Intestinal bacteria may influence our moods | Hacker News Reader

Intestinal bacteria may influence our moods

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212 pointsdrjohnson97 comments

Be very careful with probiotics; just loading your system with random strains of bacteria from your local health food store can have serious consequences. I have IBS and an anxiety disorder that had been in remission for years. I tried Primadophilus Optima and it wrecked me. I went from a mild IBS-C to severe IBS-D, and my panic attacks came back with an intensity unlike anything I've ever experienced.

I don't doubt that intestinal bacteria are related to IBS and anxiety disorders and that certain probiotic treatments may help. But such supplementation should be based on detailed research of each of the strains taken, much of which does not even exist yet.

I also have IBS and was diagnosed years ago, but I never heard of different classifications that you mentioned, IBS-C or IBS-D. Mostly, I classify the severity as "day-to-day", workdays usually being the worst. I haven't tried consuming live cultures other than yogurt, and even then I have mixed results. Have you gotten far in your research on the types of bacteria, and do you have any resources you could share?

Edit: just read about differences between IBS-C and D and it definitely sounds like there has been some headway in the last 15 years since I was diagnosed (back then it was mostly a prognosis of "here's a colonoscopy, sorry not much else we can do"). I should definitely get re-evaluated. Thanks for mentioning this.

C is constipation. D is diarrhea. I have Crohn's and didn't know these either, but Google was my friend. I personally don't distinguish. Diarrhea largely affects individuals who have Crohn's in the colon (not me) due to the colon's role in body water absorption from fecal waste. My inflammation occurs in the ileum so I rarely, if ever, have diarrhea but I do have severe, piercing abdominal pain from scar tissue and constriction. My personal opinion from a biology background is we largely don't know jack about Crohn's/IBS and the classifications are grasping at straws. If you do want to know some of the scientific stuff the genetics side is a great place to start. NOD2 is specifically involved in Crohn's: http://en.wikipedia.org/wiki/NOD2 and you can learn a lot of interesting things about our innate immune system.

From the little research I've done, it looks like the bifidobacterium genus, in particular certain strains of bifidobacterium longum [0,1] and infantis [2], have favorable effects on IBS and anxiety. Interestingly, in [1] they noted that it was able to normalize low BDNF levels, which is one hypothesis as to how SSRIs treat anxiety and depression.

However, I picked out my probiotic specifically because it has those species (among many others), and you read what happened.

[0] http://www.ncbi.nlm.nih.gov/pubmed/17172187

[1] http://www.apa.org/monitor/2012/09/gut-feeling.aspx

[2] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886445/

IBS seems like the doctors way of saying "We don't know what your problem is".

Doctors told me I had IBS for 10 years, then a friend suggested to stop eating wheat, and 95% of my symptoms went away.

I'm actually about to start testing a FODMAP diet to see if I can improve my health any further.

Have you tried anything to improve your health, or did you just accept the IBS diagnosis? I only ask because I've seen no research that suggests IBS is a real thing, just a catch-all for many potential things.

I have Crohn's and I did the FODMAP diet when I had very severe symptoms. What I found: it does actually work and remediated a lot of my severe abdominal pain centered around eating (in conjunction with medication) BUT... I also found it absolutely miserable on its own. I think Soylent might be more appetizing to me by an order of magnitude. Good luck!

What did you find miserable about it? Elimination of certain foods or something part of what you were actually eating?

Replying to your paleo comment.

Yeah, I think for those of us with "Generic IBS" we need to be aggressive in trying out different approaches to try and heal our gut issues.

I went paleo once I realized wheat was causing me all sorts of stomach issues, and over the years I drifted more and more towards a "natural and whole food" diet, and as my intake of veggies grew, I realized that asparagus and brussel sprouts seemed to do a number of me. When I went to the gastroenterologist to try and figure out what was going on there, he first recommended drugs, which I declined, but he then suggested looking into the FODMAP diet, and it turned out that most fructans were triggers, as well as some polyols.

When I ate wheat, I suffered from tenesmus, depression, back acne, short-term memory loss, alternating constipation/diarrhea, migraines, etc. Now my only symptoms are diarrhea and some stomach pain when eating fructans. I'm hoping going FODMAP only will solve the remaining issues I have.

All that said, I'm just advocating that we try whatever we can so collectively we can get data on what works and what doesn't. If we just accept the doctors diagnosis of IBS and treat it with drugs, we'll never collectively solve the underlying problem.

