For the first time, new research shows that a daily dose of vitamin D3 can improve heart function in people with chronic heart failure. These findings are a significant breakthrough and could make a huge difference in the care of heart failure patients.
Vitamin D3 levels are largely dependent upon exposure to sunlight, and can be low throughout the year. This is because, in the case of heart failure patients, they are often older and so spend less time in the sun. Older people also make less vitamin D3 in response to sunlight than younger people, and vitamin D3 production in the skin is also reduced by sunscreen.
Vitamin D is known to have bone strengthening effects by improving calcium deposition in the skeleton, yet the substance is involved in many other systems, including muscle contraction, immune function, and insulin release, all of which may be abnormal in patients with heart failure. Up until now, there was no data suggesting that replacing vitamin D has any benefit in patients with heart problems.
We found that almost all patients with heart failure in Leeds were deficient in vitamin D and the more deficient they were, the worse the heart weakness was shown to be.
Fixing broken hearts
Chronic heart failure is due to the reduced pumping function of the heart and affects about 900,000 people in the UK and more than 23m worldwide. The condition can affect people of all ages, but it is more common in older people – more than half of all people globally with heart failure are over the age of 75.
The most frequent cause of heart failure is heart muscle damage following a heart attack, although high blood pressure, heart valve problems and infections can also lead to heart failure. The weakness is reflected by symptoms including shortness of breath and fatigue.
Despite very good therapies, including tablets and in some patients special pacemakers, many people with heart failure have persistent symptoms, and the heart muscle weakness remains.
Our study, which was funded by the Medical Research Council, involved more than 160 patients from Leeds who were already being treated for their heart failure using proven treatments including beta-blockers, ACE-inhibitors and pacemakers. Participants were asked to take vitamin D3 or a dummy (placebo) tablet for one year. Those patients who took vitamin D3 experienced an improvement in heart function which was not seen in those who took a placebo.
Changes in heart function were measured by cardiac ultrasound – known as an echocardiogram. This allows us to measure how much blood pumps from the heart with each heartbeat, known as ejection fraction.
The ejection fraction of a healthy person is usually between 60% and 70%. In heart failure patients, the ejection fraction is often significantly lower – in the patients enrolled into the study, the average ejection fraction was 26%. In the 80 patients who took Vitamin D3, the heart’s pumping function improved from 26% to 34%. In the others, who took the placebo, there was no change in cardiac function.
This means that for some heart disease patients, taking vitamin D3 regularly may lessen the need for them to be fitted with an implantable cardioverter defibrillator (ICD) – a device which detects dangerous irregular heart rhythms and can shock the heart to restore a normal rhythm.
ICDs are expensive and involve an operation, so if we can avoid an ICD implant in just a few patients, then that is a boost to patients and the NHS as a whole.
One key aspect of this study is that we avoided using a calcium-based supplement, as calcium can cause further problems for heart failure patients. Crucially, the tablets were well tolerated by our patients and we saw no important side effects on kidney function.
The next step is to use the information from this study to find out if vitamin D3 supplementation reduces hospital admissions and extends the life of patients with heart failure – because let’s face it: taking a daily dose of vitamin D beats the alternative.