A new scientific study has shown that supplements of vitamin D3 equivalent to a D-vitamin capsule of 20 micrograms daily may reduce older people's risk of developing heart failure by 20-25%. The study has included data from 21 trials involving more than 13,000 elderly persons.
The study was conducted by researchers from universities in Scotland and New Zealand. It was attended by people aged 70 and or more all of whom had had a fracture within the past 10 years. The study did not show a reduced risk of vitamin D for all types of heart disease. Vitamin D seemed to counteract a decreased pumping ability of the heart, but did not seem to reduce the risk of getting e.g. a heart attack.
Known risk factors for cardiovascular disease include smoking, obesity, inactivity and advanced age, all of which are linked to low vitamin D levels in the blood and makes it difficult to pinpoint an exact cause of cardiovascular disease.
Heart failure means that the heart's pumping ability is impaired.
High dosage harmless and beneficial
In another small double-blind, placebo-controlled study of 23 elderly patients with heart failure and a vitamin D blood levels at the lower end, meaning 30 ng/ml (74.9 nmol/L) the verum group got 100 µg (4000 IU) of vitamin D per day for six months.
When the researchers compared measurements taken at baseline and at study completion, they showed, among other things, that the so-called ejection fraction (EF) which is a measure of the heart's pumping ability was significantly increased (6.71 vs.-4.3%, p <0.001) in the group that had received vitamin D. Also, the systolic blood pressure was lower in the vitamin D group, as it decreased from an average of 129.6 to 122.5 mmHg (p <0.05).
This second study reinforces the results from the first study and it also shows that a daily supplement of 100 micrograms of vitamin D is harmless - even over long periods of time.
Ford JA, et al. Cardiovascular disease and vitamin D supplementation: trial analysis, systematic review, and meta-analysis. Am J Clin Nutr 2014. E-pub ahead of print.
Dalbeni A, et al. Effects of six months of vitamin D supplementation in patients with heart failure: A randomized double-blind controlled trial. Nutr Metab Cardiovasc Dis 2014;24(8):861-8.