I completely agree. Had bowel issues for years. Finally figuring out how to avoid that was worth all the tinkering.

I hardly think about it anymore. And I'm very glad to have figured it out without pharmaceuticals.

@Graeme (can't reply double-nested): I just found it to be very bland, boring and depressing. Chicken and rice, rice and chicken, tuna, rice crackers, blah. Go to the printer room in your office and start chewing on the printer paper/some cardboard in there. That's about how tasty the FODMAP diet is after about a week. It's even harder socially when you are restricted from basically everything on the menu. I guess your mileage may vary but those are my personal thoughts. I did Low FODMAP for about 2 months and by necessity (staying out of the urgent care/emergency room), not really by choice.

Ok, interesting. I eat paleo, and I seem to unintentionally eat low fodmap. Sauerkraut and some onions are the only ones I eat regularly. I checked the wikipedia list.

But not much rice. I eat a lot of local, pastured meats, sweet potatoes, much coconut oil for cooking and seasonings, so it doesn't seem bland. I find chicken very bland and would have trouble eating it more than a few times per week.

Used to have digestive upset, though in my case I'm not convinced FODMAPS had anything to do with it (like I said, unintentionally low fodmap). Nightshades seemed to have the greatest correlation for me.

Have you been tested for Coeliac disease?

A "syndrome" is a classification of related signs and symptoms without relating them to a single underlying cause, so yeah, that's what it means. As more is learned about the causes, different disorders can be removed from the syndrome.

True. But note that "can be" does not mean "will be". For example, AIDS is a syndrome (thus the "S") whose causes have been pretty well understood for some time. However, it is still defined as a syndrome.

Not according to people like Serge Lang

Yes & no.

If one takes the position that we do not have enough evidence to come to a particular conclusion (as Lang did), then one takes that position with respect to the information available at a particular time. I don't know at what point Lang last stated such a position. Regardless, he's been dead for nearly 9 years.

AIDS is one of the most studied diseases in all of history; we learn more about it every year. It is certainly possible to state that we know HIV causes AIDS, without disagreeing with with Lang.

It's maybe worth pointing out that syndrome is completely absent any value judgment (in keeping with the scientific tradition of modern medicine); it's literally just a combination of symptoms that occur together.

From http://dictionary.reference.com/: Greek syndromḗ concurrence, combination

As far as I understand it, AIDS is a syndrome rather than a disease because while the cause of the immune system deficiency has a single cause, many of the symptoms are caused by secondary problems that arise because of the immune system deficiency, and so the symptoms do not have a single direct cause, even though they're all indirectly the result of HIV, and the immune deficiency itself is a direct result of HIV

I think it would be more accurate to say that AIDS is a syndrome because it's defined as such. You can also speak of HIV disease[1]. HIV disease would be the disease associated with the human immunodeficiency virus. AIDS refers to a particular syndrome. They mostly overlap, but they describe slightly different concepts. My speculation is that the reason the distinction persists is mainly historical: AIDS was described and became well known before the HIV virus was discovered and was demonstrated as the causative agent.

[1] http://emedicine.medscape.com/article/211316-overview

> My speculation is that the reason the distinction persists is mainly historical ....

I imagine another reason for the distinction is that AIDS is typically a late stage of HIV infection. That is, people who develop AIDS have usually been infected with HIV for some time.

That would have played a role. No doubt.

I've tried eliminating wheat, sugar (in case it was fructose malabsorption), dairy, etc. I've tried tons of supplements like fish oil or vitamin D. Interestingly, each of those except dairy had very positive effects on my health in general (weight loss, clearer skin, elimination of seasonal depression) but had little effect on IBS symptoms.

What did improve it (but not eliminate it) was taking an SSRI, which isn't surprising since they have been shown to help in trials. My mother also has both IBS and an anxiety disorder, which is consistent with research showing that there is a genetic factor. I wouldn't be surprised if there are multiple possible underlying causes, but I really think IBS is a legitimate diagnosis.

First, it's great to hear taking the SSRI helped!

Regarding the diagnosis of IBS, What I'm saying is, I've yet to have had (or seen) a test that definitively states "yes, you have IBS".

During my time with stomach issues I've been tested for UC, Crohns disease, Celiac disease and gluten sensitivity. All the bloodwork and whatever else came back with definitive nos.

