Improving the Gut Microbiome for Optimal Health 


This weeks “Ask the Nutrition Consultant” question comes from Katie!

Q: My question is a bit of a follow up to the “what is the best diet” question from a few weeks ago. A few years ago, I read The Gut Balance Revolution by Gerard Mullin. He goes into detail about the gut microbiome and how we need to reset it and then maintain it (the plan has 3 phases). After reading it, I gave it a lot of credence, but I haven’t heard much about the importance of the gut microbiome since. Was this just another diet-fad? 

A: Great question, Katie! While I have not read Gerard Mullin’s book, I can tell you that the gut microbiome is incredibly important to our overall health. 

The human body is home to trillions of microorganisms, many of which are found in the colon or large intestine. Most people think all bacteria are bad, but there are good bacterial strains that live in our colon (aka the large intestine) and perform functions that help keep us healthy. Problems arise when we have an imbalance called dysbiosis, which occurs when bad bacteria takes over. The symptoms of gas, bloating and alternating episodes of constipation and diarrhea are often times caused by an imbalance in our gut microbiome (more of the bad guys). 

Good bacteria help manufacture important B (B1, B2, B5, B12, folate, biotin) and K (K1 & K2) vitamins, metabolize phytochemical’s into antioxidants and anti-inflammatory compounds, support GI tract immunity, influence our moods (~90% of the neurotransmitter serotonin is made in the gut!), and regulate our appetite and cravings.

These good bacteria ferment undigested plant fiber into short chain fatty acids. These fatty acids are the preferred fuel source of our intestines and keep our food moving along through the GI tract. They also help prevent inflammation and cancer, and enhance the gut barrier function. The gut barrier is responsible for letting good nutrients in and keeping pathogens out. 

There are some food and lifestyle factors that can decrease our good bacteria and even help the bad bacteria take over. The consumption of processed foods, refined grains and added sugars, as well as the use of birth control pills, antibiotics and steroids can lead to dysbiosis.

There are plenty of foods we can eat to promote and support good gut bacteria. Eating plenty of high fiber foods like broccoli, asparagus, bananas, garlic, leeks, onions, celery and whole wheat can help feed our healthy gut bacteria and help prevent constipation. 

Consuming fermented foods, which are good sources of probiotics or good bacteria, help keep your good bacteria levels up so that the bad bacteria don’t have room to take over. Adding foods like sauerkraut, kimchi, yogurt, kefir, and raw milk cheese into your meals a few times a week can be very helpful. 


Blaser, M.J. (2014). Missing microbes. New York, NY: Henry Holt and Company

Sandrini, S., Aldriwesh, M., Alruways, M. & Freestone, P. (2015, May 1). Microbial endocrinology: Host–bacteria communication within the gut microbiome [Full text]. J Endocrinol, 225(2): R21-R34. doi:10.1530/JOE-14-0615

Swanson, H.I. (2015). Drug metabolism by the host and gut microbiota: A partnership or rivalry? [Full text]. Drug Metabolism and Disposition, 43(10):1499–1504.

Thursby, E., & Juge, N. (2017). Introduction to the human gut microbiota [Full text]. Biochemical Journal, 474(11), 1823–36.

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