Unit 5- Macronutrients - Carbohydrates Flashcards by ROGER ALONSO

Carbohydrates

• Monosaccharides (seldom found free in nature)
– Glucose
– Fructose
– Galactose
• Disaccharides
– Sucrose
– Lactose
– Maltose
• Oligosaccharides (Water-soluble, often sweet)
– ______ (Trisaccharide: galactose, fructose, & glucose) Found in beans, cabbage,
brussels sprouts, broccoli, asparagus, other vegetables, and whole grains
– ________ (Tetrasaccharide: 2 galactose, glucose, & fructose) Found in numerous
vegetables (e.g. green beans, soybeans and other beans)
• Polysaccharides
– Amylose
– Amylopectin
– Resistant starch
– Dextrins
– Glycogen (animal carbohydrate)

Raffinose

Stachyose

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Types of Carbs and Food Sources

Dietary Fibers: intrinsic and intact in natural foods. Mixture of un-digestible polysaccharides & NON-carbohydrate compounds

– ________ = β1——>4 glucose units

– _______ =Linear D-xylose w/ side chains

Cellulose

Hemicellulose

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Dietary Fibers: intrinsic and intact in natural foods. Mixture of un-digestible polysaccharides & NON-carbohydrate compounds

_____ = Soluble polymer of galacturonic acid

______ = Methoxy-phenol polymers

Pectin

Lignin

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Dietary Fibers: intrinsic and intact in natural foods. Mixture of un-digestible polysaccharides & NON-carbohydrate compounds

_____ = Sugar acid polymer and galactan mix

__________ = Extensin is the major form

Mucilage

Glycoprotein

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Dietary Fibers: intrinsic and intact in natural foods. Mixture of un-digestible polysaccharides & NON-carbohydrate compounds

___ _____ = Inositol hexaphosphate, chelating

______ = Esters of fatty acids and alcohols

Phytic acid

Waxes

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Role of Fiber in Digestion and Absorption

• Varies based on its solubility
• Insoluble fiber _______ stool volume and
________ gastrointestinal (GI) transit time
• Soluble fiber SLOWS GI transit time, BINDS
cholesterol and minerals, and decreases
nutrient absorption
• Fermented into short-chain fatty acids
• Absorb water, fats, bile acids and cholesterol = Lower blood glucose, TGs, cholesterol
• Provide a bulk effect to reduce food intake
• Enhance excretion of gas
• Act as ‘__________’ to promote beneficial
intestinal bacteria (probiotics)
• Some of the best are _______ (polymers of
fructose, eg inulin), found in artichoke, onions,
asparagus, dandelion root

increases

decreases

prebiotic

fructans

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Role of Fiber in Digestion and Absorption

AI =
___ g/day for men

___ g/day for women

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Dietary Fiber

• Although not digested or absorbed, they can 
prevent or ameliorate the following conditions:
– Constipation
– Diarrhea
– Diverticulosis / diverticulitis*
– Glucose intolerance
– Hypercholesterolemia
– Colon cancer
– CHD
– Obesity

KNOW

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Digestion, Absorption and Transport
Digestion:
1–Monosaccharides: do NOT require ____

2–Disaccharides: digested by _____ enzymes

digestion

intestinal

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Sucrose = glucose + fructose/ENZYME =???
Lactose = glucose + galactose/ENZYME =???
Maltose = glucose + glucose/ENZYME =??
Isomaltose = glucose + glucose/ENZYME =?

