I have been interested in our microbiome for a long time. It fascinates me that we have microorganisms living inside of us that we would soon die without. My interest is somewhat motivated by frequent upset stomach and a desire to learn more about it. Last year I took a microbiome test (from Ubiome) to determine what exactly was living inside my gut and how I rank compared to what is "healthy". My results were dismal. I scored in the lower 20% when it comes to biodiversity and I am lacking some specific organisms that are needed for a healthy digestive system. I have since been on a journey researching ways to foster a healthy microbiome. What I have discovered is that as an American, it is incredibly hard to ingest living organisms. In fact, we are actively aiming to do just the opposite.
My research into my diet started with the foods most associated with gut bacteria, fruits and veggies. The Ubiome website suggested that I start to take stock in how much fruits and vegetables I am eating and what sources they come from. It was suggested that I try to opt for unfrozen fruits or vegetables and eat varieties that are as fresh as possible. I get almost all of my fruit in the form of smoothies that I make at home, and a few seasonal varieties. I also get about 50% of my vegetables from frozen bagged veggies and 50% from leafy fresh greens. I track what food I eat with app about 3-4 times a week to make sure that I am eating a balanced diet. When it comes to diversity of foods, I fail that metric miserably. Aside from variety of foods, I set out to figure out ways to increase your gut bacteria diversity and possibly save my digestive system.
Your gut microbiome develops between ages 0-2.5 and is determined by mode of birth, diet, sanitation, and exposure to antibiotics. After age 2.5 your gut microbiome changes only marginally. The paper continues to describe that diet throughout your life will help create an environment to foster growth of beneficial bacteria. However, there is no mention of diet being a source of additional bacteria after age 2.5 when your microbiome is already established. In fact there is a lot of debate as to whether or not ingesting gut bacteria in the form of probiotics or probiotic foods has any affect at all. Unless you are on long term antibiotics or immunocompromised the jury is still out on probiotics. The largest changes you can make to your microbiome are by altering your diet to include foods that create a favorable environment in your gut. (For a full list see the source section.)
Since the environment of an infant plays such and important role in their gut microbiome, what bacteria we are exposed to as a baby is critical. One of the biggest sources of bacteria to a child's diet is in food preparation. We are told by advertisements to sanitize our kitchen with antibacterial soaps, lysol, or bleach. More than 70% of American households have a dishwasher, which has shown to be more sanitizing than hand washing dishes. This is in stark contrast to kitchens all over the world, especially in developing countries. This internet research led me to the "hygiene hypothesis" which states that children in developing countries are growing up way too clean. This cleanliness could be leading to an increase in allergies as the immune system is not able to correctly determine friend from foe.
This year in the U.S., there was an E.coli outbreak on Romaine lettuce. The outbreak was traced back to Yuma Arizona, and entered the lettuce from the water in a nearby canal. All across the United States 210 people total were infected with the bacteria and 5 people died. This is the worst case scenario that we face when it comes to living bacteria in our food. The hygiene hypothesis has a lot of scientific research backing it, and is gaining momentum. However, when it comes to bacteria, we need to be able to find a happy balance between keeping enough of the good and avoiding the bad. Our gut depends on it.
Sources for this post
Quigley, Eamonn M.M., Gut Bacteria in Health and Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3983973/
List of beneficial foods: https://www.hsph.harvard.edu/nutritionsource/microbiome/
Yatsunenko, Tanya, Human gut microbiome viewed across age and geography :
The Hygiene Hypothesis: https://www.npr.org/sections/health-shots/2015/02/23/387553285/kids-allergies-and-a-possible-downside-to-squeaky-clean-dishes