Module 2 and 3

Match the different types of simple sugars with their monosaccharide components (where applicable), how they are used in the body, major dietary sources and the name of the simple sugar with other name(s) that it goes by

- monosaccharides: 1) glucose: "blood sugar" and "dextrose"; used by all the cells for energy (particularly the brain and central nervous system), excess glucose stored as fat (used after several days of complete starvation) found in: fruit, vegetables, honey as a monosaccharide, in lactose and sucrose, starch and fiber-containing foods as a disaccharide and polysaccharide respectively. 2) fructose: "fruit sugar," used by some cells for energy, can be converted to glucose by liver, excess can be converted to fat by liver. found: in fruit, veg, honey as mono, sucrose-containing foods as di, fiber-containing food as poly 3) galactose: can be converted to glucose by the liver found: limited as mono, in lactose-containing foods as a di - disaccharides: 1) lactose (galactose and glucose): found in mammalian milk, dairy products 2) sucrose (fructose and glucose): found in fruit, veg, sugar cane extraction, honey

Rank the sweetness of fructose, sucrose, glucose, lactose, and galactose

fructose, sucrose, glucose, maltose, galactose, beta-lactose, alpha lactose

List the factors that can affect the rate of stomach emptying and predict how that could affect total calorie intake.

1) Delaying the start of stomach emptying by the presence of fat or protein. Snacks/meals containing protein or fat will leave people more satisfied and less likely to become hungry sooner and over eat. 2) The order of macronutrient release from the stomach: carbs --> protein --> fat. 3) Effects of liquid vs. solid: liquids leave the body before solids. Eating solid food is a better way to feel full rather than drinking calories. 4) Fast vs. slow eating: The brain takes 20 minutes to realize the stomach is full. Therefore, eating slow is better for intuitive eating.

Identify the two potential fates for glucose that isn't used immediately for energy.

1) Excess glucose can be used for short term energy by being converted to glycogen (2400 cals). As glycogen 2/3 can be stored in the muscles and used in fight or flight response. OR 1/3 stored in the liver as an energy source during fasting (like sleeping) 2) After glycogen stores are refilled, the rest will be converted to fat by the liver.

List the 2 basic classifications of carbohydrates and their members

1) Simple Sugars: - monosaccharides: glucose, fructose, and galactose - disaccharides: lactose (galactose and glucose), sucrose (fructose and glucose) 2) Complex Carbs - starches: polysaccharide made up of thousands of glucose only - fiber: polysaccharide made up of 10s-1000s of glucose, fructose or other monosaccharides.

Describe the process of digesting and absorbing dietary carbohydrates and predict in what form each type of dietary carbohydrate will enter the body following digestion and absorption

All dietary carbs have to be absorbed in the form of monosaccharides. Monosaccharides, glucose, fructose, and galactose are digested and then absorbed directly as themselves. Disaccharides use amylases to digest. Lactose is digested by the lactase amylase and absorbed as glucose and galactose. Sucrose is digested by sucrase and is absorbed as glucose and fructose. As for polysaccharides, starches are digested through a number of amylases and absorbed as glucose. Fiber is not digested and therefore, not absorbed.

Describe the roles that the pancreas and gall bladder play in the digestive process

The pancreas produces all the digestive enzymes and bicarbonate. Bile is stored in the gallbladder which is necessary to complete digestion in the small intestine.

Identify the 3 parts of a grain kernel, and their primary nutrient constituents

Bran (outer covering): most of fiber, many vitamins and minerals (niacin, thiamin, magnesium, phosphorus, iron, zinc) Germ (plant-to-be): contains all of above plus healthful unsaturated fats Endosperm (bulk of grain): all the remains after refining, protein, carbohydrates, few amount of vitamins and minerals

Define the terms digestion and absorption

Digestion: the chemical breakdown of complex food (carbs, protein, fat) into smaller molecules that can be absorbed. Absorption: the process of bringing those smaller molecules, along with its micronutrients into the body.

Describe the diet-related factors related to heartburn and ulcers and explain why they have the effects that they do.

