Top-Rated Free Essay

Ch

Topics: Glucose, Carbohydrate, Sugar / Pages: 21 (2714 words) / Published: Jan 29th, 2015
CARBOHYDRATES

1322

Classification
• Simple carbs consist of 1 or 2 sugar units

• Monosaccharides

• Glucose, fructose, galactose
• Disaccharides

• Sucrose, lactose, maltose
• Oligosaccharides consist of 3-10 sugar units
• Not a simple or a complex carb

• Complex carbs consist of 10 + sugar units
• Polysaccharides

• Starch and fiber

Monosaccharides
6 carbons= hexose Monosaccharides
• Glucose
• Most abundant carbohydrate
• Preferred source of energy for the RBC, brain, and

nervous system
• Fructose
• Sweetest of natural sugars
• Found abundantly in fruits
• Part of high-fructose corn syrup
• Galactose
• Rarely found on its own in nature
• Mostly found bound to glucose = lactose (disaccharide)

Disaccharides
• 2 monosaccharides form a glycosidic bond through

condensation, releasing water
• Alpha glycosidic bonds are easier to digest
• Beta glycosidic bonds are not easily digested (humans lack enzymes)

• Sucrose (table sugar)
• glucose + fructose (sweetest disaccharide due to fructose)
• Alpha
• Most common form
• Maltose (malt sugar)
• glucose + glucose
• Alpha
• Least common
• Lactose (milk sugar)
• glucose + galactose
• Beta

Polysaccharides: Starch
• Storage form of glucose in plants
• Unlimited storage capacity
• Amylose= straight chain
• 40% in plants
• More resistant to digestion due to the bonds being harder to break as they stack, not allowing enzymes to break the bonds

• Amylopectin= branched chain
• 60% in plants
• Easier to digest because they can’t stack in a linear fashion like amylose • Resistant starch= comprised of more amylose chains

making them harder to digest
• Unripe bananas, beans, pasta, raw potatoes

Similar to amylopectin Polysaccharides: Glycogen
• Storage form of glucose in animals

• Found in liver and muscle cells only
• Similar to amylopectin
• No significant source in animal proteins after they die due

to rapid breakdown
• Limited storage capacity

Polysaccharides: Fiber
• Found in the cell walls of plants= cellulose
• Linear strands stack up on top of each other creating a wall like structure • Lends to the texture in fruits and veggies
• Beta glycosidic links add to the indigestible nature
• Most goes through the GI tract undigested
• provide no energy
• Animal products do not contain fiber
• Functional fiber= extracted from plants or synthetically

produced
• Does provide health benefits like its dietary counterpart
• Metamucil

Polysaccharides: Fiber Cont.
Soluble

Insoluble

• Dissolves in water

• Doesn’t dissolve in water

• Viscous and have

• Not easily fermented in by

thickening properties
• Fermented by intestinal bacteria • Pectin, gums, psyllium

intestinal bacteria
• Cellulose, lignins

• apples, citrus fruits, legumes,

oats

• Whole grain breads and

cereals, fruits (skins), carrots, strawberry seeds

Oligosaccharides
• Look like simple carbohydrates:

• Similar in length
• Look like complex carbohydrates:
• Part of cellulose in cell walls

• Go undigested like fiber
• Gut flora ferment them
• Legumes, beans, cabbage, brussel sprouts, broccoli

• Raffinose and stachynose are the culprits for the

gas and bloating

How do you know which form of carb predominates?

Total carbs-sugar-fiber=starch
26.5-1.2-13=12.3 starch
Simple carbs are the main source followed by starch

Digestion
• Mouth
• Amylase acts on the starch

• Amylose and amylopectin

disaccharides

• Stomach
• HCL deactivates amylase and digestion ceases

• Small Intestine
• Disaccharides stimulate pancreas to secrete pancreatic





amylase to work on the disaccharides
Disaccharides are further broken down into monosaccharides by the brush boarder (enzymes)
Sucrose
Glucose + Fructose
Maltose
Glucose + Glucose
Lactose
Glucose + Galactose

Digestion Cont.
• Monosaccharides are absorbed into blood to travel to

liver for 4 fates:
• Returned to blood to travel to other cells
• Used for energy by liver
• Stored as glycogen in the liver
• Stored as fat
• Large intestine
• Only fiber and resistant starch remain

• Eliminated
• Metabolized by the bacteria

Absorption
• Galactose/glucose

active transport (carrier + energy)
• Fructose facilitated diffusion (protein carrier)
• Depending on the need:
• Galactose/fructose used for energy by liver or converted to glucose
• Glucose can then travel through the blood to needed cells
• Surplus glucose is stored as glycogen in the liver or muscle (glycogenesis)
• Once body’s needs and glycogen stores are maxed, excess glucose is finally stored in adipose tissue

