Sugars NTR 301

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

Fructose Sucrose Glucose Galactose Lactose

Describe stevia with respect to their safety/health effects, structure, and/or stability (if applicable).

- 150Xs sweeter than sugar - Stevia is an herb that grows in South America - Steviol glycosides (e.g., stevioside below) are extracted from the stevia plant. - Non-caloric sweetener for hundreds of years in Paraguay - Stable at high temperatures (can cook with it)

Describe aspartame with respect to their safety/health effects, structure, and/or stability (if applicable).

- 180-200Xs sweeter than sugar (so need very little) - Made from two amino acids—phenylalanine and aspartic acid. - Is absorbed and metabolized (like other amino acids) but need very little so contributes few total calories. - Not stable at high (cooking) temperatures - Many "urban legends" associated with aspartame

Describe cyclamates with respect to their safety/health effects, structure, and/or stability (if applicable).

- Used extensively in the 1950s-60s but banned in the US in 1970 due to some rat studies suggesting it was carcinogenic when fed in high doses. - Still available in ~50 other countries, including Canada and the UK, demonstrating the difficulty of interpreting the results of toxicology studies.

Describe sucralose with respect to their safety/health effects, structure, and/or stability (if applicable).

- 600Xs sweeter than sugar - Is sucrose with some of the OH groups replaced with chloride atoms - Is poorly absorbed and what is absorbed is not metabolized (0 calories), excreted in the urine. - Stable at high (cooking) temperatures. - Many people use it to bake with at home (it's mixed with "fillers" like maltodextrin so that it measures like sugar) - Sucralose has overtaken aspartame as the principle artificial sweetener, though it, too, is now a target of unsubstantiated claims regarding its safety.

Describe glucose and its function.

- Also known as "blood sugar" and "dextrose" on a food label Function: - Used by any cell for energy - The brain and central nervous system use glucose almost exclusively for energy - Only time these systems can use other sources to any degree is after several days of complete starvation - Glucose is critical to normal and CNS functioning - Excess glucose can be converted to fat in the liver

Describe fructose and it's function.

- Also known as "fruit sugar" Function: a. Used by some cells for energy b. can be converted to glucose by the liver c. Excess fructose can be converted to fat in the liver

Describe sucrose and it's dietary sources.

- Also known as table sugar, white sugar, refined sugar, and is "sugar" on a food label - Disaccharide of glucose and fructose - Much of the sucrose that we consume has been extracted from the sugar cane or sugar beet plant Dietary sources: a. fruits and vegetables

Describe lactose and it's dietary sources.

- Also known as the "milk sugar" - Disaccharide of galactose and glucose - Dietary sources a. milk and dairy products b. only mammalian milk

Describe sugar alcohols with respect to their safety/health effects, structure, and/or stability (if applicable).

- Candies, toothpaste, carb-restricted foods - Adds texture, retain moisture, prevent foods from browning when heated - Are very slowly, therefore only partially absorbed a. As a result, contributes only 2.5 cal/g b. Can cause diarrhea - Do not cause rapid rise in blood glucose

Describe saccharine with respect to their safety/health effects, structure, and/or stability (if applicable).

- First synthesized in 1800s. - 300Xs sweeter than sugar (so need very little) - Is absorbed but not metabolized by the body (0 calories) - Has a bitter aftertaste - Is stable at high (cooking) temperatures

Explain what agave nectar is and whether it is preferable to other sweeteners

- Marketed as a healthier/natural alternative to other sweeteners - Made from the agave plant, which contains large amounts of insulin, an indigestible carbohydrate that is a polysaccharide of fructose only - The final product is 55-90% fructose

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.

- Polysaccharides of glucose only > Very long chains added together - Starches have different thickening and gel-forming characteristics - The differences are due to... a. the number of glucose molecules in the molecule b. The degree of branching of the molecule > Glucose molecules can be arranged in a linear or branched formation - Naturally occurring dietary sources a. Tuberous Vegetables b. Cereal grains (corn, wheat, rye, barley, oats) c. Legumes d. Nuts, seeds

List the ways in which sugars are used in food processing.

- To provide sweetness - To provide "mouthfeel" - To soften other flavors - To improve texture - As a preservative

Explain why type 2 diabetes often goes unnoticed, why rates are rising in the US and describe the potential effects of this disease.

-Glucose-induced nerve damage in the retina ---> blindness-Glucose induced nerve damage → decreased awareness of injury (especially in feet) → infection ---> amputations-Glucose induced blood vessel damage → cardiovascular and kidney diseaseType 2 used to be only see in adults typically over the age 50, but it is now being seen in obese children.

