NUTR Exam 2 Review: Chapter 5

Galactose + Glucose

Lactose

Fasting hypoglycemia

Low blood glucose that occurs after 8 hours or more of fasting -Usually caused by an underlying serious medical condition, such as cancer, liver disease, or renal disease, rather than by simply fasting.

Glucose + Glucose

Maltose

Fructose

Monosaccharide found in fruits, vegetables, and honey; also called levulose -High fructose corn syrup is sweeter and cheaper than table sugar, it is used to sweeten many food products especially beverages. -9 to 11% of of total energy intake by North Americans

Galactose

Monosaccharide found most abundantly as part of lactose (milk sugar). -Almost identical in structure to glucose -When combined with glucose it creates the disaccharide called lactose (found in milk and other dairy products)

Glucose

Most abundant monosaccharide -Also called dextrose -Most glucose in our diets make up larger sugars such as disaccharides or polysaccharides -In blood stream it is called "Blood sugar"

Digestible carbs

Most of the digestible carbs in our diets are broken down to glucose. As glucose, they provide a primary source of energy, spare protein from use as an energy source, and prevent ketosis.

Large Intestine (Digestion)

Some Soluble fiber is metabolized into acids and gases by the bacteria in the large intestine

Glucose + Fructose

Sucrose

Glycemic load (GL)

Amount of carbs in a food multiplied by the glycemic index of that food, then divided by 100 -Vanilla wafer has a glycemic index of 77, a serving size of 5 wafers contains 15 g of carbs, thus yielding a glycemic load of 12: (77x15)/100 = 12

Hexose

Carb containing 6 carbons

Nonstarch Polysaccharides

Cellulose, hemicelluloses, pectins, gums, and mucilages. -Lignins are the only noncarb components of dietary fibers. -Monosacc units in fibers are linked by beta bonds and cannot be digested

Disaccharide

Class of Sugars formed by the chemical bonding of 2 monosaccharides -(CH2O)12 -Maltose, Sucrose, Lactose

Polysaccharide

Class of complex carbs containing many glucose units from 10 to 1000 or more.

Monosaccharide

Class of single sugars that are not broken down further during digestion -(CH2O)6 -Ribose and Deoxyribose are also monosaccs found in nature, classified as pentoses because they have 5 carbons -Sugar alcohols, derivatives of monosaccs, include sorbitol, mannitol, and xylitol (primarily used as sweeteners in sugarless gum and dietetic food.

Total Fiber

Dietary and functional fiber in food

Acceptable Daily Intake (ADI)

Estimate amount of a sweetener that an individual can safely consume daily over a lifetime. ADIs are given as mg per kg of bodyweight per day.

Functional Fiber

Fiber added to food to provide health benefits

Dietary Fiber

Fiber naturally in food -Only fiber on food labels

Insoluble Fibers

Fibers that are not easily dissolved in water or metabolized by bacteria in the large intestine; include cellulose, some hemicelluloses, and lignins

Soluble Fibers

Fibers that dissolve in water and can be metabolized (fermented) by bacteria in the large intestine; include pectin, gums, and mucilages; also called viscous fibers. -Occur naturally inside and around plants cells in oat bran, many fruits, legumes, and psyllium

Insulin

Hormone produced by beta cells of the pancreas. Increase movement of glucose from the blood stream into body cells, increases synthesis of glycogen in the liver, decreases the breakdown of fat.

raffinose

Indigestible oligosaccharide made of 3 monosaccharides (galactose-galactose-fructose)

stachyose

Indigestible oligosaccharide made of 4 monosaccharides (galactose-galactose-glucose-fructose).