Other Fates of Glucose
• Glycogenolysis

• 4 hours post meal the body will tap into the glycogen

stores to release glucose into the blood
• Lysis = loosening
• Once liver glycogen stores are depleted, the body moves to other sources to get glucose released into the blood
• Muscle will not be broken down to provide glucose
• Lacks the enzyme
• Uses its own stores of glucose for energy
• Only in extreme starvation cases

Other Fates of Glucose
• Gluconeogenesis
• Creating glucose from amino acids

• Gluco= sugar Neo= new
• Primarily occurs in the liver

• Can take place in the kidneys after very long periods

of fasting
• When stores are not replenished through diet, body proteins can be dismantled by gluconeogenesis to provide glucose for the blood

Ketosis
• 18 hours post meal

• Fat becomes the predominate source of energy to

spare muscle
• Partial breakdown of fat by lypolysis produces
Ketones
• Increase of ketones in the blood cause ketosis
• 2 days of fasting creating an acidic environment
• Is acidic increasing or decreasing the PH?
• decreasing

• The brain relies on the ketones for energy reducing

the need to create glucose from protein sources

Blood Glucose Control
• Our well being depends solely on our blood glucose

control
• The pancreas secretes 2 hormones to control blood glucose: • Insulin
• Glucagon

• Optimal blood glucose range is 70-100 mg
• Under= hypoglycemic
• Over= hyperglycemic

Insulin
• Stimulates the uptake of glucose from the blood into the cells
• After ingestion:

• Surge of glucose in the blood
• Presence of glucose stimulates the pancreas to release

insulin
• Receptors on the cell membrane are stimulated allowing for increase transporters to take in the glucose
• Kidney, liver, and brain don’t need insulin’s help to get glucose • After utilization:
• One all cells have what they need, insulin helps pull left over glucose from blood and make glycogen in liver and muscle
(glycogenesis)

Insulin Cont.
• Glycogen stores are full:
• Insulin will increase receptors on fat cells and glucose is

transported inside to be converted to fatty acids
Lipogenesis
• By stimulating lipogenesis, insulin prevents lipolysis
• Lysis= loosening (breakdown of fat)
• In a nutshell:
• Insulin stimulates glycogenesis (creation of glycogen)
• Insulin stimulates lipogenesis (creation of fatty acids)
• Insulin prevents lipolysis (breakdown of fat)

Glucagon
• Stimulates the release of glucose into the blood
• In a fasting or low carb mode:
• Released into blood
• Goes straight to the liver
• Stimulates glycogenolysis in liver(breakdown of

glycogen)
• 10-18 hours all glycogen is depleted if no supply comes in from diet
• In a continued fasted state:
• Stimulate gluconeogenesis (new sugar) from amino acids in liver

Skipping Breakfast
• Blood glucose _______

• Pancreas secretes _________ stimulating___________,

the breakdown of glycogen
• Glucagon also stimulates the liver to initiate
___________, creating new glucose sources from amino acids • Glucose is released into the blood, transported into the cells, leveling off blood glucose

Skipping Breakfast
• Blood glucose drops

• Pancreas secretes glucagon stimulating glycogenolysis,

the breakdown of glycogen
• Glucagon also stimulates the liver to initiate gluconeogenesis, creating new sources of glucose from amino acids
• Glucose is released into the blood, transported into the cells, leveling off blood glucose

Type 1 vs. Type 2 Diabetes
• Diabetes is inadequate glucose control
• Diabetics
• Pre-diabetic= 100-125 mg fasting
• Diabetic= >126 mg fasting
• Type 1 = insulin is not secreted or secreted in inadequate

amount
• Type 2 = Insulin is secreted but not effective due to cell resistance • Type 2 used to be called adult onset but now our children are developing Type 2
• Why?
• In both cases glucose has flooded the blood and become toxic Type 1
• Autoimmune disease
• Immunological response to the body’s own tissues

• Attacks its own beta cells of the pancreas not

allowing it to secrete insulin
• Symptoms occur due to increased glucose in the blood: • Polydipsia: Uncontrollable thirst
• Polyuria: Excessive urination
• Polyphagia: Strong desire to eat

Type 1
• Untreated will cause ketoacidosis = chronic

state of ketone bodies in the blood due to lack of insulin • Why does this happen?
• The cells not able to use glucose shifts the body into lypolysis for energy (breaking down stored fat releasing ketones)
• Very serious and can be life threatening
• Treatment: blood glucose monitoring and take insulin by injection

