Researchers Find Gut Bacteria Can Lead to Strokes | Hacker News Reader

Researchers Find Gut Bacteria Can Lead to Strokes

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153 pointsfrgtpsswrdlame42 comments

This article is interesting but misleading. (I do surgeries on patients with strokes):

CCMs (cavernous malformations) are vascular lesions, rare vascular lesions and relatively rarely they can bleed and cause "strokes" (as in neurological deficits in patients).

However CCMs that bleed make up a minuscule fraction of a percentage of all patients who have strokes (which are generally caused by ischemia - blockages to vessels with decreased oxygenated blood to the brain).

The title should read 'gut bacteria can potentially trigger rare type of brain vascular malformations'.

Can I ask your opinion on a (somewhat) related recent book? (specifically, it has examples about succesfully using diet changes instead of surgery, for people who were already scheduled to have heart surgery).

Namely "The Plant Paradox" by Dr. Gundry. From what I found he is (or used to be) a well-respected heart surgeon with some influential papers on his name. But I could find just a few summary articles on his current research program, which focuses on diet, foods with lectins in particular, and their relation to auto-immune disease, obesity, heart problems, and more.

I found the book very interesting, and his theories seem plausible to me (someone with no medical background whatsoever). But I also got the impression he may be overstating his case a bit, over-generalizing, so I was wondering about the opinions of medical experts on his work.

What's your opinion on the use of perfluorocarbons in case of ischemia?

Stomach ulcers (formerly thought to be caused by stress) and chronic fatigue syndrome (formerly thought by many to be psychological) have both been linked to infections in recent years. Now strokes, and I think I've seen something about heart problems as well.

I wonder how many other diseases will wind up having bacterial or viral causes.

> I wonder how many other diseases will wind up having bacterial or viral causes.

I was speaking to virologist socially a year or two back, and they stressed that most viruses are only discovered because we go looking for them after acute, serious symptoms. The new tools for trivial DNA sequencing are going to be interesting, it means getting a much more complete picture of the presence of viruses and bacteria, which could then be combined with epidemiology. That virologist thought that a lot of inflammatory diseases like atherosclerosis or arthritis could actually be triggered or exacerbated by infection. The next 10 years will be interesting.

Note that the "ulcer story" is more complicated that the mainstream story. In particular: ulcers are exacerbated by stress, so it's not completely surprising people thought they were "caused by" stress. Also, in many people, the bacteria that causes ulcers also have other protective effects (more commonly in third world countries with poor sanitation).

In the case of CFS, there are probably multiple underlying etiologies, only some of which are induced by microbes.

But how does stress causes ulcers?

Chronic stress also causes consistently elevated cortisol levels, which is not good long term (https://en.wikipedia.org/wiki/Cortisol -- wound healing, other areas, pretty good overview of some of the negative effects of stress)

it doesn't cause ulcers. that's the part of the theory that changed, rightly. But stress can increase the intensity of symptoms of the ulcer , changing it from non-symptomatic to a major pain in the stomach lining. So it's not surprising people once thought it was causative, since it was observed so frequently in ulcer cases. This area is still not well understood, although stress can decrease stomach pH as well as have immunomodulation effects.

That's pretty interesting. I thought ulcers were more of an erosive scenario induce by functional issues in the rest of the GI tract.

Stress/anxiety and other strong negative mental states can impact the functions of the GI tract's such as peristalsis and digestive efficiency of food.

This in turn sets up a negative feedback loop as things like nutrient absorption declines and toxin levels rise worsening the functionality of the tract. By toxins I also imply bacteria and viruses besides just 'regular' chemicals.

Erosion of various parts of the GI tract happens slowly and you get an ulcer. Ulcers in the stomach aren't the only place to see bleeding in the GI tract.

I'd guess it's because stress weakens the immune system, thus bacteria/viruses have greater effect. AFAIK stress also increases the production of stomach acid.

Stress (and especially sleep deprivation) has a noticeable effect on my immune system. Dunno about people in general.

I was diagnosed with ulcerative colitis 18 years ago and can confidently say when my sleeping pattern is off for prolonged periods of time the impact is definitely visible. I do not think it is a cause but coupled with other habits , bad eating , higher stress , weaker immune system etc I find lack of sleep to be a leading indicator that I need to prioritize getting sleep quickly...or else

And I wonder if stress isn't caused/exacerbate by ulcer. I mean, cortisol levels increasing because you have an ulcer, then suffering a sudden burst when something else triggers it.

Heart disease, plaque! Brush teeth!

Not sure why this was downvoted...

At least the last time I checked, mouth flora bacteria had been found growing in atherosclerosis lesions, and poor dental hygiene was linked to and increased risk of cardiovascular disease.

Migraine is linked to the production of NO by gut bacteria.

Eating disorders (both bulimia and anorexia) may be caused by an auto-immune response to a hormone look-alike produced by (some strains? of) e. coli. Both the hormone and the bacterial substitute cause satiety. Depending on the kind of antibodies produced, their effect can be amplified or inhibited.

I find this a fascinating subject, it would seem our gut microbiota is a driving force of much of the bio-chemistry that we experience as consciousness, serotonin, adrenaline, dopamine, oxytocin are all influenced by the state of our gut microbiota and it's great to see so much research in this area, how we feel seems to have a lot to do with what we eat...

