1. Carbohydrates

2. The Chemist’s View of Carbohydrates
Carbohydrates are made of carbon, hydrogen and oxygen atoms.
These atoms form chemical bonds that follow the laws of nature.

4. Types of CARBOHYDRATE Simple Monosaccharide's
Glucose
Fructose
Galactose
Disaccharides (Monosac + Glucose)
Maltose
Sucrose (Table sugar)
Lactose (Milk sugar)

5. The Simple Carbohydrates
Monosaccharrides are single sugars
Glucose serves as the essential energy source, and is commonly known as blood sugar or dextrose.
Fructose is the sweetest, occurs naturally in honey and fruits, and is added to many foods in the form of high-fructose corn syrup.
Galactose rarely occurs naturally as a single sugar.

7. The Simple Carbohydrates
Disaccharides are pairs of monosaccharides, one of which is always glucose
Maltose = glucose + glucose
Sucrose = glucose + fructose
Lactose = glucose + galactose

8. The Simple Carbohydrates
Disaccharides
Maltose = two glucose units. It is produced during the germination of seeds and fermentation.
Sucrose is refined from sugarcane and sugar beets, tastes sweet, and is readily available. Called table sugar
Lactose is found in milk and milk products. Called milk sugar

9. Your lab results just came back, and you tested positive for Coke
Your fired, Jack.
Your lab results just came back,
and you tested positive for Coke

10. The Complex Carbohydrates
Few (oligosaccharides) or many (polysaccharides) glucose units bound/linked together in straight or branched chains.

11. Types of CARBOHYDRATE
Complex = Polysaccharides
Starch
Fiber
Glycogen

12. The Complex Carbohydrates
Starches
Storage form of glucose in plants
Found in grains, tubers, and legumes
Glycogen
Storage form of glucose in the body
Provides a rapid release of energy when needed

13. Glycogen Starch (amylopectin) Starch (amylose)
A glycogen molecule contains hundreds of glucose units in highly branched chains. Each new glycogen molecule needs a special protein for the attachment of the first glucose (shown here in red).
A starch molecule contains hundreds of glucose molecules in either occasionally branched chains (amylopectin) or unbranched chains (amylose).
Figure 4.8: Glycogen and Starch Molecules Compared (Small Segments).
Notice the more highly branched the structure, the greater the number of ends from which glucose can be released. (These units would have to be magnified millions of times to appear at the size shown in this figure. For details of the chemical structures, see Appendix C.)
Stepped Art
Fig. 4-8, p. 106

14. The Complex Carbohydrates
Dietary fibers provide structure in plants, are very diverse, and cannot be broken down by human enzymes.
Soluble fibers are viscous and can be digested by intestinal bacteria (this property is also known as fermentability). These fibers are found in fruits and vegetables, oats, barley, legumes.
Insoluble fibers are nonviscous and are not digested by intestinal bacteria. These fibers are found in whole grains and vegetables.

17. Carbohydrates-Dietary Guidelines
Choose fiber-rich fruits, vegetables, and whole grains often
Choose and prepare foods and beverages with little added sugars or caloric sweeteners, such as amounts by the USDA Food Guide and DASH Eating Plan
Reduce incidence of dental caries by practicing good oral hygiene and consuming sugar and starch-containing foods and beverages less frequently

20. Digestion and Absorption of Carbohydrates
Carbohydrate Digestion
In the mouth, the salivary enzyme amylase begins to hydrolyze starch into short polysaccharides and maltose.
In the stomach, acid continues to hydrolyze starch while fiber delays gastric emptying and provides a feeling of fullness (satiety).

21. Digestion and Absorption of Carbohydrates
Carbohydrate Digestion
In the small intestine, pancreatic amylase among other enzymes (maltase, sucrase, and lactase) hydrolyzes starches to disaccharides and ultimately monosaccharides.
In the large intestine, fibers remain and attract water, soften stools and ferment.

22. Digestion and Absorption of Carbohydrates
Carbohydrate Absorption
Primarily takes place in the small intestine
Glucose and galactose are absorbed by active transport.
Fructose is absorbed by facilitated diffusion.