Type 2
• More common diagnosis = 90-95%
• Exhausted the beta cells in pancreas and do not produce

insulin
• Being overweight is a main risk factor
• Can be asymptomatic for a long time going undiagnosed leading to damages to vital organs
• Nerve and blood vessel damage leading to complications:
• Leg and foot amputations
• Eye diseases
• Kidney disease
• Heart disease
• Treatment: monitor blood glucose and take insulin

Other Conditions
• Hypoglycemic < 70 mg
• Very low blood glucose
• Dizzy, shaky, weak, light headed
• Takes place when take insulin and don’t eat enough to cover the

effect of medicine
• Important to eat regular meals and not skip any

• Hyperglycemic > 180 mg

Control is Key for Both Types
• Nutrition and lifestyle goals for individuals with type 1 and

type 2 diabetes are the same
• Eat a well-balanced diet
• Routinely checking blood levels
• Engage in physical activity (at least 30 minutes per day). • Increases insulin sensitivity and uptake of glucose into cells
• Reduces body fat
• Lowers blood pressure and lipids

Understanding the Glycemic Effect
• Glycemic index= rating of how the food affects blood

glucose and insulin levels
• Foods that are predominately simple carbs have a higher GI because they release glucose quicker into the blood creating a spike and rapid fall
• Foods with fiber and protein delay the release of glucose and have a lower spike of glucose into the blood and a gradual decline

Understanding the Glycemic Effect
• Glycemic Load= adjusts the GI to take into an account of an

actual serving
• 50 gm of white bread= GI is 100
• 50 gm of puffed wheat cereal = GI of 105
• 50 gm of puffed wheat, 4 cups, in one sitting is not a typical serving. Puffed cereal is actually lower than white bread • Other factors:
• Ripeness
• Overripe fruits have more easily digested sugar
• Cooking makes foods more digestible compared to raw version • Foods with soluble fiber have a lower GI

Bonking
• What factors contribute to how soon one will hit the wall?
• Amount of glycogen, how fast you run, pacing strategy, body size, and muscle mass
• What is the significance of rinsing with a carb drink and

not swallowing it?
• It tricks the brain in thinking it is going to receive carbs. This is

important because the brain anticipates glycogen depletion and will slow the body down. If it senses that carbs are coming, this communication is delayed

• Why would it benefit someone to train in a fasted state?
• Increased levels of fat metabolism enzymes improves fat utilization allowing the athletes to maintain a pace without relying on glycogen. This ultimately help the runner avoid hitting the wall too soon • http://www.youtube.com/watch?v=LKf1eTzmK14

Where do we get them and how much?
• Carbohydrates
• DRIs recommend a minimum of 130 grams/day
• MyPlate recommends:






6 servings of grain/day
3 servings of vegetables/day
3 servings of dairy/day
2 servings of fruit/day
• AMDR recommends :
• 45–65% of total kilocalories/day
• Best sources whole grains, veggies, fruits, and beans
• Do you think the US diet lacks in carbs?
• Where do we get most of our carbs?

Sources of Carbohydrates
• Dairy products
• Contain 1 to 17 grams of lactose
• Choose low-fat or fat-free products
• Lacks fiber
• Fruits/vegetables
• 100% juices, whole fruits, and vegetables
• The flesh of fruits contains simple sugars and

pectin
• The skin of fruits contains cellulose
• Vegetables contain starch and fiber

Sources of Carbohydrates
• Legumes, nuts, and seeds

• Provide an average of 4 grams of fiber per

serving
• Nuts and seeds contain very little starch but are good sources of fiber
• Packaged foods
• Can be good sources of starches but can also contain high amounts of added sugars, fat, sodium, and kilocalories
• Need to be consumed in moderation

What are whole grains?
• Complex carbohydrates
• Contain the entire grain including bran, endosperm, and germ • Associated with reduced risk of chronic diseases
• MyPlate recommends at least 3 servings of whole

grains a day
• Examples include:
• Whole-grain breads and cereals with 2 to 3 grams of fiber per serving
• Bulgur, brown rice, quinoa, oatmeal, whole wheat pasta • It has to say “whole” on the label or it is not a whole grain

Figure 4.13
© 2014 Pearson Education, Inc.

Slide 1

Figure 4.13
© 2014 Pearson Education, Inc.

Slide 2

Figure 4.13
© 2014 Pearson Education, Inc.

Slide 3

Figure 4.13
© 2014 Pearson Education, Inc.

