1st Clinical Trial Using Fecal Microbiota Transplant for Obesity

Well, there’s good news and there’s bad news.

First, a quick summary: the good news is that the first human trial was just conducted using fecal microbiome transplant (FMT) to treat obesity.  The bad news is that the treatment did not result in either weight loss or changes in the hormone, GLP1, which is involved in feelings of satiety (feeling full).[i]

There is more mixed news though so some more details for you:

22 obese, but otherwise healthy, adults took part.  For 12 weeks, half of them took a daily capsule of microbes from thin people, while the other half took a placebo.  On the good news front, the treatment proved safe.

Also more good news:  “The overall microbial makeup of the treatment group did become more similar to that of the lean donors, and a specific decrease in a type of bile acid was particularly noted.”  Remember – there is unlikely to be one cause of this epidemic, as I’ve been writing about.  The lead author of the study states, in fact, “The bile acid data is certainly intriguing and suggests that maybe there are one or more different pathways at play…Obesity is a very complex disorder, and a multifactorial process is probably at the heart of its development.”

The actual paper has not yet been published, as it’s preliminary results are just being presented at a conference.  I cannot, therefore, as yet comment on their methodology and so forth.  For example, what were the people eating during the study?   In fairness (and to be silly for a moment while making a valid point):  if the adults in the experiment group continued to eat 10,000 calories a day while sitting on the couch watching TV, I don’t care what kind of capsules they were taking.  I find it impossible to believe anyone could lose weight under those circumstances.

Still…this is a step forward.  I am always happy to be able to report to you actual human trials.  I do believe that someday  in the future, FMT (purified microbiota from healthy donors, given via oral capsules) will become a treatment norm.  In fact, I recently posted the news (on my Biome Buzz Facebook page) that the autism trials have been so successful that the FDA is fast-tracking the treatment for that population.

I will, of course, continue to keep an eye on all  this research!


[i] https://newatlas.com/fecal-transplant-obesity-human-trial/59617/

A Quick Update on the Mycobiome and Inflammatory Bowel Disease

A great article appeared last week on Gut Microbiota for Health,[i] on the overlooked mycobiome in digestive diseases.  I’ve written about this topic several times before and am always very happy to see new research focused on the topic.

The authors of the paper[ii] point out that while the gut bacteria greatly outnumber fungi, this in no way diminishes fungi’s effects on the host.  Cell size too, for example, must be taken into account – and many fungi cells are 100X bigger in volume than many bacteria.  They produce, therefore, much larger amounts of byproducts which, even in low concentrates, may have profound impact. And, like bacteria, fungi “talk” to the immune system both locally (in the gut) and remotely (in the body as a whole).

Factors that influence the make-up of the mycobiome include diet, because foods like cheese, vegetables, etc. have fungi in and on them. The host interacts with all the microbiota it houses: for example, things like bile acids and so forth, can alter the mycobiome make-up.  Finally, the other organisms of the gut influence the composition of the mycobiome.  In fact, the bacteria are not alone in their influence: archeae, viruses (bacteriophages), and so forth likely play a role in determining mycobiome composition, although very little research has been done on this to date.

Some research points to fungi having a role in metabolic syndrome as well as cancer but…we are nowhere near having enough information on this to determine true relevance yet, let alone, mechanisms of action.  Evidence is mounting for connections between fungi and other diseases ranging from autism to spondylitis to schizophrenia.  And it looks very likely that the mycobiome is involved in the development of inflammatory bowel diseases, as I’ve written about before:  “…a role of the mycobiota in disease, notably in IBD, is indicated by both descriptive data in humans and mechanistic data in mice.”  There are distinct differences between those with IBD and healthy controls, confirmed by two independent studies.

In a mouse model, fungi have been shown to aggravate the severity of inflammation in IBD.  This research supports the idea that the fungi work with the bacteria in such a way as to worsen IBD symptoms. In fact, another study in humans (which I described back in 2017)  showed that the fungi, C. tropicalis, and the bacteria E. coli and S. marcescens, work together to form a biofilm (kind of a slimy mass that protects the organisms inside – think about the plaque on your teeth) that evokes an inflammatory immune response.[iii]

A 2018 study was conducted in Saudi Arabia on 15 children with Crohn’s disease.[iv] Their mycobiomes were compared to 20 healthy controls to see if they could accurately predict which children were sick or healthy.  They found that Saccharomyces cerevisiae and S. bayanus were at significantly higher levels in the children with IBD, while overall diversity of the mycobiome was lower…and indeed, they absolutely could use these levels to correctly predict if the sample came from a child with IBD or a healthy child.

I sincerely hope I have more frequent opportunities to write about research into our commensal organisms other than our bacteria.  Each element of our internal ecosystems probably plays an equally important role in determining our health status.  The bacteria though are best known and most numerous, so they get all the press (and money).  I have high hopes though that this is all going to change in the very near future.


[i] https://www.gutmicrobiotaforhealth.com/en/the-gut-mycobiome-overlooked-in-digestive-diseases/

[ii] Richard,  ML and Sokol, H. The gut mycobiota: insights into analysis, environmental interactions and role in gastrointestinal diseases.  Nature Reviews. 2019.

[iii] https://www.gutmicrobiotaforhealth.com/en/new-review-explores-targeting-gut-bacteria-fungi-interactions-may-help-manage-chronic-intestinal-inflammation/

[iv] El Mouzan, M, et. al. Fungal dysbiosis predicts the diagnosis of pediatric Crohn’s disease.  World Journal of Gastroenterology. 2018:24(39):4510-4516.  doi: 10.3748/wjg.v24.i39.4510.

And Yet Another Food Additive Becomes Suspect

Just a couple of weeks ago, I wrote about ways in which modern food processing may be related to our growing epidemic of obesity (or globesity, as those authors called it).  In that post, I mentioned that many food additives are potentially thought to  be contributing to the problem, in that they may adversely affect the microbiome, and thus, the way we digest food.

Well, just yesterday, I spotted an article out of the University of Sydney, in Australia, wherein researchers looked at the effects of the additive titanium dioxide on human health.[i] It is apparently used as a whitening agent in high quantities in more than 900 food products (like chewing gum and mayonnaise), and in many medicines as well.  While it is an approved additive, relatively little safety testing has actually been done.


