Probiotics are live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut. They are also called "friendly bacteria" or "good bacteria." Probiotics are available to consumers mainly in the form of dietary supplements and foods.
Researchers at Baylor College of Medicine and M.D. Anderson Cancer Center investigated how Lactobacillus reuteri ATCC PTA 6475 might work to slow the growth of certain cancerous tumors. Their study documented the molecular mechanisms of the probiotic's effects in human myeloid leukemia-derived cells—i.e., how it regulates the proliferation of cancer cells and promotes cancer cell death. The researchers noted that a better understanding of these effects may lead to development of probiotic-based regimens for preventing colorectal cancer and inflammatory bowel disease.
In another study, researchers at Virginia Polytechnic Institute and Ohio State University looked at whether Lactobacillus acidophilus might enhance the immune-potentiating effects of an attenuated vaccine (a vaccine prepared from a weakened live virus) against human rotavirus infection—the most common cause of severe dehydrating diarrhea in infants and children worldwide. The investigators' tests on newborn pigs found that animals given both a vaccine and the probiotic had a better immune response than the animals given the vaccine alone. The researchers concluded that probiotics may offer a safe way to increase the effectiveness of rotavirus vaccine in humans.
In both studies, the investigators called for additional research into the mechanisms behind the health-related effects of probiotics.