23. Digestion and Absorption of Carbohydrates
Lactose Intolerance
Symptoms include bloating, abdominal discomfort, and diarrhea.
Causes include lactase deficiency due to a natural decrease that occurs with aging or damaged intestinal villi.
Prevalence
Lowest in Scandinavians and northern Europeans
Highest in Southeast Asians and native North Americans

24. Digestion and Absorption of Carbohydrates
Lactose Intolerance - Dietary Changes
Increase consumption of milk products gradually.
Mix dairy with other foods.
Spread dairy intake throughout the day.
Use of acidophilus milk, yogurt, and kefir (fermented products)
Use of enzymes
Individualization of diets
Must be careful that vitamin and mineral deficiencies do not develop

25. Glucose in the Body The Constancy of Blood Glucose
Maintaining Glucose Homeostasis
Low blood glucose may cause dizziness and weakness.
High blood glucose may cause fatigue.
Extreme fluctuations can be fatal.

26. Glucose in the Body A Preview of Carbohydrate Metabolism
The body stores glucose as glycogen in liver and muscle cells.
The body uses glucose for energy if glycogen stores are available.
If glycogen stores are depleted, the body makes glucose from protein.
Gluconeogenesis converting protein to glucose.
Protein-sparing action is having adequate carbohydrate in the diet to prevent the breakdown of protein for energy.

27. Blood Glucose Regulation
High Blood Sugar
Dietary
CHO
Muscles
Used as fuel
To glycogen
Insulin
Pancreas
Glucagon
Liver
Liver
Used as fuel
To Glycogen
To Fat
Glycogenolysis
Gluconeogenesis
Low Blood Sugar

29. Glucose in the Body A Preview of Carbohydrate Metabolism
Making ketone bodies from fat fragments
The accumulation of ketone bodies in the blood is called ketosis.
Ketosis upsets the acid-base balance in the body.
The body can use glucose to make body fat when carbohydrates are consumed excessively.

30. Glucose in the Body The Regulating Hormones
The Constancy of Blood Glucose
The Regulating Hormones
Insulin moves glucose into the cells and helps to lower blood sugar levels.
Glucagon brings glucose out of liver storage and raises blood sugar levels.
Epinephrine acts quickly to bring glucose out of liver storage during times of stress and stimulates gluconeogenesis.

31. Glucose in the Body The Constancy of Blood Glucose
Balance glucose within the normal range by eating balanced meals regularly with adequate complex carbohydrates.
Blood glucose can fall outside the normal range with hypoglycemia or HYPERGLYCEMIA (diabetes).

32. Glucose in the Body The Constancy of Blood Glucose Diabetes
Type 1 diabetes is the less common type with no insulin produced by the body.
Type 2 diabetes is the more common type where fat cells resist insulin.
Prediabetes is blood glucose that is higher than normal but below the diagnosis of diabetes.
Hypoglycemia is low blood glucose and can often be controlled by dietary changes.

33. The benefit of the glycemic index is controversial.
Glucose in the Body
The Constancy of Blood Glucose
Glycemic response is how quickly the blood glucose rises and elicits an insulin response.
Glycemic index classifies foods according to their potential for raising blood glucose.
Glycemic load refers to a food’s glycemic index and the amount of carbohydrate the food contains.
The benefit of the glycemic index is controversial.

34. Glycemic Index
is a ranking system for carbohydrates based on their immediate effect on blood glucose levels. It compares carbohydrates gram for gram in individual foods, providing a numerical, evidence-based index of postprandial (post-meal) glycemia.

35. The effect on blood glucose from a high versus low glycemic index carbohydrate.

36. Glycemic Index of selected Foods

37. Glycemic Load
The glycemic load (GL) is a ranking system for carbohydrate content in food portions based on their glycemic index (GI) and the portion size.
The usefulness of glycemic load is based on the idea that a high glycemic index food consumed in small quantities would give the same effect as larger quantities of a low glycemic index food on blood sugar

40. Health Effects and Recommended Intakes of Sugars
Sugar poses no major health problem except dental caries.
Excessive intakes may displace nutrients and contribute to obesity.
Consuming foods with added sugars should be limited.
Naturally occurring sugars from fruits, vegetables and milk are acceptable sources.

41. Health Effects and Recommended Intakes of Sugars
Health Effects of Sugars
Foods with added sugars have sugars listed as a first ingredient.
Nutrient deficiencies may develop from the intake of empty kcalories.
Just because a substance is natural does not mean it is nutritious. (Example: honey)
Dental caries may be caused by bacteria residing in dental plaque and the length of time sugars have contact with the teeth.

42. Health Effects and Recommended Intakes of Sugars
Controversies Surrounding Sugars
Excessive sugar intake can contribute to the development of body fat.
Sugar may be able to alter blood lipid levels and contribute to heart disease
There is no scientific evidence that sugar causes misbehavior in children and criminal behavior in adults.
There is a theory that sugar increases serotonin levels, which can lead to cravings and addictions.

