Microbiome – Your Most Intimate Relationship
Lisa Murray RDN, LD
Microbiome – In Us, Not Of Us
A wide variety of microorganisms inhabits almost every part of the human body — living on the skin, in the gut, and in the nose. These microorganisms are known as our microbiome and luckily, most of the time they live in harmony with us, providing functions essential to our survival.
We know that having normal, healthy gastrointestinal bacteria is important for maintaining good health and through extensive research, we have a very good idea of what “normal” looks like for a healthy Western population.
However, there are many factors that change the composition of our gut microbiome, including the foods we eat, how we cook them, the drugs we take, our environment and even stress. All of these components alter our body chemistry and therefore our microbiome, making it understandable why changes would have a correlation to health and disease.
Research has shown that there is even a link between our mood and our gut bacteria — but like the chicken and egg, it has not yet been definitively discovered which has the first effect.
The bacteria that comprise our microbiome are in us but not of us. Technically, we are in a relationship with our microbiome — and, it actually may be the most intimate relationship we can have.
Our microbiome is affected by our thoughts, our feelings, our breath, our movements, what we eat, what we drink and our state of health. Research has shown that our microbiome reacts and responds, but despite its important effects, the mechanisms by which the gut microbial community influences the host’s biology to remain fairly unknown.
Unfortunately, we are not typically aware of how our microbiome is responding, changing and affecting us, nor do we think much about it (unless we experience unpleasant GI symptoms).
Rehabbing the Gut Microbial Community
The composition of our gut flora is constantly changing. Toxins, drugs (like antibiotics or antacids), poor diet and various traumas can seriously disrupt the normal healthy balance of gut bacteria and end up favoring the overgrowth of species which have negative health effects.
Probiotics can help to “rehab the community” by boosting the population of “beneficial” bacteria and help restore a healthier balance.
Researchers currently define a probiotic as a live microorganism, which when ingested in adequate amounts confers a SPECIFIC health benefit. Researchers seek to relate a SPECIFIC health benefit to a SPECIFIC strain of microorganism to better understand and utilize probiotics in a scientifically and medically meaningful way, that is, to treat a symptom, illness or disorder/disease.
It has been found that different strains of bacteria in a given species, say Lactobacillus plantarum, do not always share the same properties, characteristics, and actions. This means that although one strain of bacteria has a proven action or characteristic, it does not mean that all other strains within that species will too, even if they are closely related. When identifying new probiotics for medical use, researchers are looking to answer these three questions:
1) What is the specific organism (strain)?
2) What is the “adequate amount” to take?
3) What is the health benefit?
For example, Lactobacillus rhamnosus gg, also known as Lactobacillus gg, is an extremely well researched probiotic strain. It was patented in 1985 and there have been numerous studies proving more than 44 health benefits. Lactobacillus gg has extremely good intestinal wall adhesion, promoting the colonization of other beneficial strains which “play well together” in the microbial community. Lactobacillus gg is best known for helping resolve diarrhea either from illness or from antibiotic use and is used extensively in pediatric as well as adult populations.
Choosing the Right Probiotic Strain
There are thousands of different probiotic products on the market today. Researchers and experts in this field encourage people to use specific strains that have been researched and found to confer a specific benefit or action. The vast majority of probiotic products contain strains of bacteria normally found in a healthy GI system or frequently found in fermented foods, though each strain may not be individually researched. Does that mean they are ineffective? Not necessarily.
As any clinician will tell you, there are many benefits to taking a high-quality, diverse probiotic to boost the population of normal, good bacteria in your GI system, but each person will have their own unique response to any given product and it may be helpful to try different products when looking for the greatest benefit. Also, it may be worth including in the treatment plan those strains which have been researched and have shown clinical effectiveness for particular health issues.
General research consensus is that probiotics are very safe and currently there is no evidence that you can take “too much”. However, there are exceptions as researchers believe that probiotics are contraindicated for immunocompromised individuals, including those undergoing cancer treatment.
 Matthew A Ciorba. A Gastroenterologists’s Guide to Probiotics. Clin Gastroenterol Hepatol. 2012 Sep; 10(9): 960–968. Published online 2012 Apr 10. doi: 10.1016/j.cgh.2012.03.024