Once all of those were ruled out, then the diagnosis became "IBS". Meaning, I didn't take a test that said I had IBS, I was symptomatic and all the actual tests they could run were negative, and hence, I had IBS by default.

What that meant to me was, something is wrong, they just don't know what it is, I should keep searching and trying things to figure out what they don't understand.

I've read so many posts where people get diagnosed with IBS, take the prescribed drugs, and just suffer for the rest of their lives. I just want people to understand they should feel empowered not to settle for the IBS diagnosis and explore options to try and solve the issue for themselves (like you did via SSRI).

What do you think about the possibility that the etiology is neurological? Here's my reasoning:

* There's also no simple yes/no test for most mental illnesses

* It explains why it correlates so heavily with anxiety disorders

* It explains why it is treatable with psychotropic drugs

* Falls in line with the increasing evidence that the enteric nervous system plays a role in both IBS and anxiety

Absolutely! The other wonky thing with my health is that I have had Vagal Atrial Fibrillation (VAF) in the past (which is rare for someone in their 30s).

One trigger for VAF is indigestion in the stomach, which irritates the vagal nerve, which messes with the heart. The vagal nerve also runs into the brain, so I bet there is some form of two way conversation happening between the stomach and brain being facilitated by something like the vagal nerve.

To your point, when I was heavily symptomatic, I felt depressed (deeper then just being sad about my situation), and changing my eating habits cleared that up, and in your case, fixing the brain chemicals seemed to have benefitted your stomach.

Its just a guess on my part, but this is really all fascinating stuff.

> fixing the brain chemicals seemed to have benefitted your stomach.

How do we know the drugs didn't fix the stomach chemicals (enteric nervous system) directly, resulting in better brain function?

To bring this full-circle, this goes real well with the original article's idea that the GE system is highly coupled with the nervous system and psychological condition—it's very likely in both directions.

There was recently a post here on HN that relates to this. As a UC sufferer I found it very interesting.

> How the Gut's "Second Brain" Influences Mood and Well-Being (2010) (scientificamerican.com)

https://news.ycombinator.com/item?id=7957057

It has often been noted that "stress or feelings of anxiety, guilt or resentment seem to trigger the symptoms":

http://www.mckinley.illinois.edu/handouts/irritable_bowel_sy...

Have you considered doing a fecal transplant?

I knew people were talking shit on Hacker News, but I didn't realize that it was such a literal thing! :P

On a serious note, yes, this. I have a cousin who had really bad problems until he did such a transplant, and he said it pretty much gave him a new life.

I'm willing to try anything safe and shown to be effective scientifically. However, at the moment I have poor health insurance and little disposable income, and my GI doc wants me to do a CT scan that would cost me $1600 out of pocket to rule out IBD and a few other things before continuing. So basically I've hit a brick wall for the time being.

Have you tried fasting?

Multiple times and not just for IBS but many reasons ranging from breaking a weight loss plateau to preventing anxiety attacks after the probiotics. It definitely reduces IBS symptoms while I'm not eating, but the hunger makes me unable to think about anything but food.

I've had mild IBS-D for as long as I can remember, and I've just had a very good experience with a 7 day water fast. It's been 2 weeks since I've finished my water fast, and I've had 0 incidents. Obviously this is anecdotal, since there is very little peer reviewed research on water-fasting in general, and specifically wrt to IBS.

They know the problem; irritable bowel, but not what causes it. That's why they call it a syndrome and not a disease.

It's the same with AIDS vs HIV infection. AIDS: we don't know what causes it, but it is acquired immunodeficiency. HIV: it's a disease caused by this virus.

IBS is a "diagnosis of exclusion," so in some sense it is not a "real thing," but more accurately the "absence of other things." I really hated that answer, but it's the conclusion that more than a half-dozen different gastroenterologists came to after trying countless tests on me over the course of many years.

After a lifetime of trying to be gluten free (on and off), with limited success, I started a low-FODMAP diet on December 15, 2012 and it completely changed my life. I could not find many dietitians that knew much about it, so I mostly followed the advice of books like IBS: Free at Last! (http://amzn.com/0982063520). Now I feel much more empowered and in control.

Also, not all FODMAPs are equal. Each individual has to figure out which FODMAPs cause the most problems. Being "low FODMAP" is WAY different from being "gluten free." I eat FODMAPs all the time -- I just limit certain ones more than others and I know my limits. And even after 19 months of being low-FODMAP, I still have to consult my list of foods regularly.

