July 6, 2009
Yogurt may be a delicious snack for many people, and can be a healthy alternative to most pastries or potato chips. But can it also raise CD4 counts and protect against some HIV-related infections? Maybe so, say some researchers. A recent article in the journal Nature Medicine explores the connection between yogurt consumption and gastrointestinal health, or "gut health," for people with HIV.
HIV researchers have known since the early days of the pandemic that HIV can wreak havoc on the gut, which is home to an abundance of CD4 cells. This apparently occurs quite soon after someone is infected with HIV. "It's almost like the gut is a magnet for the virus early on," says Bill Critchfield of the University of California at Davis. "[It] becomes compromised in weeks."
The gut also harbors roughly 100 trillion microorganisms that help with immunity and digestion. HIV infection can upset the balance of healthy bacteria in the gut, allowing "bad" bacteria and fungi to flourish there. Several recent studies have suggested that probiotics -- the "friendly bacteria" that turn milk into yogurt and also provide health benefits when eaten -- can help restore that balance by repopulating the gut with healthy bacteria or by tuckering out the bad bacteria by competing with them for nutrients.
As Nature Medicine reports, microbiologist Gregor Reid of Lawson Health Research Institute in Ontario, Canada, has been studying the health benefits of probiotics for over 25 years. He's created his own probiotic, called Lactobacillus rhamnosus GR-1, which he has put into a yogurt that is being used in research involving people with HIV. Reid and others around the world have conducted small studies that show probiotics have a positive effect on CD4 counts, though larger studies are certainly needed to confirm those findings.
In addition, because HIV attacks CD4 cells and replicates within them, Daniel Douek of the U.S. National Institute of Allergy and Infectious Diseases points out that any therapy designed to increase CD4 count needs to go hand in hand with antiretroviral therapy to reduce viral load. "One has to look at all of these different aspects of therapy simultaneously," Douek says.
One of the studies involving Reid's probiotic yogurt is based in Tanzania, a country with one of the highest HIV rates on the planet. In Mabatini, a small Tanzanian village, women nicknamed "yogurt mamas" are taught by North American interns the ins and outs of culturing yogurt with Reid's special probiotic. The women then sell cups of yogurt to the community, reserving 125 cups to be given for free to Mabatini's HIV-positive residents as part of the study.
While conclusive results showing the immune benefits of probiotics remain to be seen, probiotics have shown great promise in preventing or alleviating other infections. Studies have shown that the balancing effect of probiotics on microorganisms in the gut can stop diarrhea, which affects nearly 90 percent of untreated HIV-positive people living in developing countries (and probably a great percentage of uninfected people). In another of Reid's studies, probiotics were beneficial in clearing women of bacterial vaginosis -- the most common vaginal infection for women of childbearing age -- which experts believe increases the chance of HIV infection in HIV-negative women.
These findings are not surprising, as it's been known for some time that the probiotics in yogurt can aid in the prevention of fungal infections such as thrush (candidiasis). There has even been a study showing that a cousin of the lactobacillus bacteria often found in yogurt was shown to lower viral loads in the vaginas of women who were already HIV positive. Another probiotic in yogurt has been studied as a microbicide to protect against HIV infection.
Researchers are still far from a verdict on the benefits of probiotics, but they all seem to agree that the yogurt can't hurt.
Considering the connection between the gut and immune function, taking care of your gut is an excellent idea if you're HIV positive. A good old-fashioned cup of yogurt -- or a yogurt smoothie, even -- can be a great addition to your gut care regimen. Many commercial yogurts have probiotics in them, though be sure to check the labels for words like "Acidophilus" and "Lactobacillus."