The double-blind, randomised, placebo-controlled study, presented this week to the American College of Cardiology in Chicago, found administration of 100 micrograms of vitamin D3 daily to elderly people with chronic heart failure for one year significantly improved their heart function.
For those taking vitamin D3, blood ejection at each heart beat increased from 26% to 34% of the blood in the heart, something lead researcher Dr Klaus Witte described as “a stunning effect”.
But this blood pumping measure was a secondary endpoint of the trial which 163 people aged 70 completed.
Fewer symptoms, longer lives?
The BHF, which part-funded the trial along with the UK Medical Research Council, noted the primary endpoint of improved exercise ability was not achieved and called for more research.
“Ideally, any new treatment for heart failure should make patients feel better and live longer. This research found that giving 12 months vitamin D supplementation to heart failure patients with subnormal vitamin D levels was safe and measurements of heart function showed some improvement,” said BHF medical director professor Peter Weissberg.
“However, there was no significant improvement in the patients’ ability to exercise. A much bigger study over a longer period of time is now needed to determine whether these changes in cardiac function can translate into fewer symptoms and longer lives for heart failure patients.”
Dr Witte, a senior lecturer in cardiology at the Leeds Institute of Cardiovascular and Metabolic Medicine in England, said it was “too early to tell what the mechanisms might be” for the observed effects but noted the trial revealed no clinical adverse effects from vitamin D3 consumption.
‘Cheap and safe’
Dr Witte and his team wrote in their paper, “New therapies for serious chronic conditions including chronic heart failure are often expensive, increasingly technical and frequently fail to meet the rigorous demands of large phase 3 clinical trials.
“Vitamin D might be a cheap and safe additional option for chronic heart failure patients and may have beneficial effects on multiple features of the syndrome.”
Vitamin D is a fat-soluble vitamin family encompassing ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Both forms are found in foods and supplements, while vitamin D3 is synthesised in the body when skin is exposed to UV light (like the sun), although this capacity reduces with ageing. Elderly people are also typically exposed to less sunlight as they spend more time indoors.
Vitamin D is most commonly linked to bone and teeth health.
The blood ejection fraction is usually 60-70% in the hearts of healthy adults.
The unmet primary endpoint was a change in six-minute walk distance from baseline to 12 months.
Current UK government advice, replicated in many European nations, states no additional dietary intake of vitamin D is necessary for individuals living a ‘normal lifestyle’, but 10 microgram supplements are recommended for over-65s daily.
Last month the European Food Safety Authority (EFSA) proposed an adequate intake (AI) level of 15 micrograms (µg) per day from food sources for adults and children to achieve a blood serum level of 50 nanomoles per litre (nmol / L).
EFSA noted the difficulty in establishing vitamin D dietary reference values (DRVs) due to the complex interplay between how much of the ‘sunshine vitamin’ is generated in the body and how much is synthesised from sources like foods and food supplements.
Vitamin D has won several claims under the strict EU nutrition and health claims regulation (NHCR) including its role in bone, muscle, teeth, immune system and cellular health.
Paper presented at an American College of Cardiology congress in Chicago, April 2016
'VINDICATE: Vitamin D Supplements May Improve Cardiac Function in Heart Failure Patients'
Authors: Dr Klaus Witte et al