Title: Small intestine
Content: Iron is absorbed in the duodenum. ; Folate (Vitamin B9) is absorbed in the duodenum and jejunum. ; Vitamin B12 and bile salts are absorbed in the terminal ileum. ; Water is absorbed by osmosis and lipids by passive diffusion throughout the small intestine. ; Sodium bicarbonate is absorbed by active transport and glucose and amino acid co-transport ; Fructose is absorbed by facilitated diffusion. Digested food is now able to pass into the blood vessels in the wall of the intestine through either diffusion or active transport. The small intestine is the site where most of the nutrients from ingested food are absorbed. The inner wall, 
Title: Digestion
Content:  digestive enzymes from the pancreas and bile juice from the liver and then passes through the small intestine, in which digestion continues. When the chyme is fully digested, it is absorbed into the blood. 95% of nutrient absorption occurs in the small intestine. Water and minerals are reabsorbed back into the blood in the colon (large intestine) where the pH is slightly acidic about 5.6 ~ 6.9. Some vitamins, such as biotin and vitamin K (K2MK7) produced by bacteria in the colon are also absorbed into the blood in the colon. Absorption of water, simple sugar and alcohol also takes place in stomach. Waste material is eliminated from the rectum during defecation.
Title: Ruminant
Content:  This is also where the ruminant digests the microbes produced in the rumen. Digesta is finally moved into the small intestine, where the digestion and absorption of nutrients occurs. The small intestine is the main site of nutrient absorption. The surface area of the digesta is greatly increased here because of the villi that are in the small intestine. This increased surface area allows for greater nutrient absorption. Microbes produced in the reticulorumen are also digested in the small intestine. After the small intestine is the large intestine. The major roles here are breaking down mainly fiber by fermentation with microbes, absorption of 
Title: Malabsorption
Content:  Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety of anaemias. Normally the human gastrointestinal tract digests and absorbs dietary nutrients with remarkable efficiency. A typical Western diet ingested by an adult in one day includes approximately 100 g of fat, 400 g of carbohydrate, 100 g of protein, 2 L of fluid, and the required sodium, potassium, chloride, calcium, vitamins, and other elements. Salivary, gastric, intestinal, hepatic, and pancreatic secretions add an additional 7–8 L of protein-, lipid-, and electrolyte-containing fluid to intestinal contents. This massive load is reduced by the small and large intestines to less 
Title: Small intestine
Content:  of said nutrients to intestinal fauna. Each villus has a network of capillaries and fine lymphatic vessels called lacteals close to its surface. The epithelial cells of the villi transport nutrients from the lumen of the intestine into these capillaries (amino acids and carbohydrates) and lacteals (lipids). The absorbed substances are transported via the blood vessels to different organs of the body where they are used to build complex substances such as the proteins required by our body. The material that remains undigested and unabsorbed passes into the large intestine. Absorption of the majority of nutrients takes place in the jejunum, with the following notable exceptions:
Title: Abdomen
Content:  Functionally, the human abdomen is where most of the digestive tract is placed and so most of the absorption and digestion of food occurs here. The alimentary tract in the abdomen consists of the lower esophagus, the stomach, the duodenum, the jejunum, ileum, the cecum and the appendix, the ascending, transverse and descending colons, the sigmoid colon and the rectum. Other vital organs inside the abdomen include the liver, the kidneys, the pancreas and the spleen. The abdominal wall is split into the posterior (back), lateral (sides), and anterior (front) walls.
Title: Digestion
Content:  the stomach. Mainly proteins are digested in stomach. The partially digested food enters the duodenum as a thick semi-liquid chyme. In the small intestine, the larger part of digestion takes place and this is helped by the secretions of bile, pancreatic juice and intestinal juice. The intestinal walls are lined with villi, and their epithelial cells is covered with numerous microvilli to improve the absorption of nutrients by increasing the surface area of the intestine. Bile helps in emulsification of fats and also activates lipases. In the large intestine the passage of food is slower to enable fermentation by the gut flora to take place. Here water is absorbed and waste material stored as feces to be removed by defecation via the anal canal and anus.
Title: Human body
Content:  The digestive system consists of the mouth including the tongue and teeth, esophagus, stomach, (gastrointestinal tract, small and large intestines, and rectum), as well as the liver, pancreas, gallbladder, and salivary glands. It converts food into small, nutritional, non-toxic molecules for distribution and absorption into the body. These molecules take the form of proteins (which are broken down into amino acids), fats, vitamins and minerals (the last of which are mainly ionic rather than molecular). After being swallowed, food moves through the gastrointestinal tract by means of peristalsis: the systematic expansion and contraction of muscles to push food from one area to the next. Digestion begins in the mouth, which chews food into smaller pieces for easier digestion. Then it is swallowed, and moves through the esophagus to the stomach. In the stomach, food is mixed with gastric acids to allow the extraction of nutrients. What is left is called chyme; this then moves into the small intestine, which absorbs the nutrients and water from the chyme. What remains passes on to the large intestine, where it is dried to form feces; these are then stored in the rectum until they are expelled through the anus.
Title: Human iron metabolism
Content:  is in the form of heme iron, and is more efficient, allowing absorption of from 15% to 35% of intake. Heme iron in animals is from blood and heme-containing proteins in meat and mitochondria, whereas in plants, heme iron is present in mitochondria in all cells that use oxygen for respiration. Like most mineral nutrients, the majority of the iron absorbed from digested food or supplements is absorbed in the duodenum by enterocytes of the duodenal lining. These cells have special molecules that allow them to move iron into the body. To be absorbed, dietary iron can be absorbed as part of a 
Title: Small intestine
Content:  The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about 18 feet (6 meters) long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in width. The small intestine has three distinct regions – the duodenum, jejunum, and ileum. The duodenum, the shortest, is where preparation for absorption through small finger-like protrusions called villi begins. The jejunum is specialized for the absorption through its lining by enterocytes: small nutrient particles which have been previously digested by enzymes in the duodenum. The main function of the ileum is to absorb vitamin B12, bile salts, and whatever products of digestion that were not absorbed by the jejunum.

Question: where are most nutrients absorbed in the human digestive tract?
Answer: The small intestine.
small intestine.