What are the dietary sources of glucose?

1. As a monosaccharide - Fruits and veggies - Honey - Corn syrup 2. As part of a disaccharide - Lactose-containing foods - Sucrose-containing foods 3. As part of a polysaccharide - Starch-containing foods - Fiber-containing foods

What are the dietary sources of fructose?

1. As a monosaccharide - fruits and vegetables - Honey 2. As part of a disaccharide - sucrose-containing foods 3. As part of a polysaccharide - fiber-containing foods

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

1. Bran (outer covering) - Niacin, thiamin, riboflavin, magnesium, phosphorus, iron, zinc, most of the fiber 2. Germ (plant-to-be) - All of the above, healthful unsaturated fats 3. Endosperm (bulk of the grain) - all that remains after refining, protein, carbs, small amounts of vitamins and minerals

Match the two different types of fiber with their good sources, general characteristics, and health conditions that may be prevented or ameliorated by increasing their intake, explaining the reasons behind the health benefits as well as the potential significance, as applicable.

1. Insoluble Fiber Example: - Cellulose (100% glucose) - Provides structure in plant cell walls a. Dietary Sources: wheat bran, whole wheat, legumes, nuts, fruits, vegetables b. Characteristics: - Does not dissolve in water - Small amounts can be digested by intestinal bacteria and creates gas as by product 2. Soluble Fiber Example: - Gums; Mucilages; Pectin - The plant's cellular cement a. Dietary sources: oat bran, oat products, legumes, fruits, vegetables b. Characteristics: - Does dissolve in water, forms gels - Slows rate of stomach emptying - Larger amounts can be digested (fermented) by intestinal bacteria (creates more gas) Potential Benefits of Dietary Fiber: 1. Constipation and conditions associated with it because fiber creates bulk in the large intestine bc fiber is indigestible 2. Obesity - Eating lots of foods that are naturally high in fiber may help with weight control because... a. Both types of fiber: Helps fill the stomach bc they are not digestible by our enzymes. This increases satiety and decreases total # of calories b. Soluble fiber: Delays stomach emptying bc of gel forming characteristics

List the 2 basic classifications of carbohydrates and their members.

1. Simple sugars a. Monosaccharides - Glucose - Fructose - Galactose b. Disaccharides - Lactose - Sucrose 2. Complex carbohydrates a. Polysaccharides - starches - fiber >insoluble and soluble

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.

1. They worked in the short term: a. Rapid weight loss - losing water weight b. eat forbidden (fatty) foods = palatable c. not hungry - high protein, high fat d. limited choices e. No carbs = no junk food 2. And also because... a. appealed to men b. Don't have to eat vegetables (a source of carbs) c. Don't have to exercise - Is hard on a carb-limited diet d. Like any weight loss plan - tells you when and what to eat Evidence shows that regardless of the type of weight loss method, maintenance of lost weight after a year is generally poor. People can't stick w a no carb diet long term.

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

A. Cause: low levels or no lactase production - decreased or no digestion of lactose - undigested lactose in the large intestine B. Symptoms: - Bloating: caused by undigested lactose attracts water in the large intestine - Diarrhea: caused when undigested lactose attracts water in the large intestine - Gas: caused when undigested lactose is metabolized by intestinal bacteria in the large intestine C. Who is most likely to experience it and why? - Non-Caucasians: can begin to develop in childhood after weaning i. associated with the presence/absence of dairy in the traditional food way of a culture ii. ethnic groups with the least or no dairy in traditional foods iii. native Americans, people of Asian, African, and Hispanic descent iv. however, even these people can usually tolerate small amounts eaten as part of a mixed meal - The elderly of any ethnic group i. lactase levels decline with age in everyone D. What can be done? - Eat foods naturally low in lactose (yogurt and cheese) - Foods pretreated with lactase (e.g. lactaid products) - Small amounts of lactose-containing foods with other foods

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

A. DRIs recommend - Women: 25 grams per day - Men: 35 grams per day

What are the dietary recommendations associated with type 1 and 2 diabetes?

A. Individualized diet: Low in fat, carbohydrate choices that are good sources of vitamins, minerals, and dietary fiber (e.g. whole grains, fruits, vegetables, low-fat milk) - Monitoring carb intake and ensuring dat-to-day consistency in amount and timing of carbs)

Discuss the nutritional differences between and among refined white sugar and other cane sugars and molasses.

