NTR301 Carbohydrates Objectives

Identify the 3 parts of a grain kernel and which part represents the bulk of refined flour.

-bran (outer covering; contains fiber) -endosperm (makes up bulk of grain; small amounts of vitamin and minerals, contains majority of protein and carbs) -germ (plant to be; contains protein and unsaturated fats) *bran is where the fiber is

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

-increase fiber intake slowly to give GI time to adjust -drain/rinse canned beans before using -rinse dry beans several times, don't rinse water in cooking -digest raffinose sugars with beano

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

-polysaccharide of glucose -immediate energy supply (flight/fight response) -animal starch -highly branched

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

-polysaccharide of glucose, fructose, and/or other monosaccharides -differs from starch by the bond linking them together (it is in the theta position (pointed up)) -human amylases can't break the bonds found in fiber

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

-regulation issued by FDA in 1943 requiring refined cereal grain products to be fortified with certain nutrients -nutrient deficiencies were a problem during this time -solution because all population groups consumed grains *iron, thiamin, riboflavin, niacin, folate unbleached: matured and bleached naturally by oxygen present in air bleached: treated by chemicals to speed up whitening and maturing process

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

-work short term -rapid weight loss -eat forbidden foods -not hungry -limited choices -no carbs means no junk food -appealed to men -didn't have to eat veggies -when/what to eat -no exercise

Explain how the types of sugar being used have changed over time.

Cyclamate *1950-1960s (banned in 1970) *Carcinogens? Saccharine (Sweet n Low) *1800s *300x sweeter than sugar *bitter after-taste *absorption and metabolism *carcinogens? FDA attempted to ban in 1977 Aspartame (Nutrasweet) *180-200x sweeter than sugar *made from 2 amino acids: phenylalanine and aspartic acid *absorption and metabolism *no well designed studies have shown adverse effects *PKU *not stable at high temps Sucralose (Splenda) *developed in 1976, approved in 1998 *slightly changing structure of sucrose *absorption -not absorbed, excreted in urine Truvia *stable at high temps *150x sweeter than sugar *non-caloric sweetener for hundreds of years in Paraguay Acesulfam-K (sweet one) *200x sweeter than sugar *absorbed but not metabolized *stable at high temps *typically used commercially

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.

GLUCOSE -not digested -absorbed as glucose -the form of carb that is absorbed in the largest amount FRUCTOSE -not digested -absorbed as fructose -converted to glucose in liver once absorbed GALACTOSE -not digested -absorbed as galactose -converted to glucose in liver once absorbed LACTOSE -digested by lactase -absorbed as glucose and galactose SUCROSE -digested by sucrase -absorbed as glucose and fructose STARCHES -digested by amylases and absorbed as glucose FIBER -not digested -not absorbed

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.

Fiber=indigestible Insoluble *examples: bread *sources: wheat bran, whole wheat, legumes, nuts, fruits, veggies *doesn't dissolve in water *small amounts can be digested by intestinal bacteria *cellulose (100% glucose) Soluble *pectin, gums, mucilages (plant's cellular cement) *sources: oat bran, oat products, legumes, fruits, veggies *does dissolve in water, forms gel *slows rate of stomach emptying *larger amounts can be digested (fermented) by intestinal bacteria

Explain what first extraction and and blackstrap molasses are and how they are the same and different relative their sweetness and micronutrient content.

First extraction: *whats leftover after 1 round of boiling and crystal removing -still sugar in it, so slightly sweet -good source of micronutrients Black strap: -not sweet -leftover after all the sugar crystals have been removed -used by some as type of dietary supplement

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.

*adding inulin, oligofructose, and polydextrose to foods to boost fiber content -inulin: polysaccharides of fructose *contribute to sweetness *soluble fiber (gas forming) *chlocory root extract on a label -oligofructose:short chains of fructose molecules *souble fiber -polydextrose: mix of dextrose and other ingredients *soluble fiber -modified wheat starch *modified to make it resistant to human amylases -soy fiber -sugarcane fiber *fiber from whole foods has more health benefits *degree to which purified fibers will have similar effects is unknown *health benefits from soluble fiber must be viscous (gooey)

Describe what can cause hypoglycemia and how to prevent it.

*blood glucose levels can get to low *cause: excess insulin production in response to carbohydrate intake *result: blood glucose drops too rapidly and/or too low *symptoms: irritability, anxiety, headaches, fatigue *treatment: smaller, more frequent meals, each with protein and/or fat to moderate rise in blood glucose

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

*caused by low levels or no lactase production-----> decreased or no digestion of lactose--->undigested lactose in large intestine *symptoms -bloating -diarrhea -gas -undigested: lactose *attracts water in large intestine *metabolized by intestinal bacteria in large intestine *what can be done -eat foods naturally low in lactose (yogurt and cheese) -foods pretreated with lactose (lactaid) -small amounts of lactose containing foods with other foods *most likely to experience? -non caucasians -elderly of any ethnic group: lactase levels decline with age in everyone

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

*sweetness -fructose helps disperse the seeds *starchy -use the energy germination underground Fruits are sweet so they'll be eaten and their seeds will be spread. Role of starch in plants is to provide energy during germination and cellulose is used because it is a type of fiber to provide structure and support in its cell walls

List the levels of fiber of intake that are recommended by the DRIs and explain whether Americans are close to meeting those goals.