Factors that lead to acid reflux and heart burn include eating triggering foods that irritate the stomach. Consuming irritating foods or eating too fast can off put and weaken the sphincter, allowing food to flow back upwards. Sphincters can also be weakened due to hormones, pregnancy, alcohol, caffeine. Eating too fast or other pressure related causes include tight pants, obesity, lying down, medication. For ulcers, it is caused by smoking, alcohol, over use of medication, stress, or irritating food; it causes a bacterial infection. Usually the stomach is protected by a mucosal barrier and the duodenum is protected by bicarbonate. If the use of a drug causes an infection, the treatment is antibiotics. Symptoms can be managed by eating smaller meals more frequently and avoiding irritating food.

Describe the basic structure of fiber and how it differs from starches.

Fiber is made up of 10s to 1000s of glucose, fructose, and other monosaccharides. It differs in structure from starch due to the inability for human amylases to break down the bonds between the glucose molecules.

Describe the structure of glycogen and how it is used by the body.

Glycogen is a highly branched polysaccharide of glucose molecules that can be used as short term energy in the muscles and liver or long term energy as fat.

Predict the consequences of a loss of functioning of a component or components of the GI tract or organs associated with it. (E.g., what would happen relative to nutrient digestion or absorption if you had a disease that limited the functioning of your pancreas, liver, stomach, etc.)

If any of the GI organ and GI-related organs (gallbladder, liver, pancreas) would be removed which could impact proper digestion based on the responsibilities of that organ. For example, if the pancreas was in question of proper functioning, digestive enzymes would not be made which would impact proper digestion and absorption. Furthermore bicarbonate, which neutralizes pH in the small intestine, would not be made which could harm the SI environment.

Match the two different types of fiber with their good sources, general characteristics

Insoluble fiber: - Example: cellulose; provides structure in plant cell walls - Dietary Sources: wheat bran, whole wheat, legumes, nuts, fruits vegetables - Characteristics: --does not dissolve in water (not soluble) --small amounts can be digested by intestinal bacteria Soluble fiber: -Example: --Gums; Mucilages; Pectin --The plant's cellular cement -Dietary Sources: oat bran, oat products. legumes, fruits, vegetables -Characteristics: --DOES dissolve in water (gel forms) --Slows rate of stomach emptying --Larger amounts can be digested (fermented) by intestinal bacteria

Explain the cause of lactose intolerance, its symptoms, identify who is likely to experience it and why, and ways to handle it

Lactose Intolerance is caused by low levels of lactase production. This causes decreased or no digestion of lactose. This undigested lactose accumulates in the LI causing bloating and diarrhea since it attracts water. Gas is created as a byproduct of the intestinal bacteria metabolizing the lactose. Non-caucasian groups such as hispanics, native americans, asians, africans because their traditional food may lack dairy. Elderly people are also likely to suffer because lactase levels decline with age. Eating small amounts of lactose-containing foods, eating foods low in lactose (yogurt and cheese), or eating foods pretreated with lactase (Lactaid) is recommended.

Compare and contrast the roles that longitudinal and circular muscles play in the movement of food material along and out of the GI tract

Longitudinal muscles move food MECHANICALLY by shortening and lengthening the tract to move food along. Waves of longitudinal contractions move it the food forward. Circular muscles move food MECHANICALLY by opening and closing the tract. The contraction behind food prevents the bolus from moving backward.

List the ways by which the GI tract maximizes efficiency.

Mouth: - has been prepared by cephalic phase - rest of tract is prepared for food via taste and smell - begins digestion of carbs Stomach - begins protein digestion - slowly releases content to SI Small Intestine - emulsifies fat - mixes chyme, digestive chemicals via longitudinal and circular muscles - high surface area for absorption - diversion of blood supply Facilitators: - approx. 30 different, highly specific, digestive enzymes along tract - approx. ten hormones and regulatory chemicals produced by GI tract organs and a highly developed nervous system - ALL WORK TO: increase/decrease muscle activity, move food, open/close sphincters, increase/decreases release of digestive chemicals

Match the mouth, esophagus, stomach, small and large intestine with the digestive and/or absorptive activity(ies) that take(s) place there.