Starches and Glycogen: digested to glucose, maltose and isomaltose by α-amylase

isomaltase
maltase

sucrase

lactase

maltase

isomaltase

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Digestion, Absorption and Transport

Absorption:
__________ (only): absorbed in jejunum & ilium. Then transported to liver and other tissues. Absorbed Actively, Passively, or Both (depending on which ________)

Monosaccharides

monosaccharide

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Digestion, Absorption and Transport

In the intestine, there are 2 modes of absorption:

______= Na-dependent glucose transporter (SGLT-1)
- -Absorbs glucose + galactose
- -Symport: Co-transports Na+ into mucosal cells
- -Coupled to Na-K pump (‘antiport’) which moves Na+ out
______= monosaccharide transporter (GLUT5)
Pentose and hexoses absorbed across concentration gradient

Active

Passive

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Digestion, Absorption and Transport

_________: Passive-facilitative = Brain, kidney, placenta, colon, RBCs

GLUT-1

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Digestion, Absorption and Transport

_______: Passive-facilitative–For rapid uptake = Liver, pancreatic β cells, kidney Intestine
—->blood….___-______ syndrome

GLUT-2

Fanconi-Bickel

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Digestion, Absorption and Transport

_____: Passive-facilitative = Brain(neurons), kidney, placenta

GLUT-3

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Digestion, Absorption and Transport

_______: ACTIVE –ENERGY IS USED! =Heart, skeletal ms., adipose, Insulin-stimulated transporter for ACTIVE uptake of ______

GLUT-4

glucose

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Digestion, Absorption and Transport

GLUT-5: Passive-facilitative “___ _____” = Small Intestine For uptake of pentoses For hexoses when [high]

Fructose transporter

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Digestion, Absorption and Transport

Transport:
1–Brain: Depends on ____ & ______ for
glucose (primary energy source)
2—May SLOWLY adapt to use fatty acids/ketone bodies
3–Abrupt _______ may cause coma or death

GLUT-1 and GLUT-3

hypoglycemia

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Glucose Absorption

What affects the rate of absorption?

Resistance of _____ to enzyme digestion
Activity of _____ ______ at brush border
Presence of other dietary factors (all SLOW rate)
a. FAT slows stomach emptying
b. NON-absorbable polysaccharides
c. viscous dietary fibers (pectins, β-glucans)
dilute enzyme concentration

starch\

digestive enzymes

***Therefore, a diet rich in whole foods, such as fruits, vegetables, legumes, nuts and minimally processed grain SLOWS the pace of glucose absorption.

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Glucose Absorption
Glucose is absorbed (______) across the intestinal cell TO portal blood TO liver

1–The liver removes about ___% of the absorbed glucose for oxidation and storage as glycogen

2–Glucose exits liver, enters systemic circulation. Then, glucose is available for insulin-dependent uptake by ______ tissues

GLUT -2

50%

peripheral

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Glycemic Index:

Measurement of blood glucose following the
consumption of a carbohydrate food. Compared to the consumption of equal amount of carbohydrate in D-glucose (old days – white bread)

Glycemic Index of Glucose: 100

GI measures _____ of carbohydrate food

quality

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Factors Affecting Glycemic Index

Cooking Methods:– The more cooking/processing, the ______ the Glycemic Index
Physical Form of food:– The more _______ the food (whole grain), the SLOWER it is digested and the LOWER the GI

• Type of Starch
Amylopectin > Amylose (potatoes, corn) (legumes: kidney beans, lentils)

• Fiber:
– SOLUBLE fibers SLOW digestion, lowering a food’s GI
– (Oatmeal, dried beans, some fruits and vegetables)

• Sugar:
– Fructose, in fruits, is metabolized SLOWLY, lowering GI

higher

fibrous

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Glycemic Load

• (Glycemic Index)(grams of avail. carbs in food)/ 100
• Measures the quantity and quality of a
carbohydrate’s effect on _____ ______ and insulin release

blood glucose

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Glycemic Index

• High GI diet is a predictor of ______ __________,
hypertension, and diet-induced _______ of colon & breast

• Low GI diet is correlated with low cholesterol, low LDL, elevated HDL

So… combine low GI diet with low-fat diet for
weight management

Type II Diabetes

cancers

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Hormones in Carb Metabolism 4 Major Modes of Hormone Action. Hormones bind to receptor and activate: 1. Protein tyrosine kinase 2. Adenylate cyclase ---->cAMP 3. Guanylate cyclase -----> cGMP 4. Hormone Response Element (on gene)

KNOW

Hormones in Carb Metabolism X 4 1. Protein tyrosine kinase A. Hormone binds Receptor B. Activates Protein Tyrosine Kinase C. Phosphorylates proteins Hormones utilizing this X 4 = ??