Rectum and Anus (Digestion)

Insoluble fiber escapes digestion and is secreted in feces

Cellulose

Insoluble fiber in outer skin of fruits like apples

High Sugar Diets

-13% of calories consumed by US adults are from added sugar. -Often take the place of nutritious foods -High intakes of sugar can promote weight gain and obesity -High intakes of energy and sugar (especially fructose) have been associated with conditions that increase the risk of cardiovascular disease (increased blood levels of triglycerides and LDL cholesterol and decreaed levels of HDL cholesterol). -Diets high in sugar have been reported to cause hyperactivity in children -High sugar diets increase the risk of dental cavities

Daily Value for Fiber

-25g for a 2000 kcal diet on food labels -Nutritious diet should include 6 ounces of grains, 2.5 cups of vegetables, 2 cups of fruit, and 3 cups of milk

North American Carb Intake

-About 50% of carb intake from carbs. -Leading Carb sources are white bread soft drinks, cookies, cakes, donuts, sugars, syrups, jams, and potatoes -World Wide Carbs are 70 to 80 percent of energy consumed, greater intake of healthier variations -14.5% of total energy intake (more than 10% total intake maximum from dietary guidelines) for added sugars

Recommended Intake of Carbs

-According to the RDA adults need about 130 g/day to supply adequate glucose for the brain and central nervous system to prevent the partial replacement of glucose by ketone bodies as an energy source. -Should be 45 to 65% of daily calories -Most scientists agree that carbs in our diets should include mostly fiber rich fruits, vegetables, and whole grains and little added sugars and caloric sweeteners. -Dietary Guidelines for Americans = limit added sugars to no more than 10% of daily intake -World Health Organization = sugars added to food during processing and preparation should provide no more than 10% of daily caloric intake -Institute of Medicine's Food and Nutrition Board set an upper limit of 25% of energy intake for added sugar consumption

Actions of insulin

-Actions on blood glucose are balanced by the actions of glucagon, epinephrine, Noepinephrine, cortisol, and growth hormone.

Stevia

-Also known as rebiana -Derived from plant in Amazon Rain Forest -250 times sweeter than sucrose -Provides no energy -ADI of 4mg/mg body weight a day

ADI for Fiber

-Goal of 14g/ 1000 kcal -25g for women and 38g for men, both for adults up to age 50 -After age 50, adequate intake falls to 21g/day and 30g/day respectively

Sparing Protein as an energy source (Gluconeogenesis)

-Amino acids that make up dietary protein are used to build tissues and perform vital functions only when carb intake provides enough glucose for energy needs. -Do not consume enough cabs to yield glucose = body breaks down amino acids in muscle tissue and other organs to make glucose

Lactose Intolerance

-Amount of enzyme lactase produced in small intestine often begins to decrease after early childhood. -Primary lactose intolerance occurs up to 75% of the worlds population. In North America approximately 25% of adults show signs of decreased lactose digestion. -All races except Caucasians have a larger tendency to be lactose intolerant -Secondary lactose intolerance occures when conditions of the small intestine such as Crohn's disease and severe diarrhea, damage the cells that produce lactase. Can cause gastrointestinal symptoms

Neotame

-Approved by the FDA for use as a general purpose sweetener in a wide variety of food products, such as baked goods, non alcoholic beverages (like soft drinks), chewing gum, etc. -Heat stable -7000 to 13000 time sweeter than sucrose -ADI of 18 mg/kg of body weight a day

Glycemic Index (GI)

-Blood glucose response of a given food, compared with a standard (typically glucose or white bread) -influenced by starch structure (amylose vs amylopectin), fiber content, food processing, physical structure (small vs large surface area), and temperature as well as the amount of protein and fat in general

Fibers

-Can be found in many of the same foods as starch, so a diet rich in grains, legumes, and tubers can also provide a lot of dietary fiber. -Much of fiber in whole grains is found in outer layers. -Soluble fibers are found in the skins and flesh of many fruits and berries; as thickeners and stabilizers in jams, yogurts, sauces and filings. -Fiber is offered as a supplement to those who have trouble getting it daily

Sucrose

-Common table sugar -Composed of sucrose and fructose linked by an alpha bond -Large amounts of sucrose are found naturally in plants such as sugarcane, sugar beets, and maple tree sap

Oligosaccharides

-Complex carbs containing 3 to 10 single sugar units -Include raffinose and stachyose which are found in onions, cabbage, broccoli, whole wheat and legumes such as kidney beans and soy beans. -Beta bonds in oligosaccharides cannot be broken down by our digestive enzymes. When we eat foods like this they pass undigested into the large intestine where bacteria metabolizes them into gas and other by-products.