Only after doctors have ruled out Crohn's disease, celiac disease, diverticulitis, endometriosis, cancer, etc., and suggest you have IBS, I highly recommend trying a low-FODMAP diet.

I had IBS-D from about the age of 10 to the age of 29. I'm 42 now. What changed for me 13 years ago is that I learned that humans require eating dietary fiber and changed my diet to accomplish that.

I eat about 40 grams of dietary fiber and drink at least a gallon of water every day. It actually takes work to reach this goal, but the plus side is that once I started doing this I have had no symptoms of IBS for the past 13 years.

Wow, that's a pretty amazing amount of fiber and a great success story. I would caution applying this advice to everyone, though. As anyone who has a lot of intestinal inflammation can tell you very quickly: fiber is like steel wool dragging through there. Ouch! I think this especially highlights how IBS is a range of causes/symptoms, not one distinct disorder.

IBS does not typically present with inflammation. Those are typically hallmarks of inflammatory bowel disease like colitis or Crohns.

http://www.healthychildren.org/English/health-issues/conditi...

There are some sources that say inflammation does play a role in IBS but every study I've read says it does not.

Very interesting. I indeed have Crohn's, not IBS. I thought they would be more closely related, but this article [1] from the CCFA has made me change my mind a little bit...

[1] http://www.ccfa.org/resources/ibs-and-ibd-two-very.html

Do you have another other dietary restrictions, other than the fiber and water? Just curious. Thanks.

No other dietary restrictions.

> I tried Primadophilus Optima and it wrecked me.

How can you be sure that taking probiotics for your IBS is the cause of your IBS getting worse?

I don't for sure. In fact, it is definitely confounded by the fact that I quit my SSRI a month and a half prior. However, the reaction I described began a day after I started the probiotic. Also, it gradually decreased in intensity over the two weeks after I stopped the probiotic and I resumed my SSRI. Just to be sure, I took another and the whole thing happened again.

Interesting that you mention anxiety. After particularly poor eating, where I start to feel physical distress, I've noticed alprazolam seems to help considerably. Likewise, for some cases of light nervousness, I've noticed pepto bismol seems to calm my nerves.

Most of my panic attacks occurred immediately after a meal as well. I discovered a couple of interesting things:

* Magnesium Citrate tablets were able to stop or lessen the attacks, but only when they occurred after a meal. I suspect the laxative effect of magnesium is responsible. * The only food that wouldn't trigger anxiety was coconut-based items, which I suspect has to do with coconut oil comprising mostly MCTs, which take less work to digest.

Just to provide an alternate anecdote, I take probiotics fairly regularly (one to three in sequence every 1-2 weeks, or whenever I get out of whack) and have only had neutral or positive results. The flora in the probiotic is really nothing that shouldn't already be in a healthy gut, although of course you do want to be very careful as it's clear that your gut micro-biome is very important to your overall health. Just another data point.

> The flora in the probiotic is really nothing that shouldn't already be in a healthy gut

Perhaps the important factor isn't which species are present, but their distribution or some other factor of which we are still ignorant. In any case, I'm glad you've seen positive results and I may try them again in the future with single-strain supplements once this ordeal is long behind me.

Brewing your own probiotics may be a safer option. People have been eating Sauerkraut for 1000s of years. I just add chopped cabbage and a tablespoon of salt into a quart-sized jar, fill with filtered water and wait a week or so until it tastes sour enough.

This.

Ex IBS sufferer here.

Fixed it myself after 3 years of hell from doctors who quite clearly were a) short of any realistic knowledge on the matter and b) quite clearly using me as an experimental subject for everything the drug company was pushing at the time.

Worked out how to reset it myself: just drank water for the best part of two weeks and low end carbs (bran flakes with water on) and nothing else. Felt like crap for about 4 days then started to improve. After my butt stopped wrenching daily, I introduced normal foods back one at a time over the space of 3 months, ending with meat and heavy carbs.

I got these steps from a microbiologist rather than a doctor.

That worked for me wonderfully.

If you still have IBS you might want to try http://nordicrebalance.dk/en

I was told about it recently and am going to start treatment in a couple of weeks. They claim a 95% rate in chance of improvement amongst test subjects according to [1]. There are also a few more studies on their website supporting the product. They do however seem to be a relatively new company and I haven't been able to find much information besides their website. I have been told that the doctors behind it have been researching IBS and CD for about 20 years, so that seems to be a plus.