Mouth: - mechanical breakup of food via teeth and tongue, facilitation of swallowing - secretion of saliva: lubricates food, contains an amylase to begin digesting carbs, contributes to taste - detection of food's taste and texture: stimulates the secretion of gastric juices to prepare for food. Esophagus: - serves as a pathway to the stomach, food material moves through via peristalsis (NO DIGEST/ABSORP) Stomach - serves as a holding tank - some mechanical breakup of food (chyme) via peristalsis - denaturation of protein via HCl - initial digestion of protein: some gastric proteases that begin process - some absorption of alcohol Small intestine: - PRIMARY SITE OF DIGESTION AND ABSORPTION 1. Neutralization of acidic chyme from the stomach via bicarbonate 2. emulsification of lipids via bile salts 3. Release of digestive enzymes from the pancreas and small intestine 4. Mixing of chyme, bile, and digestive enzymes via longitudinal and circular muscles. 5. Completion of carb, protein, and fat digestion 6. Absorption of nutrients/other food components and reabsorption of digestive secretions via villi cells. Large Intestine: -serves as a holding tank that controls the release of fecal matter - reabsorption of water and some minerals and vitamin K - bacteria activity

Describe ways to reduce discomfort (gas) associated with high-fiber vegetable and legume consumption.

One can decrease discomfort (gas) from draining and rinsing legumes multiple times. It is also advised to increase fiber consumption at a slow rate to not cause GI stress.

Identify reasons why carbohydrate restricted diets (including Paleo) became so popular, explain why they work over the short term and whether there is evidence for their effectiveness over the long term.

Paleo and Atkins (Keto) are popular carb restricting diets because they can work in the short term. This is due to losing water weight, being able to eat "forbidden," fatty, palatable food, users are not hungry due to high fat and protein, there are limited choices, and there is no room for junk food (because junk food has carbs). People also like it because you are not required to work out or eat vegetables, it includes a plan to tell you what and when to eat. There is little evidence that after a year, weight loss is maintained.

Explain what peristalsis is.

Peristalsis is the powerful movement of food through the tract via longitudinal and circular muscles; it also includes the mixing of food material with digestive chemicals.

Explain how plants might use simple sugars and complex carbohydrates (why fruits are sweet and seeds are starchy).

Plants use simple sugars to make up other substances such as cellulose. They are made through photosynthesis and used for energy to make cellulose which is used to build cell walls. Complex sugars are made with glucose energy and is stored in seeds and other parts of plants. Starch provides energy during the germination process.

Explain the difference between a probiotic and a prebiotic

Prebiotic: composed of non-digestible material that promotes growth of good bacteria; is found in fiber-filled food such as fruit, vegetables, and whole grains (so no need to supplement) Probiotic: are the helpful good bacteria can be consumed in bacteria-containing foods and supplements such as fermented foods with live cultures. ex) cottage cheese, pickles, kombucha, yogurt

Explain the structure, function and location of sphincters.

Sphincters are located between organs along the GI tract. Between the esophagus and stomach, sphincters prevent backflow of food into the esophagus. Between the stomach and small intestine, the sphincter limits the rate of flow into the small intestine. The sphincter between the small and large intestine also limits the rate of flow from the small to the large. The anal sphincter controls the elimination of waste from the body. The sphincters maximize absorption and digestion by controlling the flow of food. The sphincters maximize absorption and digestion by controlling the flow of food. They are in the closed position until hormones and other factors allow them to open.

Describe the basic structure of starches, how they differ from one another and how that affects their characteristics, and list examples of their dietary sources.

Starches are composed of thousands of glucose molecules. They differ by thickness and gel-forming characteristics bases on the number of glucose molecules and the arrangement or branching of molecules. Food sources include tuberous vegetables, cereal grains, rice, legumes, nuts, seeds.

Predict the potential consequences of using a cellulase supplement and explain why, and a soluble fiber supplement that binds to dietary fat and explain why.

Taking a cellulose supplement will digest normally indigestible cellulose. This leads to an increase in calories (that were once indigestible) and constipation because it removes bulk. Taking a soluble fiver supplement will be ineffective in lowering dietary fat because it binds to milligrams of fat which is irrelevant because we consume it in grams.

Describe the role that taste plays in the digestive process and in health more generally.

Taste is a complex interaction between the receptors on your tongue and olfactory receptors in your nose. It plays an important role in the digestive process because it Tells us what food contains and encourages us to eat more to survive.

List the levels of fiber of intake that are recommended by the DRIs and explain why Americans are/are not close to meeting those goals.

The DRIs for fiber is 25g in women and 35g/day in men. Americans are likely not reaching these recommendations because they are not eating enough whole grains, fruits, and vegetables (and legumes). They are replacing these calories with less nutritious, fiber-less foods.

