Meat-related ammonia in advanced liver cirrhosis patients

(Joey) #1

Seems that a recent study on how patients with advanced liver cirrhosis respond to a serving of meat raises some interesting questions.

Although I cannot access the full study (and the Abstract omits mention of many key study parameters) there’s enough to make one wonder about the study’s conclusion: Skipping a meat item in the context of a meal lowers measured serum ammonia levels in those with advanced liver cirrhosis.

Okay, but the UPI article reporting on the study (link further below) makes this key statement…

“… Western diets low in fiber and high in meat and carbohydrates boost levels of ammonia produced by the gut.”

Since both meat and carbohydrates are thought to boost ammonia levels, why did the study only test for meat-related effects and not bother examining what happens when carbohydrates are restricted?

[So many other questions (e.g., length of study? confounding factors? other consequences of limiting meat intake? …) and most of all, whether observed changes in ammonia are at all relevant to an individual with a healthy liver?]

BTW, the UPI article headline claims that avoiding meat may help reverse advanced liver cirrhosis. The study’s conclusion makes no such claim about reversing the disease - merely reducing diet-sourced serum ammonia production.

Your thoughts?

UPI Article:

Study’s Abstract: https://journals.lww.com/ctg/abstract/9900/substitution_of_one_meat_based_meal_with.253.aspx

(KM) #2

I’m sorry, but what the hell is a diet high in “meat (i.e. fat and protein) and carbohydrates?” How exactly can a diet be high in all three macronutrients? Unless they’re simply talking about a diet with too much total food, a diet cannot literally be high in all three of its components. I assume their mention of fiber means they are defining carbohydrates as processed carbs / grain products as opposed to whole fruits and vegetables, but this is still sloppy.

Ok, grudging edit, a packaged product will show its total carbohydrate content, and I suppose by that metric you could ignore the type of carbohydrate and simply call that number high in the average diet.

And I agree, what use is a study limiting only one of the suspect factors and exonerating the other. Show me the garbage?

(Joey) #3

Perhaps this reveals the buried assumption that “low fat” eating is the healthy baseline, such that protein implicitly means lean (low fat) protein? Then again, the meat item described in the study was a burger … not a chunk of broiled salmon. :man_shrugging:

(Bob M) #4

It was about 4 ounces of pork/beef mix (odd for a burger – I’ve never eaten a burger like that). And, what does this mean overall for people with cirrhosis of the liver? How bad is this?

Plus:

“Of course, the study group was very small, so the Richmond team stressed that the findings are preliminary. Still, they believe it can’t hurt for physicians to relay the new findings to patients with cirrhosis, and encourage them to move away from meat.”

How do you know there are no effects with moving away from meat? What about iron? Better protein, more vitamins/minerals, etc.?

(Joey) #5

@ctviggen Yeah, both the hyperbolic headline and the weak underlying study raise more questions than they answer.

Low talent researchers + a slow news day => typical dissemination of “The Science.”

(Bob M) #6

I did look to see what the lead researcher had been publishing. Sometimes, you see that they publish papers that are slanted one way (e.g., vegetarian or vegan). For this person, though, most of the papers were highly detailed and in the area of the liver.

Like you, though, I wonder about studies where they do one thing (in this case, eat one meal), look at one metric, and then make some type of determination. That does not seem like a lot of data to make any real determination.

(Joey) #7

Thanks for the additional legwork.

I retract my implication that this researcher was “low talent” … although the study protocol seems quite narrow in both scope and duration for anyone to suggest such a broad conclusion (which he may have offered up to friendly science reporters eager for another story?)

#8

I’d agree there, but the key is advanced cirrhosis! Those people actually have both liver and kidney problems with high meat, but even then it’s nuanced, because high isn’t a number, high is too much for them and what they can utilize. Then of course if you were to take things like even a broad spectrum digestive aid, or in that case if it were me, higher dosed proteolytic enzymes, then a lot of the breakdown is being assisted, so less beating on the organs.

I’ve had it happen many times over the years when I’m eating bulking levels of protein, but in cuts when my workouts aren’t as intense and I’m not really needing that much, and had the sides of ammonia odor, my gym bag smelling like a litter box from the sweaty clothes, almost to ammonia inhalant levels! (That’ll wake ya up!) cramps, kidney pain, and noticeable increase in the kidney and liver values on labs, but that never happens when I’m in a bulk and actually using much more of it, I just naturally kinda eat that way.

(Joey) #9

Interesting stuff. Hadn’t heard of this before.

(Bacon is a many-splendoured thing) #10

It would be interesting to know what the study participants were actually eating. The researchers are probably blaming the burger meat for what the bun and the fries did. Not to mention the soda!

I’ve never heard of a case where someone eating an all-meat diet developed cirrhosis or high ammonia levels. If one is eating enough fat to fuel bodily processes, the liver will not be needing to de-aminate many amino acids, and certainly not enough to overwhelm the uric acid cycle.

As far as the claim of “reversing” cirrhosis is concerned, my understanding is that cirrhosis damage is irreversible.* Steatohepatitis can indeed be reversed, however, as a number of studies have shown. Cutting out fructose intake is a large step towards that goal, not to mention alcohol and branched-chain amino acids

Also, the standard questions apply: what was the size of the study? How large was the observed effect, in absolute terms? Was it clinically meaningful, as well as being statistically significant? Was this a randomised, controlled study, or merely an epidemiological study? Enquiring minds want to know!

* That said, however, the liver is capable of a surprising amount of regeneration, so it is possible that cirrhosis damage could eventually heal, but I’d expect the process to be exceedingly slow.