This article was reposted from Harry Rakowski enewsletter.
Dear Friends,
When you woke up this morning, did you realize that your gut housed more small living organisms than the number of people who have ever lived? Each of us has a different mix of trillions of healthy microbes that are bacteria, viruses or fungi that live in a generally symbiotic relationships with our bodies. Over 90% reside in our gut. These “bugs”, their genes and the materials they produce are called the human microbiome.
Our microbiome is first populated by our passage through our mother’s birth canal and from breast milk. This gets us off to a good start. A different microbiome starts from skin and hospital bacteria if we are born by C section which may not be as beneficial. The food we eat and the environment we live in then further populates our microbiome. It peaks in biodiversity during our adolescence and as with many functions, wanes as we age. Most of us have a peak of up to 1,000 different microorganisms weighing 2-3 Kg. which change in composition based on our diet, our environment and how we age. Cutting edge tools such as next-generation gene sequencing are identifying how these microbes help the body function.
In the early 1900’s, Elie Metchnikoff, a Russian zoologist, first theorized that harmful bacteria in our gut were associated with disease. He is widely regarded as the father of our concept of cellular immunity for which he won the Nobel Prize in 1908. He was an early proponent of introducing “good bacteria” such as lactobacilli from yoghurt in our diet to prevent ageing.
The microbes in our nose and mouth are known to aid with mucous production and assist with digestion. Skin microbes protect our skin from pathogens that cause infection. In our lungs different microbes help lubricate lung tissue. In our colon they have the most benefit. They help with the digestion of complex carbohydrates and produce vitamins such as B12, hormones and neurotransmitters.
The concept that gut microbes can cause disease has taken a long time to be accepted. The theory that H. Pylori stomach infections are an important cause of peptic ulcers was ridiculed not so long ago until Barry Marshall won the Nobel prize in 2005 for the discovery. He proved his hypothesis by initially showing that his stomach did not harbour the organism; however, following drinking an infected brew, developed the classic symptoms of gastritis.
Our microbiome lives in ecological balance harbouring both good and bad organisms. The mucous membranes of our gut are a major source of immune protection. Our good microbes can help control inflammatory diseases and bad ones can worsen these diseases and may also contribute to the development of cancer and diabetes.
We need a greater focus on how to maintain the homeostasis of a healthy microbiome by eating the right foods, reducing stress, exercising more and having an adequate intake of important minerals. We also need to prevent dysbiosis, that is, an unhealthy gut microbiome that can hasten the development of diseases as shown below.
Wendy Garrett a professor of immunology and public health at the Harvard T.H. Chan School of Public Health has studied how our diverse microbiomes contributes to the risk of colorectal cancer. She and others have found that a particular gut bacteria, fusobacterium nucleatum, can live in large numbers in some colonic tumours and may suppress the immune system that would normally attack the tumour. She is also working on the theory that Irritable Bowel Disease is caused by an imbalance of the microbiome that leads to a gut immune system that is hyperactive, leading to GI distress.
So what foods and supplements can lead to a healthier microbiome?
Prebiotics are foods that preferentially nourish our protective gut bacteria and foster growth or activity of beneficial microbes. Dr. Mark Hyman is a Functional Medicine Practitioner at the Cleveland Clinic who is also a pioneer on healthy eating. His book “Food: What The Heck Should I Eat?” is a source of what is best to eat. He recommends fibre rich foods that are good for your gut. These include apples, avocados, beans, berries, green vegetables, coconut, lentils, onions, pumpkin and nuts and seeds.
Probiotics are foods or supplements that contain live healthy microbiota that maintain a healthy gut microbiome. These include fermented foods such as yoghurt, miso, kefir (unsweetened fermented milk), apple cider vinegar, sauerkraut, kombucha and pickled vegetables. Not everyone likes or tolerates these foods, but for those that enjoy them, they are generally healthy.
Foods that disrupt our microbiome and may damage our gut include highly processed foods, high fructose corn syrup, refined oils such as corn oil and excessive alcohol consumption. Many people also have a sensitivity to gluten and dairy. These foods may help to feed an overgrowth of bad bacteria. It is preferable to eat organic foods free of pesticides and herbicides. It is also better to eat pasture raised meat, and vegetables, especially sourced from a regenerative farm that grows food in an environment that contains few bad organisms.
My interest in the importance of the healthy microbiome is relatively recent. Very few physicians learned about its importance in medical school. A great deal of research is currently ongoing as to the direct benefits of creating a healthier microbiome to treat a variety of diseases. It is clear that a healthier diet and lifestyle will pay dividends. There is also ongoing research in quantifying an individuals specific gut microbes and seeing if introducing specific probiotics are effective. The NIH in the U.S. has funded a Human Microbiome Project. For now, functional medicine specialists can advise on the use of specific probiotics which can have benefits and side effects. The ideas make sense even if hard science to date is somewhat lacking.
Some repair efforts are taking place in the form of fecal transplants used to repopulate good gut organisms when C. Difficile superinfection occurs after prolonged antibiotic use.
In conclusion, “we are what we eat”. Our microbiome plays a vital role in our health. We all need to pay more attention to strengthening it with a healthier lifestyle. I look forward to following the exciting developing science that may lead to novel pathways for disease therapy. Who knew that what “bugs us” could be so good for us?
Harry Rakowski
