question: Why are our feces brown? Is it because we eat foods of all different kinds of colors that end up mixing and creating brown?
comment: URL_0 When red blood cells get old and worn-down, white blood cells eat them. The hemoglobin (the stuff that makes them red, and carries oxygen) is broken down into a chemical called bilirubin. Your liver extracts the bilirubin from your blood and turns it into bile, which helps digest fats in your small intestine. Later, in your large intestine, it ends up being oxidized into stercobilin, which is brown in color. So the color of feces has nothing particularly to do with the color of food. It is, rather, the color of a specific chemical that is both (1) formed from broken-down blood cells, and (2) involved in digesting fats.
passages: After the meconium, the first stool expelled, a newborn's feces contain only bile, which gives it a yellow-green color. Breast feeding babies expel soft, pale yellowish, and not quite malodorous matter; but once the baby begins to eat, and the body starts expelling bilirubin from dead red blood cells, its matter acquires the familiar brown color.
  
  At different times in their life, human beings will expel feces of different colors and textures. A stool that passes rapidly through the intestines will look greenish; lack of bilirubin will make the stool look like clay.
  
  Section::::Uses of animal feces.
   BULLET::::- The brown bear ("Ursus arctos") is a large bear distributed across much of northern Eurasia and North America.
  
  BULLET::::- The ermine ("Mustela erminea") has a brown back in summer, or year-round in the southern reaches of its range.
  
  Section::::Brown in science and nature.:Biology.
  
  BULLET::::- The solid waste excreted by human beings and many other animals is characteristically brown in color due to the presence of bilirubin, a by-product of destruction of red blood cells.
  
  Section::::Brown in culture.
   Section::::Brown in science and nature.:Mammals and birds.
  
  A large number of mammals and predatory birds have a brown coloration. This sometimes changes seasonally, and sometimes remains the same year-round. This color is likely related to camouflage, since the backdrop of some environments, such as the forest floor, is often brown, and especially in the spring and summertime when animals like the snowshoe hare get brown fur.
  
  BULLET::::- The brown rat or "Norwegian rat" ("Rattus norvegicus") is one of the best known and most common rats.
   BULLET::::- There is no known direct genetic influence, and no single gene variant, that differentiates excreters from non-excreters.
  
  Section::::Factors affecting beeturia.
  
  The extent of excreted pigment depends on:
  
  BULLET::::- The pigment content of the meal, including:
  
  BULLET::::- The type of beetroot (for instance, the pigment concentration of the "Detroit Rubidus" variety is twice that of the "Firechief" variety)
  
  BULLET::::- The addition of concentrated beetroot extract as a food additive to certain processed foods
  
  BULLET::::- The storage conditions of the meal, including light, heat, and oxygen exposure, and repeated freeze-thaw cycles that all could degrade the pigments
   Depending on the individual and the circumstances, human beings may defecate several times a day, every day, or once every two or three days. The extensive hardening that interrupts this routine for several days or more is called constipation.
  
  The appearance of human fecal matter varies according to diet and health. Normally it is semisolid, with a mucus coating. A combination of bile and bilirubin, which comes from dead red blood cells, gives feces the typical brown color.
   Sometimes food may make an appearance in the feces. Common undigested foods found in human feces are seeds, nuts, corn, and beans, mainly because of their high dietary fiber content. Beets may turn feces different hues of red. Artificial food coloring in some processed foods, such as highly colorful packaged breakfast cereals, can cause unusual coloring of feces if eaten in sufficient quantities.
  
  Undigested objects such as seeds can pass through the human digestive system, and later germinate. One result of this is tomato plants growing where treated sewage sludge has been used as fertilizer.
  
  Section::::Analytical tools.
   The Turkey Devonshire, first served in Pittsburgh, Pennsylvania in the 1930s, has been described as being similar to the Hot Brown.
  
  Section::::In the media.
   The first recorded use of "burnt umber" as a color name in English was in 1650.
  
  Section::::Additional variations of brown.:Chestnut.
  
  Displayed at right is the color chestnut.
  
  Section::::Additional variations of brown.:Chocolate.
  
  Displayed at right is the color chocolate.
  
  Section::::Additional variations of brown.:Chocolate.:In numismatics.
  
  The Reserve Bank of India (RBI) issued a Chocolate Brown colored banknote of ₹10 denomination in January 2018 under Mahatma Gandhi New Series. The bank note measures 123 mm × 63 mm.
  
  Section::::Additional variations of brown.:Cocoa brown.
  
  Displayed at right is the color cocoa brown.
  
  Section::::Additional variations of brown.:Desert sand.
   A number of foods and medications can turn the stool either red or black. Bismuth found in many antacids may turn stools black as may activated charcoal. Blood from the vagina or urinary tract may also be confused with blood in the stool.
  
  Section::::Diagnostic approach.
   In the four tissue sections shown here, many of the intestinal glands have cells with a mitochondrial DNA mutation in the "CCOI" gene and appear mostly white, with their main color being the blue-gray staining of the nuclei. As seen in panel B, a portion of the stem cells of three crypts appear to have a mutation in "CCOI", so that 40% to 50% of the cells arising from those stem cells form a white segment in the cross cut area.
   Many other animal species may also be "pied" or piebald including, but not limited to, birds and squirrels. Snakes, especially ball pythons and corn snakes, may also exhibit seemingly varying patches of completely pigmentless scales along with patches of pigmented scales. In 2013, a piebald blood python was discovered in Sumatra. Some domesticated foxes born from the Russian Institute of Cytology and Genetics also carry this coloring.
   Section::::History and classification.
   Section::::Process.:Configuration.:Residence time.
  
