People in the UK are low in vitamin D because of the weakness of the sunlight and the short summers. In addition there is greater concern in the UK about getting skin cancer from sunbathing or being out in the sun. Almost every rheumatoid arthritis sufferer has low levels of vitamin D and this is likely to be true for people with other inflammatory diseases too.
Sunshine isn't the only source of vitamin D. Some foods such as eggs, oily fish such as sardines and salmon are rich in vitamin D too. Reserachers from the university of brimingham are the lastest to report in the importance of vitamin D. In a series of tests, they discovered that the immune cells of rheumatoid arthritis pateients could still respond normally to vitamin D by supressing inflammatory signalling - if those cells were circulating in the blood, but the same cell type when localisec to the fluid around the arthricitc joints, showned no anti-inflamatory reaction to vitamin D. This is because arthritis leads to vitamin D insensitivity which means that cells no longer respond to it.
The research suggest that vitmain D therapy could still work on patients if they are given very high doeses, although standard suplements amy not. Prof Martin Hewison says that "almost everyone in the Uk has vitamin D deficiency". High levels of vitamin D can help prevent inflamatory diseases including rheumatiod arthritis.