These researchers found, in a mouse study, that titanium dioxide adversely affects the activity of the bacterial microbiome (i.e. it altered the production of their normal metabolites) and also stimulates gut inflammation, potentially triggering inflammatory bowel diseases and colorectal cancer.  It seems to promote the formation of biofilms – those slimy masses of bacteria that protect the organisms inside:  ““This study investigated effects of titanium dioxide on gut health in mice and found that titanium dioxide did not change the composition of gut microbiota, but instead it affected bacteria activity and promoted their growth in a form of undesired biofilm. Biofilms are bacteria that stick together and the formation of biofilm has been reported in diseases such as colorectal cancer…”

The article states: “The interaction between gut microbiota and host plays a central role in health. Dysbiosis, detrimental changes in gut microbiota, and inflammation have been reported in non-communicable diseases. While diet has a profound impact on gut microbiota composition and function, the role of food additives such as titanium dioxide (TiO2), prevalent in processed food, is less established….[Our] findings collectively show that TiO2 is not inert, but rather impairs gut homeostasis which may in turn prime the host for disease development.”[ii]

Says the co-lead author, Dr. Laurence Macia:  ““Our research showed that titanium dioxide interacts with bacteria in the gut and impairs some of their functions which may result in the development of diseases. We are saying that its consumption should be better regulated by food authorities.”

So…I did a quick search of my kitchen.  I buy organic and found no titanium dioxide (so far) in my foods.  But, I then did an internet search of my medicines and supplements, and low and behold, there it was.

Titanium dioxide is in so many things, in fact, that I don’t know if there’s any way to avoid all of it.  It’s everywhere!


[i] https://sydney.edu.au/news-opinion/news/2019/05/13/common-food-additive-found-to-effect-gut-microbiota.html

[ii] Pinget, GV, et. al. Impact of the food additive titanium dioxide (E171) on gut microbiota-host interaction.  Frontiers in Nutrition. 2019.  doi: 10.3389/fnut.2019.00057

And Yet MORE Evidence of the Efficacy of the Specific Carbohydrate Diet in Inflammatory Bowel Diseases

I continue to make my way through the stacks of articles I’ve collected these last few months and decided today to treat myself to a description of a paper from 2015 that used survey data to analyze the effects of the Specific Carbohydrate Diet (SCD) on those suffering from inflammatory bowel disease. Of course there are issues with using such data, and this is far from the gold-standard double-blind, placebo controlled cross-over studies that eventually prove scientific certainty (or…at least as much certainty as science ever gets). Still, it’s a valuable paper, especially as there is dearth of studies on using diet to treat disease (there’s simply no money, and thus no motive, to do them).  In spite of that fact that the few studies that have been done have been 100% successful,   SCD continues to get generally ignored by the medical community.

My regular readers know I have a very personal SCD story: the diet saved my son, Alex, from inflammatory bowel disease hell. It was my experience with SCD, in fact, that led me to change careers from teaching special education to becoming a nutritionist. I witnessed a miracle that changed me forever. You can read more about that here.

Thus, I am always thrilled to be able share any kind of published study on SCD.

50 patients filled out a survey and also included their medical records, a 3 day diet diary and validation from an American physician confirming their diagnosis of IBD (via endoscopy, radiology, and pathology reports by a board certified gastroenterologist). The survey included a wide variety of accepted measurements of disease severity, quality of life measurements and so forth. 36 of the patients had Crohn’s disease, 9 had ulcerative colitis, and 5 had other forms of IBD. A few interesting notes on the breakdown of the patients:

a. “The mean time the SCD was followed was 35.4 months.” I found that fascinating as I have always told my nutrition clients that the diet must be strictly followed for 3 years (minimum) to achieve full effect and not risk relapse.
b. “The patients followed SCD strictly with a mean adherence rating of 95.2%.” Good for them!  Compliance is crucial to success!
c. “Mean time to see some improvement when following SCD was 29.2 days. Thirty-three subjects (66%) noted complete symptom resolution, which did not occur until a mean of 9.9 months after starting the SCD.” I am truly astounded by the nearly exact match, in terms of time frame, with what I have seen in using the diet for the last 16 years with clients. I personally found that most patients begin to see improvement in symptom closer to 35-48 days but still…my anecdotal experience is not far off this paper’s findings. And almost everyone I have ever worked with, my own son included, got complete resolution of symptoms between 9 and 10 months on the diet. The consistency is truly incredible.

From the paper’s conclusion: “This is the first clinical description of a large series of patients with IBD following the SCD. Our survey results suggest that SCD can potentially be an effective tool in the management of some patients with IBD…”

Not to sound like the world’s biggest cynic, but if you are wondering then why SCD is not recommended as the medical norm as a part of a treatment plan for those suffering with IBD, you probably need look no further than this sentence: “Our results also suggest that in some patients with moderate to severe disease who follow this diet, discontinuation of immuno-suppressive agents has been feasible.”

The authors point out the strengths and weaknesses in their study, many of which are apparent. But they conclude:

“…we now show that at least a subgroup of patients with IBD may notably improve as a result of following the SCD and/or dietary interventions in general. Our findings enhance those of prior limited case reports of dietary therapy with SCD…Further evidence suggesting diet can be an effective treatment for some patients with IBD stems from the fact that diet has the potential to change the intestinal luminal environment, specifically the intestinal microbiome. Our prior preliminary findings hint at a change in the microbiome of patients with IBD who follow the SCD. If following the SCD changes the microbiome significantly and/or reverses some of the dysbiosis reported in patients with IBD, this may be a low-cost intervention to induce and maintain remission with little or no known adverse reactions. As such, further interventional studies of SCD and diet therapies in general for IBD are urgently needed.”

I’m not holding my breath.


Kakodkar, S, Farooqui, AJ, Mikolaitis, SL, Mutlu, EA. The Specific Carbohydrate Diet for inflammatory bowel disease: A cases series.  Journal of the academy of nutrition and dietetics. 2015. 115(8):1226-1232.  doi: 10.1016/j.jand.2015.04.016.

The Microbiome and Mental Illness: An Old Story that is Too Far From its Happy Ending

I just finished reading an article from 2018 on mental health and the microbiome that describes some of where we are now, knowledge-wise, and where we need to be before psychobiotics become a treatment norm.[i]  There were multiple pieces of information in it which were either new to me, or worth repeating.

The history lover in me very much enjoyed the first section which points out that while we are currently undergoing a medical revolution in terms of biome research, in actuality, the link between the gut and health was recognized as early as the 4th century, when a Chinese physician, Ge Hong,  treated severe diarrhea using  fecal microbiota transplant (except that he administered the concoction orally…which must have been special for the patient!).  In terms of recognizing the relationship of these bacteria to the brain, back in 1908, a paper was published which suggested that “…health could be enhanced and ‘senility’ delayed by manipulating the intestinal microbiome with host-friendly bacteria.”  Yes…unfortunately for all of us, science moves painfully slowly sometimes!  Here is a cheerful statistic though:  “Links between microbiota and pathophysiology triggered an explosion of interest in this field, with 85% of the over 10,000 PubMed publications on ‘intestinal microbiota’ arising in the last 5 years, currently averaging about 5 new publications per day.”  It’s no wonder that I am constantly feeling overwhelmed, bringing you the latest and greatest!  Sorry folks, but no…I do not have time to read and write about 35 papers every week!