Slide 4

Differences in Grains
• Refined= milling process strips the bran and germ

leaving just the endosperm
• Lacking B vitamins, iron, phytochemicals, and fiber
• White and wheat flours, whit rice
• Higher glycemic index because they are less
“complex” and create a rapid surge of glucose into blood • Enriched= nutrients added back due to being stripped during milling process
• Folic acid, thiamin, niacin, riboflavin, and iron
• No fiber or phytochemicals

Fiber: the bonus to whole grains
• Fiber

• DRIs recommend 14 grams for every 1,000

kilocalories consumed
• AI: 25 to 38 grams per day
• Adults in the United States consume about 1218 gm/day

Soluble Fiber Health Effects
• Viscous nature allows for it to form a gel-like

substance
• lowering serum cholesterol (blood)
• Binds bile acids before they can be reabsorbed and are excreted in the stool
• Bile acids are comprised of cholesterol
• With less available, the liver has to remove

cholesterol from the blood to create bile acids that were lost, lowering overall blood cholesterol levels

Soluble Fiber Health Effects
• Delays absorption

• Traps nutrients delaying the transit time

through the GI
• Slower transit= slower absorption and there is a delayed release of glucose and fat
• Delayed glucose absorption prevents release of glucose into blood, no spike
• Delayed absorption of fat prevents release of fat into blood helping insulin sensitivity

Insoluble Fiber Health Effects
• Increases transit time
• Adds bulk to stool stimulating peristalsis,

moving it through quicker
• Helps prevent constipation
• May have cancer fighting properties
• Increasing transit time decreases the amount of time harmful substances have to stay in contact with the cells
• Encourages the growth of colon-friendly bacteria and their fermentation by-products
• Reduces acid in the colon

Fiber is good regardless!
• There are Exceptions to the rule

• Not all soluble fiber lowers blood

cholesterol
• Some soluble fibers can relieve constipation • Eat more Fiber!

Natural vs. Added
• Your body doesn’t know the difference between natural and

added sources of sugar
• Natural
• found naturally in foods (fructose in fruits)
• More nutrient dense
• Fruits can contain more that 15% of weight from sugar

• Added
• Added by manufacturers
• Empty calories
• Sugar is added for:







Added moisture
Baked products turn golden brown
Preservative
Thickener
Yeast needs it to rise
Overall taste

Natural vs. Added
• Sucrose and fructose are the most common added sugars
• Lots of names for added sugars:
• Molasses
• Corn syrup, malt syrup
• HFCS
• Dextrose
• Fruit juice concentrate
• http://www.choosemyplate.gov/weight-managementcalories/calories/added-sugars.html

Natural vs. Added
• Food labels are misleading:
• Sugar on food labels combines natural sources and added

• Only ingredients will tell you
• FDA is proposing to have manufactures list added separately
• American Heart Association recommendation for added:
• 6 tsp for women

• 9 tsp for men
• Avg is 21 tsp
• How many grams in a tsp?
• Granulated sugar = 4 gm/tsp

• Depends on the types of sugar used (volume vs. weight)
• Number 1 source of added sugars?
• Soft drinks, energy drinks, and sports drinks

68 gm
24 gm

40 gm

Artificial Sweeteners
• FDA regulated

• Sugar alcohols
• Cause a slower rise in blood glucose due to

slower absorption
• Range from 1.6 -2.6 kcal/gm
• Chemical structure of sugar + alcohol
• Sugar free but not calorie free
• Incompletely absorbed and can cause gas and diarrhea in large amounts
• Found in gum, supplement bars, drinks, shakes

Artificial Sweeteners cont.
• Calorie free sweeteners:
• Blue, pink, and the yellow
• Saccharin (pink)

• One of the first ones
• Initially thought to cause cancer due to studies on rats

but later removed from harmful list after further research found that the mechanism causing cancer in rats is not found in humans

Artificial Sweeteners cont.
• Aspertame (blue)

• Two amino acids= aspartic acid and phenylalanine
• Can provide 4 kcal/gm but it’s concentrated

sweetness lends to using minimal amounts that don’t equate to 4 kcals
• Phenylketonuria= genetic disorder disallowing the metabolism of phenylalanine
• FDA mandates all products to have disclaimer
• ADI= 50 mg/kg of body weight
• 150 lb person =16 12oz cans of diet soda daily for a lifetime Artificial Sweeteners cont.
• Sucralose (yellow)
• Made from sucrose
• Has a similar chemical structure but body does not digest or absorb it
• Can be used in baking due to resistance to high temperatures

You May Also Find These Documents Helpful

  • Ch
  • Ch
  • Ch
  • CH
  • Ch
  • Ch
  • Ch
  • QUIZ CH 01 CH 02
  • ch. 11
  • APUSH Ch