A new Norwegian study suggests that getting the right amount of vitamin D could substantially reduce an individual's risk of death.

Carried out by researchers at the University of Bergen (UiB), the study looked at 4,114 patients with cardiovascular diseases to assess the possible link between their vitamin D levels and risk of death from cardiovascular disease and all causes.

Participants had an average age of 62 at the start of the study and were followed for a period of 12 years.

After taking into account cardiovascular risk factors such as age, gender, smoking status, body mass index, and blood pressure, the team found that those who had a normal intake of vitamin D had a 30 percent lower risk of death from cardiovascular disease.

However, too much or too little vitamin D increased the risk of cardiovascular disease.

The study showed that it is favorable to have a level of 42 to 100 nmol/l of vitamin D in the blood, however study leader Professor Jutta Dierkes added that giving a general recommendation on how much vitamin D supplementation people need is difficult.

"The optimal amount of vitamin D-supplement varies from one person to another. It depends where you live, and what kind of diet you have," says Dierkes.

For example, Nordic countries recommend an intake of 10 microgram per day from all vitamin D sources, whereas the USA recommends a higher level of 15 micrograms, and Germany 20 micrograms.

"Even if Norwegians receive less sun then the Germans, the Norwegians have more fish in their diet. Fish and cod liver oil are important sources to vitamin D during the winter, in addition to physical activities outdoors during the summer," Dierkes explains.

Dierkes now advises those who have a history of cardiovascular disease to have their levels of vitamin D measured regularly by their doctor so their level of supplementation, if needed, can be asessed.

"It is, however, important to take in account that the levels vary seasonally. A measurement in September will not show the same results as in January, in the Nordic countries."

"The levels in January or February are often lower because of the lack of sunlight, which induces the skin to form vitamin D," added Dierkes.

Previous studies have also suggested that vitamin D can be beneficial for a range of other health concerns, helping to reduce the risk of asthma attacks, boost the immune system, improve muscle strength, and help prevent conditions such as autism and multiple sclerosis.

The findings can be found published online in The Journal of Clinical Endocrinology & Metabolism.