Some highlights of current evidence pointing to the microbiome/mental illness connection:

  1. As my regular readers know, there is plenty of experimental evidence that the gut bacteria influence the brain and behavior.  15 years ago, one of the earliest studies in this modern era of biome research showed that “…germ-free mice lacking intestinal and other microbiota display maladaptive and exaggerated responses to stress that can be normalized by probiotic-induced intestinal recolonization.”  The article goes on to say that, “…germ-free mice show that gut microbiota are essential for development of neuronal circuits underlying motor control, anxiety behavior, and social responses.”  I actually remember when that first study came out.  It is research like this, of course, that provided the fodder for much of the work currently being done on autism and the microbiome.
  2. The article gives really interesting examples of the commutation pathways between the gut and brain.
    • For example, the probiotic Lactobacillus rhamnosus can send signals directly to the brain via the vagus nerve and in mouse studies, can decrease stress-induced anxiety and depression, and lower cortisol (stress hormone) levels. If the vagus nerve connection between the gut and brain is cut,  the probiotic has no effect.
    • The intestinal microbiota, as you know, produce much of our neurotransmitters. “Specific examples include generation of GABA by members of the Lactobacilli and Bifidobacteria families, dopamine and noradrenalin by members of the Bacillus family…” Also, remember that short-chain fatty acids have profound physiological effects, on both the gut and the brain.  While we know SCFAs can cross the blood-brain barrier (the tight cell membrane that protects the brain from the rest of the body), how much this actually happens is as yet unknown.  We do know though that SCFAs help maintain the integrity of this barrier which is unbelievably important in terms of keeping toxins, germs, etc. out of the brain.  Obviously, if this barrier becomes compromised, the effects on the brain (and thus behavior and mental health) can be profound.
    • You already know this, as I’ve written about it many, many times before, but would be remiss if I didn’t emphasize it once again: “Intestinal microbiota influence the generation, maturation, and function of numerous immune cells, which in turn, modify the balance and metabolic activity of intestinal microbes.”


In terms of our current knowledge of how to achieve and maintain the health of the biome (and thus, the brain), 4 key points that merit repeating:

  1.  To me, is one of the scariest phenomena we have yet discovered is how biome depletion is passed down from generation to generation: “…recent experimental data indicate that chronic consumption of high fat/low fiber diets across generations in mice progressively decreases intestinal microbiome diversity, and that this pattern becomes irreversible even when fiber is reintroduced.”  This paper is over a year old though and in the time between its publication and now, this has also been shown in humans, as I wrote about here.
  2. I have also (probably too frequently…I’m getting boring!) written about the crucial importance of diet in terms of what we are discovering about its relationship to the advent of disease: “…highly processed, lower quality foods that decrease microbial diversity and disrupt pathogen/commensal balance are linked to increased risk for mental disorders and clinical studies show significant inverse relationships between symptoms of mental illness and metrics of diet quality.”  As I wrote about just last week, way  more research is needed in this area, but as this paper states, “…a diet rick in diverse and seasonal plant-based products is in keeping with most general dietary guidelines and would likely foster a more diverse and resilient microbiome.”
  3. Probiotics: “B.longum reduces depression and increases quality of life in IBS patients…Other randomized trials confirm beneficial effects of probiotics on mood; and a recent placebo-controlled trial showed that L.casei reduces physiologic responses to stress while increasing intestinal microbial diversity.”  I’ve stated about a million times before that WAY more research is needed in this field, and many studies show contradictory results because of a lack of consistency in methodology, and so forth.  Still…we have made a start.
  4. There are some randomized human trials using prebiotics. For example, one shows that the prebiotic fiber galactooligosaccharide (GOS) decreases the stress response improved emotional affect in healthy volunteers.

In the conclusion, the authors point out that one of the many things we still don’t know all too often is what is cause and what is effect, “…when dysbiosis causes disease rather than accompanying it…”   So in spite of the fact that there are five papers per day on average being published, and the evidence connecting bacterial microbiome alterations to mental illness continues to mount, we know a minute fraction of what we need to know before biome manipulation becomes the medical norm.


[i] Bruce-Keller, A, Salbaum, JM, Berthoud, H-B. Harnessing gut microbes for mental health: getting from here to there.  Biological Psychiatry. 2018. 83(3):214-223.  doi:10.1016/j.biopsych.2017.08.014.

Food Processing: Another Suspect in the ‘Globesity’ Epidemic?

Last night, I read an article that fit absolutely perfectly into my unintentional but prominent theme of the last couple of weeks:  the relationship of the microbiome to weight issues…and to food:  “Food Processing, Gut Microbiota and the Globesity Problem.”[i]  Yup – we face an epidemic of“globesity”!  Great word, right?!

In fact, on the subject of globesity, the article’s first sentences point out some depressing statistics:  “In 2016, 39% of the global population aged 18 years or older was overweight and 13% was obese.  Elevated BMI, a parameter of obesity, is a risk factor for NCD [non-communicable diseases], which include cardiovascular disease (CVD), cancer, respiratory diseases and diabetes.  CVD alone cause 26.9 million deaths per year and all NCD combined cause 71% of the world annual deaths…”

Remember: as I pointed out earlier this week,  there is no one truth and the article emphasizes that we simply do not yet know all the factors that are feeding (ugh..another inadvertent pun by Judy!) into the obesity epidemic.  And when it comes to some of the most likely culprits, we don’t yet fully know any mechanisms of action.  So what I’m about to report is a status update on some ongoing research…it is not THE answer.

To emphasize this point, I want to share with you a quote from the article that sums this sentiment up:  “The development of the global obesity problem has triggered researchers worldwide to study the effects of human dietary and lifestyle patterns on energy balance and body weight trends…How and why this energy disbalance occurs so widespread and why this phenomenon seems so difficult to control or counteract is subject to research all over the world.”  Scientists are working to figure it out but as yet, there are unfortunately, no definitive answers.

