Good bacteria modify our immune response by changing existing gut flora

02/14/2019 / By Ellaine Castillo

Most people are familiar with the benefits of probiotics on digestive health. However, not as many people know about its effects on the immune system. Your gut contains up to 80 percent of your body’s entire immune system. This highlights the crucial role of gut health in the body’s immune response.

A study published in the International Journal of Pharmaceutics provides further evidence for the close relationship between the gut and the immune system. It showed that the good bacteria in live probiotics changed the existing gut flora and caused modifications in the body’s immune response. These were determined using a novel Simulator of the Human Intestinal Microbial Ecosystem (SHIME). With the help of the in vitro simulator, the researchers were able to monitor bacteria without needing invasive procedures and measurements.

The researchers wanted to determine if bacteria in probiotics could help feed a simulated gut microbiome made from bacteria donated by healthy humans. To do this, they evaluated the lactate levels in the different compartments of the gut.

Data from this study revealed that probiotic bacteria immediately colonized the gut and consequently, increased lactate concentrations. Elevated lactate levels stimulated the growth of bacteria that consume this compound, indicating that taking probiotics can alter gut bacterial diversity. In addition to this, they observed an increase in the production of short-chain fatty acids (SCFAs) like butyrate. This is great because high levels of SCFAs have been associated with a lower risk of inflammatory diseases, type 2 diabetes, obesity, and heart disease.

Bacteria like firmicutes and actinobacteria grew in abundance after adding probiotics to the simulated gut. This change in population was beneficial since a lack of these bacteria in the gut is associated with health problems like irritable bowel syndrome.

The study also showed that live probiotics increased anti-inflammatory chemicals like interleukin-6 (IL-6) and interleukin-10 (IL-10). Meanwhile, they reduced the pro-inflammatory chemicals interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), and C-X-C motif chemokine ligand-10 (CXCL10) that are associated with inflammatory conditions and viral infections. Furthermore, changes in gut microbiome composition had positive anti-inflammatory and immuno-modulatory effects.

“The diversity of the donor microbiotas clearly changed for the better and importantly the effect was sustained week-on-week,” said Dr. Simon Gaisford, a professor of pharmaceutics at the University College London and one of the authors of this study. “We saw that the addition of [live probiotics] reduced inflammatory markers and raised butyrate levels. If we can make a healthy microbiome healthier, the potential to improve conditions of dysbiosis is incredibly exciting.”

Overall, the results of this study suggest that taking live probiotics can help boost the immune system.

More reasons to increase your probiotic intake

By increasing your probiotic intake, you can also enjoy the following health benefits.

Improved mental health — Studies have shown that taking probiotics with Bifidobacterium and Lactobacillus can improve anxiety, depression, autism, obsessive-compulsive disorder (OCD) and memory. (Related: Probiotics fight depression: Healthy gut bacteria found to reduce symptoms.)
Protection of the heart against disease — Taking probiotics can help keep your heart healthy by reducing bad cholesterol and improving blood pressure. This results from an increase in lactic acid-producing bacteria that can break down bile, a fluid in the gut that is mostly made of cholesterol.
Reduced risk of eczema — Studies have shown that pregnant women who take probiotics gave birth to infants whose risk of developing eczema was lower by 83 percent.
Weight loss — If you want to lose weight, try adding probiotics to your diet. These can help you feel sated for longer and burn more calories. Furthermore, probiotics interfere with the absorption of dietary fats so they are excreted through feces rather than stored.