Yes indeed. Tomorrow I'm presenting my rotation findings on outer membrane vesicle (OMV) formation in Bacteroides thetaiotaomicron in the lab of Mario Feldman. Here's a TEM image of this bacteria and its OMV's: http://imgur.com/a/oJiaT

The Bacteroidetes phylum make up the largest fraction of the gut microbiome. Bacteroides is the largest class of that phylum. Unlike the OMV's of other gram negative bacteria, those of Bacteroidetes are selectively packed with cargo such as sugar hydrolyzing enzymes facing the outside.

This increases the surface area available for the producing cell, but also allows nearby cells to indulge on the now public goods. http://www.cell.com/current-biology/fulltext/S0960-9822(13)0...

Good luck with your presentation, you're in an astounding field at an astounding time, synthetic enzymes and bacteria will I believe open a huge field in medicine. Our understanding of the human experience, understanding mind and body as fully integrated system, is making good progress.

Here in Canada the CBC TV show 'The Nature of Things' recently had a show about the human gut microbiome: http://www.cbc.ca/natureofthings/episodes/it-takes-guts

Small prediction - Over the next 5 years you are going to see all the media pick up gut bacteria as the next revolution of medical science as we learn how all this shit works. It is like a 2nd brain in your body and the foreign bacteria are so interesting in what they can do.

I'd be more willing to bet that the media will pick up on it because of advertising dollars. Companies like dupont are raking in cash on probiotics, they can't brew up enough of those little buggers.

It's already happening, I actually first read about kefir (fermented milk drink with great properties for increasing gut bacteria) through the MSM a few months ago.

'pick up gut bacteria as the next revolution of medical science as we learn how all this shit works'

well, quite :D

The next "whole grain."

I wonder if fecal transplants could prevent or hold this off. https://en.wikipedia.org/wiki/Fecal_microbiota_transplant

Or a diet rich in resistant starches? Higher levels of butyrate et al might help keep these B. fragilis communities in check. Or maybe not. That's sort of the kicker with gut bacteria, it's such a complex system and so hard to measure that getting at causality can be tough.

A recent book called The Plant Paradox argues exactly this (among many other things). (But, also see my question about the author of the book elsewhere in this thread).

Resistant starch is awesome for your good bacteria as it helps them produce butyrate and other short chain fatty acids that are really good for your gut cells. Excellent video on the subject here: https://nutritionfacts.org/video/getting-starch-to-take-the-...

I'd be wary of:

- Someone with 2 comments in total pointing to the same site

- A site called 'facts' showing a doctor selling books

- A site about nutrition focusing almost entirely on veganism

- A doctor who seems to push a vegan agenda and has a sort of cult following in the vegan community

- Cherry picking sources. It's quite obvious from reading some of the articles, and while I don't doubt veganism is good for you, it makes me doubt the site's credibility even more.

> Someone with 2 comments in total pointing to the same site

I have some more posts here, and also refer to the site a lot.

> A site called 'facts' showing a doctor selling books

I think the name of the site is a pun on the label that provides some info on the macros of many packaged food products. Afaik that label is titles "nutritionfacts" in the states.

The book he sells is great. Most (I guess all) of the info is also available for free on the website. And he donates the proceeds of the book. I'm also wary of doctors selling stuff (and pharma for that matter), but this guys seems not to be getting excessively rich on this. He seems intrinsically motivated.

> A site about nutrition focusing almost entirely on veganism

It focuses on evidence based nutrition. The doctor and his team claim to have evidence that a "whole plant food" diet is superior when it comes to preventing/reverting some diseases that are the leading killers/disablers in the western world.

> A doctor who seems to push a vegan agenda and has a sort of cult following in the vegan community

There's a list of prominent doctors that come to the same conclusions. Sure vegans feel at home with this narrative. But that should not make it less valuable information.

> Cherry picking sources. It's quite obvious from reading some of the articles, and while I don't doubt veganism is good for you, it makes me doubt the site's credibility even more.

That he (and others in this "nutrition against disease" movement) is cherry picking is often said. I believe it is hard to prove or disprove. And there is a lot of evidence that pharma is also guilty for cherry picking and manipulation. So it comes down to us having to make a choice ourselves. Who do you trust? Doctors/pharma selling chemicals without any consideration of diet, or doctors telling you to fix your diet to something "whole plant based" before trying chemicals? This is the main question for me at least.

I agree with your last point, it's hard to trust, which is why I err on the side of caution and try to avoid sites pushing one radical opinion over others. Paleo, vegan, atkins, there are tons of people, physicians included, insisting their research is the best. So I think it's prudent to hold a more moderate stance on nutrition, an attitude of 'we don't know, let's find out' instead of 'I know best, trust me'.

Vegans almost always point to that site as some sort of gospel. Meanwhile, in the real world, the conclusions of the authors of many of the studies Greger cites don't line up with the conclusions he draws from them.

So is it a good idea to take supplementary prebiotic fibre and/or probiotics?

Who are we to argue with that! Changed above.

We detached this subthread from https://news.ycombinator.com/item?id=14320890 and marked it off-topic.

Did you understand that? The article's title is 100% correct and did not need to be changed.

Parent is making a non sequitur point that most strokes are caused by blockages, not lesions.

You people are a tough review board. How about we take 'lesions' out?

Sadly I am not one of the 3 users who understand everything that gets posted here.

A more salient point would be that the lesions rarely lead to strokes, which the parent made

Am I the only one that thinks medical science seems vastly behind where it ought to be? Is there something holding it back or is it just phenomenally complex and difficult?

eat yer yogurt folks!

I take it people here do not like yogurt.

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