[1]http://www.ncbi.nlm.nih.gov/pubmed/11711768

Popular media reporting on complex scientific/technical/legal/etc topics should always be viewed with suspicion. Googling for the researchers' and journals' names produced the following:

Dr. Mayer's study about women's responses to facial expressions. http://www.ncbi.nlm.nih.gov/pubmed/23474283

Elaine Hsiao's study about certain autistic behaviors in mice. http://www.cell.com/abstract/S0092-8674(13)01473-6

Here on HN, we should favor articles that link to the original sources so that the domain experts among us have an easier time digging into the claims. For example, NPR's reporting at http://www.npr.org/blogs/health/2013/11/18/244526773/gut-bac...

No expert on the topic, though it really interests me. Have been drinking EM (http://en.wikipedia.org/wiki/Effective_microorganism) every day for the past 6 months which has improved my digestion a lot.

Thought this comment on the NPR article was really insightful:

There's so much more to developing a healthy microbiome than just eating yogurt and drinking kombucha, as many people like to claim. It starts at birth. As you travel through the birth canal, you come into contact with many different and important microorganisms through contact with your mother's vaginal fluids and even fecal matter. If you're born via C section, you're starting out at a disadvantage. Then breastfeeding is the next step. Mother's milk is where you get your next dose of a very broad spectrum of microorganisms. Then throughout life, as you come in contact with other people, you eat dirt, you hang around farm animals, etc, these are all mother nature's way of helping you develop that microbiome, which is essentially the core of your immune system. Eating is important too, and one of the biggest problems with our modern food system is that everything is pasteurized, cooked all the way through, sterilized, irradiated, etc. All of the healthy microorganisms that used to exist are being killed.

So the point here is that people need to rethink many of their lifestyle choices if they want to heal their guts. Every time you take an antibiotic, you likely suffer much collateral damage because you may be permanently killing beneficial species that you may never be exposed to again. They don't exist in yogurt or kombucha. Either that, or consider fecal bacteriotherapy (fecal transplants) since it seems to be one of the the most promising new approaches to healing microbiomes. ~Julie Latham

Totally non-scientific response to this, but I can say that after having to take antibiotics a few years back for a pretty bad sinus infection my digestive system has never completely recovered. I never had any sort of digestive issues that I can think of but have had numerous since then. I can't directly contribute it to the antibiotics, but it certainly seems to correlate.

Taking probiotics helped quite a bit, which I did a month or so after the antibiotics started causing these issues, but yeah, never completely felt 'better' since then. I guess this is yet another example of why/how over prescription of antibiotics is a bad thing.

>as you come in contact with other people, you eat dirt, you hang around farm animals, etc, these are all mother nature's way of helping you develop that microbiome

I find that way of personifying our environment counter productive. It's not mother nature's way of helping us, it's that we evolved over millions of years in this environment and to change that is to hinder ourselves. I find this a much more accurate and convincing way of arguing for a back to nature style of development and nutrition.

I must agree with this. I've been suffering from IBS for a while now. Anytime I have a flare up, I most certainly have severe anxiety (and it's not just anxiety of having to deal with the flare up. Anxiety symptoms like chest pain, shortness of breath, weakness just show up). I've tried a few probiotics but didn't see any noticeable difference though.

I'm just asking, but is there any chance the connection is the reverse?

Stress and anxiety can cause digestive symptoms.

I have Crohn's disease (similar) and you have a good point. In reality it's a vicious feedback loop where 1) you get stressed out 2) your symptoms flare as a result of stress 3) you get more stressed out because of the symptoms. Works both ways and there's no easy way around it.

The interesting part is that even if that's the case, treating the digestive symptoms in an effective way could provide meaningful relief, cascading back into the emotional state that caused the initial problem.

I've had it described to me in the following way; stress creates physical manifestations of that stress, those physical manifestations create discomfort, that discomfort creates stress. The feedback loop, once in place, can accelerate the anxiety. It can also be used to shut the anxiety down. It is possible to focus on the physical manifestations and "cut the strings" of the cycle by relieving those symptoms through meditation and treatment. You're left with the original stressor, but the feedback cycle doesn't help you get better as long as it is active.