One of the likely culprits though appears to be the way in which food is commonly processed in the industrialized world:  “The development of a so-called Western dietary pattern has been strongly related to the obesity problem and can be attributed to major worldwide changes in the agro-industrial systems.  Since 1850, but especially after WWII, sucrose, high fructose corn syrup (HFCS) and vegetable oils are increasingly produced and consumed, strenuous milling and sieving of grains has led to highly refined four without fiber or germ…and the practice of feeding grain to cattle instead of grass provides us with meat with higher saturated fat contents than wild or pasture-fed animals could deliver.”

So what we know is that the way our food is prepared has radically changed in the last 150 years, especially in the last 70 years or so.  And highly processed food is calorie dense and nutrient deficient, exposing us to markedly greater levels of unhealthy fats, sugar, salt – and increasing low amounts of fiber. And this shift entirely parallels the increase in obesity.

The authors emphasize what is now accepted as fact and what is still hypothesis or conjecture and I will let you know what’s what, as I hit the high points for you.

  1. It is accepted as fact that the gut microbiome plays a pivotal role in obesity, but what is more important than individual species is the “changed functionality” of the microbiota meaning an obese person’s bacteria are more adept at pulling calories out of food (which they refer to as “increased energy harvesting”), as well as affecting other pathways that alter signals of satiety (feeling full)…and of course, affecting the immune system:  “Impaired mucosal and intestinal barrier function in obesity, for instance, leads to closer contact between gut bacteria and their host, increasing the bacteria’s potential to cause inflammation.  Also, inflammatory bacterial components…can more easily enter into the blood circulation, leading to low grade systemic inflammation.  This feature is regularly mentioned as a key and common aspect of metabolic diseases, like type two diabetes, cardiovascular disease, impaired glucose and lipid metabolism…”  Leaky gut rears its ugly head yet again.
  2. There is not a huge amount of research into the effects on weight of micronutrient deficiency. Heavily processed foods are very low in vitamins and minerals and some recent studies have suggested that this may be a factor.  For example, deficiency in vitamin A has been “related to increased adiposity and body weight gain.”  Some antioxidant vitamins like E and C, beta-carotene, and the mineral, selenium, influence the secretion of a chemical called leptin by fat cells, which is known to regulate appetite and fat deposits.  It’s also important to recognize that our gut bacteria are also reliant upon the intake of adequate micronutrients, and deficiencies are known to be associated with biome alterations.  Several studies have shown that, for example, “…diets deficient in vitamin A, zinc, folate or iron shift the gut microbiota composition…”
  3. Ultra processed food have a much higher density of calories, and while high in fat and sugar, they are low in fiber and water, which have little to zero calories. Both water and fiber too, increase feelings of fullness.  So while eating many calories in a highly processed food diet, people still tend to feel more hungry longer…and thus continue eating more.  Fiber too feeds gut bacteria and thus, increases production of not just anti-inflammatory short-chain fatty acids, but also the production of hormones that induce feelings of satiety.  Multiple studies have been conducted that show that people feel markedly more full eating an equal amount of less processed food (for example, whole grain oat porridge) versus highly processed foods (like ready-to-eat breakfast cereals).
  4. Food additives started to be used back in the 1800s, and since then, we have increased the amounts so that now, over 2500 different additives are present in the food supply. There is inadequate data still on how these add to the obesity epidemic and worse, most have not been evaluated in terms of their effect on the human gut biome.  What we do know right now:
    • There is suspicion, but no definitive proof yet, that artificial sweeteners (like sucralose and aspartame) may be a part of the obesity picture.  However, we do have some convincing evidence that they are bad for the gut bacteria.  The most convincing study to date was conducted in Israel in 2014 and consisted of adding aspartame, saccharine or sucralose to food or water of mice.  The results showed “…significant effects on gut microbiota composition, paralleled with increases in glucose intolerance…Saccharin showed the most pronounced effect….” Further studies are now being run.
    • Emulsifiers are suspect but not nearly enough research has been done. Some appear to cause gut inflammation by allowing the gut bacteria “translocate” (i.e. move) into the lining of the gut.  Some also seem to cause loss of bacterial diversity.
    • Back to our old friend, high fructose corn syrup (HFCS), which you’ll remember, I wrote about back in February and then again, wrote more about back in March, “Consumption of HFCS has risen sharply over the last decades, from .292 kg per person per year in 1970 to 33.4 kg per person per year in 2000, absolutely paralleling the rise in obesity.” The link to obesity may be due to the increased calorie consumption, with all that added sugar, but there are other factors at play.  For example, the article points out that fructose is metabolized differently than glucose, and is more prone to being converted into fat.  More than that, as you all know, if you regularly read my blog, HFCS effect on the gut bacteria is being studied right now, and thus far, research points it to causing major alterations.
  5. The last factor in food processing raised by this article is thermal processing, which consists of exposing foods to extremely high and dry heat, in order to increase shelf-life and improve “flavor, color and texture.”  This destroys micronutrients and also causes chemical changes in the structure of the food, sometimes causing the production of “health damaging chemicals.”  There is some research linking these chemicals to insulin resistance and diabetes, weight gain, and so forth.  Data though is sadly lacking, especially when it comes to the effects of this kind of processed food on the gut bacteria.

The article concludes by stating that, “Reviewing recently addressed features of processed foods, it can be concluded that all these factors can in some way be related to obesity, metabolic syndrome and NCD…All considered processing features have been evidenced to affect or disturb the gut microbiota, to a greater or lesser extent.  As such, all features induced shifts in microbiota composition.”

But remember – as they also say, “It is obvious that research around the subject of this paper is still in its infancy.”  So as I said at the start, much of this is hypothesis or suspect, but not as yet, fact.  Still, as you all know, I am all about things you can do now and so…maybe eating a diet that is mainly whole foods is a really good idea?!


[i] Miclotte, L and Van de Wiele, T.  Food processing, gut microbiota and the globesity problem.  Critical Review in Food Science and Nutrition. 2019.  DOI:10.1080/10408398.2019.1596878

Health and the Human Body: There’s No Such Thing as One Truth

A couple of weeks ago, I wrote about obesity and the concept of evolutionary mismatch.  As always, I posted it up on my Biome Buzz Facebook page.  A few days later, in response to a comment that the whole problem is nothing more than glyphosate, another Facebook user wrote, “Reductionism is never helpful.”  Not to make a bad pun here (well…kinda to make a bad pun!):  he reduced this issue to 4 perfect words.

The question of what is causing the epidemics of obesity, autism, allergy, autoimmune diseases, etc. in the industrialized world is unbelievably complicated and involves bodily processes that may not have been discovered yet, let alone,  we still have no idea what outside influences might be involved or how much influence they may have.  We don’t even yet know fully how our immune system works, let alone how all the trillions of organisms in and on us affect each other and our bodies, what part the foods we eat plays – and the toxins we come into contact with, the lifestyle factors, etc.