*women: 25 grams per day *men: 35 grams per day Americans are not close to meeting the goals because of limited consumption of legumes, whole grains, fruits, and veggies and high consumption of highly processed foods

List and explain the factors that can influence the rate of carbohydrate digestion and absorption.

1) length of cooking time -longer cooking time results in higher absorption/digestion rate 2) starch structures -greater degree of branching results in higher absorption/digestion rate 3) relative amounts of fructose or galactose versus glucose -slower rise in blood glucose levels because must be converted into glucose 4) amount of soluble fiber, fat, and protein in the food -all delay stomach emptying, less quickly absorbed/digested

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

1) to provide sweetness 2) to provide "mouthfeel" or "bulk" 3) to soften other flavors 4) improve texture 5) as a preservative

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

1. Conversion to glycogen (polysaccharide of glucose) 2. Conversion to fat (only after glycogen reserves have been filled)

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

1. Fructose (173%) 2. Sucrose (100%) 3. Glucose (74%) 4. Galactose (35%) 5. Lactose (20% beta and 16% alpha)

Explain the carbohydrate-related components on a food label.

1. Total carbs per serving (g) i. total fiber (g) ii. total sugars (g) (added and natural) 2. % daily value i. 300g for carbohydrates ii. 25g dietary fiber

Explain the differences between honey and sugar (sucrose).

Chemically they are the same thing except honey isn't bound together. Nectar=sucrose; bees break it into glucose and fructose. Humans have enzymes that break sugar into glucose and fructose. Honey contains same monosaccharides as sugar

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

DRI for total cars: 45-65% DRI for added sugars: <25% of total calories -primary function of digestible carbs is to provide energy in the form of glucose -rationale for both recommendations is to ensure not only that we get enough energy for the brain and CNS during exercise, but also because foods naturally rich in cards are excellent sources of variety of micronutrients and fiber too

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

Few outward symptoms rates rising because obesity rates increasing One effect is an economic burden

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

GLUCOSE: Blood sugar (dextrose) *used by ANY cell for energy *systems that use glucose almost exclusively for energy (rather than fat/protein) *only time these systems can use other sources for energy Dietary Source: *As monosaccharides (fruits/veggies/honey/corn syrup) *Part of disaccharides (lactose and sucrose containing food) *Part of polysaccharides (starch and fiber containing food) FRUCTOSE: *used by some cells for energy *can be converted to glucose by the liver *cell to cell communication Dietary Source: *as monosaccharides (fruits/veggies/honey) *as part of disaccharides (sucrose containing food) *part of polysaccharide (fiber containing food) GALACTOSE: *can be converted to glucose by the liver Dietary Sources: *limited as monosaccharide *part of disaccharide (lactose)

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

It is a way of predicting how quickly a food's carb content will be absorbed into the body -high GI is over 70 -low GI is below 55 *determined by feeding test subjects the amount of that food that provides 50 grams of CHO...subject's blood is drawn over two hour period and blood glucose levels plotted against time and compared to standard (50g pure glucose) *limitations -don't always eat food by itself -don't always eat amount of food used in test -difference in GI based on temp *appropriate use -eat foods with naturally low GI -like legumes -include low GI foods more frequently in diet

Describe and explain the relationship, or lack thereof, between sugars and: obesity, heart disease, cancer, diabetes, and tooth decay.

No evidence! Any carbohydrates could cause tooth decay

List the 2 basic classifications of carbohydrates and their members

Simple Carbohydrates -Glucose (monosaccharide) -Fructose (monosaccharide) -Galactose (monosaccharide) -Sucrose (disaccharide) -Lactose (disaccharide) Complex Carbohydrates -Fiber (polysaccharide) -Starch (polysaccharide)

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

Starches have multiple compounds, polysaccharides. Have different gel-forming and thickening characteristics due to the number of molecules and degree of branching of the molecules Dietary sources: veggies, grains, rice, legumes, nuts, seedsExplain how plants might use simple sugars and complex carbohydrates (why fruits are sweet and plants are starchy).

Explain why sugar has been demonized over the years.

Sugar has been associated with sin and slavery

Match the characteristics (cause and symptoms) and dietary recommendations associated with each of the two types of diabetes and explain why carbohydrate intake might need to be restricted in some Type 2 diabetics.

TYPE 1 -cause: pancreas stops producing insulin -symptoms: excessive urination and thirst and weight lost -treatment: insulin injection -makes up 5-10% of cases TYPE 2 -cause: cells become resistant to insulin -symptoms: develops gradually, few outward symptoms -treatment: weight loss if overweight, individualized diet, lowering carbs can help decrease triglyceride levels in blood -makes 90-95% of all cases-

Explain what is known about the relationship between sugars and hyperactivity.

There is no correlation that increase in sugar specifically causes hyperactivity. There are confounding factors however. Sugar has a GI of 65%

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

i. Comes from corn starch (polysaccharide of glucose) -not sweet ii. Convert polysaccharide to monosaccharide of glucose -sweet iii. convert some of the glucose to fructose---> HFCS -really sweet Manufacturers like to use it because its cheap so they use less of it and its domestic (made from corn) *no evidence that its any worse than sugar)

Describe how refined cane sugar is made and discuss the nutritional differences between and among refined white sugars and other cane sugars.

squeezing sugar canes between rollers to extract sugary juices, evaporating off the water to make a syrup, boiling the syrup to make sugar crystals grow, removing crystals and leaving behind "mother liquor". At this point, crystals can go through additional series of refining steps that remove more and more non-sugar components until you get pure white sugar