So essentially changing diet is partly (or mostly) a placebo effect. IMO it is better to understand the causes of IBS/anxiety/stress and make changes to your lifestyle that address the root cause, rather than believing dubious science about gluten. (I'm not saying that you personally believe this crap science, but there are a lot of people out there who do). That has certainly worked well for me. I still do have IBS on occasion, but after doing some research into the HPA axis and ANS (and how the control gastric emptying, colonic transit and absorption) I now understand exactly why I have the symptoms, and they are very manageable. I don't have CFS, burnout, fatigue, anxiety or depression any more, but mild IBS seems to be a fact of life. Working for myself at home certainly helps a lot.

> So essentially changing diet is partly (or mostly) a placebo effect. IMO it is better to understand the causes of IBS/anxiety/stress and make changes to your lifestyle that address the root cause, rather than believing dubious science about gluten.

That sounds very much like the approach a software/hardware engineer would have towards a bug. And it's great!

However, I'd say that the human body can't really be approached that way because of its, very much, inconstant nature (at least until we've figured out 100% how our bodies function).

In the current state of knowledge human kind has about biology, it would be very hard to pin-point a "bug" (IBS/stress/anxiety for example) to a specific root cause (bacteria x or y). On the opposite end, a software bug ultimately has one (or multiple) very much identifiable root causes.

All that to say that, it might not be possible to understand the causes of IBS/anxiety/stress, and thus, treating the symptoms might actually be the cure. (who knows, maybe treating a "biological bug" fixes the actual bug?)

It's also a chicken and egg problem: which started first? IBS or stress/anxiety?

Yes, it's a little more difficult pinning down problems with the human body than in a piece of code, and these kind of functional problems even seem to have stumped most of the medical profession. However I see it as an engineering challenge. Essentially you are looking at a complex system and trying to solve a problem in a piece of machinery that you don't have any information about. Sometimes working around bugs in android or iOS can involve similar detective work.

In terms of IBS, there is very little doubt that in my own situation that stress causes the IBS rather than the other way around. Diarrhea during the week, followed by constipation during weekends. Or diarrhea preceeding before a novel event. These are repeatable and predictable - it just requires taking a close look at your situation and seeing if you can see any correlations. Unfortunately it can be easy to get fooled into seeing correlations that don't exist.

I think this vicious cycle is one of the biggest human bugs around. It's a malfunctioning recursive negative feedback loop.

I wonder if there's a strong correlation between those who suffer IBS and people working in this industry. Seems to me like the mentality to continually push forward and overwork/stress ourselves can only contribute to poorer health both mentally and physically. Personally I suffer from.. Hmm, I'd say IBS-D based on the classifications mentioned here, although my symptoms are fairly mild (however, very consistent - ~5 years and counting..) save for a few more painful symptoms every now and again. There was an article on here last week talking about the strong correlation between our guts and our brain as well. These articles seem to gain a lot of popularity here on HN, which makes me think that this problem is more wide spread than it appears (perhaps just amongst HNers)

I'll report that I too have personally experienced a strong link between my gut and my mental state (I occasionally suffer mild panic attacks). I'm tired of having bowel problems - if anyone has any suggestions that have worked for them I'm open to hearing them (and I'm sure there's plenty of people reading who too are looking for suggestions). I've been working on removing wheat from my diet - I can't speak to the effectiveness yet as I've only just begun.

Good point. I'd be interested in knowing as well.

I stopped drinking sodas, alcohol and milk. That helped a lot. I also physically moved and started working from home. This combination has almost stopped the symptoms.

It seems like a combination of my diet, stress and overworking are the biggest factors for me.

My anecdotal evidence suggests the probiotics that fix your pooping problems fix your mood too. If they make your poop worse, your mood will suffer as well.

Constipation has sometimes produced the bloodiest scenes. My grandfather, who died a centenarian, was Cromwell's apothecary; he has often told me that Cromwell had not been to the toilet for a week when he had his king's head cut off. - Voltaire

It's always interesting to think of humans as giant integrated microbiomes. Our bacteria is part of who and what we are.

Hi there, I'm CEO of uBiome. It's a really fascinating area and there are a lot of interesting discoveries coming out. If you'd like to learn more about your microbiome, check us out at www.ubiome.com.

Similarly, hypothesis like these were why I invested in uBiome.

