The University of South Australia says its findings provide an important biomarker to identify people at higher risk of chronic illnesses.

The study examined the genetic data of 294 ,970 participants in the UK Biobank, to show the association between vitamin D and C-reactive protein levels, an indicator of inflammation.

Lead researcher Ang Zhou said the findings suggested boosting vitamin D in people with a deficiency might reduce chronic inflammation.

"Inflammation is your body's way of protecting your tissues if you've been injured or have an infection," Dr Zhou said.

"High levels of C-reactive protein are generated by the liver in response to inflammation, so when your body is experiencing chronic inflammation, it also shows higher levels of C-reactive protein."

Dr Zhou said the study found a one-way relationship between low levels of vitamin D and high levels of C-reactive protein.

"Boosting vitamin D in people with deficiencies may reduce chronic inflammation, helping them avoid a number of related diseases," he said.

Senior investigator and director of the university's Australian Centre for Precision Health Elina Hypponen said the study's results were important in the ongoing debate over increasing levels of vitamin D.

"We have repeatedly seen evidence for health benefits for increasing vitamin D concentrations in individuals with very low levels, while for others there appears to be little to no benefit." Prof Hypponen said.

"These findings highlight the importance of avoiding clinical vitamin D deficiency."

Australian Associated Press