Gut health, microbiota & probiotics update

Hello friends. Today’s post, I get a little science-y.  For you science nerds…you’re welcome. And for those that don’t like the microscopic details and science terms… you might skip this post 🙂

I thought I would share with you a few of the highlights from Harvard Medical School’s recent Gut Health, Microbiota & Probiotics throughout the Lifespan 2016 conference which took place last week in Boston. Top researchers came together to sift through their microbiota research providing exciting news from their labs. The cost of analyzing the microbiome has reduced significantly making research more cost effective and possible for many more researchers interested in this growing area of study.

Topics ranged from the perinatal microbiome to adult disease states and conditions related to gut microbial changes such as: Parkinson’s disease, diabetes, obesity, inflammatory bowel conditions and autism. I have to admit, I feel so grateful to have access to these educational events that bring in the top experts from the US and abroad.  If I had to provide you one common take-away from the experts it would be: “this science is new, evolving and individual.” We all have our very own gut microbial fingerprint–and this impacts how other environmental factors impact our health, including diet. It is not a one size fits all approach. The gut microbiome is a fragile interactive ecosystem. One change in the gut microbiota will induce other changes to the ecosystem. 

Here are a few interesting take-aways about newborns, mode of delivery (c-section vs. vaginal), and gut microbiota

• Contrary to popular belief, the newborn is not born sterile. Gut microbes may transfer from via vaginal, oral or gastrointestinal tract of the mother to fetus.
• Over 50% of the microbes in the meconium match those in the amniotic fluid.
• About 35% of the metabolites in mammalian blood are from bacteria.
• C-section has been related to microbiota differences in the newborn compared to vaginal delivery but is it the difference in mode of delivery itself that drives these changes? Other overlapping factors could play a role in the difference of microbiota seen in a baby delivered via c-section. Possible contributors to the change in gut microbiota seen in a newborn born via c-section vs. vaginal delivery include:
  • The reason for the c-section  (fetal stress or maternal stress)
  • Antibiotics use during c-section
  • Was the baby removed from mom longer after c-section?
  • Was the onset of breast feeding different for mom post c-section?

In other words, it is important to look at all variables that occur during c-section compared to vaginal birth before we connect the dots on why and how there are changes in the gut microbiome.

Rob Knight, co-founder of the Earth Microbiome Project and the American Gut Project spoke about the influence of the gut microbiome on body weight regulation along with many other interesting points about the driver’s of diversity of the gut microbiome. In the American Gut Project, they have analyzed gut microbiota from individuals with cancer, ICU patients, with C. Diff infection to the healthiest student athlete. What they have found is that diet has a BIG effect on the microbiome–often more so then the effects of disease and medicine.

What changes diversity of our gut microbiome? Age, sleep, inflammatory gut processes such as IBD, antibiotic use, BMI, alcohol, exercise, to name a few.

What disease states are linked with our gut microbiome: heart disease, autism, arthritis, cancer, obesity, IBD, IBS, diabetes and many more.  {note: many related to the inflammatory state}

Dr. Knight said that most commercial probiotics, which have been designated to be ‘generally recognized as safe’ by the FDA, do not contain the right bacterial taxa to show significant benefit in humans–and many more years of research will be necessary to safety test other probiotic bacteria before they can be used in human trials. Again, this science is in its infancy!!

Dr. C. Ronald Kahn from Joslin Diabetes Center in Boston spoke about role of gut bacteria metabolites in obesity and type 2 diabetes revealing changes in the gut microbiome can lead to changes in the gut barrier which can alter bile acid metabolism. The combination of gut microbial interactions and genetics play a role in obesity and diabetes.

Dr. Gewirtz from Georgia State University in Atlanta spoke about the gut microbiota and chronic inflammatory diseases. Dr. Gewirtz called the gut microbiata– our best “frenemies” because they can promote immune and metabolic health BUT can also promote inflammatory disease. It’s all about balance. The gut mucosal layer keeps bacteria away from systemic circulation(acting as a line of defense) and when bacteria invade the front line of the gut, he referred this as ‘bacterial encroachment’, inflammation and other deleterious effects may occur.  Dr. Gerwirtz’s lab has revealed the link with intake of emulsifying agents (polysorbate 80 and carboxymethylcellulose), common in the food supply, with gut inflammation and metabolic syndrome in animal studies. His final advice, ‘eat more whole foods’ and less food products.

In further study, adding inulin to mice chow, reversed some of the damaging effects of the processed food diet in animal studies; however, adding inulin to immune compromised mice may have negative effects. An important reminder: modifying diet for gut health is not a one size fits all approach!

Many microbes have been shown to make neurotransmitters in the gut which can impact the function of the nervous system. Elaine Hsiao, PhD from University of California in Los Angeles, reveals that about 60% of peripheral serotonin (an important neurotransmitter associated with behavior and mood) is regulated by our gut microbes.

Interesting, interesting science! But, please note: we are far from providing individual recommendations to manipulate the human gut microbiome. But…there is great interest in this area of study so expect to learn more and more every year.