We have to accept that there is no single or simple answer to these questions.  Period.

Years ago, I gave a joint talk with a medical professional who used the following 3 slides to try to express to our audience just how complex the human immune system is – let alone the entire rest of the body.

easy      medium


While I try to make the science I read understandable for us lay people, the reality is, there is nothing simple about it at all.

A few articles in the last few days exemplify this point.  Over the weekend, as one example, I read an article on the Conversation that looks at the bad and good of antibiotics.[i]  The article points out, “In the past decade, we have become more aware of the health-promoting characteristics of the microorganisms that live on and in our bodies – the microbiome. For example, a diverse and stable gut microbiome is necessary for digestion and protection against gut infections. Changing the microbiome with antibiotics can be helpful…but also harmful.”  The author points out that in animal studies, antibiotics – by altering the gut bacteria – have been found to be responsible for weight gain and adverse metabolic effects; for poor immune response to cancer; and with the development of depression.

Conversely, antibiotics also save millions of lives every day and more than that, scientists have found they often do as much good as they do bad:  “More than six decades ago, researchers first noticed that certain antibiotics had beneficial effects that were not explained by killing bacteria.”  60+ years ago, scientists noticed that prontosil, one of the first antibiotics, improved the functioning of immune cells responsible for killing bacteria.  A recent review of 10 clinical trials of antibiotics showed that they can promote child growth in those with infectious diseases and malnutrition.  Another antibiotic called cotrimoxazole promotes health and is frequently used in those with HIV to block infection and persistent inflammation.  In a randomized, controlled trial conducted on children with HIV in Africa, those taking the antibiotics had improvements in systemic inflammation, including in the gut.  The authors of this article, who ran this study, surmised that the antibiotic reduced inflammation in 3 ways:  “One, it suppressed a group of gut bacteria called viridans group streptococci, which trigger gut inflammation. Two, it directly reduced harmful activation of blood immune cells. And, three, it blocked inflammatory signals from gut cells.” No one yet knows fully the mechanism of action but the fact remains, the medications are doing something beneficial.

The author concludes, “To guide better antibiotic choices, we need to look deeper than just their effects on infections that make us sick into the underlying body processes they can change. As antibiotic use continues to expand and change worldwide, its time we understood more fully how they work.”  Well, amen to that.  The fact is, how they work, what exactly they are doing in us, etc. is not even vaguely as simple as “they kill bacteria.”

A second example of the incredible complexity involved in researching chronic diseases was provided by an article I posted on Facebook from Medscape a few days ago:  “New Approaches Targeting the Microbiome in CV Disease.”[ii]  The article describes a review from the Journal of the American College of Cardiology on the relationship of the bacterial microbiome to the development of cardiovascular illness.  “While previous studies have focused on what specific organisms are implicated, we are beginning to realize that it is their balance of the ecosystem within the body that creates an environment that protects or promotes various cardiovascular diseases…”  That is, it’s the balance of the entire body and its biome that is important – not just the individual organisms that live in us.

The lead author of the review, Dr. Tang, states that “…prior studies have hypothesized that specific bacteria may directly promote pathophysiologic processes, and that by eliminating them with antibiotics, might lead to fewer adverse events. This approach has not worked because the underlying mechanisms were poorly understood, and there is an assumption of one-size-fits-all…Now we appreciate that much of our gut bacteria are likely beneficial and their compositions in our healthy gut are often difficult to alter, yet their metabolism can be modulated by dietary exposures that are unique across individuals.”

In fact, diet is one of the biggest environmental exposures humans have, but again remember that ONE SIZE DOES NOT FIT ALL!  “Unique across individual.”  Says Dr. Tang, “…the concept of classifying food groups or diets as ‘good’ or ‘bad’ for health is somewhat outdated, since it depends largely on how nutrients are digested and interact with the body’s gut bacteria…”

It gets even more complicated than that!  To quote Dr. Tang again, “Individuals can have vastly different gut bacterial compositions, so the same food may have different short- and long-term effects in different persons…This is further complicated by the fact that we all have our own unique physiological response to nutrients and metabolites independent of our gut microbiome.”  Remember a couple of years ago, when a study in Cell Metabolism found that people respond differently to white versus whole wheat bread?  Some people actually had a lower glycemic response to white, shocking the scientists…who found the response was actually tied into the composition of the gut flora.[iii]

So no!  We cannot reduce the discussion of “why is heart disease so much more common today than in the past” to any one factor.  It is not “diet” or “toxins” or “weight.”  It is complex interplay of factors many of which we probably haven’t even yet discovered.

Dr. Tang points out that this why studies so often have contrasting results:  we have not as yet learned out to account for individual microbiomes and individual physiological responses.  In the future though, as we learn more, we can hope that personalized therapies in terms of diet, probiotics, prebiotics and on will become the norm.

So please:  do not think that because becoming vegan, or following a paleo diet, or giving up carbs, etc. has made you feel like a million bucks that it is right for everyone.  Do not think that toxins are THE answer, or that a probiotic that has worked for you is right for everyone. There is no such thing as one truth.


[i] https://theconversation.com/antibiotics-beneficial-side-effects-are-starting-to-come-to-light-115004

[ii] https://www.medscape.com/viewarticle/912240?fbclid=IwAR2lEsdbRHZSOJFKVyXorHstkU0BJrCXTBPpgM0KV93KSuIVFRPYOYjEL3g#vp_2

[iii] https://www.cnn.com/2017/06/16/health/white-whole-wheat-bread-food-study-drayer/index.html

Anorexia: Yet Another Microbiome Induced Autoimmune Illness?

I’ve written a fair amount lately about the association of obesity to bacterial microbiome alterations, but have thus far, only had the chance to write a few times about the relationship of dysbiosis to anorexia nervosa (AN).  In my frenzy of reading these last couple of weeks, I came across an incredibly interesting article on the subject, which suggested something I had never read before:  many researchers now believe that, “…AN is an autoimmune disease caused by delayed exposure to common microorganisms (hygiene hypothesis) in which autoABS [auto antibodies] to appetite-regulating neuropeptides, neurotransmitters, and hypothalamic neurons, disturb appetite and result in decreased intake of food.”[i]  Is biome depletion once again rearing its ugly head?

