The latest potential HIV therapy comes from a surprising place: topsoil. A new study suggests that the mineral selenium (nontoxic in appropriate doses) could slow disease progression. Selenium plays an important role in the body’s antioxidant defense system and its maintenance of immune responses, and—if test-tube evidence pans out—may actually help prevent HIV replication. This may explain why University of Miami researchers found a dramatically elevated risk of death for selenium-deficient HIVers. After three and a half years of following 125 HIV positive men and women, the relative risk of death—even when adjusted for baseline CD4 counts under 200 and CD4 counts over time—was shown to be almost 20 times greater for those with low selenium levels. The study tied other nutrient deficiencies to less dramatic, but still greatly increased, chances of death—vitamin A (a risk 3.23 times higher), vitamin B-12 (8.33), and zinc (2.91), as well as not-yet-apparent malnutrition, as shown by low blood levels of prealbumin (4.01).

Following up on multiple studies that have shown widespread selenium deficiencies among PWAs, the researchers have begun a 328-person trial to assess the effects of 200-microgram daily doses of the mineral on disease progression and viral changes that might reduce replication.