This weekend, I was immersed in learning more about the microbiome. First, I was enjoying my “free gifts” for registering for the upcoming Microbiome Medicine Summit 2 (no affiliation). Secondly, as I noted on my homepage, I was also reviewing some of my favorite headlines for my upcoming “Top Reads.” In doing this, I noticed that, as usual, there were many microbiome studies which were topping my list of favorites.
Therefore, I decided that once again these critters have earned another monthly spotlight. The discoveries on how these buggy inhabitants which line our outsides and insides continues to be a “game changer” in medicine and is uniting all practitioners. Every doctor is now considering how their treatments will impact this newly discovered, yet ancient organ, and the resultant downstream effects.
Let’s take a look at a few recent studies that reported their findings on what happens when we mess with our microbiome. I’ve also referenced some older studies that show how these discoveries are building and supporting on the powerful impact the microbiome has on our health.
Killing Critters Haphazardly and An Angry Immune Response
Although antibiotics may be helpful in killing a dangerous overgrowth of harmful bacteria, they have the negative consequence of causing unwanted side effects. Furthermore, antibiotic use has been associated with an imbalance of microbiota and a reduction in the repopulation of resident microbes that are health-promoting. In fact, one study reported that one course of antibiotics can alter the gut microbiome for an entire year!
This 2014 review in the Journal of Clinical Investigation summarized the disturbing relationship between antibiotics and the microbiome. The authors report on how they impact our gut environment and can increase resistance to pathogenic organisms as follows:
Antibiotics have been a cornerstone of innovation in the fields of public health, agriculture, and medicine. However, recent studies have shed new light on the collateral damage they impart on the indigenous host-associated communities. These drugs have been found to alter the taxonomic, genomic, and functional capacity of the human gut microbiota, with effects that are rapid and sometimes persistent. Broad-spectrum antibiotics reduce bacterial diversity while expanding and collapsing membership of specific indigenous taxa. Furthermore, antibiotic treatment selects for resistant bacteria, increases opportunities for horizontal gene transfer, and enables intrusion of pathogenic organisms through depletion of occupied natural niches, with profound implications for the emergence of resistance. Because these pervasive alterations can be viewed as an uncoupling of mutualistic host-microbe relationships, it is valuable to reconsider antimicrobial therapies in the context of an ecological framework. Understanding the biology of competitive exclusion, interspecies protection, and gene flow of adaptive functions in the gut environment may inform the design of new strategies that treat infections while preserving the ecology of our beneficial constituents. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4191029/)
Now let’s look at some recent studies on the association between antibiotics and resulting immune imbalances.
Women, Prolonged Antibiotics, and Increased Risk for Colon Polyps
A recent article in Health Day reported there was an association found between prolonged antibiotic exposure in women and an increased risk for colon growths. The authors felt this could also hold true for men:
Taking antibiotics for an extended period in early to middle adulthood might increase your risk for precancerous growths in your colon, a large study suggests.
Women who took antibiotics for two weeks or more in their 20s through their 50s were more likely to have colon lesions in their 60s than women who didn’t take the drugs for an extended period, researchers found.
If not removed, these lesions — called polyps or adenomas — can lead to colon cancer.
“This suggests that alterations in the naturally occurring bacteria that live in one’s intestines caused by antibiotics might predispose individuals to colorectal cancer,” said lead researcher Dr. Andrew Chan. (https://consumer.healthday.com/infectious-disease-information-21/antibiotics-news-30/prolonged-antibiotic-use-tied-to-precancerous-colon-growths-721326.html)
This study was supported by a discovery from Baylor College of Medicine that specific types of bacteria are found in those with colon cancer. Science Daily reported on the researchers’ findings as follows (4/19/2017):
The type of bacteria in your gut may help diagnose colorectal cancer. Researchers at Baylor College of Medicine and other institutions have identified specific types of bacteria that seem to be abundant in individuals with colorectal cancer. Using a combination of markers specific for these fecal microbes, scientists anticipate that a noninvasive, sensitive clinical diagnostic test potentially can be developed. The study is published in Gut. (https://www.sciencedaily.com/releases/2017/04/170419121958.htm)
Which bugs? This is what the abstract from Gut states from findings of nine studies and 509 samples:
Definitive taxa, including Parvimonas micra ATCC 33270, Streptococcus anginosus and yet-to-be-cultured members of Proteobacteria, were frequently and significantly increased in stools from patients with CRC compared with controls across studies and had high discriminatory capacity in diagnostic classification. Microbiome-based CRC versus control classification produced an area under receiver operator characteristic (AUROC) curve of 76.6% in QIIME-CR and 80.3% in SS-UP. Combining clinical and microbiome markers gave a diagnostic AUROC of 83.3% for QIIME-CR and 91.3% for SS-UP. (http://dx.doi.org/10.1136/gutjnl-2016-313189)
Rodent Studies Show Clues in Mechanisms
Several rodent studies revealed potential mechanisms on how antibiotics could lead to inflammation and how this resulted not only in disturbances in the intestine, but other inflammatory disorders as well.
Science Daily stated:
A new research report involving mice shows that antibiotic use very early in life that alters the normal development/growth of gut bacteria, may contribute to the development of inflammatory bowel disease, and potentially other inflammatory diseases like asthma and multiple sclerosis. (https://www.sciencedaily.com/releases/2017/04/170403123304.htm)
Here is a summary on the link between these imbalances in gut microbes, age-associated inflammation, and premature death…leaky gut:
Inflammation increases with age and is a strong risk factor for death in the elderly, but the underlying cause has not been clear. A new study reveals that gut microbes are one of the culprits behind age-associated inflammation and premature death in mice. Imbalances in the gut microbes in older mice cause the intestines to become leaky, allowing the release of bacterial products that trigger inflammation and impair immune function. (https://www.sciencedaily.com/releases/2017/04/170412132332.htm)
Summary
If we make our microbes mad, and haphazardly kill the “bad and good ones”, it can cause a bodily upset with massive consequences. Although antibiotics have saved many lives in the past 80 years, the downstream, collateral damaging effects are catching up with us.
A 2016 review from Genome Medicine summarizes this as below:
The widespread use of antibiotics in the past 80 years has saved millions of human lives, facilitated technological progress and killed incalculable numbers of microbes, both pathogenic and commensal. Human-associated microbes perform an array of important functions, and we are now just beginning to understand the ways in which antibiotics have reshaped their ecology and the functional consequences of these changes. Mounting evidence shows that antibiotics influence the function of the immune system, our ability to resist infection, and our capacity for processing food. Therefore, it is now more important than ever to revisit how we use antibiotics. This review summarizes current research on the short-term and long-term consequences of antibiotic use on the human microbiome, from early life to adulthood, and its effect on diseases such as malnutrition, obesity, diabetes, and Clostridium difficile infection. Motivated by the consequences of inappropriate antibiotic use, we explore recent progress in the development of antivirulence approaches for resisting infection while minimizing resistance to therapy. We close the article by discussing probiotics and fecal microbiota transplants, which promise to restore the microbiota after damage of the microbiome. Together, the results of studies in this field emphasize the importance of developing a mechanistic understanding of gut ecology to enable the development of new therapeutic strategies and to rationally limit the use of antibiotic compounds. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4831151/)
Keeping Our Buggies Happy
In the past, I discussed the use of probiotics, but diet and lifestyle also play a big role in a balanced microbiome. So, eat well, stress-less, swallow healthy bugs, use antibiotics appropriately, and click here to learn how essential oils can help make our microbes happy!
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