To balance the high-GI foods on the Thanksgiving table with low-GI foods, follow some of these suggestions:. Skills to Develop Discuss how carbohydrates are digested and absorbed in the human body.
From the Mouth to the Stomach The mechanical and chemical digestion of carbohydrates begins in the mouth. From the Stomach to the Small Intestine The chyme is gradually expelled into the upper part of the small intestine.
Absorption: Going to the Blood Stream The cells in the small intestine have membranes that contain many transport proteins in order to get the monosaccharides and other nutrients into the blood where they can be distributed to the rest of the body.
Maintaining Blood Glucose Levels: The Pancreas and Liver Glucose levels in the blood are tightly controlled, as having either too much or too little glucose in the blood can have health consequences. Leftover Carbohydrates: The Large Intestine Almost all of the carbohydrates, except for dietary fiber and resistant starches, are efficiently digested and absorbed into the body. A Carbohydrate Feast Figure 3. Glycemic Index The glycemic responses of various foods have been measured and then ranked in comparison to a reference food, usually, a slice of white bread 50 g or just straight glucose, to create a numeric value called the glycemic index GI.
Glycemic Index Database. Interactive 3. Leave the skins on the potatoes. The skin contains fiber and adds texture to mashed potatoes. Do not use instant potatoes. Instead of canned green beans with cream of mushroom soup and fried onions for a side dish, combine butter beans and green peas for a colorful, low-GI food.
Make your stuffing with whole-grain bread and add mushrooms and extra celery and onions. Try a new low-sugar pumpkin pie recipe and make the crust from whole-grain flour. Offer homemade banana bread for dessert. Key Takeaways Carbohydrate digestion begins in the mouth with the mechanical action of chewing and the chemical action of salivary amylase.
Carbohydrates are not chemically broken down in the stomach, but rather in the small intestine. Pancreatic amylase and the disaccharidases finish the chemical breakdown of digestible carbohydrates. The monosaccharides are absorbed into the bloodstream and delivered to the liver.
Some of the indigestible carbohydrates are digested by bacteria in the large intestine. Glucose itself participates in regulating its levels in the blood.
Not all carbohydrates have the same effect on blood-glucose levels. The glycemic response is a measurement of the effects of a carbohydrate-containing food on blood-glucose levels. Discussion Starters Experience the taste sensations of different carbohydrates. What are some foods that satisfy your sweetness sensation?
Even though fiber contains calories, albeit less than half of other carbohydrates, why do we generally discount its caloric contribution from our diets? How long a person feels full after eating a carbohydrate-rich meal depends on the type of carbohydrate consumed and what other nutrients are in the meal. Conduct an experiment and determine how long you feel full after eating a candy bar; after eating a slice of whole-grain bread; after eating an apple; and after eating a potato.
Compare your results with your classmates and discuss why some of these carbohydrate foods make you feel full longer than others. Source: University of Sydney. Salivary amylase continues for the short duration that the carbohydrates are in the mouth, after which the mixture of the partially digested carbohydrates travels down the esophagus into the stomach.
Due to the inhibition of salivary amylase activity by the acidic gastric juices, digestion of carbohydrates does not occur in the stomach. As the combination of gastric juices and partially digested food enters the small intestine, the pancreas secretes pancreatic juices, which contain the enzyme pancreatic amylase. This enzyme acts on the remaining polysaccharides and breaks them into disaccharide units of maltose.
In the final step of complex carbohydrate digestion, the enzyme maltase present in the lining of the small intestine breaks maltose into two units of glucose. Glucose is then absorbed and enters the bloodstream. Two additional enzymes present in the small intestine digest other disaccharides in foods. The enzyme sucrase digests sucrose or table sugar into its constituent units of glucose and fructose, while lactase breaks lactose or milk sugar into glucose and galactose.
Different types of enzymes can break down different nutrients:. Carbohydrates are digested in the mouth , stomach and small intestine. Carbohydrase enzymes break down starch into sugars. The saliva in your mouth contains amylase, which is another starch digesting enzyme.
If you chew a piece of bread for long enough, the starch it contains is digested to sugar, and it begins to taste sweet. Proteins are digested in the stomach and small intestine. Lactose intolerance occurs when you aren't able to digest lactose because of insufficient production of lactase by the small intestine. When you consume dairy products, you may experience:.
There are several forms of lactose intolerance. Congenital Lactase Deficiency. Congenital lactase deficiency also called congenital alactasia is a rare inherited form of lactose intolerance. It happens when newborns are unable to break down lactose in breast milk or formula. They get severe diarrhea if they aren't given a lactose-free alternative.
Congenital lactase deficiency is caused by mutations in the LCT gene that provides instructions for making the lactase enzyme.
Lactase Non-Persistence. Lactase non-persistence is a common type of lactose intolerance that some people develop as adults. Symptoms typically begin 30 minutes to two hours after eating or drinking dairy. Most people with lactase non-persistence keep some level of lactase activity and can continue to include a small amount of lactose in their diets. This may be in the form of cheese or yogurt since both tend to be tolerated better than fresh milk. Secondary Lactose Intolerance.
Secondary lactose intolerance develops when lactase production is reduced because of diseases that can damage the small intestine. These diseases include celiac disease or Crohn's disease as well as other illnesses or injuries that affect the intestinal wall. The pancreas produces the key digestive enzymes amylase, protease, and lipase. People with exocrine pancreatic insufficiency EPI have a deficiency of these enzymes. As a result, they are unable to digest food properly, especially fats.
The health conditions that affect the pancreas and are associated with EPI are:. People who don't have sufficient amounts of digestive enzymes or who are looking to support healthy digestion should consider supplementing their diet with digestive enzymes. They can do this by eating healthy foods that contain naturally occurring digestive enzymes. But they can also take nutritional supplements under a healthcare provider's guidance.
A variety of foods, especially tropical fruits and fermented vegetables, are naturally high in digestive enzymes that might speed up the digestion of certain nutrients. It's best to eat them raw since heat can lessen or destroy these plant enzymes. Digestive enzyme supplements can come in:. There are prescription supplements regulated by the FDA as well as over-the-counter supplements. Prescription enzyme supplements are recommended for conditions that affect the functioning of the pancreas, such as chronic pancreatitis or pancreatic cancer.
Brands of prescription pancreatic enzyme supplements pancrelipase include Creon, Pancreaze, Zenpep, Ultresa, Viokace, and Pertzye.
Over-the-counter enzyme supplements are not regulated by the FDA. There haven't been enough high-quality studies on them, so it's hard to know how effective they are. The following are some of the supplemental enzymes that don't require a prescription:. As with any supplement, check with your healthcare provider before taking an over-the-counter digestive enzyme to make sure it's safe for you.
They're secreted by the salivary glands and cells lining the stomach, pancreas, and small intestine. Sometimes people have a digestive enzyme deficiency. These deficiencies are connected to various health conditions. Many of these health conditions are related to the pancreas. Before you decide to take an enzyme supplement, get your healthcare provider's advice.
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