In my first ever post about AN, I wrote about the relationship of other autoimmune diseases to the development of eating disorders:  “The researchers found ‘…significantly higher hazards of eating disorders for children and adolescents with autoimmune or autoinflammatory diseases:  36% higher hazard for anorexia nervosa, 73% for bulimia nervosa, and 72% for an eating disorder not otherwise specified.’”  I go on to mention that there is a growing body of literature associating eating disorders to alterations in the microbiome.  The second time I wrote about it, I went into these alterations in much more detail:  “Specifically, the authors of this paper note that there seems to be a general pattern found in those with anorexia:  ‘…a depletion of Lactobacillus and butyrate-producing Roseburia. In contrast, the relative abundance of Bifidobacteria, Proteobacteria, Akkermansia muciniphila and archaeon Methanobrevibacter smithii increases.’”

Now before you snap at me, “Judy, isn’t anorexia a cultural issue?  Isn’t it brought about by girls wanting to emulate the airbrushed, Photoshopped super models they see everywhere, in the media?” let’s take a big step back and remember that the human body is a whole – that the mind and body are one organism, and not separate entities.  Just as you get butterflies in your stomach when nervous or upset (the mind affects the body), remember too that it works both ways.  You get the flu, for example, and your body will engage in what is known as “sickness behavior” which is “…characterized by loss of appetite, reduction in activity and social interactions, depressed mood, and loss of libido.”  The communication between body and mind is bi-directional.  So the answer is YES – stress and anxiety brought about by attempting to emulate the fictional perfection of these models most certainly may play a part in the development of eating disorders:  “Genetic factors contribute to the etiology of AN based on various genetic studies.  Moreover, psychological risk factors as well as sociocultural influences and biological factors contribute to the risk of AN development.”

Remember:  stress and anxiety affect your microbiome, just as your microbiome affects your mind and behavior.  You have all read about this over and over on my blog.

So back now to AN and highlights from this article:

These authors restate what I have written about in the past regarding known microbiome alterations, including the archaea, Methanobrevibacter smithii.  And whoa…would you look at that!  I wrote about that too, in this post on archaea from earlier this month:  “An interesting couple of sentences from the abstract:  ‘They have been implicated in dysbiosis of the oral microbiota…They have also been associated with dysbiosis of the digestive tract microbiota linked to metabolic disorders (anorexia, malnutrition and obesity) and with lesions of the digestive tract (colon cancer).’”[iv]

Biome Buzz readers really are up to date with all the latest!

These researchers state, “It was reported that AN patients possess greater concentrations of the archaeon Methanobrevibacter smithii in the gut.  This increase of a methane producing archaeon can result in the optimization of food transformation in a very low-calorie diet.”  That is, this particular archaea helps maximize the body’s ability to get energy from food, which is pretty critical when you’re barely eating.  They go on to say, “AN is associated intestinal microbial dysbiosis marked by lower microbial diversity and taxonomic differences in comparison with healthy controls.  This dysbiosis is also associated with depression and eating disorder psychopathology.”

Back to the autoimmune connection for a moment:  the intestinal bacterial play a crucial role in the “…increased permeability of tight junctions to macromolecules…This so called ‘leaky gut’ is associated with the development of inflammation, chronic diseases, sepsis, and also with some neurological and psychiatric disease.  The increased intestinal permeability enables the transport of microbial metabolites into the peripheral circulation….A ’leaky gut’ can be provoked by starvation…”

Bacterial metabolites, crossing through the leaky gut, look like invaders to the immune system, which then produces antibodies to them.  These cross-reacting autoABS have been observed and documented by researchers, who have found they react with chemicals in the body that stimulate appetite. In fact, in both humans and animals, antibodies to a hormone called alpha-melanocyte stimulating hormone (α-MSH), which, as the name suggests, stimulates appetite, are generated in response to a protein produced by some gut bacteria including E.coli.  In fact, “The levels of α-MSH autoABS correlate with core psychobehavioral abnormalities in patients with eating disorders.”

To sum that up:  metabolites from gut bacteria, like E.coli, cross the permeable gut barrier into the blood stream.  In response, the body produces antibodies to those metabolites, which also unfortunately, attack and destroy the α-MSH, which stimulates appetite.  And of course, the worse your appetite, the less you eat…and the leakier the gut becomes.  A vicious cycle is born.

Just a couple more items of interest:

As you may know, the bacteria of the gut produce many of our neurotransmitters.  It always surprises people when I tell them that 90% of the serotonin in their bodies is actually in the gut.  This article points this out, and goes on to state:  “The production of serotonin in the gut is affected by diet and regulates the motility of the gut as well as mood, appetite, sleep, and the cognitive functions of the individual.”  Dopamine, GABA, acetylcholine, etc., are also products of the gut flora.  Thus, anything that affects these microbes also affects the central nervous system.  Of course, decreased food intake also affects the immune system:  “Decreased food intake may have an impact on the interactions among the immune system and the CNS.  The impaired communication between these systems may be responsible for several associated psychiatric symptoms, such as stress, anxiety, and depression.”  So back to where I started this post:  psychological stress affects the microbiome…and the microbiome affects the emotional well-being and behavior of the person, including feeding behaviors.

The conclusion of the paper:  “Evidence has been published that behavioral disorders including eating disorders are accompanied by significant perturbations in the composition of the gut microbiota…The presence of antibodies primarily aimed against the compounds of the gut microbiota and cross reacting with neuroregulatory peptides in AN patients leads to a hypothesis that autoimmune mechanisms play an important role in the pathogenesis of AN.”

It will be incredibly interesting to see where this research leads.  I remember a few years ago, a doctor friend of mine went to a conference on complex inflammatory diseases.  The keynote speaker made a bold statement that really resonated with both my friend and me:  “Until proven otherwise, assume that all chronic illness is autoimmune.”  He may well turn out to be right!


[i] Roubalova, R, et. al. Anorexia nervosa: gut microbiota-immune-brain interactions. Clinical Nutrition. 2019.  https://doi.org/10.1016/j.clnu.2019.03.023

Some Early-Stage, But Promising, Science About the Microbiome and Cancer

Yesterday morning, I posted a story on my Biome Buzz’ Facebook page about 2 new studies that independently showed that there is a distinctive microbiome composition associated with colorectal cancer.[i]  One study “…identified a set of 29 species indicative of colorectal cancer across 7 countries,” while the other showed “…higher gut microbiome richness” than controls, which ordinarily sounds like it should be a good thing but in this case, that richness came from bacteria that are native to the mouth that had moved to the colon, where they are not meant to be.  This led to altered glucose metabolism in the large intestine, as well as the “putrification” of amino acids, etc.

