Digestive Wellness: Strengthen the Immune System and Prevent Disease Through Healthy Digestion, Fourth Edition by Elizabeth Lipski Read Free Book Online
Authors: Elizabeth Lipski
When this occurs, there is a problem of increased intestinal permeability, commonly known as “leaky gut syndrome.” This syndrome contributes to skin problems, food sensitivities, osteoarthritis, migraine headaches, and chronic fatigue syndrome. (See Chapter 4 .)
The small intestine has three parts: the duodenum, the jejunum, and the ileum. The duodenum is the first 12 inches of the small intestine, the jejunum composes about 40 percent of the digestive system (about 11 feet), and the ileum composes the last segment (about 8 feet). The jejunum and ileum are connected by the ileocecal valve. Each nutrient is absorbed at specific parts of the small intestine. The duodenum has an acidic environment that facilitates absorption of some minerals, including chlorine, sulfur, calcium, copper, iron, thiamin, manganese, and zinc. We also begin the process of absorbing fat-soluble vitamins (A, D, E), fats, and some water-soluble vitamins (B 1 , B 2 , B 6 , C, and folic acid). People with low hydrochloric acid levels may become deficient in one or more of these nutrients because they need acid for absorption. In the jejunum, we continue absorption of nutrients plus sugars, proteins, and amino acids. In the ileum, we finish the job of digesting many nutrients and add absorption of cholesterol, B 12 , and bile salts. And finally, in the colon, we absorb potassium, water, salt, vitamin K, and short-chain fatty acids. If you look at the nutrient absorption chart in Figure 2.4 you can see specifically where each nutrient is absorbed along the digestive tract.
Pancreas
The pancreas has two main roles: to aid in the digestion of food and to produce insulin and glucagon, which regulate blood sugar levels, thereby maintaining both digestive and global function.
When food passes from the stomach to the duodenum, cholecystokinin is secreted and enhanced by secretin. This stimulates the pancreas to secrete bicarbonate-rich alkaline fluid, essentially baking soda, which neutralizes the acidity of the chyme. The hydrochloric acid has already finished its work and a more neutral pH is where the rest of the digestive system functions best. The pancreas also manufactures and secretes specific digestive enzymes. Pancreatic amylase digests starches and sugars. The protein-splitting enzymes are called trypsin, chymotrypsin, carboxypeptidase, and elastase (also called pancreatic elastase). Pancreatic lipase and colipase break fats into fatty acids and glycerol. Ribonuclease and deoxyribonuclease digest old RNA and DNA. Once our food has been fully digested, nutrients can be absorbed into the bloodstream and used by the cells. Low secretion of pancreatic enzymes can lead to nutritional deficiencies. For example, vitamin B 12 requires protein-splitting enzymes to separate it from its carrier molecule, so poor pancreatic function can lead directly to vitamin B 12 deficiencies.
The second role of the pancreas is the production of hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide in the pancreatic islets (also called islets of Langerhans). Insulin is secreted when blood sugar levels rise; glucagon is secreted when blood sugar levels are low. Common problems in the pancreas are diabetes, which is a systemic disease, and pancreatitis, that is, inflammation of the pancreas.
Figure 2.4 Nutrient absorption chart.
Liver: The Body’s Fuel Filter
The liver is the most complex of the body’s organs. It performs more than 500 functions and is critical to most of our metabolism. I once heard the dean of a medical school say, “I’d rather run all of the operations of General Motors for a day than be my own liver.” Your four-and-a-half-pound liver manufactures 13,000 chemicals and has 2,000 enzyme systems, plus thousands of synergists that help with body functions. It regulates the metabolism of carbohydrates, fats, and proteins; it manufactures bile to emulsify fats for digestion; it makes and breaks down many hormones,
The small intestine has three parts: the duodenum, the jejunum, and the ileum. The duodenum is the first 12 inches of the small intestine, the jejunum composes about 40 percent of the digestive system (about 11 feet), and the ileum composes the last segment (about 8 feet). The jejunum and ileum are connected by the ileocecal valve. Each nutrient is absorbed at specific parts of the small intestine. The duodenum has an acidic environment that facilitates absorption of some minerals, including chlorine, sulfur, calcium, copper, iron, thiamin, manganese, and zinc. We also begin the process of absorbing fat-soluble vitamins (A, D, E), fats, and some water-soluble vitamins (B 1 , B 2 , B 6 , C, and folic acid). People with low hydrochloric acid levels may become deficient in one or more of these nutrients because they need acid for absorption. In the jejunum, we continue absorption of nutrients plus sugars, proteins, and amino acids. In the ileum, we finish the job of digesting many nutrients and add absorption of cholesterol, B 12 , and bile salts. And finally, in the colon, we absorb potassium, water, salt, vitamin K, and short-chain fatty acids. If you look at the nutrient absorption chart in Figure 2.4 you can see specifically where each nutrient is absorbed along the digestive tract.
Pancreas
The pancreas has two main roles: to aid in the digestion of food and to produce insulin and glucagon, which regulate blood sugar levels, thereby maintaining both digestive and global function.
When food passes from the stomach to the duodenum, cholecystokinin is secreted and enhanced by secretin. This stimulates the pancreas to secrete bicarbonate-rich alkaline fluid, essentially baking soda, which neutralizes the acidity of the chyme. The hydrochloric acid has already finished its work and a more neutral pH is where the rest of the digestive system functions best. The pancreas also manufactures and secretes specific digestive enzymes. Pancreatic amylase digests starches and sugars. The protein-splitting enzymes are called trypsin, chymotrypsin, carboxypeptidase, and elastase (also called pancreatic elastase). Pancreatic lipase and colipase break fats into fatty acids and glycerol. Ribonuclease and deoxyribonuclease digest old RNA and DNA. Once our food has been fully digested, nutrients can be absorbed into the bloodstream and used by the cells. Low secretion of pancreatic enzymes can lead to nutritional deficiencies. For example, vitamin B 12 requires protein-splitting enzymes to separate it from its carrier molecule, so poor pancreatic function can lead directly to vitamin B 12 deficiencies.
The second role of the pancreas is the production of hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide in the pancreatic islets (also called islets of Langerhans). Insulin is secreted when blood sugar levels rise; glucagon is secreted when blood sugar levels are low. Common problems in the pancreas are diabetes, which is a systemic disease, and pancreatitis, that is, inflammation of the pancreas.
Figure 2.4 Nutrient absorption chart.
Liver: The Body’s Fuel Filter
The liver is the most complex of the body’s organs. It performs more than 500 functions and is critical to most of our metabolism. I once heard the dean of a medical school say, “I’d rather run all of the operations of General Motors for a day than be my own liver.” Your four-and-a-half-pound liver manufactures 13,000 chemicals and has 2,000 enzyme systems, plus thousands of synergists that help with body functions. It regulates the metabolism of carbohydrates, fats, and proteins; it manufactures bile to emulsify fats for digestion; it makes and breaks down many hormones,
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