Starch

-Contribute much of the carbs in our diets -Plants store glucose as polysaccs in the form of starches. -Plant based foods such as legumes, tubers, and the grains used to ake bread, cereals, and pasta are the best sources of starch. -Diet rich in starches provide ample carbs, as well as micronutrients

Reduced obesity risk

-Diet high in fiber likely aids weight control and reduces accumulating body fat and becoming obese. -Bulkiness of fiber foods fill you up but do not yield a lot of energy. -Fibrous foods absorb water and expand in the Gi tract, adding to sense of satiety and fullness

High Sugar Intakes

-Dietary fiber recommended intake falls below 14g per 1000 calories. -Men and women eat 25 to 50% less fiber than recommended. -Insufficient fiber intake due to low intake of fruits and veggies and high consumption of refined grains like pasta and corn chips

Beta Bonds

-Differ from alpha bonds in that they cannot be easily broken down by digestive enzymes for absorption in the small intestine. -Food with Beta bonds (milk and fiber) are often difficult or impossible for individuals to digest because they lack the necessary enzymes.

Maltose

-Disaccharide containing two glucose molecules joined by an alpha bond. -When seeds sprout they produce enzymes that break down polysaccharides stored in the seed to sugar, such as maltose and glucose. -Malting, the first step in the production of alcoholic beverages such as beer , lets grain seeds sprout. -Most maltose we ultimately digest in the small intestine is produced when we break down long chain polysaccharides.

Digestion

-Enzymatic digestion of some carbs begin in mouth. -Saliva contains an enzyme called salivary amylase, which mixes starch containing amylose when the food is chewed. -Amylase breaks down the starch into smaller polysaccs called dextrins and disaccs. -^^^Only a minor part of the overall digestive process.

Untreated Diabetes

-Excessive ketone prouction can occur -Diabetic ketosis develops when insulin production is inadequate or cells resist insulin action, thereby preventing glucose from enter body cells. -Accumulation of these ketones in blood results in more acidic PH (called diabetic ketoacidosis) - very serious complication of untreated or poorly controlled diabetes.

Ketosis

-Fatty acids released due to a lack of carbs and a decrease in insulin for energy use, unsuccessful breakdown of these fatty acids results in acidic compounds called ketone bodies and a condition called ketosis.

Promoting Bowel Health

-Fiber adds bulk to feces, making bowel movements easier. -Adequate and fluid are consumed, the stool is large and soft because many types of plant fibers absorb water. -Overall less force is needed to expel feces -Overexertion can lead to hemorrhoids. This high pressure exertion causes parts of the large intestine wall to protrude through the surrounding bands of muscle, forming small pouches called diverticula.

Indigestible Carbs

-Fiber is indigestible but plays a major role in maintaining integrity of GI tract and overall health. -Fiber helps prevent consitpation and diverticular disease and enhances the management of body weight, blood glucose levels, and blood cholesterol levels.

Hormones that counteract insulin

-Glucagon is secreted in response to a decreased level of blood glucose in blood stream. -Glucagon prompts the breakdown of glycogen in liver and promotes gluconeogensis, resulting in release of glucose into blood and normalization of blood glucose levels -Epinephrine (adrenaline) and noepinephrine from adrenal glands also trigger the breakdown of glycogen in liver and result in glucose release into blood stream. -Epinephrine and Noepinephrine are released in response to fight or flight -Cortisol and Growth hormone help regulate blood glucose by decreasing glucose use by muscle

Common Monosaccharides

-Glucose, Fructose, Galactose

Carb digestion and absorption

-Goal of carb digestion is to break down starch and sugars into monosacc units that are small enough to be absorbed. -Food preparation can be viewed as the start if carb digestion because cooking softens the tough, fibrous tissues of veggies, fruits, and grains. -When starches are heated, the starch granules swell as they soak up water, making them much easier to digest. All these effects of cooking generally make these foods easier to chew, swallow, and break down digestion.

Very-High Fiber Diets

-High intake of fiber of 50 to 60 g/day can cause health risks -High fiber consumption combined with low fluid intake an result in hard, dry stools that are painful to eliminate (may cause hemorrhoids, rectal bleeding - from increased exertion and pressure). -Decreases the absorption of minerals and increase risk of deficiencies.