Identify which organs are part of the GI tract itself and which are related to its function

The GI tract is composed of the mouth, esophagus, stomach, small intestine, and large intestine. NOTE: anything inside the GI tract is technically outside the body. The gall bladder, pancreas, and liver are "digestion-related" organs that release digestive chemicals into the GI tract.

Explain the history of the development of the glycemic index and list and explain the factors that can influence the rate of carbohydrate digestion and absorption.

The Gylcemic Index (GI), a way to predict how quickly a food's carb content will be absorbed, was thought to be helpful b/c they THOUGHT complex carbs were digested slower (lower increase of blood glucose) as compared to simple sugars. However, we now understand this was not tested til 80s and many factors affect the rate of absorption... - length of cooking time (long=quick ab) - starch structure (more branch=quick) - amount of soluble fiber, fat, and protein (more delays stomach emptying- slow) - relative amounts of fructose or galactose vs. glucose (slower rise in blood glucose b/c has to be converted to glucose by liver and split by amylases to be digested)

Explain the differences between honey and sugar (sucrose) and the implications for choosing honey instead of sugar.

The body sees sugar/sucrose the same that it sees honey because the nectar is the sucrose; bees have enzymes that split sucrose into glucose and fructose; sugar=sucrose in the body because our enzymes also split sucrose into glucose and fructose.

Explain the carbohydrate-related components on a food label.

The carb components of a food label include total carbs per serving AND dietary fiber and total sugars. They include fiber to avoid confusion but it DOES not contribute to total calories. Therefore if a product contains 4g of fiber, it actually has 16 less calories than advertised.

Describe the roles that the cephalic phase and cooking play in digestion.

The cephalic phase is the thinking about food which causes salvation and the release of gastric juices into the stomach to prepare for consumption. Cooking plays a role by softening connective tissue in animals and tough, fibrous tissue in plants.

Explain the genesis of the federal enrichment program and the ways in which enriched flour is the same and different from whole wheat flour.

The federal enrichment program added certain nutrients to refined grain and cereal products to eliminate deficiency diseases. They are added in amounts that exceed the amount occurring naturally in whole wheat and whole grain products. However, whole grains still have a larger amount of fiber

Identify and explain the inaccuracies related to digestion and absorption found in popular fad diet plans that focus on the principle of "food combining"

The food combining fad diet that claims certain foods can't be eaten together due to the body's inability to digest them simultaneously is seriously flawed. Our bodies are very good at detecting different components of food when mixed together. The body can digest these different compounds simultaneously and efficiently due to the complex features of the GI tract.

List the roles that bacteria play in health.

The friendly bacteria in the small intestine live in undigested material in the large intestine, prevent pathogenic bacteria from growing, helps maintain a healthy colon by producing by-products that can be used for energy, produce some vitamin K (can be absorbed from colon).

Explain the roles that the liver and kidneys play in processing and/or eliminating absorbed compounds.

The liver #1 serves as a secondary gatekeeper by screening for unwanted toxins such as alcohol/drugs that have been absorbed, detoxifies them to be eliminated. #2 the liver procures incoming nutrients for use by the body. The kidneys are the last stop in post absorption. The kidneys filter blood by excreting absorbed, unwanted/excess water-soluble compounds and excreting water-soluble waste products of metabolism. The kidneys ALSO control certain nutrient levels by in/decreasing excretion as the body's needs dictate.

Explain the primary function of digestible carbohydrate in the body, list the DRI for total carbohydrate consumption and for added sugars, and explain the rationale for each.

The primary function of carbs in the body is to supply the body with energy in the form of glucose (especially the brain and central nervous system). The recommendation for carbs says that it should be 45-65% of total calories and less than 10% should come from added sugar. This DRI is appropriate because carbs are the brain's main source of energy.

Explain the purpose of the glycemic index, how it is determined for an individual food, and describe its potential significance, limitations and appropriate use

The purpose is to compare different food's effect on blood glucose levels. It is determined by feeding test subjects different foods in 50g amounts, drawing blood sampled over 2 hour period, and plotting the blood glucose levels, and comparing them to a standard, 50g of pure blood glucose. It is calculated by dividing the area under the curve for the test food by the area under the curve for pure glucose x100. Significance: low GI food=under 55 high GI food= 70 USE: It is recommended to consume foods such as legumes, fruit, vegetables, and whole grains that are low on the GI scale (more often than high GI) to feel more satiated and not be hungry quicker. LIMITATIONS: the test only showed a certain food alone, in a specified amount, in one state (raw, cold, hot). Lists vary depending on the source and there can be a large difference in GI depending on if eaten hot or cold.

