Wednesday, February 22, 2017

Pandas, Celiac and Fecal Transplants!

In my last blog post I put forward the Discordance Theory of disease (specifically modern degenerative diseases such as type 2 diabetes, neurodegeneration and cardiovascular disease) and introduced a rough timeline of change that humans have faced over the past 10,000 years. These changes are wide reaching and affect every element of the Four Pillars of health (Sleep/photoperiod, food, movement, community). It’s fascinating to me that many people find the Discordance Theory and associated concept of Ancestral Health to be incredibly informative and helpful for everything from orienting research to making clinical decisions, while other people dismiss both concepts out of hand and find no value in anything other than reductionist, symptom-based medicine. I’m of the opinion that we will not untangle chronic degenerative disease without some nod towards the Ancestral Health template. I might be wrong about that, perhaps there is a magic bullet waiting that can “fix” poor sleep+bad food+inactivity+inadequate social interactions….but I both think that is unlikely AND I’m not waiting around for that fairy tale to come to reality.

I’ve thought about this Discordance subject a lot and I have to admit: it’s a more nuanced topic than what I’d first thought or suggested. In the early days of the Paleo Diet movement, anything that was considered “non-paleo” was held as suspect. Salt, coffee, tea (to name a few items) have all been dismissed as “non-paleo” by the few folks who have turned paleo into a religion. Unfortunately these same folks seem to have missed all the research indicating reasonable amounts of the aforementioned substances are likely beneficial. So, we seem to have a few different competing concepts here:

1-The Discordance theory suggests that too rapid a change may produce deleterious health effects.

2-Some people interpret the above as meaning ANYTHING that is “evolutionarily novel” is inherently bad, somehow ignoring “the rest of science” (coffee for example).  

3-Some of the people who dislike the Ancestral Health concept rightfully point out that some not insignificant genetic change has happened to humans since the paleolithic.

4-Despite point #3, we still see far more degenerative disease than what I think anyone would like. And as I mentioned in the previous post, those metabolic changes are of sufficient severity that the associated diseases (type 2 diabetes, CVD, neurodegeneration, certain cancers)  are poised to cripple our economy and overwhelm our medical systems.

The trite advice of “eat less move more” and “everything in moderation” (the singular message we seem to receive from the medical world, particularly mainstream dietitians) is, let’s face it, an epic failure. My wild suggestion, dripping in nefarious ulterior motives, is that we really do need to think about modern, degenerative disease from the perspective of the Discordance Model, but we can’t turn the implications of that theory into religious doctrine like the Orthodox Paleoites have done. We need a governing theory to direct our inquiry, but this must be coupled with good clinical outcome based medicine and the studies these clinical outcomes inevitably generate.

So, we are about 500 words into this mess and you may be wondering “Hey Robb, this is all nice, but the title of the article is about pandas and poo…what gives?” This build-up is likely attributable to equal parts senility and a borderline obsessive need to provide Framework and ContextI want to look at a critter we are all likely a bit familiar with, the Giant Panda, as this cute, iconic Ursid is actually an interesting example case study of the Discordance Theory but with some interesting subtleties. Giant Pandas evolved from ancestors which were, like most bears, omnivores. For as yet unknown reasons panda ancestors likely started eating some amount of bamboo as part of their mixed diet, eventually shifting to a diet almost completely composed of bamboo. Estimates of this transition range from 2-5 million years ago, which is a decent period when considering evolutionary change. What this would suggest is pandas should be quite well adapted to their new dietary approach and in some ways they are. Pandas have evolved a kind of false thumb (derived from a wrist bone of all things) which helps pandas to grasp and pull down bamboo.

But recent research looked at panda digestion and the findings were fairly surprising as they suggest that pandas are not that well adapted to their current diet of bamboo. Whether in the wild or captivity, pandas display a remarkable amount of GI problems. They are almost the IBS poster animal given how many problems they have. The GI physiology of the panda is quite close to that of a carnivore, with none of the specialized GI structure we see in animals that digest cellulose (fibrous plant material). Some cellulosic fermentors use multiple stomachs, some use a larger cecum to provide more time to ferment this plant material, coupled with more surface area to absorb the short chain fatty acids produced by cellulose fermentation. Most of these animals have a symbiotic relationship with certain strains of bacteria which possess the enzymes to degrade cellulose, yet pandas are interesting in that they seem to still, after 2 million years of mainly consuming bamboo, possess a gut microbiome that looks virtually identical to that of a carnivore. The panda is a potentially confusing critter! As interesting as all this might (or might not) be, what does it mean for you?

1-Despite 2 million years of evolution on it’s current diet, the giant panda still has serious digestive problems. Problems which are sufficiently severe as to limit panda reproductive success.

2-Even though the gut microbiome of pandas looks a lot like that of a carnivore, there MUST be something more to this story. Although the efficiency of converting bamboo cellulose to energy appears to be rather low (compared to the efficiency of say a cow converting grass to usable energy) clearly the panda is getting SOMETHING out of the bamboo. It may be that they are relying more on the protein and fat content of bamboo to make their living. It’s also possible that although the microbes they harbor are not typically associated with cellulose fermenters, that does not mean these bugs have not acquired the genes to do so. Bacteria are remarkably promiscuous little bugars and they appear to be able to swap genes at a rate that until only a few years ago was thought to be impossible.

3-Given point #1, if we see a chronic disease (in humans, pandas or sand flies) it might be helpful to start asking questions using the Discordance Theory as a means of orienting our thinking. This is not the end of that investigative process but may prove to be a critical beginning. 

4-Given point #2, we need to be cautious in how we interpret and promulgate the Discordance Theory. Of particular note I think we need to be very careful in how we treat the topic of the human microbiome. Despite a relatively short period for evolution to occur on the human genome (10,00 years since “the paleolithic”), there is a remarkable amount of time available (in bacterial terms) for a symbiotic organism to develop or obtain the genes necessary to help it’s host organism (that’d be us). We are in the absolute infancy of understanding this story, so I think we need equal parts caution and optimism in how we approach this material. In my next blog post I’ll look at some human symbiotic bacteria which have proven to be remarkably helpful for a very pesky condition.

I am one of the folks that really went whole-hog into the Discordance Theory and unfortunately did not see the details and caveats to make that model work better. Time and pain have been good instructors and have hopefully moved me a bit down the Dunning Kruger graph.  In my second book Wired to Eat (available for pre-order everywhere books are sold, release date March 21) I do my best to talk about these subtleties and to provide a path for you to find your own truth with regards to health. I lean heavily on the Discordance model as so far it has provided what appears to be an unfair advantage in unraveling complex degenerative disease. I do however try to temper that message with an honest appraisal of what we do and do not know, what we can only discover via self experimentation.

ALSO!! If you pre-order Wired To Eat I have several fantastic bonuses here.


from The Paleo Diet

No comments:

Post a Comment