By Dr. Meredith Aistrup, N.D.

The gut microbiome is defined at all the organisms living in your digestive system from bacteria, viruses, and fungus. There are trillions of bacteria living in your gut and their life span is about 20 minutes, so over a course of 24 hours they will overturn 72 lifespans! Their short life means that your gut microbiome is constantly in flux from different meals, supplements, stress, antibiotics, or the innumerable other factors that affect your bacteria. Your microbiota genes outnumber human gene by 100:1, so they are a massive part of you. Your bacteria perform various tasks in return for the beautiful home you provide them. Your healthy gut bacteria produce vitamins such as Vitamin K and B12, produce neurotransmitters, regulate your immune system, decrease inflammation, help your system burn fat, produce food for your intestinal cells, and support a good mood. These microscopic organisms do so much for us, their health is inextricably intertwined with our health.

Functions of a healthy gut Microbiome:

  • Produces neurotransmitters for good mood like Serotonin & GABA
  • Produce vitamins like Vitamin K and B12
  • Supports a healthy immune system
  • Protects you against pathogens and toxins
  • Burns fat and regulates your metabolism
  • Produces Butyrate; food for our intestinal cells

The old paradigm was that all bacteria were pathogenic or ‘bad,’ something to eliminate and rid us from. We unleashed a war on bacteria with our excessive-hygienic hand-sanitized world. Sanitization is a wonderful thing and does decrease disease, but the ideology behind it that all bacteria are bad is just plain wrong. The few pathogenic bacteria have given the whole species a bad reputation. We need bacteria for our survival; in studies where mice were born and raised in a germ-free environment, the mice suffered cognitive defects, lacked a functioning immune system, and had poorly developed organs. Babies that are born via C-section, rather than vaginally where they pick up the mother’s bacteria flora, have higher rates of allergies, asthma, and skin infections from decreased immune regulation from the microbes. We cannot live life all alone, we need our bacteria.

The Gastrointestinal (GI) tract can operate completely independent of our brain, it contains the enteric nervous system which boasts more than 100 million neurons, this is often referred to as the second brain. The GI tract communicates with our brain and the brain to the GI tract through the vagus nerve. This plays a fascinating role in our mental health. A dysbiotic gut contains a less diverse microbiota, meaning it is dominated by just a few species, this can wreak havoc on our system. The out of balance microbiota increases inflammation and endotoxins. This can progress to leaky gut* which creates chronic systemic inflammation leading to depression and anxiety. Researchers have shown that you can induce depression with just a tiny amount of pathogen cell wall. Research has also shown that mice given a fecal transplant from an anxious person, become anxious. Our gut bacteria also control our cravings, if we have a dysbiotic gut, the bad bacteria that predominantly feed on sugar will send signals to our brain to crave sugar for their own survival! Bacteria mind-control. This also works the other way, when we have a healthy microbiota we crave healthier foods. All very interesting, but it’s not just a 1-way street, our mental wellbeing (stress, anxiety, joy) is transmitted through the vagus nerve to our gut to create health or dysbiosis. This is why techniques that tone the vagus nerve* or calm the nervous system* help to heal our gut. 

What are the symptoms of an imbalanced microbiome?

  • Sugar cravings
  • Anxiety and Depression
  • Fatigue and brain fog
  • Weight gain
  • Gas, bloating, and abdominal pain
  • Diarrhea and constipation
  • Chronic inflammation
  • Acne and rashes

Our diet plays a huge role in the health of our microbiome. Our healthy gut bacteria feed on fiber, the part of our food that doesn’t get broken down. Our western diet of meat and processed foods has drastically reduced the typical Americans fiber intake. Staple foods like white bread and fruit juice are processed to be devoid of fiber. We are on the verge of an extinction of some of our healthy gut bacteria due to the extent of our poor diet. The bad bacteria feed on sugar and simple carbohydrates like white bread, pasta, and pastries, so we want to limit this in our diet as much as possible. I have listed below the top three diet changes you can implement to improve the health of your gut microbiome.

  • Limit added sugar to <25g a day (this does not include whole foods like fruit) the unhealthy microbes feed on sugar and can cause you to crave more of it. Switch out table sugar for honey, agave, or maple syrup.
  • Increase your fiber intake: fiber is food for our gut bacteria. Aim for 25g a day. Tips: Eat whole grains (quinoa, brown rice, whole grain bread), increase vegetable intake, increase beans and legumes in the diet, and eat whole fruit rather than drinking fruit juice. The Microbiome superfoods are asparagus, garlic, artichoke, jicama, and onion. These contain inulin and arabinogalactans, specific types of fiber that our healthy gut bacteria love.  
  • Increase your Omega-3 fatty acids in the diet. This improves the diversity of your microbiota (more diversity = healthier microbiota). Eat more olive oil, nuts, seeds, olives, fish (salmon, trout, tuna, sardines, cod).