Taking monthly vitamin D supplements is unlikely to increase life expectancy in the general Australian population, according to research from QIMR Berghofer Medical Research Institute.
The researchers analysed results from the Institute’s landmark D-Health Trial to understand whether a monthly dose of vitamin D would reduce the mortality rate in Australians aged over 60.
Lead researcher Professor Rachel Neale launched the D-Health Trial in 2014 because there was a lot of uncertainty about the health benefits of taking vitamin D.
Professor Neale stressed that being vitamin D deficient is harmful for bone and muscle health, and may carry other health risks.
“However, most Australians are not vitamin D deficient according to current guidelines, and the D-Health Trial suggests that if people are not deficient, taking vitamin D does not increase the chance of living for longer.”
The NHMRC-funded D-Health Trial is one of Australia’s largest clinical trials and the world’s second-largest trial of high-dose vitamin D.
More than 21,000 Australians aged between 60 and 79 took vitamin D for up to 5 years to establish the role vitamin D plays in improving health outcomes.
Some participants were given a supplement while others received a placebo and the rate of mortality overall, and from particular conditions, was compared between the two groups.
Professor Neale said exploratory analyses found some indication that taking large monthly doses may slightly increase the risk of dying from cancer, but the difference was small and this increased risk is unproven.
“Out of an abundance of caution we would advise that if people want to take a vitamin D supplement, they take a regular daily dose rather than a larger monthly dose,” Professor Neale said.
She said the study offered insight into how much vitamin D people need in their blood stream.
“This study does not support increasing the amount of vitamin D people are advised to have in their blood,” Professor Neale said.
The research has been published in journal The Lancet Diabetes & Endocrinology. It’s the latest of several studies to be produced from QIMR Berghofer’s D-Health Trial.
Another study published in the same journal in 2021 found vitamin D supplements did not protect most people from developing colds, flus and other acute respiratory infections. It did suggest a small reduction in the length or severity of these conditions.