London: Vitamin D, the sunshine vitamin, seems to be the nature`s best antibiotic, for a new study says that it fends off infections by boosting the immune system.
Researchers in Denmark have found that vitamin D, which can be obtained from food or manufactured by human skin exposed to the sun, triggers and arms the body`s T-cells which seek out and destroy any invading bacteria and viruses.
According to them, vitamin D is crucial to activating human immune defences and that without its sufficient intake, the killer cells of the immune system -- T-cells -- willn`t be
able to react to and fight off serious infections in the body.
For T-cells to detect and kill foreign pathogens such as clumps of bacteria or viruses, the cells must first be "triggered" into action and "transform" from inactive and harmless immune cells into killer cells that are primed to seek out and destroy all traces of invaders.
The researchers found that the T-cells rely on vitamin D in order activate and they would remain dormant, "naive" to the possibility of threat if it is lacking in the blood.
Lead researcher Professor Carsten Geisler of Copenhagen University was quoted by `The Daily Telegraph` as saying, "When a T-cell is exposed to a foreign pathogen, it
extends a signalling device or `antenna` known as a vitamin D receptor, with which it searches for vitamin D.
"This means that the T-cell must have vitamin D or activation of the cell will cease. If the T-cells cannot find enough vitamin D in the blood, they won`t even begin to
According to the researchers, the discovery provides much needed information about the immune system and will help them regulate the immune response. This is important not only in fighting disease but in dealing with anti-immune reactions of the body and the rejection of transplanted organs also.
For the research team, identifying the role of vitamin D in the activation of T cells has been a major breakthrough.
"Scientists have known for a long time that vitamin D is important for calcium absorption and the vitamin has also been implicated in diseases such as cancer and multiple sclerosis, but what we didn`t realise is how crucial vitamin D is for actually activating the immune system -- which we know now," the researchers said.
"The findings could help us to contain infectious diseases and global epidemics. They will be of particular use when developing new vaccines, which work precisely on the basis of both training our immune systems to react and suppressing the body`s natural defences in situations where this is important -- as is the case with organ transplants and
autoimmune disease," Prof Geisler said.
The findings are published in the latest edition of the `Nature Immunology` journal.