent, while the rest experienced not change.
For some patients, this discovery means regularly taking vitamin D3 could lessen the need for them to be fitted with an implantable cardioverter defibrillator (ICD), which can correct dangerous heart rhythms.
ICDs are expensive and require an operation to implant, so avoiding it would be a boost to patients and the NHS as a whole.
The researchers were careful to use pure vitamin D supplements in the trial, rather than calcium-based pills, since calcium was found to cause further problems for heart failure patients. However, replenishing vitamin D through exposure to sunlight would likely produce the same results, Dr. Witte said.
“It's not about the tablet per se, it's about the vitamin D levels which you achieve. The difficulty is actually reaching these levels in a normal western society.”
Ancient humans, who lived outdoors in warm climates and didn't wear as many clothes as we do, had no problems with vitamin D deficiencies, Dr Witte said.
The problems arose when we moved indoors, began covering our bodies with clothes and created cities covered in pollution, which can prevent the sun's beneficial rays from reaching the ground.
“I think western societies and cultures have led to us becoming vitamin D deficient as a result of our lifestyle choices,” Dr Witte said.
The findings from the team's study will be presented at the American College of Cardiology's 65th annual summit in Chicago on 4 April.
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