Researchers have found a direct link between low levels of vitamin D and high levels of inflammation.
The findings, led by a team from University of South Australia, provides an important biomarker to identify people at higher risk of or severity of chronic illnesses with an inflammatory component.
Inflammation is an essential part of the body's healing process. But when it persists, it can contribute to a wide range of complex diseases including type 2 diabetes, heart disease, and autoimmune diseases.
According to lead researcher Ang Zhou, from the varsity, the study suggest that boosting vitamin D in people with a deficiency may reduce chronic inflammation.
"Inflammation is your body's way of protecting your tissues if you've been injured or have an infection," Zhou said.
The study, published in the International Journal of Epidemiology, examined the genetic data of participants to show the association between vitamin D and C-reactive protein levels, an indicator of inflammation.
The team found a one-way relationship between low levels of vitamin D and high levels of C-reactive protein.
"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," Zhou said.
The study also raises the possibility that having adequate vitamin D concentrations may mitigate complications arising from obesity and reduce the risk or severity of chronic illnesses with an inflammatory component, such as cardiovascular diseases, diabetes, and autoimmune diseases.
"Boosting vitamin D in people with deficiencies may reduce chronic inflammation, helping them avoid a number of related diseases," Zhou said.
These results are important and provide an explanation for some of the controversies in reported associations with 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," said Professor Elina Hypponen, Director at the varsity's Australian Centre for Precision Health.
"These findings highlight the importance of avoiding clinical vitamin D deficiency, and provide further evidence for the wide-ranging effects of hormonal vitamin D," she noted.