43. Health Effects and Recommended Intakes of Sugars
The USDA Food Guide states that added sugars can be included in the diet as part of discretionary kcalories.
Dietary Guidelines state to limit intake of foods and beverages that are high in added sugars.
DRI suggest added sugars should contribute no more than 25% of a day’s total energy intake.

44. Health Effects and Recommended Intakes of Starch and Fibers
Health Effects of Starch and Fibers
May be some protection from heart disease and stroke
Soluble fibers bind with bile and thereby lower blood cholesterol levels.
Fiber may also displace fat in the diet.
Reduce the risk of type 2 diabetes by decreasing glucose absorption
Enhance the health of the GI tract which can then block the absorption of unwanted particles
May protect against colon cancer by removing potential cancer-causing agents from the body

45. Health Effects and Recommended Intakes of Starch and Fibers
Health Effects of Starch and Fibers
Promote weight control because complex carbohydrates provide less fat and added sugar.
Harmful effects of excessive fiber intake
Displaces energy and nutrient-dense foods
Abdominal discomfort and distention
May interfere with nutrient absorption

46. Recommended Intakes of Starch and Fibers
RDA for carbohydrate is g per day, or 45-65% of energy intake.
Daily Value is 300 grams per day.
Dietary Guidelines encourage a variety of whole grains, vegetables, fruits and legumes daily.
Healthy People 2010 recommends six servings of grains and five servings of fruits and vegetables.

47. Health Effects and Recommended Intakes of Starch and Fibers
Recommended Intakes of Fiber
FDA recommends 25 grams for a 2,000-kcalorie diet.
DRI at 14 g per 1000 kcalorie intake (28 grams for a 2,000 kcalorie diet)
American Dietetic Association recommends g per day.
World Health Organization suggests no more than 40 g per day.

49. Recommended Intakes of Starch and Fibers
From Guidelines to Groceries
Grains – encourage whole grains
Vegetables – starchy and nonstarchy vegetables differ in carbohydrate content
Fruits – vary in water, fiber and sugar content
Milks and Milk Products – contain carbohydrate; cheese is low
Meat and Meat Alternates – meats are low but nuts and legumes have some carbohydrate
Food labels list grams of carbohydrate, fiber and sugar; starch grams can be calculated.

51. Center Meals around the Carbohydrate Foods
Answers the question
“What am I supposed to eat”?
Provides the best source of energy.
Provides a lot of most nutrients, (including fiber)
Low in fat, and has the ‘good’ type and contains no cholesterol.
Most have protein, certainly enough.
Are not fattening--fats are!

52. Alternatives to Sugar

53. Artificial Sweeteners
Also called nonnutritive sweeteners
Saccharin = Sweet n low
Used primarily in soft drinks and as a tabletop sweetener
Rapidly excreted in the urine
Does not accumulate in the body
Has been removed from list of cancer-causing substances

54. Artificial Sweeteners
Aspartame = Equal
General purpose sweetener
Warning about phenylalanine for those with PKU
Controversial finding that aspartame may have caused cancer in rats
Excessive intake should be avoided by those with epilepsy

56. Artificial Sweeteners
Acesulfame-K (acesulfame potassium) = The sweet one
Research confirms safety

57. Artificial Sweeteners
Sucralose = Splenda
Made from sugar
Passes through digestive tract
Neotame
Most recent on the market
Very sweet
Phenylalanine not an issue

59. Artificial Sweeteners
Tagatose
Used for foods and beverages
Provides less kcalories than sugar
High doses can cause flatulence and loose stools.
Alitame and Cyclamate
Pending FDA approval
Approved in other countries

60. Artificial Sweeteners
Acceptable Daily Intake (ADI) is the level of consumption, maintained every day and still safe by a wide margin.
Moderation and variety are still recommended.
Artificial Sweeteners and Weight Control
Much research still being done
Using artificial sweeteners will not automatically reduce energy intake.

61. Stevia – An Herbal Alternative
Lacks research
Classified as a dietary supplement
Not required to have testing and FDA approval

62. Sugar Replacers
Also called nutritive sweeteners, sugar alcohols, and polyols
Maltitol, mannitol, sorbitol, xylitol, isomalt, and lactitol
Absorbed more slowly and metabolized differently in the body
Low glycemic response
Side effects include GI discomfort