The Microbiome and Obesity-What’s the Relationship?
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The microbiome is such a hot health topic, and the research of it has exploded over the last 20-30 years. It’s hard to imagine that some of the first scientists to suggest the presence of microbes and that they might be responsible for illness were ridiculed and even criminalized or placed in mental institutions.
I had often read that we have ten times more microbial cells than human cells in our bodies, and that they represent 100 times more genes than the human cells in our bodies. In my research for this newsletter, I found out here that that wasn’t true! It was a factoid cited in one paper and then “the masses” cited as fact! (it’s another example of the “everyone knows” red flag rule-if “everyone knows” something is true…better check it out) Full disclosure, I was going to use that factoid myself in this article until I found that correction! It’s actually closer to 1.3 times as many bacterial cells than human cells and even that is a very rough estimate. The number of cells in a human depends on age, sex, and many other factors!
We have multiple microbiomes in the body-in different areas of the body. We most often hear about the microbes in the gut, but we have microbiomes on our teeth, our eyes, our bladder (I was taught in nursing school that it was a sterile environment!), our nose, our skin. Each of these microbiomes is somewhat different from the other. I also learned in researching for this newsletter that these microbial populations respond to changes in each other and to changes in the body.
There has been great anticipation of results from the Human Microbiome Project in hopes that it will bring new insights to help us identify risks and causes (like a microbiome signature) of diseases, as well as hopes to identify a healthy microbiome and possible use that information for therapeutic purposes, to help prevent, treat or cure various disorders. It is a reasonable place to look for help in achieving health. These microbes influence all sorts of things! They affect how we absorb nutrients and how effectively we metabolize them. They can influence immune cells, hormones, and neurotransmitters. They do A LOT.
One of the conditions they have hoped to gain meaningful insights about is obesity. It makes sense that there would be a connection, as many of gut microbes influence secretion of chemicals in our body that signal hunger or satiety, as well as how efficiently energy (calories) is extracted from food we eat. So the thought has been: Is a certain microbiome responsible for obesity? Can we alter that microbiome to treat or prevent obesity? Also, as obesity is correlated with illness like Type 2 Diabetes and heart disease, the question could be: does obesity create dysbiosis, or an Unhealthy microbiome that leads to disease? Can we prevent poor health by preventing obesity by creating a different microbiome???
I think what researchers have primarily learned in studying the microbiome is that there is SOOOOOO much more to learn!
As you probably know there are “good guys” (commensal) and “bad guys”(pathobionts) in the microbial neighborhood. And those aren’t really absolute terms. Whether microbes are beneficial or harmful depends on the “mix” of these tiny guys. A certain balance of microbes that do different things promotes health and wellness, and when that balance is off (when there are TOO MANY of a certain organism, then it becomes a trouble maker, and-ill health can happen. With the human gut project, it was anticipated that a “healthy signature” of a microbiome would be found. It was/IS also hoped we could figure out how to ALTER a person’s microbiome to make it healthy again. Researchers were hoping to identify the same type of signature with obesity. And in ANIMALS (mostly mice)…they have made some interesting findings.
Animal Science
Germ free mice compared to “normal mice” (with microbiota). Normal mice had 40% more body fat even though they consumed less food! When germ-free mice received fecal transplant from normal mice-there was a 60% increase in body fat within 2 weeks.
In another study, when germ-free mice were (fecal) transplanted with feces from human twins (one lean, one obese) the mouse adopted the microbiome as well as the body type (lean or obese) of the donor.
Human Research
Human research has been much less conclusive. That makes sense, as humans do not live in cages like mice, where they all live in the same environment, eat exactly the same food, are exposed to the same things. We humans live much messier lives, don’t we? We do seem to have found out that diversity (meaning a mix of different species) of microbes is good. A lack of diversity is bad, or shall I say, is more associated with poor health.
There is some but VERY inconclusive evidence that obesity is correlated with a LACK of diversity, and a greater number of bacteria called Firmicutes and a lesser number of Bacteroidetes, compared to non-obese people. But I caution again, these were very Inconclusive results.
If you think about it, it’s easy to see how difficult it is to compare microbiomes between people. No two of us are the same…we have different bodies, live in different places, eat different things, get different illnesses, go different places, live with different families. Some of us have pets, kids (which have some effect of the microbiome!)…some of us spend a lot of time outside, some none. The amount of sunlight we get, fresh food, etcetera varies so very much!
A great study that demonstrated that our microbiomes are in fact as different as we are was a real gem that I found doing this research! It was just published in 2024!
This study followed 86 individuals for up to 6 years (+/- 455 days). Ages were 29-75 years old. In this study they not only looked at microbes in the gut (in stool, or poop), but they looked at microbiomes in the nasal cavity, oral cavity and skin also. This study looked at insulin sensitivity and insulin resistance, as well as many other biomarkers like lipids, inflammatory markers, cytokines. They evaluated the microbiomes after illness or stressful periods. So it was pretty comprehensive.
They did not find a “healthy microbiome” signature, but found that microbiomes were highly individualized, with the host (the person) having the greatest influence (compared to environmental exposures). These individual microbiomes were found to be pretty resilient, but vulnerable to things like viral infection, which can lead to microbiome imbalance (dysbiosis) and metabolic disturbances. They also discovered that these microbiomes at different sites could influence each other.