Insulin IGF-I, IGF-II Growth Hormone

Hormones in Carb Metabolism X 4 2. Adenylate cyclase A component of GTP-dependent ‘G protein complex’ ATP--->cAMP---> activates cAMP-dependent protein kinase--->phosphorylates proteins/enzymes Hormones utilizing this system X 4 =??

Epinephrine, glucagon, calcitonin, ADH

Hormones in Carb Metabolism X 4 3. Guanylate cyclase A component of GTP-dependent ‘G protein complex’ GTP---->cGMP---->activates cGMP-dependent protein kinase----->phosphorylates proteins/enzymes ***Hydrolyzed by cGMP phosphodiesterase (Viagra inhibits cGMP phosphodiesterase) Hormones utilizing this system: X 2 =??

1---Nitric oxide (NO) 2---Arginine-------> Citrulline + NO (Nitric Oxide = Synthase)

Hormones in Carb Metabolism X 4 4. Hormone Response Element (HRE) – Hormones can bind receptors or diffuse across cell membrane and nuclear membrane – Bind to segment of DNA “HRE” – Regulates transcription (up or down) Hormones utilizing this system: X 9!!

``` Androgens, estrogens, Thyroxins (T3, T4), calcitriol, glucocorticoids, mineralocorticoids, progestins, Retinoic acid (vitamer of vitamin A), Vitamin D ```

Blood glucose • Blood glucose – Normoglycemic: = 60-100 mg/dL – Hyperglycemic: = ____________ – Hypoglycemic: = ___________ • Factors affecting blood glucose: – Diet, hormones, metabolites, PAL, BMI, WHR • After eating (postprandial), blood glucose can be 117- 130 mg/dL – Will return to fasting level ~1.5 hr • HbA1c normal levels  4.6-5.4% (5.1%~ 100mg/dL)

> 100 mg/dL

Blood glucose Diabetes mellitus: one or more of the following: 1. Fasting blood glucose > 126 mg/dL 2. Random blood glucose > 140 mg/dL 3. > 200 mg/dL 2hr after ingestion of 75g glucose 4. HbA1c (glycated hemoglobin) > 8% • ___________ LOWERS blood glucose by – Stimulating uptake in muscle and adipose

Insulin

Hormones in Carb Metabolism: INSULIN Insulin _________ Glucagon/Epinephrine – Increases entry of glucose and neutral amino acids into target cells – Increases protein synthesis in skeletal muscle – Increases glycolysis (activates glucokinase, PFK-1) – DECREASES gluconeogenesis (inactivates PEPCK gene) – Increases glycogenesis (activates glycogen synthase) – DECREASSES glycogenolysis (inactivates glycogen phosphorylase) – Increases lipogenesis (activates acetyl-CoA carboxylase) – DECREASES lipolysis (inactivates hormone-sensitive lipase)

opposes

Hormones in Carb Metabolism: ``` Glucagon/Epinephrine OPPOSE Insulin – Increases protein BREAKDOWN in skeletal muscle – DEcreases glycolysis – INcreases gluconeogenesis – DEcreases glycogenesis – INcreases glycogenolysis – DEcreases lipogenesis – INcreases lipolysis ```

OPPOSITE OF INSULIN

Storage of Carbohydrates • 2 forms: ____________--Stored in extra-cellular fluids ______________---Stored in liver and muscle • Glycogen: polymer of glucose in α1--->4 and α1--->6 • Body content of glycogen fluctuates with diet and physical activity • Typical example: A 70 kg man may have an 18hr supply: 1---150-600 g in muscle 2--90-160 g in liver 3---5-25 g in blood (as glucose)

Glucose Glycogen

Function of Carbohydrates 1. Provide energy 2. Biosynthesis of Lipids 3. Biosynthesis of certain amino acids 4. Biosynthesis of nucleic acids 5. Biosynthesis of glycosaminoglycans (GAGs) 6. FORMATION of _____+____________

glycoproteins and glycolipids

