Thirty test subjects will be recruited during the first four months of the study, for inclusion in a trial starting at the 4-6 month time-point, with completion by 10-12 months. A crossover study will be performed in London in which 10 HIV positive volunteers with CD4 counts between 200 and 400 on their standard treatment (including Highly Active Antiretroviral Therapy), and 10 subjects with Cancer who are in the recovery stages and not currently receiving chemotherapy or radiation therapy, and 10 healthy adults (aged 18-30) will randomly be assigned to receive one cup of Yogurts 1, 2 or 3 and a control unsupplemented yogurt 4, daily for one month, followed by a two week washout where no yogurt will be consumed, then one month on the second yogurt, two weeks off etc for 162 days. Subjects will not be receiving antibiotics, not have any mental illness that would affect compliance, or not be requiring surgery during the study. No restrictions will be placed on subjects continuing prescribed or other remedies, but none will consume any other probiotic product during the study. The volunteers will be gender matched and a randomization scheme will ensure that subjects are blinded and different yogurts are distributed at each time (thus, for example two subjects will receive yogurt 1, two yogurt 2, three yogurt 3 and three yogurt 4 on day sample day one). The two week washout period will be used, as probiotic organisms do not persist for longer than that. Various measurements will be taken on the day of consuming the first and last batches of yogurt (days 0, 30, 44, 74, 88, 118, 132, 162). These will include weight, height, and from blood samples the CD4 count, CBC, levels of TNFα, IL-12, IL-10 and G-CSF [Kim, et.al. 2006], liver function test (AST, ALT), serum albumin, total protein, blood urea, serum zinc levels, serum selenium levels and HIV-1 RNA. A linear analogue self-assessment tool will be used to assess the subject's energy levels, daily activities and overall quality of life [Kaiser, et.al. 2006].