Reducing cholesterol absorption

-High intake of soluble fiber inhibits the absorption of cholesterol and the re absorption of bile acids from the small intestine, thereby reducing risk of cardiovascular disease and gallstones -Short chain fatty acids resulting from the bacterial degradation of soluble fiber in the large intestine also reduce cholesterol synthesis in the liver.

Symptoms of hypoglycemia

-Hunger, Shakiness, irritability, weakness and headache as energy availability decreases.

Diabetes Symptoms

-Hunger, Thirst, Frequent Urination, Weight loss.

Small Intestine (Digestion)

-In small intestine, the polysaccs in the food that were first acted on in the mouth now are digested further by pancreatic amylase and dextrinase.

Diverticular disease

-Is asymptomatic (no noticeable symptoms) in about 80% people affected. -Asymptomatic form of disease is called diveritculosis ( one of the most common conditions in western countries ). -If diverticula become inflamed and symptomatic is becomes diverticulitis.

Acesulfame-K

-K stands for potassium -200 times sweeter than sucrose -Not digested by the body -Provides no energy -ADI is 15mg/kg of body weight per day

Luo han guo

-Known as monk fruit and is very sweet -Fruit juice is 150 to 300 times sweeter than sugar

Reactive hypoglycemia

-Low blood glucose that may follow a meal high in simple sugars, corresponding symptoms of irritability, headache, nervousness, sweating, and confusion; also called postprandial hypoglycemia -caused by an exaggerated insulin response after eating.

Hypoglycemia

-Low blood sugar -condition that occurs in people with or without diabetes -In those with diabetes, hypoglycemia can occur if they inject too much insulin, dont eat frequently enough, if they exercise without eating additional carbs. -Hypoglycemia and Fasting hypoglycemia have been reported in those without diabetes -limiting caffeine and alcohol intake can be beneficial in preventing symptoms of hypoglycemia.

Providing Energy

-Main function of glucose is act as a source of energy for body cells. In fact, red blood cells and cells of the central nervous system derive almost all their energy from glucose. Glucose also fuels muscle cells and other body cells, although many of these cells rely on fatty acids to meet energy needs, especially during rest and light activity. Recall that glucose provides 4 kcal of energy per gram.

Glucose Intolerance

-Maintaining blood glucose levels within normal ranges is important for providing adequate glucose for body functions and for preventing the symptoms associated with changes in blood glucose levels. -Abnormal regulation of blood glucose can lead to either hyperglycemia (high blood glucose) or hypoglycemia (low blood glucose). -Hyperglycemia is more common than hypoglycemia

Starch

-Major digestible polysaccharide in our diets is the storage form of glucose in plants -Includes Amylose and Amylopectin (Both are major sources of energy for plants and animals that eat plants) -Amylose and Amylopectin contain many glucose units linked by alpha bonds -Difference is that amylose is a linear unbranched chain of glucose molecules that contains only 1 type of alpha bond -Amylopectin is a highly branched structure that links glucose molecules using 2 types of alpha bonds. -Alpha 1-4 bonds are broken by amylase enzymes produced in the mouth and pancreas. -Alpha 1-6 bonds are broken by an intestinal enzyme called alpha-dextrinase -Properties of amylopectin and amylose make them useful in food manufacturing -Branches in amylopectin allow it to retain water to form a very stable starch gel. -Amylose-rich molecules can be bonded to each other to produce modified food starch, a thickener used in baby foods, salad dressings, and instant puddings.

Digestive enzymes for carbs

-Maltase enzyme acts on maltose to produce 2 glucose molecules -Sucrase breaks down sucrose to produce glucose and fructose -Lactase digests lactose to produce glucose and galactose

Disaccs in Digestion

-Maltose from breakdown of starch -Lactose from breakdown of dairy products -Sucrose from sweetened foods

Preventing Ketosis

-Minimal intake for carbs is 50 to 100 g/day to break down fats to carbon dioxide and water in body. -When carb intake is below this level, the release of the hormone insulin decreases, results in release of large amount of fatty acids from adipose tissue to provide energy to body cells. -^These fatty acids travel in the blood stream to the liver. -Subsequent incomplete breakdown of these fatty acids in liver results in the formation of acidic compounds called ketone bodies, or keto-acids, and a condition called ketosis.