Function of Carbohydrates 1 OF 6 1. Provide energy: Metabolism of 1g carb = 4 kcal Can be metabolized under aerobic OR anaerobic conditions A. Protein and lipid MUST be metabolized under ___________ conditions B. __________ regulated at 2 points: – Glycogenolysis – Glycolysis

AEROBIC Metabolism

Function of Carbohydrates 2 OF 6 ``` 2. Biosynthesis of Lipids Dietary glucose: ~50% for energy release ~40% for fat synthesis ~10% for glycogen ``` Carbs provide: For carbon backbone = _______________ For hydrogen / cofactor = ________ For bond energy = ___________

Acetyl-CoA a. Carbs provide acetyl-CoA b. Blood insulin increases = stimulates lipogenesis NADPH ATP

Function of Carbohydrates 3 OF 6 3. Amino acid biosynthesis: by ____________ Transamination of pyruvate results in: _________, lactate, acetyl-CoA, citrate

transamination alanine

Function of Carbohydrates 4 OF 6 Nucleic acid biosynthesis: PPP R-5-P, ATP and GTP are all produced in carb metabolism, and involved in synthesis of ___________

nucleotides

Function of Carbohydrates 5 OF 6 5. Biosynthesis of Glycosaminoglycans – “GAGs” (mucopolysaccharides) : polymers of carbohydrate derivatives, (esp. amino sugars and uronic acids) Example 1: ______ _____: Joint lubricant in synovial fluid; component of vitreous humor of eyes Example 2: _____ ________: component of bone, cartilage and other CT Example 3:_____ ________: Endogenous anticoagulant, and binds proteins to alter their function

hyaluronic acid chondroitin sulfate heparan sulfate

Function of Carbohydrates 6 OF 6 Biosynthesis of glycoprotein: Glycoproteins (mucoproteins): proteins with attached oligosaccharides Key examples of glycoproteins: 1. antibodies 2. _____ _______ (req’d for VitB12 absorption) 3. __________ : erythrocyte membrane protein 4. When GAGs are ATTACHED TO PROTEIN, they are known as ________________ (or peptidoglycan)

Intrinsic factor glycophorin Proteoglycans

Daily Requirement, Deficiency & Excess Deficiency could result in: 1– Ketosis 2– An excessive loss of ____ ________ 3– Problems associated with lacking _____ _______ Carbohydrate deficiencies • South Beach diet • Ketogenic diet • Alcoholism Excess – FNB: ___% kcal from sugar UL.

body protein dietary fiber 20%

Lactose intolerance Digestive problem in people who lack the intestinal enzyme ___________ • Undigested lactose: – Absorbs an excess amt of ______ – Promotes the growth and fermentation of ________ = excess gas & irritating substances = diarrhea, cramping, stomach pain.

lactase water bacteria

Lactose intolerance • 2 types of lactase deficiency: A--– ___________ of the lactase gene (post-infant) • In people with ancestry from places other than northern Europe, central Africa, Indian subcontinent B--– People who stop eating foods with lactose • Lactase can be restored by gradually resuming lactose consumption

Deactivation

Lactose intolerance • Lactase (available w/o prescription) can be added to milk several hours in advance to _________ lactose. A--– Addition of Lactobacillus acidophilus is ________ in preventing lactose intolerance B--– ~___% of lactose intolerant people can eat yogurt because Lactobacillus bulgaricus and Lactobacillus thermophilus, which release β-galactosidase, are used in the preparation

pre-digest ineffective 80 ****From 1962 to 2000, worldwide intake of sugar increased by 32% (74 kcal per capita per day)

