Technical Tuesday Interview: Microbiome
In this issue of Technical Tuesday we speak with our nutritionist Bill Wiadrowski to understand why there is so much talk these days about gut health and the gut microbiome.
LifeWise: Good morning Bill. Why are we spending so much time these days talking about the gut microbiome?
Bill: In nutrition we’ve always known that gut flora existed but until relatively recent times the full extent of the composition of that flora was unknown. With the development of gene sequencing technology, researchers have discovered the range of organisms that inhabit the gut, and this has given rise to our understanding of what we now call the gut microbiome.
LifeWise: When you say, “relatively recent times”, when did all this research start?
Bill: The existence of the microbes that make up the gut microbiome were never fully known simply because most of these organisms can’t be cultivated in a petri dish. So, these discoveries have only been made since gene sequencing technology was first developed in the mid 1970’s, but initially it was a slow and expensive process. It has only been in the early part of the 21st century that science has been able to develop high speed, low cost analysis techniques that have allowed nutritionists the ability to understand the actual composition of the gut and consequently the role of the individual species involved.
LifeWise: Does that mean we now have a full understanding of the role the gut microbiome plays in digestion and health?
Bill: No way! This is such a complex field of research and such a monumental leap in understanding, that I doubt we will ever fully understand all the processes and influences in play.
LifeWise: But surely if we know the contents of the microbiome, we can go forward from there?
Bill: Unfortunately, there is a lot more to the story. Firstly, the gut microbiome, which is the largest biome, is just one of many biomes that inhabit the body of any highly developed organisms such as our dogs or ourselves. Secondly, the gut microbiome is not a stable thing with a set structure. It is far better to think of the microbiome as an ecosystem in much the same way as we would think of a rain forest ecosystem or the Great Barrier Reef ecosystem. As with all ecosystems, the gut microbiome changes according to the factors that influence its composition, and the term “plasticity” is used to describe the microbiome’s ability to change its composition.
LifeWise: OK, so the microbiome changes, but is this plasticity you describe a measurable and therefore a predictable event?
Bill: Yes and no. As I said before we should think of the microbiome as an ecosystem, and as with any ecosystem you can have short term change as well as long term structural changes. For example, if we change our dog’s diet we sometimes see an upset stomach for a day or two, and the recovery from the upset is simply the microbial population in the gut evolving to adapt to the new food. At the other end of the scale, a poorly designed diet can cause, over time, a major shift in the diversity and population concentration of the microbiome in much the same way as the warming of the ocean is making long term structural changes to the Great Barrier Reef.
LifeWise: OK, we get that, but where does the microbiome come from in the first place?
Bill: The gut microbiome is just one of the biomes in the body. Practically every part of the body is inhabited by microbial life and all higher order animals actually live within a microbial cloud. There is as skin microbiome, an ear microbiome, a nose microbiome and even a lung microbiome. But the relevant aspect of all this is we inherit much of our microbiome from our parents. It was recently discovered there is actually a microbial population present in the womb of a pregnant animal, so the origins go right back to the development of the unborn pup. In the lead up to birth, the vaginal microbiome changes in readiness for the pup’s transition, and as the newborn travels down the birth canal it starts accumulating the microbial load required for healthy living. On arrival to the outside world, the pup continues to pick up more species as it licks and snorts its way in search of a teat, and the subsequent microbial load strongly represents its mother’s microbial population. In other words, either voluntarily or involuntarily, the newborn inherits the mother’s microbiome.
LifeWise: Well this is a good thing isn’t it?
Bill: This is natures way of ensuring the continuity of life, but it can be a double-edged sword. If the mother’s microbiome is compromised, then so will be the pup’s, and we often see puppies with sensitivity issues early in life simply because they have not received their inoculation of the desired microbial population from the mother. It is not unusual to see specific health problems passed down through family lines simply because this chain of inheritance was not broken. The other aspect that plays into this is human interference during the birth process. Assisting in the birth by cleaning up the pups as they appear and placing them on a teat interrupts that inoculation process and can be the forerunner to digestive issues in the short term.
LifeWise: Does that mean the process is completed at birth, or is there more to the story?
Bill: This initial inoculation of the newborn is only the start. The puppy’s microbiome is quite immature and further develops. Breast milk contains indigestible proteins that are present solely to feed specific organisms that are important members of a healthy gut, and the transition to solid food further nurtures the diversity required for a healthy life.
LifeWise: This is now starting to sound a little far-fetched! Are you really suggesting the microbiome is that important for normal healthy life?
Bill: Absolutely. High order animals cannot exist without the presence of these organisms. From a digestion point of view, the bugs not only assist in the digestion of the food and the absorption of nutrients, they also create essential nutrients required by the body, as well as undertaking house-keeping duties in the gut. It must be remembered the microbes were here first; high order animals evolved around, and because of, the existence of this microbial population.
LifeWise: Well if it this important, are we spending enough on research to fully understand the implications of a healthy gut?
