Diet modulates Vibrio cholerae colonization and competitive outcomes with the gut microbiota

Summary

The amount or type of dietary macronutrients dramatically changes the microbiota and physicochemical environment of the gut. Because the microbiota plays key roles in pathogen susceptibility, macronutrients could impact infection outcomes. We show that dietary protein sources differentially restrict colonization of Vibrio cholerae (V. cholerae) as well as impact pathogen-dependent changes in microbiota composition. Specifically, dietary proteins, notably casein, alter levels of the V. cholerae central flagellar regulator, FlrA, which controls expression of the type VI secretion system (T6SS), a key mediator of intra-bacterial competition. Resultant decreases in T6SS lead to a competitive disadvantage for V. cholerae against human commensal Escherichia coli, as well as changes in the abundance and composition of a model human gut microbiota. Mutations in FlrA restore V. cholerae T6SS expression and abrogate diet-dependent impacts on V. cholerae infection. These findings suggest dietary interventions for restricting V. cholerae and highlight the importance of diet in pathogen-commensal interactions.

Seems that I need to persist with my new casein rich diet.

Is it a coincidence that the Venn diagram for endemic cholera and lactose intolerance overlap considerably? Or just one of life's little ironies.

Casein also has been linked to greater prostate cancer risk, in some studies, though I think this remains an avenue for more study and not definitive.

https://pmc.ncbi.nlm.nih.gov/articles/PMC4166373/

A family member has been eating a high casein diet (eggs and cheese, as major elements of a vegetarian diet), but they already have enough eating issues that I don't want to bring that up. I'm sure the potential cholera protectant aspect would please them.

1 hour ago, sethoflagos said:

Is it a coincidence that the Venn diagram for endemic cholera and lactose intolerance overlap considerably?

Curious how that is tracked.

1 hour ago, TheVat said:

Casein also has been linked to greater prostate cancer risk, in some studies, though I think this remains an avenue for more study and not definitive.

So I'm caught between Scylla and Charybdis. Thanks! 🥺

1 hour ago, TheVat said:

Curious how that is tracked

Geographical correlation?

3 hours ago, sethoflagos said:

So I'm caught between Scylla and Charybdis. Thanks! 🥺

Haha. Charybdis may only be a weak statistical correlation. I think the jury is still out.

3 hours ago, sethoflagos said:

Geographical correlation?

I meant that lactose intolerance is really hard to track. Most people, especially in areas with fewer doctors and medical infrastructure, never create much if any public record. Milk doesn't sit well, so they avoid it.

Edited January 14Jan 14 by TheVat
Blarngh

1 hour ago, sethoflagos said:

Seems that I need to persist with my new casein rich diet.

I don't think that this conclusion can be drawn from the outcome of a single study. One of the issues is that FlrA regulation is highly dependent on multiple signaling cues as well as energy status. In many cases, the study trying to figuring out their role in infection have a hard time to distinguish effects of their expression with other changes to things like energy status and other factors that are not directly measurable.

2 hours ago, TheVat said:

I meant that lactose intolerance is really hard to track. Most people, especially in areas with fewer doctors and medical infrastructure, never create much if any public record. Milk doesn't sit well, so they avoid it.

With the notable exception of South America, there is a certain degree of correlation. Maybe it's just ''the poors''.

50 minutes ago, CharonY said:

I don't think that this conclusion can be drawn from the outcome of a single study. One of the issues is that FlrA regulation is highly dependent on multiple signaling cues as well as energy status. In many cases, the study trying to figuring out their role in infection have a hard time to distinguish effects of their expression with other changes to things like energy status and other factors that are not directly measurable.

Point taken. Without wishing to overdramatise, I've had a few mildish bouts of cholera when I was younger and fitter, and know a few people who've lost friends and relations to it. Under the circumstances and in the absence of evidence to the contrary, might even a single study be enough to justify a modest shift of dietary habits? I''ve a long line of ancestors who seemed to fare pretty well with dairy products.

12 hours ago, sethoflagos said:

Under the circumstances and in the absence of evidence to the contrary, might even a single study be enough to justify a modest shift of dietary habits?

So basically it might help but at least it doesn't harm? If there are no downsides, I don't think it is a bad thing as such. The main worry I have with these things is that especially in recent times, they tend to get a life on their own and suddenly there will be trends on folks binging on casein (or whatever the hype of the week is). In a way I think it has become more important to work out the nuances as the internet has become a horrible amplifier of really bad ideas. Not that I am accusing this thread of anything like that, it is just a matter of professional struggle I am having.

1 hour ago, CharonY said:

The main worry I have with these things is that especially in recent times, they tend to get a life on their own and suddenly there will be trends on folks binging on casein (or whatever the hype of the week is). In a way I think it has become more important to work out the nuances as the internet has become a horrible amplifier of really bad ideas.

My dairy intake for 25 years has been limited to the occasional bit of cheese due to food poisoning concerns back in the day. Your point is well-taken. My interest is in a bit of balanced risk management.

14 hours ago, sethoflagos said:

With the notable exception of South America, there is a certain degree of correlation. Maybe it's just ''the poors''.

Access to safe water, water treatment and management are AFAIK the biggest determinant of cholera outbreaks.

48 minutes ago, sethoflagos said:

My dairy intake for 25 years has been limited to the occasional bit of cheese due to food poisoning concerns back in the day. Your point is well-taken. My interest is in a bit of balanced risk management.

Point taken. I would however advise caution to take the data from the study as protective. The effects are modest, which might (or might not) be clinically helpful when exposed to low levels of vibrios. But it wouldn't protect form unsafe water sources, for example. I would put it in somewhat the same category as eating a balanced diet. It might have positive effect (certainly better than, say meat only or highly processed foods) but I don't expect specific protection from diseases from it and it shouldn't induce risky behaviour.

The image that comes to mind is RFK Jr swimming in sewage, because he believes that his diet protects him.

21 minutes ago, CharonY said:

The image that comes to mind is RFK Jr swimming in sewage, because he believes that his diet protects him.

But then I'm not an American am I. 🧐

I wished only Americans would be susceptible to that type of magical thinking.

Such people don't last very long here.

One thing that tends to diminish my confidence in correlations is that when people add more of something to a diet, it often means they consume less of something else.

1 hour ago, CharonY said:

The image that comes to mind is RFK Jr swimming in sewage, because he believes that his diet protects him.

What protects RFKJr from sewage is that it perfectly matches his cranial contents. 😁

8 minutes ago, TheVat said:

One thing that tends to diminish my confidence in correlations is that when people add more of something to a diet, it often means they consume less of something else.

What protects RFKJr from sewage is that it perfectly matches his cranial contents. 😁

What hasn't been eaten by the worm, you mean?

Yes. That logic is inescapable.

Sigh, I will never understand how the pro-virus lobby got so strong.

On 1/14/2026 at 8:22 PM, sethoflagos said:

Such people don't last very long here.

Darwin rules?

5 hours ago, CharonY said:

Sigh, I will never understand how the pro-virus lobby got so strong.

The behavior bears a strong resemblance to Oppositional Defiance Disorder in children, except it's happening in adults. Adults in positions of authority.

2 hours ago, Phi for All said:

The behavior bears a strong resemblance to Oppositional Defiance Disorder in children, except it's happening in adults. Adults in positions of authority.

So is that a perpetuum mobile of resentment?

19 hours ago, StringJunky said:

Darwin rules?

Quite.

In many ways, it's a very free society here - gives you the opportunity to be an adult, as my friend put it many years ago.

Only, there's no safety net for the reckless. Suits some people: others not so much.