Your Microbiome, Dysbiosis and Probiotics

Your Microbiome, Dysbiosis and Probiotics

You have probably heard that the microbes that live in our gut can affect our health.  The microbiotia, or microflora in our gut, consisting of bacteria, yeast, fungi and archea (let’s call them collectively, the “bugs”), can be thought of as another organ in the body as it does so much for us. There are about 10 times more microbes in the gut then there are human cells in the body.  We are more “them” in terms of DNA than “us”!  In total, they weigh about 1 to 2kg, about as much as our liver.  And these bugs are responsible for more biochemical reactions than what happens in the liver.  

The microbes in our gut do some amazing jobs for our overall health. Some of the ways they work for us include helping our immune system; helping our intestines to move at the right pace; improving digestion and absorption of energy and nutrients; producing some vitamins, like vitamin K and some B vitamins; and preventing gut infection. They also produce very important short chain fatty acids which improve the function of our intestinal wall, help protect against colon cancer, improve circulation to the colon and liver and even decrease inflammation to the gut and the whole body.  The biochemical processes our microbes are involved in are important for our mood, weight and blood sugar regulation.

We often hear about “good” bugs (like lactobacilli) and “bad” bugs (like the evil candida).  We all have a variety of both “good” and “bad” bugs living in our gut.  When the “good” bugs dwindle in numbers and the “bad” bug populations increase, we have problems. A lack of variety in gut bugs is another cause of problems.  The imbalance of microbial species, or the lack of variety, is called dysbiosis.

Dysbiosis is seen in people who have autoimmune issues, IBS, chronic fatigue syndrome, eczema, allergies, obesity, acne, depression, type 2 diabetes, heart disease and many, many conditions. Can you see now how important it is to keep these microbes in good balance?  

So what causes microbe imbalance or lack of variety?  Quite a few common things in our society, including:

  • Antibiotics.  The most disruptive force to our microbial balance.  It’s not surprising that these drugs that are designed to kill bacteria can kill off off the number of, and the variety of our gut bugs.  Some gut bug populations are killed off completely and will never recover.  New research shows that it can take years for the remaining microbes to recover from the significant changes (4 years after triple antibiotic therapy).
  • Other drugs.  Proton pump inhibitors, non-steroidal antiinflammatory drugs, the pill and chemotherapy drugs.
  • A typical western diet!  More on this, and how to change your diet to support your gut microbiome, in my next blog post.
  • Babies born by Caesarian section have less bacterial diversity and lower numbers of some of the “good” microbe types.   
  • Babies who are formula-fed have a very different microbiome from breast fed babies.  Breast milk delivers probiotics from mum’s gut as well as the appropriate prebiotics to support a healthy microbiome.
  • Stress. There is two-way communication here.  Dysbiosis can increase the responsiveness of the stress system, and prolonged stress can cause unfavorable shifts in microbial composition and diversity.
  • Radiotherapy. Radiation-induced dysbiosis is a likely contributor to some of the side effects of treatment.


Probiotics and Fermented Foods to ‘Fix’ Dysbiosis – some mythbusting

Probiotics are live microorganisms that we take to for health benefits.  They can be taken in supplement form to prevent some of the damage to the microbiota while taking antibiotics and other microbe altering drugs.  They have many wonderful actions in reducing symptoms; such as constipation and abdominal pain, preventing problems; such traveler’s diarrhea, and even allergies in babies; they can help to activate immune cells, create beneficial substances for the gut, they can induce anti-inflammatory activity.  However, contrary to what you may have heard, they do all of this as travelers in passing.  You see, research trials have never shown probiotics to permanently colonize (or, decide to live in) the gut.  No probiotic strain has ever been shown to stay in the gut for longer than a few weeks.  Some strains of probiotics have been shown in research to help our own beneficial bacteria to grow (Bifidobacterium lactis HN019, Bifidobacterium lactis Bb12, Lactobacillus casei Shirota and Lactobacillus rhamnosus GG).  Other than that, taking probiotics does not fix dysbiosis in the long term.

Fermented foods, like sauerkraut, kimchi, kombucha, kefir and yoghurt contain probiotic organisms like lactobacilli and bifidobacteria species.  Similar to probiotic supplements, the probiotics from fermented foods aren’t able to stick around in the gut very long.  It’s a myth that you can inoculate your gut with the bugs from these goods.  Research shows that the probiotics they contain only stick around for a little while after they are eaten.

They are still very healthy foods!  Probiotic foods can help our gut health in other ways, such as increasing salivation and secretion of gastric acid and pancreatic enzymes.  They are also quite nutritive and the fermentation process can increase the concentrations of certain nutrients.  I believe they are great to include in the diet for gut and general health, despite their microbes not being able to stay and live in our gut.  

So what are you meant to do to fix dysbiosis?  Luckily, we can selectively feed the good guys in our gut and help them form strong and large colonies, while reducing the “baddies”.  Prebiotics, fibre, phytonutrients and other foods we eat help to nourish a healthy microbiome and create lasting changes.  


My next blog will tell you the need to know info on diet and gut bugs.