Hyppönen explained that vitamin D is a hormone precursor that inhibits the production of inflammatory cytokines such as interleukin-12 (IL-12).

“By doing this, it acts to modify the immune responses so that T-cell polarization moves away from an inflammatory type response (Th1) to the production of more protective T-cell phenotypes (Th2 and regulatory T-cells),” Hyppönen told Healthline.

According to the study, these actions may help to lower inflammation, thus reducing the risk or severity of many chronic diseases.

Study data also indicates the prevalence of vitamin D deficiency is around 40% in some European counties.

Therefore, the authors suggest that increasing vitamin D consumption across the population by adding it to widely consumed food products could be a cost-effective way to reduce chronic disease.

Although the research found an association between vitamin D and CRP, it also had some limitations. For example, participants were individuals of white-British descent. So, it is not known if these results transfer to people of other racial or ethnic groups.

What’s more, CRP is not the only biomarker involved in inflammation. Other biomarkers may also indicate an inflammatory response, including tumor necrosis factor alpha (TNF-α) and interleukin 6Trusted Source (IL-6). The scientists say further investigations should examine these biomarkers to fully understand the anti-inflammatory effects of vitamin D.

“For many of the diseases and influences, evidence for causality [is] still to be established, and we need to look further into the effects on hard outcomes such as mortality risk,” Hyppönen said. “It also looks that the prevention of severe vitamin D deficiency is the key for many of the likely benefits, and we need to develop efficient strategies to target and treat those people who are in need.”

According to experts, vitamin D deficiency is when the serum 25(OH)D levels in the blood are less than 20 ng/mL. Serum levels of 20-30 ng/mL are considered insufficient.

“Vitamin D deficiency can manifest itself in several ways, including muscle pain, weakness, depression, poor bone health, and fatigue,” Iza Correll, a licensed physician associate and founder of OVI Healthcare, told Healthline.

Correll added that it’s critical to correctly diagnose vitamin D deficiency because the treatment plan may vary depending on the severity.

“If a deficiency is suspected, your doctor will likely order a blood test to measure the vitamin D level in your blood. The most common diagnostic test for vitamin D deficiency is a blood test to measure the level of 25-hydroxyvitamin D in the blood,” she explained.

As far as treatments go, Correll noted that “treatment for vitamin D deficiency usually involves taking supplements or, most importantly, increasing exposure to sunlight to a minimum of 10 minutes daily.”

“Most people with vitamin D deficiency require 400–800 IU of vitamin D daily to bring their levels back to normal. Your doctor may also recommend increasing your intake of foods high in vitamin D, such as fatty fish, eggs, and fortified milk or cereal,” she added.

Chronic inflammation is thought to be a factor in many health conditions, including heart disease, cancer, and autoimmune disorders, among others.

The latest research suggests that vitamin D may help reduce chronic inflammation — but only in people with a vitamin D deficiency.

Prevention and treatment of vitamin D deficiency involve ensuring you have an adequate but safe amount of sunlight exposure and consuming vitamin D-rich foods. Supplementing with appropriate amounts of this essential nutrient can also help reduce the chance of becoming deficient.