A LARGE-scale study into the effects of Vitamin D in the body is under way with the sponsorship of the QIMR Berghofer Medical Research Institute.
Volunteers have been selected in all states, with Queensland having the highest number.
Local Gympie Times correspondent Peter Hughes is one person who has volunteered to take part in the five-year study.
Mr Hughes said volunteers in one of the largest trials in the world into vitamin D were part of research into whether taking the vitamin changed the risk of the person being diagnosed with diseases such as diabetes, heart disease, multiple sclerosis, some types of cancers or infections.
He said it was thought that the vitamin may have some effect, but it was by no means proven or certain.
Vitamin D in the body comes from exposure to sunlight and having enough is vital to maintain healthy and strong bones.
Research principal Dr Rachel Neale said that while it was known what Vitamin D did, it was not known how much was actually needed.
"We are aiming to find out what would happen to the overall health of the population if food was to be 'fortified' with Vitamin D," she said. "We are looking to find a safe level for possible future use."
As in any scientifically correct trial, participants are randomly selected to take either a Vitamin D tablet or a placebo. Also participants have been selected so there are as near as possible equal numbers in each group for all possible factors that may affect future health.
"We can then be pretty sure that any differences are due to the Vitamin D tablets taken," Dr Neale said.
Dr Neale has recently contributed to a CSIRO publication titled Sun, Skin and Health, with her contribution dealing with Vitamin D health and the Sun: Finding the Right Balance.
Participants are asked to take one tablet (Vitamin D or placebo) on the first of the month. A memory jogging email or phone call is made by the research team.
While the trial aimed for 25,000 people taking part, it has so far recruited just over 15,000 and would like more people to consider volunteering.
To date there have been slightly more men volunteers, 52%.