Insulin resistance was associated with changes in microbiome make up and stability, as well as other metabolic markers that highlight an influence on metabolic function.
Obesity related gut dysbiosis, irritable bowel disease associated oral dysbiosis, and psoriasis related skin dysbiosis are all correlated with an abundance in the Firmicutes family of microbes. Each of these conditions are associated with inflammation. The cytokines (chemical messengers) related to the inflammation are involved in immune response as well. This is an example of how obesity might influence the microbiome, generating an illness response.
Another study of lean and obese twins showed a difference between lean twins and obese twins…with an enrichment (more) of microbes involved in processing of carbohydrate. This twin study did show more Firmicutes in the obese and more Bacteroidetes in the lean. But no specific signature was found but certain functions and capabilities seem to be consistently represented.
But THIS study: showed a relationship between diet and the microbiome that kind of brings my discussion back to my usual starting point…WHAT YOU DO, (recipe for optimal health) is what drives your health and well-being. What you eat is one of the most controllable aspects of our lifestyle choices.
More high quality (less processed) and plant based foods were associated more beneficial microbiomes. This study showed that dietary patterns and cardiometabolic risk factors were associated with microbial “signatures” that were closely related but not identical. Visceral fat was more strongly linked to the gut bug make-up than BMI (body mass index). Interesting, as in healthcare it is usually BMI that drives diagnosis and recommendations around health.
One limitation of this study is that food intake was based of of self-reported data (Food Frequency Questionnaires). Self-reported data is not super reliable, but for such a large study group, over 1000 people, you can see why this method was used.)
In regards to what and how we eat…the focus should be on what makes us (AND our microbiome) healthy, not what makes us thin! Sometimes a plant strong dietary pattern does both, and there is nothing wrong with that-but no matter your weight or you size, your microbiome will be best supported by eating a healthy diet (lots of plants!) These good buggers love-FIBER. Where do you get fiber? Plants. Animal food has NO FIBER. Zero.
One point I want to make sure you hear: There is still so much we don’t know about microbiomes, how they influence us and how we influence them. We have learned some basics, but there is so much more to learn! There does seem to be some kind of a relationship between weight and the microbiome, but that relationship isn’t clear, and it seems like it may look different in different individuals. I want to acknowledge; I just presented some very basic findings from these studies. I encourage you to click on the study links (in blue) to read them if this is interesting to you. It is fascinating and exciting stuff! The website for the Human Microbiome Project is here: https://www.hmpdacc.org/ihmp/
But when we are searching for how to restore or get or keep our health and well-being…the most important thing is to do the most important things. Eat whole foods as much as you can, move your body, often and regularly with vigor (and enjoyment!), do work you believe is important, be in community (with people is best, but even pets will do!) Get outside, in the sunshine. Manage your stress response (Issue 13 of Don’t Weight!) and make informed decisions about your health (don’t just do what the doctor, or the internet, or your friend, or the people on the news tell you to do!)
PS-Some may be wondering about probiotics, and whether they should be taken for health. A lot of things can influence the answer to that question for an individual, and it would be irresponsible to answer in a forum like this newsletter. The studies I reviewed for THIS article were not about supplementation or treatment with probiotics, so they did not give me information to answer that question either. If you have questions about health concerns and would like help in taking an informed approach to resolving them-please reach out! My email is mary@eat-learn-live.com
Mindset Matters Most-Time is On Your Side (for your listening pleasure click here)
In my group coaching program-MGP (Mindset, Goals, Progress), a common discussion point is TIME. And I am sure most reading this newsletter have had at least some moments where they felt there just weren’t enough hours in a day.
You can find “time management” suggestions and programs in abundance.
I would like to invite you to SHIFT your thinking from managing your time, to TREASURING your time.
Time gives us so much, think about it! Am I right?
Act AS IF your actions demonstrate how much you treasure your time.
Here is a “mindset reset” for time that I crafted for myself a couple of years ago in a workshop I did with Dana Wilde. Feel free to tweak it and use it!
Coaches Corner
Where did the time fly? If you feel like you need more time to do what you want to do-you may want to look at how your using your time and your priorities.
Mindfully look at your time. Of course, with curiosity, not judgement or with a hidden agenda. Look at how you spend your time and document it for several days. There are apps you can use-I didn’t have a lot of luck with that, but you might! (I would “start” something on the app, and the next time I came back to it, it said I had been like, washing dishes for 20 hours!) Never.gonna.happen.
Sometimes we just underestimate how long something is going to take, or we think that magically we won’t take that long again. Hmmm, my magic want still hasn’t worked on this one!)
Once you see how you spend your time, ask-is THIS use of my time getting me where I want to go? Is it in line with what is most important to me somehow?
When you answer those questions, then you can decide if you want to do something with that information. Keep doing what your doing, change what your are doing now, or make a plan to decide later (put that date in your planner).
I hope you found value in this newsletter. Please share if you know someone who might like to receive it as well!
Keep enjoying a lovely summer!
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