What makes poo brown: Cecil is wrong

[dubbin]

Cecil is wrong in his answer to the question of what makes poo brown at http://www.straightdope.com/classics/a2_381.html

The pigment that makes poo brown is not bilirubin (which is yellow - it causes jaundice) but stercobilinogen, a brown break-down product of bilirubin.

Ed Wild MRCP(UK)

[Fear_Itself]

@dubbin

Cecil is wrong in his answer to the question of what makes poo brown at http://www.straightdope.com/classics/a2_381.html

The pigment that makes poo brown is not bilirubin (which is yellow - it causes jaundice) but stercobilinogen, a brown break-down product of bilirubin.

Ed Wild MRCP(UK)

According to this site, strecobilonogen has no color:

Stercobilinogen is a bile pigment derived from conjugated bilirubin during transit through the gastrointestinal tract. It is formed due to a reduction reaction carried out by bacterial enzymes.** It is colourless** and water soluble.

[Duck_Duck_Goose]

The thing that makes poo brown is stercobilin, not stercobilinogen. And stercobilin is a breakdown product of bilirubin, thus Cecil is not completely wrong.

Also, bear in mind that the column in question was written in 1987, and no doubt biochemistry has moved on since then in the matter of identifying obscure chemical compounds found in poo.

Cites.

http://www.ibms.org/index.cfm?method=science.clinical_chemistry&subpage=clinical_chemistry_gilberts_syndrome

Conjugated bilirubin is secreted from hepatocytes to the bile canaliculi of the liver and outwards in bile from the liver via the gall bladder and common bile duct to the gastrointestinal tract. Bacterial action within the ileum and colon converts bilirubin to stercobilinogen. Finally stercobilin, the product of stercobilinogen oxidation, is excreted in faeces.

Although most bilirubin is excreted as stercobilin in faeces, a small amount of stercobilinogen is reabsorbed from the gastrointestinal tract back into the blood system and subsequently excreted in urine as urobilinogen.

So stercobilinogen is not excreted; it’s converted to stercobilin, which is then excreted.

http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digestion/largegut/absorb.html

The characteristic brown color of feces are due to stercobilin and urobinin, both of which are produced by bacterial degradation of bilirubin.

[Troy_McClure_SF]

C’mon, folks. The proper, actual question is “What makes shit brown?”

Let’s not re-write history.

[dubbin]

OK, I stand corrected, it’s stercobilin, not stercobilinogen, but it’s certainly not bilirubin and I was way closer than Cecil.

[dubbin]

Furthermore Pubmed has articles on stercobilin and stercobilinogen going back to 1948, so the “written in 1987” defence isn’t going to help Cecil. Moreover, jaundice (the yellow discolouration of the skin caused by bilirubin, which Cecil thinks is brown) was described in the days of Hippocrates.

[Fear_Itself]

@dubbin

OK, I stand corrected, it’s stercobilin, not stercobilinogen, but it’s certainly not bilirubin and I was way closer than Cecil.

Way closer? Thats a bit of an overstatement. Besides, you were still wrong. I think there’s a kharmic rule for that. I think it is * Dubbin’s Corollary to Gaudere’s Law*

***“When pointing out a factual error by the Perfect Master, you will make a factual error yourself.” ***

[Duck_Duck_Goose]

???

What does jaundice having been recognized back in ancient times have to do with the subject at hand? AFAIK the ancients never addressed the issue of “Why is poo brown?” And AFAIK they didn’t know that the cause of jaundice is bilirubin in the bloodstream. So why bring that up?

Cecil doesn’t say that bilirubin is “brown”. He says it’s “brownish-yellow”.

BTW, welcome to the Straight Dope Message Board–50,000 specialists in nitpickery, at your disposal.

[John_W.Kennedy]

Actually, brown is the same thing as dark yellow.

[dubbin]

@Duck Duck Goose

???

What does jaundice having been recognized back in ancient times have to do with the subject at hand? AFAIK the ancients never addressed the issue of “Why is poo brown?” And AFAIK they didn’t know that the cause of jaundice is bilirubin in the bloodstream. So why bring that up?

Cecil doesn’t say that bilirubin is “brown”. He says it’s “brownish-yellow”.

BTW, welcome to the Straight Dope Message Board–50,000 specialists in nitpickery, at your disposal.

My point is that Hippocrates, Socrates and all the other -crateses recognised jaundice as a yellow, not brown, discolouration. All modern science has added is a name for the yellow pigment: bilirubin.

To complicate matters further, there are 2 types of bilirubin - conjugated and unconjugated. Unconjugated bilirubin is VERY yellow, not “brownish” at all; conjugated bilirubin is rightly described as “brownish yellow”. Stercobilin, as we’ve discussed, is very brown indeed, and not at all yellow.

By the time poo hits the pool, there is negligible bilirubin left in it. It’s all been converted to stercobilin.

So (JWK) it doesn’t matter whether “brown is dark yellow” or not (IMHO this is only true of mixing light, not mixing pigment, but that’s another issue) - there’s negligible yellow, or yellow-brown pigment (bilirubin) in faeces; but there’s tons of a pigment that’s SO brown it doesn’t have to worry about being dark yellow: stercobilin.

Cecil can describe bilirubin in whatever adjectival terms he wishes- he’s still wrong about it being the pigment that’s directly responsible for the brown colour of poo.

Thanks for the welcome, I have plenty of nits for y’all.

[Duck_Duck_Goose]

'Kay, you’re right–Cecil is wrong. I checked PubMed, too, and yeah, you’re right, stercobilin goes way back.

So the question then becomes, what shall we do about it? Or more to the point, what should Cecil do about it?

[DrDeth]

But also brown is what you get when you mix many different colors together.

[Fish]

Especially if you eat crayons.

Well, that’s what I hear.

[Snooooopy]

@Fear Itself

Way closer? Thats a bit of an overstatement. Besides, you were still wrong. I think there’s a kharmic rule for that. I think it is * Dubbin’s Corollary to Gaudere’s Law*

***“When pointing out a factual error by the Perfect Master, you will make a factual error yourself.” ***

And Gaudere’s Corollary to Dubbin’s Corollary to Gaudere’s Law states that when you point out someone’s incomplete attempt to defy the Perfect Master, you will misspell something.

[Fear_Itself]

@Snooooopy

And Gaudere’s Corollary to Dubbin’s Corollary to Gaudere’s Law states that when you point out someone’s incomplete attempt to defy the Perfect Master, you will misspell something.

Oh heck, the rule is, I always misspell something.

[friedo]

One time I ate like six bowls of Froot Loops and my shit was blue. I thought perhaps I had eaten Grover for dinner and forgotten.

[dropzone]

That ain’t nuthin’! First time I ate beets I produced red shit as well as a red fluid. Thought I was bleeding out for a moment.

[MaryEFoo]

Experimental observation:

A three-day-plus diet of very bland content produced surprising pale poop, a light tan.* Where was the sercobilin?

Said diet consisted of bland pale unseasoned non-acid fiberless items like tapioca pudding, cream of wheat, milk, white bread, breast of chicken, etc.
*Not that different from the background color seen when doing “Reply to Thread”.