Provide a critique of the claims made by proponents of the raw food diet.

The raw food diet claims that eating raw plants and food that contain their own enzymes (that can digest macronutrients within plants; used by plants for metabolic processes) will greatly aid our digestion. They claim that due to the denaturing of proteins in the heating process, not eating food without the enzymes found in raw food will make digestion more difficult, deprive the body of enzymes, lead to toxicity, excess consumption, obesity, and chronic disease. HOWEVER, eating foods without enzymes will not make digestion more difficult because we make more than enough digestive enzymes on our own. Furthermore, a lack of digestion would not cause obesity. If we were lacking our own digestive enzymes and enzymes from plants we would be absorbing fewer calories anyway.

Compare the efficiency of macronutrient and micronutrient absorption and explain why the difference exist.

The small intestine controls the degree of absorption of vitamins and minerals once the body has received enough. For example, as calcium intake increases, absorption decreases because once the body reaches it's needed amount, there is no reason to absorb excess (no energy gained). The small intestine has an efficiency of at least 90% for macronutrients regardless of how much is consumed as a historical survival adaptation (stores rest as fat).

3 ENZYMES involved in digestion and identify their functions, sites of synthesis, and sites of action.

There are 3 enzymes that are involved with digestion: Proteases, Amylases, Lipases Proteases: This enzyme digests protein, is made in the stomach, pancreas, and small intestine, functions in the small intestine and stomach. Amylases: digest carbohydrates, are made in the mouth, pancreas, and small intestine, functions in the mouth and small intestine. Lipases: digest lipids, made in the pancreas and small intestine, functions in only the small intestine. NOTE: the small intestine is involved in the making and functioning of all these enzymes.

3 CHEMICALS involved in digestion and identify their functions, sites of synthesis, and sites of action.

There are three chemical involved with digestion: Hydrochloric acid, Bicarbonate, and Bile. HCl: made in the stomach, functions in the stomach to the create acidic pH. Bicarbonate: made in the pancreas, functions in the small intestine to neutralize the acidic pH. BIle: made in the liver but is stored in the gallbladder; it functions in the small intestine.

Describe how someone can be sure that a product is truly whole grain and other issues to be aware of when evaluating a food for its fiber content.

To make sure a product is a whole grain, one must look at the ingredient list to see if the first word is whole. Fiber is naturally higher in whole grain products but can vary by serving size (grams) and if a refined grain has added fiber.

Distinguish between the roles that the circulatory and lymphatic systems play in the absorptive process.

Water-soluble nutrients enter the circulatory system through the capillaries in villi cells. Fat soluble nutrients enter the lymphatic system through lacteal in villi cells.

List the components of fecal matter and explain what the excretion of waste from the GI tract requires.

composed of undigested material and fiber. Friendly bacteria lives on undigested material (mostly fiber). The large intestine reabsorbs water and turns liquid fecal matter into stool. Peristalsis helps with excretion.

Match the digestive chemicals saliva, the digestive enzymes, hydrochloric acid, bicarbonate and bile with the compounds upon which they act and/or their function.

digestive enzymes: - protease: digest protein in stomach and small intestine - amylase: digests carbs in the mouth and small intestine - lipase: digests lipids in the small intestine saliva: functions in the mouth to lubricate food, start breakdown of carbs through amylase and contributes to taste. digestive chemicals: - Hydrochloric acid: creates an acidic pH in the stomach that can denature protein - Bicarbonate: neutralizes pH in the small intestine and protect the duodenum - Bile: functions in the small intestine to emulsify lipids; bile mixes with chyme and enzymes to complete digestion.

Identify ways by which manufacturers can add purified fiber to foods and discuss what is, or is not known, about their healthfulness as compared to whole food fiber sources.

manufacturers can increase the fiber content by adding purified fibers. Examples include: Insulin/chicory root extract, Oligofructose, Polydextrose, modified wheat starch, soy fibers, and sugarcane fiber. The research done on the health benefits of fiber were done on whole foods. The degree to which that purified fiber has the same effect is unknown. These health benefits are due to soluble fiber being gooey and viscous which insulin are not.