#111: John Alverdy, MD- Gut Surgeon Shares Microbiome Insights

by Mike Mutzel


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About John C. Alverdy, MD

Dr. Alverdy performs a wide variety of complex minimally invasive and open gastrointestinal surgical procedures with 25 years of experience in the field. He is nationally recognized for introducing several new operations into the field, including minimally invasive pancreatic surgery, bariatric surgery, and surgery for disorders of the foregut including the esophagus and stomach.

Scientific Studies Published by Dr. Alverdy as Mentioned in this Podcast

Stool consistency as a major confounding factor affecting microbiota composition: an ignored variable?

The opposing forces of the intestinal microbiome and the emerging pathobiome.

Proceedings of the 2013 A.S.P.E.N. Research workshop: the interface between nutrition and the gut microbiome: implications and applications for human health

Sponsored Content

SHEI CON Mike Mutzel and Ben Lynch


Contact Dr. Alverdy

Show Notes

1:37 Understanding Post-Surgical Infections and Gut Bacteria: Dr. Alverdy is a gastrointestinal surgeon. He also has an NIH-funded laboratory that studies how gut bacteria complicates recovery from surgery. Every patient’s fear is that they will develop an infection after an operation. Infection is especially problematic when prosthetic material is placed in the body. Dr. Alverdy has been working for 20 years to apply the latest molecular techniques to understand problems that most doctors tend to blame on mechanical issues.

4:06 Healing from Surgery and Gut Flora: When you are a surgical patient, you have your procedure, you go home, and you start eating your regular food. You have generally had one shot of antibiotics, which assaults your gut microbiome, but you can rebuild your gut flora quickly at home by resuming your regular diet. There are about 80,000 elective operations done every day and most of us heal quickly at home.

5:00 Longer Hospital Recovery and Gut Biodiversity: Sometimes we have a prolonged recovery, for example after, a car accident, a liver transplant, or burn injuries. In the intensive care unit, even when there is no identified source of infection, doctors will put 80% of us on antibiotics unnecessarily.

6:37 The Consequences of Unnecessary Antibiotics in Prolonged Recovery: It is called ecological collapse of the normal gut biome. Your normal health-promoting microbiome is replaced with a pathobiome. Harmful, pathogenic, bacteria become predominant in your gut. This dysbiosis can directly impair the immune system and directly and adversely affect the outcome. Instead of being better in a day or two, it may take you 2 weeks to recover.

7:23 The Impact of a Pathogenic Gut Microbiome on the Immune System: There is now evidence that your normal gut bacteria drive your entire body’s immune response. Studies in animals show that even a sterile incision distant from the gut heals much worse if you destroy the gut microbiome.

8:25 Overuse of Antibiotics: Dr. Alverdy is glad that we have antibiotics. They save countless lives.   Clearly, we are overusing them. Now that we have the molecular tools to understand it and as we have the science to back it up, we can use this science to change the clinical course of treatment. Perhaps, we could narrow the antibiotic’s spectrum or use alternative approaches like delivering the antibiotic to the wound site rather than systemically.

9:17 Sometimes With Antibiotics less Works: A recent study of patients with post-surgical infections was published. One group was given the recommended 7 to 10 day regimen of antibiotics. The other group was given 5 days of those antibiotics. The results for both groups were the same. It is time to re-examine the protocol.

10:36 Chemically Defined Diets Impact Upon Gut Biodiversity: With food, the whole is greater and more powerful than the sum of its parts. Using chemicals that have many of the components of food does not feed the microbiome and does not fully nourish the body. Using chemicals that have the components of the gut flora byproducts does not nourish the body either. Chemically defined diets are inadequate. They do not have the same effect on the microbiome, and thus the immune system, as real food. We cannot eat real food when we are very sick. Dr. Alverdy is hoping that through the sciences of metabolomics, proteomics, and microbial genetics, we will make discoveries that will allow us to better nourish our people and their gut microbiome.

14:15 Prophylactic Probiotics before Surgery: We take probiotics; strains of bacteria that we believe are beneficial, in the hopes that they will overpower the strains of bacteria that are less beneficial. When you are given antibiotics with your surgery, you hope that more of the good guys stick around. This may or may not be the case. Dr. Alverdy thinks that if we could figure out exactly what we need, it could be a very powerful tool, but we are not there yet. Probiotic supplements offer a few strains of bacteria for the gut. To re-faunate the gut, you would need a multitude of bacterial strains to create the diversity required to maintain your health.

