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Neuroactive potential of human gut microbiota in quality of life and depression (nature.com)
135 points by nyxtom 17 days ago | hide | past | web | favorite | 61 comments

Purely anecdotal but, I've been expirmenting drinking and making kefir and fermented veggies (mostly spinach). After a few days, my digestive system was the most regular it's ever been. I feel happier too but correlation vs causation and what not.

If you're eating a lot of spinach, you could just be experiencing the well-known effects of dietary fiber.

True, and people are investigating new ideas about dietary fiber thinking that perhaps it's not just for "bulk" and helping keep things "regular": https://www.ncbi.nlm.nih.gov/pubmed/29902436

"In this review, we will focus on dietary fibers, which interact directly with gut microbes and lead to the production of key metabolites such as short-chain fatty acids, and discuss how dietary fiber impacts gut microbial ecology, host physiology, and health."

I though it was already known that soluble fiber contributes to microbiome health (and not much to motility) and insoluble fiber is mostly helpful for bulk and motility.

Does this study address the role of insoluble fiber in microbiome health?

Interesting, I thought spinach was a hard vegetable to ferment because it gets soft and sloppy quickly. Could you share a recipe?

Spinach is great but don’t overdo it. The high oxalate content can cause problems for some people. Good to get a variety of different greens, of course including spinach.

So.. for the non biochem crowd.. what should I eat to get the kind of bacteria that helps with depression ?

What follows is purely anecdotal and just my experience, but protracted fasting had obvious changes on my general mental health.

My experiences were a month of 3 day water fasts followed by a meal (whole foods like plants and steak), and since then (this was 2 years ago) I do a 3 day fast every 1-2 months or so.

I also was able to stop craving sugars (sodas/ candy, etc) after that first long fast.

I have nothing conclusive, but I suspect that the changes in my mental health and dietary cravings have to do with killing off chunks of my microbiome in the first long fast. Could just be either placebo or other life changes (I turned 40, my wife had left me a month before, and I gave up drinking for 6 months during and after the fast).

So your milage may vary, but if your question is sincere, it might be easier to modify a biome by trimming it back rather than adding to it.

I'd be super stoked to have contradictory / corroborating evidence, though.

Your life left you a month before and you think that it wasn’t that but the fasting that affected your mental health?

Well, who knows?

The changes to my general modes of dealing with stuff were pretty dramatic. I don't think that my wife leaving made it easier to not eat sweets, but who knows?

I was still pretty upset, I just wasn't suicidally depressed, which was a fair improvement. And as I have continued with the fasting through the months, I have felt better around those times when I'm fasting.

Another voice for fasting from here too.

I do 16:8 intermittent fasting and my energy levels are a lot better. Basically I just eat my last meal around 19:00 and skip breakfast. Lunch around 11:00.

I may have a sugar free energy drink in the morning to pick me up (my poor stomach doesn't approve coffee any more, too much of it in my younger days... =) )

I’ve been doing this too and I was skeptical but it does seem to be making a significant difference. My blood sugar levels are a lot more stable and I don’t get hungry and shaky anymore. I can easily skip another meal now too if needed and it’s no problem.

wait, are you saying that you're general mental health changed for the better, or for the worse? I think you forgot to mention that.

LOL. Yeah, for the better.

I had to ask because the tone of the article is beneficial microbiota that corresponds with happiness. To kill microbiotas by fasting seems to go against the article...

I imagine, if there's any relationship to fasting at all, it's that the fast doesn't so much kill all bacteria but changes the population profile in a beneficial way. For example, perhaps bacteria that subsist on refined sugars can't tolerate starvation so easily.

giving up alcohol is doing wonders for me too

The SMILES trial ( http://foodandmoodcentre.com.au/media/smiles-trial/ ) had good resultat with their diet.

But in general many different kinds of plant based foods to promote biodiversity. According to ( https://youtu.be/-LUuqxQSaFQ )

Poop from somebody who isn't depressed.

That sounds like I'm making it up, but unfortunately I'm not.

Yup. It's called a fecal microbial transplant (FMT) and it works for several problems, notably C-diff infection. (Unfortunately it isn't the first-line treatment for that nasty bug, it is usually preceded by weeks of antibiotics and only used when they fail. Source: personal experience.)



I worry that there may be currently unknown compatibility issues between donors and recipients, and that a recipient could be worse off after the wrong donation.

Also: unfortunately, it's hard to get your hands on.

My God... Alex Jones is going to have a field day... "they force our kid to eat poo poo!"

I noticed a huge lift in my mood when I switched to a completely plant based diet but if that’s too radical for you I think you can get a lot of the benefits by just massively increasing the amount of fresh fruits and vegetables you eat and sticking to whole, unprocessed carbs. Adding some fermented foods like natto or kimchi should help too.

I just stopped eating meat that had 4 legs at one point. (Beef, Pork, game meats)

Digestion issues didn't go away completely, but everything is noticeably better now.

going plant based improved my health dramatically too. i used to think i was carnivorous. turns out i was just speeding up aging

One consistent thing I've heard never to consume because it destroys gut bacteria is diet soda.

