Whilst there have been many studies with promising in vitro results for vitamin D and its effects on the function of the immune system, it does not always transfer to significant clinical effects. Despite this, researchers are still confident that there is a relationship between vitamin D and the immune system.(8)
There is a direct relationship between the immune system and the inflammatory responses in the body, with inflammatory responses precipitating from the immune system. As with normal functioning of the immune system, a cause and effect relationship between the dietary intake of vitamin D and healthy inflammatory response was agreed by EFSA in 2010.(2)
Chronic inflammation is associated with numerous diseases, including cardiovascular diseases, diabetes and neurodegenerative conditions. It is also a consequence of numerous diseases and conditions.
The role of vitamin D in inflammation has been widely discussed, however, its exact role is yet to be fully understood.(9) Studies have indicated that vitamin D deficiency can be associated with severe inflammatory diseases. But it is not fully clear whether vitamin D deficiency is a manifestation of those diseases or the deficiency contributes to the aetiology of inflammatory disease. The pathophysiology of chronic inflammatory disease, including atherosclerosis, is complex can and be further complicated by various metabolic factors, making it challenging to identify a direct relationship between vitamin D intake and its effects in these conditions.
Recent studies have explored the role of vitamin D supplementation in inflammatory conditions such as COPD,(10) diabetic nephrology(11) and osteoarthritis.(12) All these show some promising results and further highlight the potential health benefits of vitamin D in inflammatory states.
However, in recent years several Cochrane reviews have been conducted to evaluate the effects of vitamin D in inflammatory conditions such as sickle cell disease (SCD),(13) multiple sclerosis(14) and asthma.(15)