I read that article with great interest as I was intending to start writing this post about a recent summary of what we currently know about using probiotics in treating and preventing cancer – and you all know I love coincidences![ii]

Upon reading this new article, the first thing that struck me was how long ago research into the connection of cancer to the gut bacteria began.  Back in 1980, two researchers (Goldin and Gorbach[iii]) first demonstrated an, “…association between a diet enriched with Lactobacillus and a reduced incidence of colon cancer (40% vs. 77% in controls)”!  That’s almost 30 years ago!  And so very little progress, really, has been made since then.  Of course though, thankfully, there has been at least some.

So a few highlights:

  1. The authors enumerate several potential mechanisms of action as to how probiotic bacteria prevent cancer.  Of course, “A specific mechanism associated with anti-tumor properties of probiotics remains unclear.”
    • Probiotics can help prevent excessive bile acids (which is carcinogenic) from adversely affecting the lining of the colon: “…probiotic bacteria such as L. acidophilus and B. bifidum have been demonstrated to be a promising tool in cancer prevention.”
    • Putrification (pathogenic) bacteria, like E. coli and Clostridium perfringens, both of which are naturally found in the human gut, create carcinogenic compounds using certain enzymes. In the late 1970s, the two researchers I mentioned above (Goldin and Gorbach), showed – in rats – that eating fermented milk products (ie. yogurt or kefir) had a beneficial effect on the amount of L. acidophilus in the rodents’ intestines which “…subsequently resulted in a reduction of putrefactive bacteria and decrease in the level of harmful enzymes.”  This has been confirmed in more recent research.
    • Lactobacillus and Bifidobacillus bind and degrade potential carcinogens. For example, these strains alleviate the effect of eating carcinogenic compounds found in unhealthy foods, like fried meats.
    • Many of the metabolites produced by the probiotic bacteria themselves play “…an essential role in maintaining homeostasis and suppressing carcinogens.” The authors specifically talk about short chain fatty acids (SCFAs), which you’ve heard me talk about many, many times on this blog. (For example, here and here.)  SCFAs beneficially affect the immune system, cell proliferation and cell death (which, in the case of tumor cells, you can imagine is pretty critical!), as well as help maintain “epithelial integrity” (ie. leaky gut).
      • At this point, the authors actually make a really interesting point: lactic acid producing bacteria are not directly involved in SCFA production, but they modulate the gut microbiota which, in turn affects the production of SCFAs.  That is, Lactobacilli and Bifidobacteria, are indirectly crucial in SCFA production.
      • “Colorectal cancer is strongly correlated with decreased levels of SCFA and SCFA-producing bacteria dysbiosis,” as I mentioned in the opening paragraph of this post. In mice, boosting levels of bacteria which produce the SCFA, butyrate, for example, inhibits the progression of tumor development.  So…eat your fiber (said Judy, for the millionth time…like here!)  Or, as these authors write, “…the prebiotic activity of fiber-enriched diet…is a promising strategy to prevent CRC [colorectal cancer].”
    • Probiotic bacteria also have the ability to increase and decrease inflammatory cytokines (chemical messengers) in the body, as well as modulating the production of prostaglandins, which are immune compounds which suppress cancer formation. They can also activate immune cells called phagocytes, which directly eliminate early-stage cancers.
    • Probiotic bacteria can suppress gastric cancers related to H.pylori infections, as well as clear the virus, HPV, which is associated with cervical cancer. A study on humans showed enhanced clearing of HPV with 6 months of consumption of probiotics.
  2. A 2012 meta-analysis of 19 different human cohort studies showed an “association between consumption of dairy products (except cheese) and a decreased colorectal cancer risk.” A second study confirmed these findings.  (However, high fat dairy does increase bile acid levels in the colon, which – as noted early – may be carcinogenic.) Also of note: a huge cohort study, on 45,241 subjects, “proved a significant association between single probiotic-rich product intake (yogurt) and decrease colon cancer risk.”
  3. The paper takes a brief look at the future, in terms of using probiotics to treat cancer. For example, scientists have used probiotic bacteria to modulate the immune response and have even been able to entirely inhibit tumor development.  Others are working on using probiotics as “vaccines,” manipulating the immune system to fight off various carcinogenic pathogens, like HPV (the virus that can cause cervical cancer).  And still others are using probiotics to more effectively deliver medicines to where they are most needed.


Unfortunately, as I said earlier, all this research – as promising as it is – is still pretty early stage, as most studies have been done in animals.  On the bright side, I hope with all my heart (considering how many people I already know who have had to fight (and all-too-often succumbed to) cancer:  “…evidence from the latest studies points towards the idea of possible implementation of probiotics in cutting-edge cancer therapy.”


[i] https://www.gutmicrobiotaforhealth.com/en/two-new-studies-reveal-universal-gut-microbiome-signatures-in-colorectal-cancer/?fbclid=IwAR0sxmjbAqukZDi-XAxgD4WRlrntCx5_QhRQZn4dt68VR2nafxN8eZTxqVQ

[ii] Gorska, A, Przystupski, D, Niemczura, MJ, Kulbacka, J. Probiotic bacteria: a promising tool in cancer prevention and therapy. Current Microbiology. https://doi.org/10.1007/s00284-019-01679-8

[iii] Goldin BR, Gorbach SL (1980) Effect of Lactobacillus acidophilus dietary supplements on 1,2-dimethylhydrazine dihydrochloride-induced intestinal cancer in rats. J Natl Cancer Inst64:263–265.


Evolutionary Mismatch, the Human Biome…and a Bit More on Obesity

Recently there was a lot of discussion on the Biome Buzz’ Facebook page in regards to a post on obesity, wherein some people expressed their opinions that our current epidemic of obesity is due to nothing more than people eating too much junk food.  While there is zero doubt that diet is a (probably THE) major factor, I pointed out that it is not that simple.

Dr. William Parker, et.al., of Duke University Medical School, wrote a paper back in 2013 which described the concept of “evolutionary mismatch.”[i]  This encompasses the idea that through evolutionary pressures (survival of the fittest), our bodies have developed in such a way as to account for the presence of our “old friends” (the trillions of organisms that co-exist in us) and modern living has deprived us of that which is now necessary for our bodies to function properly:  “Species depleted or even eliminated from the human biome include a wide range of pathogens, commensals and mutualists whose reproductive cycle is greatly diminished or even eliminated by modern sanitation, water treatment and medical practices…The absence of species from the human biome leaves the immune system in a hypersensitive state that, when combined with environmental triggers and genetic predisposition, leads to allergic and autoimmune disease. The wide range of evidence pointing incontrovertibly at this conclusion…”

My regular readers are very familiar with this idea as nearly every post I have written over the years describes the emerging science that connects biome depletion to our current epidemic (in the industrialized world) of chronic, immune-related illness.