A. Less refined sugar products are not better for you nutritionally than completely refined sugar because: - The cane plant from which they come is not particularly nutrient rich - You generally don't eat sugar in the same serving sizes that you would eat bread or rice - teaspoons or tablespoons v. slices or cups B. Molasses - Byproduct of sugar refining - is the liquid left behind (the mother liquor) after the sugar crystals have been removed - can be a good source of micronutrients

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.

A. You are losing the benefits of fiber. You would eat cellulose (indigestible) and take the cellulose product which breaks down cellulose B. Lower dietary fat absorption: - Because it can bind to fat in the GI tract to prevent absorption (quantity = milligrams) - Is this effect significant? No, because it is binding milligrams of fat, but what we consume is in the quantity of grams

Explain the relationship, or lack thereof, between sugar(s) and: obesity, heart disease, cancer, diabetes, tooth decay and hyperactivity.

A. obesity - There is no evidence that sugar causes obesity - However, when sugars are flavored, and/or coupled with fat, they do help to create a highly palatable food that is easy to eat in large quantities B. Diabetes - There is no evidence that simple sugar causes diabetes - However, there is some evidence that long-term intake of diets high in refined carbs (v. high in whole grain carbs and fruits and vegetables) increase the risk of diabetes C. Acne, Heart Disease, Cancer - There is no evidence that sugar causes these - However, diets high in refined carbs may increase serum TG levels in some people, increasing the risk for heart disease C. Tooth Decay - Any carb can contribute to tooth decay - What is important is how long the carb stays in contact with the teeth = "stickiness" D. Hyperactivity

Describe galactose and it's dietary sources.

Can be converted to glucose by the liver Dietary sources: 1. As a monosaccharide - limited 2. As part of a disaccharide - lactose containing foods *Not found in polysaccharides

Describe what can cause hypoglycemia and how to prevent it.

DEF. - when blood glucose levels can get too low Cause - a. Excess insulin production in response to carbohydrate intake b. As a result, blood glucose drops too rapidly and/or too low Symptoms - a. Irritability, anxiety, headaches, fatigue Treatment - a. Smaller, more frequent meals, each with some protein and/or fat to moderate rise in blood glucose

Define the term hyperglycemia and match the characteristics (cause, symptoms, treatment) with type 1 and 2 diabetes.

Hyperglycemia---> an elevated fasting blood glucose level- but the name of the condition is derived from the original means of detection: Diabetes Mellitus meaning sweet, sugar, glucose in urine, and flow through. - Type 1: 5-10% of call cases.Cause: the pancreas stops producing insulin due to an autoimmune response. The body's immune system attacks its own insulin, likely due to an environmental trigger, such as a virus. There is some genetic predisposition, it is linked to celiac disease in some people. It can occur at any age but most commonly develops in childhood (juvenile diabetes)Symptoms: excessive urination, thirst. The body is having to eliminate all that excess glucose through the urine. Weight loss- the body's cells are basically starving, because glucose cannot get inside them in the absence of insulin.Treatments: Insulin injections and an individualized diet, consuming healthy diet with low fat and carbs for good source of vitamins, minerals, and fiber. Carb count. Ensure day to day consistency. Diet must be carefully timed with insulin injections. - TYPE 2: 90-95% of all cases.Cause: the body's cells respond less well to the presence of insulin. THis is known as insulin resistance. Strongly associated with abdominal obesity (80% are obese). There is a strong genetic predisposition.Symptoms: Develops gradually, are often few outward symptoms (nighttime urination, tiredness)Treatment: Weight loss if overweight. Individualized diet: consuming a healthy diet that is low in fat and contains carb food choices that are good source of vitamins, minerals, and fiber. Monitor carbs and use consistency. Drug treatments.

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.

I. Monosaccharides a. Glucose - absorbed as glucose b. Fructose - absorbed as fructose c. Galactose - absorbed as galactose II. Disaccharides a. Lactose - digested by lactase1 and absorbed as glucose and galactose b. Sucrose - digested by sucrase2 and absorbed as glucose and fructose III. Polysaccharides a. starches - digested by amylases3 and absorbed as glucose b. Fiber - not digested; no enzymes to break down All dietary carbs are absorbed in the form of:

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.

