Adequate blood vitamin D concentrations and vitamin D3 supplementation seem to activate genes that are important for an optimal working immune system and response to stress, says a new US study.
To determine the effect of vitamin D status and subsequent supplementation on broad gene expression, the randomized controlled trial involved 8 healthy adults, who received a supplement of either 400 IU or 2000 IU vitamin D3 every day for 2 months (1). White blood cell samples were collected at the beginning and end of the study. A gene expression analysis was conducted on the samples to see if their activity had changed as a result of supplementation. The study results showed that at the end of the study, the participants who took a supplement of 2000 IU/day achieved a vitamin D status of 34 ng/ml, while the group taking 400 IU/day achieved a level of 25 ng/ml. Among the participants whose vitamin D status increased, there was a 1.5 fold alteration in the expression of 291 genes related to 160 biologic pathways important for immune function, response to stress and DNA repair. There was a significant difference in the expression of 66 genes between participants with a vitamin D deficiency at baseline (25(OH)D concentration below 20 ng/ml) and those with 25(OH)D levels higher than 20 ng/ml. After vitamin D3 supplementation, the expression of these 66 genes was similar for both groups.
The researchers concluded that an improvement in vitamin D levels seems to have a positive impact on the expression of genes that have a wide variety of important functions, playing a key role in improving immune health and potentially lowering the risk of cancer, cardiovascular disease, infectious diseases and autoim-mune disorders. Further research would need to be conducted to confirm these observations.
In addition to the established role of vitamin D in maintaining bone and muscle health, numerous observatio-nal studies have linked vitamin D deficiency to an increased risk of developing chronic diseases (2, 3). Stu-dies based on the immune system modulating effects of vitamin D have recommended vitamin D supplemen-tation for the prevention of autoimmune diseases and several forms of cancer (4, 5). It is believed that vitamin D receptor activation may directly and/or indirectly regulate the expression of a very large number of genes (6).