A rapid and almost complete loss of CD4+ T cells from the gut associated lymphoid tissue (GALT) occurs early in HIV infection, with a permanent damage in the intestinal barrier, changes in gut microbiota, increased bacterial translocation and persistent immune activation, changes that are not restored after the initiation of antiretroviral therapy. The investigators hypothesize than an intervention targetting the enterocyte barrier and the gut microbiota might modify the gastrointestinal tract towards a bifidogenic microbiota and improve markers of bacterial translocation, inflammation, immune activation and endothelial dysfunction.

This is a randomized placebo-controlled clinical trial to evaluate the safety and effectiveness to modify gut microbiota, bacterial translocation, immune activation and markers of endothelial dysfunction of a dietary supplement (prebiotics + glutamine) during a period of six weeks. The study will enroll four cohorts: 1) HIV-infected, treatment naive individuals; 2) HIV-infected subjects, currently on ART, with >350 CD4+ T-cells/uL; 3) HIV-infected subjects, currently on ART, with <350 CD4+ T-cells/uL; 4) HIV negative healthy controls.

Inclusion Criteria:

• After receiving information on the design and objectives of the study, the possible risks involved, and the fact that they can refuse to collaborate at any time, patients will give their informed consent to participate in the study and agree to provide material for the cellular and molecular studies.
• Aged over 18 years.
• Group 1: HIV+, Not receiving ART and no previous exposure to ART, at least 2 years since HIV diagnosis.
• Group 2: HIV+, currently receiving ART for more than 2 years, HIV-1 RNA levels less than 40 copies/ml and more than 350 CD4+ T-cells/uL.
• Group 3: HIV+, currently receiving ART for more than 2 years, HIV-1 RNA levels less than 40 copies/ml and less than 350 CD4+ T-cells/uL.
• Group 4: HIV-, healthy controls.

Exclusion Criteria:

• Major cardiovascular risk factors.
• Concomitant acute diseases.
• Gastrointestinal disorders.
• Pregnancy.
• Antibiotic exposure in the previous month.
• Regular use of foods or supplements containing prebiotics or probiotics within the 2 weeks prior to initiation of the study.