Definition
Urine is a fluid that is produced in the kidneys by filtration. Various products are excreted with the urine, which the body no longer needs. The main component of urine is water.
So-called urochromes are dyes that give urine its color. These are produced by bilirubin, a breakdown product of the blood pigment haemoglobin. The urine is normally clear and has a yellowish color.
From pale yellow to amber, anything is possible. The color of the urine is often dependent on the fluid intake. In the morning, the urine is often darker because it is more concentrated overnight. However, a dark colored urine can also have other causes and can indicate certain diseases or medication intake.
Causes
There are several causes that can lead to a darkening of the urine. One explanation may be increased or decreased fluid intake. In the case of dehydration, i.e. reduced fluid intake, the dyes are more concentrated in the urine.
This results in a darker urine. This can be the case in the morning, after exercise, in the case of diarrhoea or heat. With increased fluid intake, the dyes in the urine are less concentrated and the urine is lighter.
However, diseases can also be responsible for the dark discoloration of the urine. An accumulation of bilirubin, due to increased breakdown of the blood pigment haemoglobin, can lead to a dark urine color. Increased bilirubin in the urine can be an indication of liver or bile disease.
In some diseases, the urine may even turn brown-black. An excessive concentration of melanin can be responsible for this. Melanin occurs naturally in the body and is responsible for the color of our skin and hair.
If urine is left standing for too long, it can turn black if melanin is present. However, melanoma can also lead to discoloration of the urine. Porphyria can also lead to a black coloration of the urine.
This is a rare enzyme disease in which the formation of the blood pigment is disturbed. In addition, some drugs may be responsible for the discoloration of the urine as a side effect. These include the antibiotic nitrofurantion and the Parkinson’s drugs L-dopa and methyldopa. In order to exclude serious diseases and discoloration of the urine by blood, a urine diagnosis should be carried out by a doctor.
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