The results suggest that vitamin D supplementation may prevent winter anaemia and boost white blood cell count, possibly serving as a cost-effective intervention to reduce risk of HIV infection and slow down HIV progression in infected individuals, according to the authors.
To assess the rate of vitamin D deficiency in Cape Town, which exhibits a high rate of HIV infection, a study conducted by academics from UCT and the Universities of Stellenbosch (Stellenbosch) and Pennsylvania State (Penn State), United States, examined various factors affecting vitamin D levels in 100 healthy adults between 18 and 24 years old. The subjects of the study, which was conducted in 2013, were recruited from Khayelitsha and Bellville in Cape Town.
Dr Anna Coussens (UCT), Professor Robert Wilkinson (UCT), Rene Goliath (UCT), Dr Celeste Naude (Stellenbosch), Professor George Chaplin (Penn State) and Professor Nina Jablonski (Penn State) assessed the participants’ vitamin D status, skin pigmentation, seasonal UVB exposure, dietary vitamin D intake, genetic variation, smoking status, serum vitamin D binding protein and the ability of HIV-1 to infect and replicate in blood cells in the lab, during different times of the year and following vitamin D supplementation.
Although dietary vitamin D intake did not vary seasonally, the authors found that UVB exposure was lower in winter, leading to seasonal vitamin D deficiency that could be reversed by vitamin D supplementation, and that UVB exposure was the major determinant of individual vitamin D status. Further, the study’s authors found that when blood cells isolated from participants were infected with HIV, viral replication was attenuated in blood from individuals who had received vitamin D supplementation in winter.
The study was published in PNAS on 10 June 2015.