I have seen that idea popularized here on HN for sure - it seems almost every physical or mental health and diet related post gets a comment about "the gut microbiome" which either mentions or is replied to by a comment that claims diet soda "destroys" it. The frequency with which this is mentioned is definitely pretty high, but I've not come across any links to studies or further reading on the idea.

EDIT: Here is what I believe to be a source of many such claims, a 2014 study suggesting that artificial sweeteners can alter gut flora in mice to lead them to being glucose intolerant: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4615743/

I'd be interested if there's anything more recent or conclusive about this - plenty of sensationalistic articles seem to be out there either extrapolating from or challenging this study, but I'm not able to deduce anything further.

My low-information read of the current state of knowledge is: we've established at very high confidence that the gut microbiome really is very important.

And that's it; we don't know anything more detailed than that.

I would add that acidophiles specifically have a good amount of evidence behind them.

Here's a random study about vaginal microbiota:


There's also a probiotic called visbiome (formerly* known as vsl #3, which is the name the research literature uses) that has shown a lot of effectiveness for IBS and similar issues. I don't feel like digging up the studies for that unfortunately but there's quite a bit of evidence.

* vsl #3 is still marketed but is supposedly a different manufacturing process now. thus visbiome is now the "real" one

The state of nutrition science is so poor.

But intuitively eating unprocessed foods that are not made with artificial or chemical anything (including artificial sweeteners) is probably a good start.

Fasting is probably another good way to reset your gut.

I don't think "resetting your gut" is a good way to think about it. Taking oral antibiotics will "reset your gut", in the sense of killing most of the existing biome and leaving space for new flora to grow into, but that can lead to problems as the biome that develops from a clean field isn't the same as the standard biome. To the best of my knowledge, you normally inherit your gut flora from your mother during birth and nursing, and then your gut hopefully stays stable over time. "Resetting" is more likely to give you a worse biome than a better one.

Resetting by fasting is nothing like taking antibiotics


Drosofila. Flies. Linked article is about flies.

your point is...? scientific experiments are often done on genetically similar animals.

Is it because diet soda doesn't provide nutrition to gut bacteria, but still takes up the space actual nutrition could have been in, and thus the gut bacteria don't get access to as much nutrition?

Edit: poor wording above. I meant to ask whether the artificial sweeteners could take the place of nutrition for the gut bacteria but not actually provide enough nutrition.

(not a scientist but that doesn't seem plausible. water takes up equal space to diet soda and also provides no nutrition.)

Ah, I should've written a more generic "takes the place of" instead of space. I meant to ask something along the lines of whether the artificial sweeteners of diet sugar might be confused for nutrition by the gut bacteria. Basically, I was picturing a situation where the gut bacteria might try to "eat" the artificial sweeteners, but then don't end up getting enough energy from it and can't do the things they need to do.

Like how xylitol can kill mouth bacteria because they eat it instead of other sugars but can't metabolise it.

Yes! That's pretty much the mechanism I was thinking of.

Couldn't you say the same thing about water?

Good point. I worded it very poorly and your answer would definitely fit. I meant to ask whether the artificial sweeteners in diet soda were taking the place of nutrition for the gut bacteria, but don't end up giving the bacteria enough energy/resources to live on.

Can confirm. The artificial sweeteners in Pepsi MAX make my farts smell goddamn awful.

Coke Zero doesn't do that, but I still try to stay away from diet sodas.

Kimchi - full of pro-biotics and good for your gut, apparently - is what makes my farts smell worst of all. Worst incident was a freshly-home-made batch, played bass in a show the after eating it at dinnertime and the smell actually made the drummer vomit :(

I'd be interesting in reading some papers on this if anyone has them

Never seen a depressed person who had a full slice of cheesecake in front of them ;)

I get your jest, but as someone who struggles with depression and uses food as a coping mechanism, this is sadly not the case. My personal experiences also make me acutely aware of others in food courts who really aren’t enjoying the food they are consuming.

I bet at least one pharmaceutical giant is working on an extended-release cheesecake.

Does anyone know about the role oral microbiome plays here?

Kissing the wrong person could be a gateway to depression. I wonder how long it might be before one could sue for damage to their microbiome.

By that logic -- kissing a depressed person could just as well be a cure for their depression. Cheer up! (Pucker up?)

Wow, didn't think of that. I wonder if that's a possibility.

As a clueless person, I'd think the quantity and stomach acids would make it a negligible risk but worth studying.

I feel like that would be easier to study because cheek-swabs are easier than colon-swabs.

How soon till the happiness pro-biotics are available for purchase?

I wouldn’t be surprised to see anti-anxiety anti-depressive type yogurt being made.

Sauerkraut helped me get better. I included it in my dinner salads. Careful with store bought fermented foods though which uses vinegar.

Anyone knows if probiotics like yakult may help?

Get yourself some kefir or ayran instead. Yakault is a "pro-biotic" only in the sense that it provides sugar to the bacteria in your body.

This video from the Royal Institute has a lot of good info on the microbiome.


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