I read a really interesting article yesterday that further explores this idea.[ii]  These authors, from the University of Louisville, examine the idea of evolutionary mismatch and natural selection, in light of biome depletion and the effect upon public health – and forward some ideas of how our society can (and must) deal with this threat.

So a few really interesting bits from the paper:

1. Many (if not most) microorganisms’ effects on human health are unknown.  They refer to these organisms as “indeterminate symbionts,” defining a symbiont as an organism that lives “intimately with other organisms.”  Commensal organisms are symbionts that have “neither a harmful nor beneficial overall effect.”  If you imagine a spectrum then, commensal is the dividing line between parasites and mutualists (those organisms that benefit the host while themselves, benefiting from the host).

2. Some organisms are “strong mutualists,” and are at the far end then of this spectrum on the beneficial side. They provide an example in the Bifido strain, infantis. In infants, “It releases antibacterial compounds that inhibit pathogenic bacteria, synthesizes vitamins, improves immunological responses, and protects premature infants against ulcerative colitis.” And guess what?  Human breast milk is uniquely suited to helping B. infantis grow, with its rich supply of human milk oligosaccharides (prebiotics), which are particularly suited for this organism.  “The diversity of HMOs produced in milk appears to have coevolved for B. infantis more than for any other bacterium.”  Thus, the increased use of formula – which contains neither the probiotic, B.infantis, nor the prebiotic, sets babies up for a myriad of health issues.

A paper appeared in 2018 from the American Academy of Pediatrics, that states “…breastfeeding has many established benefits for child health; in fact, previous meta-analysis of research found that breastfed infants have a 26 percent reduced risk of obesity later in life. In a study in the October 2018 Pediatrics (published online Sept. 24)… researchers found that breastfeeding was associated with lower body mass index (BMI) and a reduced risk of excessive weight gain in the first year of life.”

From an evolutionary standpoint, “The mismatch between formula feeding and breast feeding is a particular example pertaining to a dietary change because infant formula differs from breast milk.”[ii]  Thus, by not feeding the infant’s developing microbiome as nature intended, we have created an evolutionary mismatch that is associated with obesity (and other chronic diseases) later in life.  Another recent paper looked at the gut bacteria in 2 year old children (who had no weight issues), and correlated this to obesity by the age of 12: “One recent study in this regard showed infant gut microbiota could be used as a biomarker to identify the children who are at risk of becoming overweight and obese later in childhood. That study…concludes that gut microbiota composition at 2 years of age can be used as a predictor for obesity at age 12. Although the toddlers may not be overweight or obese at 2, the research identified a correlation between their gut microbiota composition at early stages and their body mass index (BMI) at 12.”

3. On this same subject (i.e. obesity): there have been many papers lately pointing out that gastric bypass surgery improves insulin sensitivity even before weight loss has occurred.  “The rapidly ameliorating effects of gastric bypass surgery are consistent with microbiome influences on diabetes, which could occur quickly as a result of the short generation times of bacteria.  Gut microbiota are strongly affected by gastric bypass surgery.”[ii]  Another coincidence (that you all know I love):  an article on this appeared this morning on Gut Microbiome for Health which states,   “…interactions between the gut microbiota and bile acids metabolism may partially mediate the success of bariatric surgery in the medium term…the authors showed specific core gut microbiome profiles, with patients from the success group showing the most diverse gut microbiome”  In fact, success of the surgery appears to be reliant upon the composition of the gut bacteria.

4.  The authors point out that different microbes have a greater and lesser affinity for glucose. Those that thrive on it are essentially competing with their host human for the molecule. For example, Staphylococcus aureus loves glucose.  Therefore, it releases a peptide (short string of amino acids) that binds to insulin and blocks it from uptake by human cells, thereby increasing the amount of available glucose to the microbe, and “favoring insulin resistance” in the human:  “In a study assessing the relationship between neonatal microbiota and obesity seven years later, S. aureus was found in the fecal samples that had been taken from obese 7-year olds when they were neonates, whereas bifidobacteria dominated the neonatal feces of children who did not become obese.  Accordingly, breast feeding is associated with a substantially reduced probability of being overweight or obese during childhood.”

5. And of course, our modern “western” diets are a complete evolutionary mismatch: “The evolutionary mismatch of a diet low in fiber and high in sugar and fat and the radical increase in formula feeding have led to near global disturbance of the human gut microbiome with shifts in species diversity and proportions.”

6. Other illnesses that are clearly associated with evolutionary mismatch, according to this article, include celiac disease, diabetes, obesity, as I just mentioned, autism and allergies.  (Dr. Parer’s paper has a far more extensive list.) A quick example:  in a mouse model, infantis ameliorates allergy:  “Has the nearly worldwide shift to vast numbers of children being formula fed…led to a reduction in the population level prevalence of important gut bacteria for the newborn?”

7. One new vocabulary word for all of us:   There are organisms, which I have actually written about several times before, that, depending on environmental circumstances, are either parasitic or mutualistic.  The paper provides an example:  the bacterium, Bacteroides thetaiotaomicron, which is a commensal organism that is ordinarily mutualistic (in that it breaks down non-digestible carbohydrates into sugars usable by us)…unless it is in the presence of E.coli, in which case, it exacerbates the damage caused by this parasitic bacteria.  From now on, I’ll be using that term – ambisymbiont – when talking about such organisms.  I like it!   It has a ring to it…

8. Back to my the paper I mentioned in the opening paragraph: Parker et. al. point out that our modern diet and the decrease in breast feeding are just two of the current evolutionary mismatches to which we humans (and our domesticated pets, by the way) are subjected.  Others include our general lack of exposure to sunlight, in regards to vitamin D production, potentially “unrequited psychological stress,” and the eradication of our native macrobiomes.  “The identification of biome depletion as the cause for pandemics of immune disease carries with it a solution:  biome reconstitution.  Although the extent to which biome reconstitution can reverse disease remains unknown at present, biome reconstitution is hypothetically a readily available means of preventing disease associated with biome depletion.”

Or…as today’s paper concludes:  “Public health efforts to counter negative effects of the Western diet, support breastfeeding, and assure access to high-fiber, low-sugar, and low-fat foods may have an outsized effect on seemingly unrelated widespread diseases such as diabetes, autism, and childhood obesity.”


[i] Parker, W and Ollerton, J.  Evolutionary biology and anthropology suggest biome reconstitution as a necessary approach toward dealing with immune disorders. Evolution, Medicine, and Public Health. 2013;89-103.  doi:10.1093/emph/eot008

[ii] Ewald, HAS, Ewald, PW. Natural selection, the microbiome, and public health.  Yale Journal of Biology and Medicine. 2018;91:445-455.