Normal and healthy urine is pale yellow in color. The human body produces urine as a way to rid itself of harmful toxins, which are broken down by the kidneys, getting them ready for disposal. It also contains sugars, water, and urobilins.
Urobilins are the broken-down products of bilirubin, which is itself the broken-down product of old blood cells. Bilirubin is what gives color to bile, bruises, and feces, and most bilirubin is gathered from the blood stream by the liver. From there, it is broken down by the gall bladder and intestines, and then excreted by the bowel. Some bilirubin, however, stays in the blood until it is picked up by the kidneys, where it is then broken down into urobilins and removed from the body in urine. Also known as urochrome, urobilins are the pigment that gives urine its yellow color.
Urine is usually pale yellow, but it can range from clear to a deep amber color in a healthy person. The level of yellow is determined by how hydrated a person is. A person who is very hydrated has more water to release through urinating, and thus has a lesser concentration of urobilin in their urine. A person who is very dehydrated will have a much higher concentration, and thus much darker urine.
Some foods, such as beets, may temporarily change the color of urine. Eating a lot of carrots, or drinking a lot of carrot juice, can turn it orange.
Asparagus can make urine much brighter in color, as can some vitamins — usually vitamins C and B. Certain medications can also affect the color, as can food dyes. An unusual urine color may also indicate a health problem. Brown or red could indicate a severe problem in the kidneys, for example.
The best way to bring dark urine back to a healthier pale yellow is to drink several glasses of water or other clear fluids each day. Most health care professionals recommend eight glasses of water, although some people may need a little more or less. After a few glasses of water, the body should start to rehydrate and urine will return to a normal color. If it remains dark after a day of increased water intake, it may be necessary to be checked out by a doctor to make sure there is no underlying medical cause for the color.