Some time back, the wise and magnaminious Mr. Adams
enlightened us as to why shit is brown. (Dead red blood
cells.)
Okay, so then why is pee some shade of yellow?
I admit, I’m stumped on this one. Do your kidneys
filter beta carotine out of your blood or something?
Lastly, why is pee sometimes cloudy and sometimes
clear. Well, obviously cloudy pee has some kind of
small particulate matter in it. But what is it, and
since it was presumably filtered out of my blood by
my kidneys, how did it get there??
-Ben
Urochrome is what makes pee yellow. It’s not fully understood where it is created in the body, but that’s the substance. For all you ever wanted to know about pee and probably a lot more, the composition is Urea (the actual waste products that the body is eliminating), and Chloride. Sodium, Potassium, Phosphate, Sulfate, Creatinine, Uric acid, Glucose, Protein and Urochrome make up the rest. The more dehydrated you are, the yellower it is. When you are well hydrated, it’s nearly colorless as you’ve been cleaning out your system more efficiently and are “flushing the pipes” more than you are cleaning them out.
Yup. At least in part. And, I stand by my answer in that thread regarding the colour of urine.
Regarding pee’s cloudiness, infection is always a possibility, but a more common and more mundane explantion is that it reflects the concentration of various salts. In particular, many people excrete a fair a bit of phosphates after eating. Mucous in the urine is also common and may lead to cloudiness as well. AFAIK, both these phenomena are benign.
Urine is filtered by your kidneys, sure, but once it sits in the bladder it can pick up things like bacteria. Cloudy urine is a sign of a bacteria infection, usually, not always.
First, feces gets its color not only by dead red blood cells, but also (and I think primarily) by bile.
And a cloudy urine is not ususally a sign of infection. Viruses and bacteria are invisible to the naked eye. Urine has to be tested for an infection. Cloudy urine is usually caused by dehydration.
I think we need to update Murphy’s Law for the
electronic age. To whit - “A few hours surfing can frequently save a few minutes at Google.”
The yellow color is from a pigment named “Urochrome.”
Yup, they named a pigment after piss! Apparently it’s
produced when your liver destroys a red blood cell.
Your kidneys filter it out and it makes your
pee yellow. See http://beakman.com/beakman/news/020600/020600b.html
There’s also a reference on the next page to riboflavin/vitamin B2. Maybe both are responsible.
Jury’s still out on the cloudy urine. As several
people have said, it can indicate infection (essentially,
bacteria shit in your pee!) or as someone else said it
can be precipitated phosphates. Apparently the phosphates
precipitate out of the urine in reponse to the urine
going alkaline after eating. I suppose that keeping
your pee acidic by drinking cranberry juice with
dinner might prevent this from happening.
As a minor aside, I had a chemistry teacher tell us that Bromo Blue (the indicator) will turn your urine blue, and that phenothyaline (sp.) will turn your urine black. Sounds like a good science experiment to me.