Bill: This journey in the accumulation of knowledge is an ongoing process. The medical researchers look at what the veterinary researchers have discovered, and the veterinary researchers look at what the medical researchers have discovered. It’s worth remembering the process remains largely the same across animal species, so there is a lot of information exchange going on. It is now understood the composition of the gut microbiome has far reaching effects and that many metabolic and mental disorders can be traced back to the gut microbial balance. Both Alzheimer’s and Parkinson’s disease are linked to specific changes in the microbial population in the gut which results in certain compounds being deposited in the brain via the enteric system, whilst changes to the species diversity in the gut has been shown to alter the short chain fatty acid profile in humans which acts as a preventative to the onset of heart disease. And this is just a simple example of the extent of current research.
LifeWise: Well that certainly changes the relevance of the discussion, but what are the important aspects of a healthy microbiome in our dogs?
Bill: Without doubt the largest influence in our dog’s life centres on food sensitivity issues. Commonly called “allergies”; allergies are actually genetic based disorders; food sensitivities are the single largest issue facing the dog owning population today. Upwards of 85% of all sensitivity issues are the result of inadequate diet design. We not only see this as sensitive stomach problems such as Irritable Bowel Disorder and the like, but as skin and coat problems including Stinky Coat Disorder and skin inflammation and itching issues, sometimes referred to as seasonal allergies, that affect so many of our canine companions.
LifeWise: How is the gut microbiome relevant to these conditions?
Bill: A healthy gut microbiome is home to a thousand or so species of bacteria, viruses and fungi. When the food the dog eats doesn’t support the broad population in the gut, some gut species grow stronger whilst some gut species are starved. Ultimately, the strong crowd out the weak and the microbial diversity in the gut reduces. If this diversity reduces to a critical point it triggers an unnatural response in the immune system because the immune system incorrectly diagnoses this reduction as an invasion by pathogens. Accordingly, the immune system creates inflammation to overwhelm the “invaders” and this inflammation acts to further reduces microbial diversity in the gut. This is why we see dogs that have had a normal life for the first few years suddenly develop a mild contact allergy. If the situation is not addressed correctly at this point we commonly see a gradual decline that sees the dog becoming progressively more and more sensitive until they are either scratching themselves stupid and chewing their feet off, or having continuous diarrhoea and displaying leaky gut syndrome.
LifeWise: That’s a rather gloomy picture you have painted, so what is the solution to the problem, and can these conditions be reversed?
Bill: In the vast majority of cases they can be reversed, but the process can be quite a lengthy one depending on the severity of the loss in gut microbial diversity. It usually takes quite a length of time to lose the diversity in the first place thanks to nature’s inherent resilience, but equally it can take just as long to restore that diversity.
LifeWise: How long is “long”?
Bill: With some of the really challenged animals we have worked with it has taken up to 18 months to fully restore the gut microbial diversity to a healthy level. On the other hand, we have seen dogs with Stinky Coat develop soft healthy coats within a couple of weeks. It really depends on how far below the trigger point the gut microbial diversity has descended.
LifeWise: So how do we fix the problem?
Bill: As you can imagine, the microbial population is fed by the food the dog eats, so it’s all about the ingredients in the food. Firstly, the ingredients must be complementary to the animal, which means the ingredients must collectively support the desired gut microbial population, and secondly each ingredient needs to be present in the food in the correct proportion to feed the relevant organisms that require that particular food source.
LifeWise: But aren’t many pet foods on the market made from the same basic ingredients?
Bill: Absolutely. But think of it in terms of having a feed of fish and chips. If we order a piece of fish and $10 of chips, we end up with a meal of some protein, a fair bit of carbohydrate and a lot of fat, but if we were to order 5 pieces of fish and the minimum chips our meal would now be high in protein and low in carbs. Same ingredients, different mix, and this is how pet foods commonly differ, but more importantly, why they don’t necessarily support good gut microbial diversity.
LifeWise: Are there any other ways we can build up the microbial diversity?
Bill: Most definitely. For these challenged animals we use a lot of probiotics to help start the recolonisation process, and try to limit as much as possible chemical interference and pollution. Stress is another negative impact on the gut, so we seek to set management practices that help in that area as well. This natural approach of food and probiotics works well in conjunction with veterinary intervention, and we often implement this type of program to follow on from treatments such as cortisone, Apoquel or Cytopoint treatments. Any treatment that provides the animal with stress relief helps enormously in this remediation process.
LifeWise: Unfortunately, that’s all we have time for today and I know we could have kept talking for just as long again! Thanks Bill for your valuable insights; it’s been most enlightening and I’m sure we will talk again soon as there is undoubtably a lot more in the detail of this fascinating topic.
Well we hope you enjoyed this edition of Technical Tuesday. If you have any questions relating to this audio presentation, please send them through to [email protected], and in the meantime keep an ear out for our next discussion on aspects of pet related nutrition.