Microbes, immune balance / immune homeostasis, antibiotics and probiotics

Our bodies have the highest known density of microbes on Earth. Bacteria inside and outside our body are represented by 3.3 million genes. The number of genes in these organisms far exceeds the number of human genes in our own bodies. Samples of 124 healthy Europeans found an average of more than 530,000 unique genes in each sample, and 99.1% of the genetic material comes from bacterial cells.

While we provide bacteria with food and shelter, they provide us with benefits, including helping to digest food, breaking down toxins, and providing some of our nutritionally essential vitamins and amino acids.

There is a significant interrelation between our microbial populations and our immune systems, and this relationship is an important factor for our health. Immune cells not only regulate the balance of the types and numbers of bacteria, but the types and numbers of bacteria also affect the functioning of the immune system, especially its inflammatory responses.

Dr. David A. Relman of Stanford University, Palo Alto, CA found that when people take antibiotics that kill bacteria, the returning microbial ecosystem is different from the microbial population that existed before taking the antibiotics. Also, if the same antibiotic is taken again, even 6 months later, the bacteria populations take longer to return and the bacteria are even more different than the original spectrum of bacteria that had existed in the gut.

Dr. Relman says, “Everything has a cost,” he said. “The problem is finding the right balance. As physicians, we have not been looking at the cost to the health of our microbial ecosystems.” *

In addition, there is the problem of the interaction of gut microbes with drugs. More than 40 different medications can be activated or deactivated, depending on the microbe. This event influences one’s response to medication.

Many people take supplemental probiotics, beneficial gut bacteria, in hopes of changing their gut ecosystems. Unfortunately, the evidence suggests that organisms in probiotic mixtures do not develop into established populations in the gut and that they only last for a relatively short period, or while ingestion of the probiotic continues.

Once again, the importance of balance in the body is paramount. Considering that more than 75% of the immune system is represented in the intestine, immune balance, inflammatory homeostasis, helps the body provide natural resistance to disease. If the immune system is not working properly, if it is in disarray, the physical and emotional aspects of our life and health will be out of balance and in disarray.

A body in immune homeostasis is able to respond appropriately to challenges either by “increasing” the “firepower” of an inflammatory immune response to “burn out” an infection, or by suppressing an overly inappropriate immune response to challenge. The key is to maintain digestive and immune homeostasis.