Monosaccs in carb digestions

-Monosaccs that occur in food (usually glucose or fructose) do not need further digestion in the small intestine

Brain and other cells of nervous system

-Normally cannot utilize energy from fats, but these cells can adapt to use ketones for energy when carb intake is not enough. -Inability to do adapt like this would result in a reduced ability to tolerate starvation

Saccharin

-Oldest alternative sweetener -Approximately 300 times sweeter than sucrose. -ADI is 5mg/ kg of body weight per day.

Pancreas (Digestion)

-Pancreatic amylase and dextrinase are secreted into the small intestine to break polysaccs from the starch into disaccharides.

Undigested Fibers

-Pass through the small intestine into the large intestine, where bacteria metabolize some and form short-chain fatty acids and as. -Short chain fatty acids provide fuel for cells in the large intestine and enhance intestinal health. -Pectins, gums, and mucilages are most readily digested by the intestinal bacteria, yielding about 1.5 to 2.5 kcal. -Cellulose, hemicellulose, and lignins form the outer covering of all seeds; thus, whole grains (those in which the bran and outer layers have not been removed in processing). are good sources of fiber.

Non-Nutritive (Alternative Sweeteners)

-Provide low calories -Non-caloric subs for people with diabetes and those trying to lose or control body weight. -Saccharin, Cyclamate, Aspartame, neotame, sucralose, acesulfame-K, tagatose, stevia, and monk fruit -Do not promote dental caries. -All but cyclamate are available in U.S. -Safety of sweeteners determined by FDA and indicated in Acceptable Daily Intake (ADI).

Tagatose

-Sold as Naturlose -Isomer of Fructose -almost as sweet as sucrose -Poorly absorbed by body -Yields 1.5 kcal/g

Sucralose

-Sold as Splenda -is 600 times sweeter than sucrose -made by subbing 3 chlorines for 3 hydroxl groups on sucrose -Heat stable and can be used in cooking -ADI is 5mg/kg of bodyweight per day

Sugar alcohols

-Sorbitol, Mannitol, and Xylitol, are nutritive sweeteners used in sugarless gum and candies. -Not easily metabolized by bacteria in mouth and thus do not promote dental caries as readily as sugars such as sucrose. -Do contribute energy (1.5-3 kcal/g), but they are absorbed and metabolized to glucose more slowly than sugars. -In large quantities, sugar alcohols cause diarrhea.

Polysaccharides

-Starch, Glycogen, and Fiber -Complex carbs that often contain hundreds to thousands of glucose molecules. -include some that are largely digestible such as starch and some that are largely indigestible such as fiber.

Carb Family

-Sugars, Starchs, Fibers -Most composed of Carbon, Hydrogen, and Oxygen

Fructose during Absorption

-Taken into absorptive cells via facilitated diffusion -slower in absorption than that of glucose or galactose -glucose and galactose remain in same form when they enter intestinal cells, whereas fructose is converted into glucose. -These monsaccs are then transported via portal vein to the liver. -Fructose and Galactose are converted to glucose in river -Glucose is transported through the blood stream for use by the cells of the body. iF blood glucose levels are adequate to meet energy needs of the body, the liver stores additional glucose as glycogen.

ADI

-The amount of alternative sweetener considered safe for daily use over one's life time. -Based on lab studies -Set to a level 100 times less than the level at which no harmful effects were noted in animal studies.

Lactose

-The primary sugar in milk and milk products -Consists of glucose joined to galactose by a beta bond. -People are unable to digest large amounts of lactose because they do not produce the enzyme lactase. -Can cause intestinal bloating, gas, cramping and discomfort as the unabsorbed lactose is metabolized into acids and gases by bacteria in the large intestine.