Bacteria feed on nutrients we ingest with our food, and like people, bacteria don't use everything they eat. Whatever doesn't fuel their growth and reproduction, the bacteria expel as waste.

That waste gets into the blood and probably into the brain, changing its chemistry.

If this theory is correct, does it mean that a drastic change in diet might change a person's behavior? I'm imagining a future where people match their diet to their intestinal bacteria to increase or reduce the "waste" that gets produced to achieve a desired mood or behavior.

This goes beyond just bacterial waste into macronutrients like sugars messing with your blood sugar level and thus mood. And who knows what a lifetime of pesticide or herbicide consumption will do to you... I guess we'll find out, some of us anyway.

Or the short answer is yeah your diet strongly affects your behavior. If you don't believe me do drink a couple Mt Dew and see what happens, or a couple beers.

> If this theory is correct, does it mean that a drastic change in diet might change a person's behavior? I'm imagining a future where people match their diet to their intestinal bacteria to increase or reduce the "waste" that gets produced to achieve a desired mood or behavior.

The concept is really not new. Diet has long been linked to mood and behavior in traditional medicine. It wouldn't be a shocker to learn that some traditional approaches to dietary therapy are actually effective, though probably not for the reasons they proclaimed.

In fact the concept is very old (not to say anything about whether it's correct or not).

"All Disease Begins in the Gut" ~ Hippocrates

According to Wikipedia, Carl Pfeiffer[1] researched mental illnesses, mainly schizophrenia, from the point of brain chemistry imbalances and dietary changes to alter it.

The theory is, that there are chemical imbalances with patient's brain chemistry which can be influenced by dietary means. There's a book called Nutrient Power[2] which goes on about this theory and Pfeiffer. I haven't read it, but admittedly it sounds interesting. But then again, maybe it's all woowoo (It's rated as #1 bestseller in homeopathy medicine by Amazon, go figure).

Then again, for example many vitamin deficiencies alter mood and general "energy levels", and for example fish oil (or omega-3 fatty acids), according to Examine.com's[3] user-collaborated round-up, shows some effects on mental well-being, more on the physical functioning of the body though.

Be skeptical.

1: https://en.wikipedia.org/wiki/Carl_Pfeiffer_%28pharmacologis... 2: http://www.amazon.com/Nutrient-Power-Heal-Biochemistry-Brain... 3: http://examine.com/supplements/Fish+Oil/

It's interesting that your digestive system 'thinks'. I've always found the Vagus nerve's role in satiety to be interesting. It's a big nerve from the brain that extends directly down into the abdomen. http://neuroscience.uth.tmc.edu/s4/chapter04.html

Although I see a connection, I stopped taking this article seriously when I read this sentence:

"Their study, published last year, was funded in part by Danone Research, a division of multinational food company Danone."

So? Danone makes yogurts with probiotics. I think they might be interested in knowing if there is any value to a diet <=> mood connection. If you would take your head out of the sand you'd know that lots of research is funded by industry and that's not necessarily bad.

Yeah, no conflict of interest whatsoever...

Breaking: people invest money in things that interest or could benefit them. I can see what you're saying but your own personal (subjective) opinions about corporations may be clouding your reasoning.

"your own personal (subjective) opinions about corporations" What do you know about my opinions?

@Paul_Dessert: you don't try especially hard to hide them.

Just because they have a special interest doesn't mean that there is a conflict of interest. You can still get useful science from people that are hoping for a particular outcome.

First of all, they acknowledged the conflict of interest.

Are you suggesting, based on zero evidence, that their findings were somehow fabricated - a claim that if true would ruin the careers and lives of the scientists at hand?

While not unthinkable, it is a type of conspiracy theory thought. Should you have a problem with their methods, data acquisition, etc etc. then it would be a completely different story, but to dismiss something based on some sort of belief is very unscientific.

I'm not arguing the science. It may be 100% correct. My issue the fact that a corporation with a very big upside is funding the research. That's all.

Think about it.

You'll have to do better than "think about it" if you want your reasons to make sense outside of your own head.

It's okay. I understand common sense isn't so common...

> Are you suggesting, based on zero evidence, that their findings were somehow fabricated - a claim that if true would ruin the careers and lives of the scientists at hand?

It's usually more that if a researcher is trying to research something they really want to believe, it is extremely difficult to stay objective. Subconsciously, they can easily miss or overlook things that appear insignificant at first glance, but are actually very important.

