When it comes to the poorest nations of the world, an inexpensive means of fighting the spread of HIV is vital. Researchers may have found just such an ally according to a recent study of how vitamin D affects the immune system response to HIV. What did they find?

The Test Subjects

The study was performed using 100 young individuals, half from the Cape area in Africa and the other half from the Xhosa indigenous tribe. Blood samples were taken from the healthy individuals during the sunny summer months when vitamin D levels are the highest and again during the winter when they are at a seasonal low due to less sun exposure. During the winter, both groups proved to be vitamin D deficient, and the women who were in the study suffered even more from the deficiency than men.

Exposure to HIV-1

Next, these blood samples were exposed to HIV-1. After giving the virus nine days to work, the samples were tested. The amazing result was that the vitamin D deficient winter samples were more prone to infection than the summer samples with normal vitamin D levels.

The deficient individuals were next given a six-week supply of vitamin D supplements to get their levels back to normal. Then their blood was taken and tested again. Infection rate was reduced back to what it had been for the summer samples. The results were clear – vitamin D was helping ward off the disease.


While there is no immunization for HIV, this study reveals that vitamin D can reduce the chances of infection. Since vitamin supplements are far less expensive than vaccinations, this is also a far more viable solution for reducing the risk of infection in developing countries. Also, additional health benefits associated with vitamin D would be achieved by combating deficiency. It’s a win-win for some of the underdeveloped countries that are the hardest hit by the spread of HIV.