Glycogen

-The storage form of carbs in humans and other animals, also contains many glucose units liked together by alpha bonds. -Structure is similiar to that of amylopectin, but is even more highly branched -The branched structure of glycogen allows it to be broken down quickly by enzymes in the body cells where it is stored. -Liver and muscle cells are the major storage sites for glycogen (influenced by intake of carbs). -Glycogen storage is limited (90 grams or 360 kcal in liver and 300 grams or 1200 kcal in muscle)

Regulation of Blood Glucose

-Under fasting conditions (several hours after not eating), blood glucose varies 70 and 100 mg/dl of blood. -if fasted blood glucose is above 126 mg/dl it is diabetes -When blood glucose falls below 50 mg/dl it is hypoglycemia -Liver = important in controlling amount of glucose in blood stream -Liver is first organ to screen sugar absorbed from small intestine. -Liver helps determine the amount of glucose that enter the blood stream after a meal -Excess sugar is stored as glycogen for later use by Liver and muscles -Pancreas releases small amounts of insulin as soon as a person starts to eat -After carb digestion and absorption the pancreas releases large amount of insulin -Insulin promotes increased glucose uptake by muscle and adipose cells. -Use of glucose for energy and storage as glycogen leads blood glucose to return to normal fasting range within a few hours of eating.

Aspartame

-Used throughout world to sweeten beverages, gelatin deserts, chewing gum, cookies and the toppings and fillings of prepared bakery goods. -Breaks down when heated and loses its sweetness when foods are cooked or heated. -Yields 4 kcal per gram (same as sucrose) it is 160 to 220 times sweeter than sucrose. -ADI of 50mg/ kg of body weight per day.

Nutritive Sweeteners

-Various substances that impart sweetness to foods fall into 2 broad categories: nutritive sweeteners (can be metabolized to yield energy) and non-nutritive sweeteners which provide no food energy -Sweetness of sucrose (table sugar) makes it the bench mark against which all other sweeteners are measured. The alternative sweeteners are much sweeter on per gram basis than the nutritive sweeteners. -Monosaccs and Disaccs are classified as nutritive sweeteners. -More processed the food = the more simple the sugar it contains. -High fructose corn syrup is nutritive sweetener used frequently by food industry

Enhancing Blood Glucose Control

-When consumed in recommended amounts, soluble fibers slow glucose absorption from small intestine and decrease insulin release from pancreas -Contributes to better blood glucose regulation, which can be helpful in the treatment of diabetes. -Adults with high fiber diets are less likely to develop diabetes than are those with lower fiber diets

Stomach (Digestion)

-When food reaches stomach, the salivary enzyme is inactivated by the acidity of the stomach. Thus, digestion of carbs stops until it passes into the small intestine.

Absorption

-With exception of fructose, monosaccs are absorbed by an active absorption process. Recall from chapter 4 that this process requires a specific carrier and energy input for the substance to be taken up by the absorptive cells in the small intestine.

Metabolic syndrome

-characterized by a group of factors that increase the risk for type 2 diabetes and cardiovascular disease -includes insulin resistance or glucose intolerance (Causing high blood glucose ), abdominal obesity, high blood triglycerides and LDL cholesterol with low HDL cholesterol -Associated with overall obesity, physical inactivity, genetic predisposition, and aging

Criteria for Metabolic syndrome diagnosis

-waist circumference of 35 inches or more for women and 40 inches or more for men -fasting triglyceride level above 150 mg/dl -blood HDL cholesterol below 40 mg/dl for men and below 50 for women -elevated blood pressure above 130/85 mm Hg and fasting blood glucose above 110 mg/dl -Lifestyle modification (weight loss, decreased dietary fat intake, and increased physical activity) is fundamental to decreasing health risks associated with metabolic syndrome

How much should Carbs Constitute Or Diet

45 to 60%

Liver (Digestion)

The absorbed monosaccs are transported to the liver by the portal vein

Condensation Reaction

The linking of 2 monsaccharides occur during this. -During this reaction 1 molecule of water is formed and released by taking a hydroxl group from 1 sugar and a hydrogen from the other sugar -One carbon on each monosacc participating in the condensation reaction chemically bonds with a single oxygen. Two forms of this is C-O-C alpha bonds and Beta bonds