17:25 The Leaky Gut and Endotoxin Relationship: In leaky gut, your gut lining has been compromised and toxins, released by your gut bacteria, leaks into your bloodstream in small amounts, triggering an immune response. Leaky gut is being linked in theory to diseases for which there is no identified infectious agent, like autism, MS, and fibromyalgia. It is unclear whether the endotoxin in the blood is a marker for the problem or it is driving the problem. In Dr. Alverdy’s opinion, it is more likely that the endotoxin is the result of the leaky gut rather than the cause.

18:58 Your Gut is REALLY Smart: Your GI tract is discriminating. It lets the good stuff in and keeps the bad stuff out. It constantly surveys what is in the gut, so it can be ready for anything at any time. It is a very molecularly complex process. Lymph nodes serve as checkpoints where intruders are identified and detoxified. The endotoxin that may seep through a permeable intestine would probably be mostly detoxified.

20:25 Microbial Shifts Post Surgery: In a recent study, gastric bypasses were performed on mice. Their stool microbiome dramatically changed. Pre-surgery stools and post-surgery stools were transplanted into over-weight mice. The overweight mice that received the post-surgery stool lost weight. They also had improved glucose tolerance, improved metabolic syndrome, and improved fatty liver. Gastric bypass, through alterations in the gut microbiome, appears to change energy efficiency and energy regulation. We are nowhere near a place where we can take a pill to implement these changes and lose weight. It could be that people who struggle with their weight all of their lives, have some sort of altered energy balance. They are eating more than they burn off, but why do they want more food than they actually need? Dr. Alverdy does not think it is volitional or socio-cultural.

23:19 Can We Replace Our Fat People Bacteria with Thin People Bacteria? We are a long way away from wiping out an overweight person’s gut bacteria and repopulating it with thin person’s gut bacteria. It is an exciting prospect. Your gut microbiome has been with you from birth and stays relatively stable. Many bacteria have home field advantage and stick with you through antibiotics, poor diet, poor sleep and poor behavior. So the prospect of cleaning it all out to repopulate is going to be a long complicated process with potential side effects and repopulation, like any transplant, may not last.

26:46 Can We Manipulate Gut/Hunger Hormones? Medical science is host-centric. When something is wrong, we want to distill the cause to a hormone, a mediator, or maybe a chemical. Drugs are developed to deal with whatever it is. It is the pipeline for new drugs. Obesity, Alzheimer’s and the like are complicated problems with no distilled trigger. Ghrelin is one of the hormones that make you feel hungry. Some of the procedures done for obesity knock down that hunger hormone. There are many factors beyond hunger hormones, like your age, the health and composition of your gut microbiome, tastes, memories and emotions, that drive and mediate the feelings of mechanically full (I ate too much.), feeling pleasure (that tasted good.), and feeling satisfied and full (I feel full and I won’t want any more for quite a while). Obesity drugs have tried to exploit our hunger and satiety hormones. They are not fully effective and you build up a tolerance to them, so they become ineffective. In addition, the minute you stop the drug, you are hungry.

30:38 Dr. Alverdy’s Advice for Maintaining a Healthy Gut: Don’t overeat. Don’t eat more than you need. Try to stay lean. Eat a balanced diet of real food: fruits, vegetables and small amounts of meats. Avoid eating too much animal fat. Make sure you get exercise. That is his best advice based on current science.

32:14 Something Americans Should Know: We have embarked upon a very important aspect of science that has the potential to prevent disease in a way that we have never imagined. When the Human Genome Project came out, we thought we would find the answers to disease in our DNA. We are discovering that, through our GI tract, our environment changes the way our genes are expressed. Our modern diseases may have more to do with foods and chemicals that are harmful. Dr. Alverdy would like to see more funding for microbiome research, so we can also work on prevention and have the science to show the deep impacts of antibiotics. If autism, Alzheimer’s, and diabetes are diseases in human progress, what in human progress are we doing wrong?

35:18 Dr. Alverdy’s Next Projects: He is working to implement an exciting new trial which includes 20 of the premier university medical centers. The study will be on the anastomotic leak. This happens when a surgeon cuts away part of your intestine and sews the ends together. In 5 to 7% of patients, even though the stitching is near perfect, it leaks. Anastomotic leaks are very serious, causing you to be very sick and maybe die. In animal studies, it has been proven that this leakage is linked with bad microbiome bacteria lingering at the site of the incision. The goal of the study is to show that it is the case in humans and to find a way to prevent it. If the results are what they anticipate, it will be a game changer.

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