Background: Despite findings that selenium supplementation may improve immune functioning, definitive evidence of its impact on human immunodeficiency virus (HIV) disease severity is lacking.

Methods: High selenium yeast supplementation (200 mug/d) was evaluated in a double-blind, randomized, placebo-controlled trial. Intention-to-treat analyses assessed the effect on HIV-1 viral load and CD4 count after 9 months of treatment. Unless otherwise indicated, values are presented as mean +/- SD.

Results: Of the 450 HIV-1-seropositive men and women who underwent screening, 262 initiated treatment and 174 completed the 9-month follow-up assessment. Mean adherence to study treatment was good (73.0% +/- 24.7%) with no related adverse events. The intention-to-treat analyses indicated that the mean change (Delta) in serum selenium concentration increased significantly in the selenium-treated group and not the placebo-treated group (Delta = 32.2 +/- 24.5 vs 0.5 +/- 8.8 microg/L; P<.001), and greater levels predicted decreased HIV-1 viral load (P<.02), which predicted increased CD4 count (P<.04). Findings remained significant after covarying age, sex, ethnicity, income, education, current and past cocaine and other drug use, HIV symptom classification, antiretroviral medication regimen and adherence, time since HIV diagnosis, and hepatitis C virus coinfection. Follow-up analyses evaluating treatment effectiveness indicated that the nonresponding selenium-treated subjects whose serum selenium change was less than or equal to 26.1 microg/L displayed poor treatment adherence (56.8% +/- 29.8%), HIV-1 viral load elevation (Delta = +0.29 +/- 1.1 log(10) units), and decreased CD4 count (Delta = -25.8 +/- 147.4 cells/microL). In contrast, selenium-treated subjects whose serum selenium increase was greater than 26.1 microg/L evidenced excellent treatment adherence (86.2% +/- 13.0%), no change in HIV-1 viral load (Delta = -0.04 +/- 0.7 log(10) units), and an increase in CD4 count (Delta = +27.9 +/- 150.2 cells/microL).

Conclusions: Daily selenium supplementation can suppress the progression of HIV-1 viral burden and provide indirect improvement of CD4 count. The results support the use of selenium as a simple, inexpensive, and safe adjunct therapy in HIV spectrum disease. Trial Registration isrctn.org Identifier: ISRCTN22553118.