Making note that there's a conflict of interest is very important, and when there is one, it's not unreasonable to wait for the experiment to be reproduced before really believing it.

but which research is favoured, published and promoted?

The book 'Not All in the Mind'[1], published in 1976, is definitely worth a read. It's been a while since I picked it up and my copy is in another state while I'm away from work, but I remember it being very pertinent to this conversation. (I'd write more about, but it's 01:00 where I am and I'm falling asleep at the keyboard).

1. http://www.amazon.com/Not-All-Mind-Richard-Mackarness/dp/033...

Having been diagnosed with probable IBS, I have noticed mood changes related to the intestines. But I always linked it to impaired absorption of some nutrient or another, but never with bacteria.

Wanting to get a product rich in Resistant Starch out there is part of our process motivation for MealSquares. We're presoaking our oat flour in an acidic medium and then asking customers to refrigerate their MealSquares in order to maximize the amount of RS formed by retrogradation.

Resistant starch is starch you can't digest but your gut bacteria can. It's been shown to have a variety of health benefits.

But which came first, the intestinal issue or the mental health condition? These studies seem to begin with an assumption that the physical ailment arises first. What if it's not the case... What if that assumption is just the opposite, and it's the mental health issue impacting the physical well-being?

If you're interested in the Bacteria-autism connection mentioned in the article, here's a great talk by the researcher: https://www.youtube.com/watch?v=FWT_BLVOASI (The topic is "Mind Altering Microbes")

The newspaper article by a freelance journalist kindly submitted here proved to be interesting to read all the way through, and prompted me to read all the comments here posted before I saw the thread, and also to look up the researchers mentioned in the article and the author of the article. There are interesting ideas here, but this is very preliminary research, based on early animal studies mentioned with human studies with very small n and a short time frame. ("The researchers gave 12 healthy women fermented milk containing a probiotic supplement made up of five different strains of bacteria thought to have a positive effect on the intestines. The women drank the milk two times a day over the course of four weeks. Another group of 11 women drank milk without probiotics.")

It's quite a bit too early to tell if altering your personal dietary habits will have any predictable long-term effects on your mood (the article title says "may" after all) and especially what alterations in intestinal microorganisms have what interaction with what other health outcomes.

So far, "modern life" appears to be good both for reducing mortality and reducing morbidity, as life expectancy at age 40, at age 60, and at even higher ages is still rising throughout the developed countries of the world.[1] A variety of incremental changes over the last century have allowed us all to enjoy longer, healthier lives than our ancestors a hundred years ago, as reported in an article in a series on Slate, "Why Are You Not Dead Yet? Life expectancy doubled in past 150 years. Here’s why."[2] If deeper understanding of the health effects of intestinal microorganisms leads to even more incremental improvement in disease prevention and treatment, and increase in healthy lifespan, that would be great. So I heartily support research on these topics. (I remember that the father of Freakonomics co-author Steven Levitt spent his career at my alma mater university studying intestinal gas with federal grants--I'm not making this up.) But we can't be sure yet what the recommended practice will be for how we eat or whether or not we should have particular microorganisms put into our intestines.

Meanwhile we can be happy that ongoing medical research and perhaps other factors we don't fully understand seem to be driving steady increases in healthy lifespan. Girls born since 2000 in the developed world are more likely than not to reach the age of 100, with boys likely to enjoy lifespans almost as long. The article "The Biodemography of Human Ageing"[3] by James Vaupel, originally published in the journal Nature in 2010, is a good current reference on the subject. Vaupel is one of the leading scholars on the demography of aging and how to adjust for time trends in life expectancy. His striking finding is "Humans are living longer than ever before. In fact, newborn children in high-income countries can expect to live to more than 100 years. Starting in the mid-1800s, human longevity has increased dramatically and life expectancy is increasing by an average of six hours a day."[4]

[1] http://www.nature.com/scientificamerican/journal/v307/n3/box...

[2] http://www.slate.com/articles/health_and_science/science_of_...

[3] http://www.demographic-challenge.com/files/downloads/2eb51e2...

[4] http://www.prb.org/Journalists/Webcasts/2010/humanlongevity....

Follow @phylogenomics, look at recent his recent rants. Almost certainly this is correlation/causation bunk about the microbiome (in addition to the other problems noted here).

It's not really surprising that intestine and heart systems have their own state and impact on your whole self. I believe they came first in our design history.

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