I. Past a. It used to be assumed that complex carbohydrates (starches) would take longer to be digested (and therefore for their monosaccharide subunits to be absorbed) than simple sugars, simply because complex carbs were bigger molecules b. Thought that complex carb consumption would result in slower increases in blood glucose, as compared to simple sugars c. Led to dietary advice for diabetics to limit simple sugar intake to control blood glucose levels d. however, this was not tested until the 1980s II. Now, research showed that many other factors affect rate of absorption: a. Length of cooking time - the more the starch grains swell, the more quickly the starch is digested (and therefore absorbed) b. Starch structure - the greater the degree of branching, the more quickly the starch is digested (and therefore absorbed) c. Amount of soluble fiber, fat, and protein in the food - delay stomach emptying, so the higher these levels are in food, the less quickly the carbs will reach the small intestine to be digested and absorbed d. relative amounts of fructose or galactose v. glucose - fructose and galactose must first be converted to glucose in the liver following absorption, so carbs containing these monosaccharides will produce a slower rise in blood glucose levels

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

I. purpose: Created as a way to compare different foods' effects on blood glucose levels; Glycemic response II. The GI is determined by feeding test subjects the amount of that food (at one time) that provides 50 grams of CHO. Then the test subjects blood is drawn over a 2 hour period and blood glucose levels are plotted against time and compared to a standard (usually 50g pure glucose) III. Limitations - We do not always eat food by itself - we don't always eat the amount of food used in the GI test - the lists themselves vary widely depending on the source of the data - there can even be a significant difference in an individual food's GI based on whether you eat it hot or cold IV. Appropriate use a. eat foods with a naturally low GI (<55) - especially legumes - include them more frequently in your diet than foods with higher GIs (>70) b. Many fad diets avoid "white" foods such as rice, white flour, and refined sugars c. But many cultures with lower obesity rates than the US eat relatively large amounts of refined grain-based pasta and breads and refined rice

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

Polysaccharides of glucose and/or other monosaccharides (10s to 1000s of glucose, fructose, and/or other monosaccharides) Starch v. Fiber Starch - Human amylases can break these bonds Fiber - Human amylases are unable to break these bonds; Cannot digest this fiber

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 could add inulin (chicory root extract), oligofructose, polydextrose, modified wheat starch, soy fiber, and sugarcane fiberDegree to which these purified fibers will have similar effects remains largely unknownThe health benefits specific to soluble fiber require it to be viscous (gooey). Most of the purified soluble fibers (e.g. inulin) are not

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.

Primary function of digestible cards in the body is to provide energy in the form of glucose a. Brain and CNS - at rest, uses 80% of glucose being used - The DRIs recommend that 45-65% of the total calories in our diets come from carbs. We want to put this a little bit higher so that the body can easily carry out all functions - The DRIs also recommend that added sugars be limited to less than 25% of total calories. a. Restricting added sugars is designed to restrict foods that are nutrient poor

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

SHORT TERM energy storage: conversion to glycogen --> basically like an animal starch. Glycogen is a highly branched, polysaccharide of glucose molecules.Function of glycogen: muscle energy storage to be used during fight or flight responseLiver- engery during time of fating overnightLONG TERM energy storage-coversion to fat in storage in liver, when are glycogen store are full, we can store the excess to be used later as fat.

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.

Scan ingredient list for the word "whole" in front of grain identified first on listOnly whole grain products if specifically state "100% whole grain"Dark or brown bread does not indicate whole grain contentWhen evaluating a food for fiber content, remember: Lots of grain does not mean lots of fiber (e.g. enriched wheat flour does not contain lots of fiber)

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

Sugar = sucrose - Enzymes in our body split sucrose into glucose and fructose - See them as the same thing Honey - Honey breaks sucrose into glucose and fructose using enzymes

Explain what high fructose corn syrup is, why food manufacturers like to use it and whether there should be concerns about its consumption.

To make high fructose corn syrup (HFCS): a. Start with corn syrup, which is 100%. It comes from corn starch, which is likewise 100% glucose. b. Break down that polysaccharide of glucose (corn syrup) into monosaccharides (glucose). c. Take some of the glucose and convert it to fructose

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

To provide energy during the process of germination

Explain the carbohydrate-related components on a food label.

Total carbohydrates per serving is in grams of total fiber (g) and total sugars (g) (added and natural) Percent Daily Value a) 300g for carbohydratesb) 25g for Dietary Fiber

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

a. Glycogen is a highly branched polysaccharide of glucose molecules b. Functions of glycogen: i. Muscles - energy storage to be used during "fight or flight" response. This does not require oxygen and is a quicker source of energy than fat stores (2/3 of those 2400 cals) ii. Liver - energy source during times of "fasting" (i.e. overnight) (1/3 of those 2400 cals)