  The residence time in a digester varies with the amount and type of feed material, and with the configuration of the digestion system. In a typical two-stage mesophilic digestion, residence time varies between 15 and 40 days, while for a single-stage thermophilic digestion, residence times is normally faster and takes around 14 days. The plug-flow nature of some of these systems will mean the full degradation of the material may not have been realised in this timescale. In this event, digestate exiting the system will be darker in colour and will typically have more odour.
   Section::::Dietary habits.:Other vertebrates.
   Section::::History.:Flour milling.
  
  Historically, brown meal was what remained after about 90% of the coarse, outer bran and 74% of pure endosperm or fine flour was removed from the whole grain. Using slightly different extraction numbers, brown meal, representing 20% of the whole grain, was itself composed of about 15% fine bran and 85% white flour. In 1848 it was asserted grain millers knew only of bran and endosperm, but by 1912 it was more widely known that brown meal included the germ.
  
  Section::::History.:Colour.
   Section::::Biology and behaviour.
   Section::::Predators and parasites.
   The mammalian excretory system involves many components. Like most other land animals, mammals are ureotelic, and convert ammonia into urea, which is done by the liver as part of the urea cycle. Bilirubin, a waste product derived from blood cells, is passed through bile and urine with the help of enzymes excreted by the liver. The passing of bilirubin via bile through the intestinal tract gives mammalian feces a distinctive brown coloration. Distinctive features of the mammalian kidney include the presence of the renal pelvis and renal pyramids, and of a clearly distinguishable cortex and medulla, which is due to the presence of elongated loops of Henle. Only the mammalian kidney has a bean shape, although there are some exceptions, such as the multilobed reniculate kidneys of pinnipeds, cetaceans and bears. Most adult placental mammals have no remaining trace of the cloaca. In the embryo, the embryonic cloaca divides into a posterior region that becomes part of the anus, and an anterior region that has different fates depending on the sex of the individual: in females, it develops into the vestibule that receives the urethra and vagina, while in males it forms the entirety of the penile urethra. However, the tenrecs, golden moles, and some shrews retain a cloaca as adults. In marsupials, the genital tract is separate from the anus, but a trace of the original cloaca does remain externally. Monotremes, which translates from Greek into "single hole", have a true cloaca.
   BULLET::::- The Chestnut tree has also been used since ancient times as a source brown dye. The bark of the tree, the leaves and the husk of the nuts have all been used to make dye. The leaves were used to make a beige or yellowish-brown dye, and in the Ottoman Empire the yellow-brown from chestnut leaves was combined with indigo blue to make shades of green.
  
  Section::::Brown in science and nature.:Brown eyes.
   In the four tissue sections shown here, many of the intestinal glands have cells with a mitochondrial DNA mutation in the CCOI gene and appear mostly white, with their main color being the blue-gray staining of the nuclei. As seen in panel B, a portion of the stem cells of three crypts appear to have a mutation in CCOI, so that 40% to 50% of the cells arising from those stem cells form a white segment in the cross cut area.
   Brown rat
  
  The brown rat ("Rattus norvegicus"), also known as the common rat, street rat, sewer rat, Hanover rat, Norway rat, Norwegian rat, Parisian rat, water rat, or wharf rat, is one of the best known and most common rats.
   Kopi Luwak (pronounced ), or civet coffee, is coffee made from coffee berries that have been eaten by and passed through the digestive tract of the Asian palm civet ("Paradoxurus hermaphroditus"). Giant pandas provide fertilizer for the world's most expensive green tea. In Malaysia, tea is made from the droppings of stick insects fed on guava leaves.
  
  In northern Thailand, elephants are used to digest coffee beans in order to make Black Ivory coffee, which is among the world's most expensive coffees.
   Section::::Causes.
   The presence of pale stools and dark urine suggests an obstructive or post-hepatic cause as normal feces get their color from bile pigments. They can, however, occur in many intra-hepatic illnesses and are therefore not a reliable clinical feature to distinguish obstruction from hepatic causes of jaundice.
  
  Patients also can present with elevated serum cholesterol, and often complain of severe itching or "pruritus" because of the direct and indirect effects of pruritogens in bile such as bile salts.
   Bolus (digestion)
  
  In digestion, a bolus (from Latin "bolus", "ball") is a ball-like mixture of food and saliva that forms in the mouth during the process of chewing (which is largely an adaptation for plant-eating mammals). It has the same color as the food being eaten, and the saliva gives it an alkaline pH.
  
presuppositions: The color of feces is caused by all different kinds of colors of foods we eat that end up mixing and creating brown. Feces are brown because of the different colors in food mixing together.
corrections: The color of feces is not caused by the color of food but by the color of a specific chemical formed from broken-down blood cells and involved in digesting fats. Feces are brown because of a chemical formed from broken down blood cells.
raw_presuppositions: The color of feces is caused by all different kinds of colors of foods we eat that end up mixing and creating brown. Feces are brown because of the different colors in food mixing together.
raw_corrections: The color of feces is not caused by the color of food but by the color of a specific chemical formed from broken-down blood cells and involved in digesting fats. Feces are brown because of a chemical formed from broken down blood cells.