Sugars: Are they really bad? 4 reasons why excess sugars are unhealthy: 1. Energy-dense = Get extra kcal easily= overweight, OB 2. Poor in nutrients = May actually cause deficiency of ___________. Metabolism can deplete body’s reserve of __ vitamins, because need NAD, FAD coenzymes 3. Promote growth of bacteria= Oral bacteria in particular = dental cavities and __________ disease 4. Lipogenic = Sugars cause release of insulin, activates glycolysis and acetyl Co-A carboxylase to make malonyl-CoA, ________ hormone-sensitive lipase which is lipogenic. (Anti-lipolytic)

micronutrients B periodontal inactivates

Carbohydrate regulation of blood lipids * Brain uses most of ____ g of glucose required daily * If blood glucose <40 mg/dL = ___________

200 glycogenolysis

Carbohydrate regulation of blood lipids If blood glucose >180 mg/dL = _________in urine • High carb intake = ______ insulin levels

glucose high

Carbohydrate regulation of blood lipids • ~2hrs after meal, intestinal absorption is complete, but insulin effects persist = ______ _______ DECREASES = body fears hypoglycemia = lipolysis = FA packed into VLDLs in the liver = __________ serum triglycerides

blood glucose elevated

_____________-- is a condition in which the body is unable to use (metabolize) the simple sugar galactose. 1--- Hereditary metabolic defect (1:65,000) (autosomal recessive) 2---_________ can be used to detect before birth ``` Symptoms: Anorexia / Weight loss Vomiting / Diarrhea Lethargy Icturis / Hepatomegaly Poor growth Cataracts MR Edema Death ```

Galactosemia Amniocentesis

Galactosemia ``` Treatment – Avoid foods with galactose! – These foods include • Milk, milk products • Legumes • Organ meats • Cocoa • Chocolate • Coconut • Some people may develop an alternative enzyme to metabolize ____________, usually after 6 years of age ```

D-galactose

Diabetes Mellitus • Type I: Insulin-dependent--Body does NOT produce insulin • Type II: Non-insulin-dependent--Faulty _____ _______ • Gestational-----Hormones affect level of glucose __________ ``` Symptoms: 1---General weakness 2---Polydipsia 3---Polyuria 4---Polyphagia 5--Ketosis (fruit breath and ketonuria) 6--Hyperglycemia 7--Glycosuria 8---Coma (severe case) ```

insulin receptors transporters

Diabetes Insipidis Similar symptoms as DM, but different CAUSE: Disorder of the ______ ________ or hypothalamus = deficiency of vasopressin (ADH) = REDUCED water resorption. Trauma or _______ may also cause this condition. Treatment: vasopressin and __________

pituitary gland tumors diuretics

Risk factors for DM type II Overweight: BMI> ___ kg/m2 1– Overnight fasting blood glucose levels significantly correlate to BMI and WHR 2– (correlation to total body fat level is weaker) 3---_____ _______ = Ethnic group: high risk groups include– African-, Native-, Asian-American, Hispanic / Latino, Pacific Islander

25 Family history

Risk factors for DM type II Gestational diabetes: during pregnancy or having a baby > __ lbs • Hypertension: (consistently > 140/90 mm Hg) • Fat & Cholesterol: HDL _______ mg/dL

9 250

Blood glucose: Lab criteria Normal blood sugar: _____-______ mg/dL

60-100

Blood glucose: Lab criteria Diabetes mellitus: one or more of the following: – Fasting blood glucose > ____ mg/dL – Random blood glucose >_____ mg/dL – > 200 mg/dL 2hr after ingestion of 75g glucose – HbA1c (glycated hemoglobin) > 8% ***Normal blood sugar: 60-100 mg/dL

126 140

Blood glucose: Lab criteria ________ ________ INCREASES the risk of Type I diabetes. 3+ of the following: – _________ obesity – Impaired Fasting Glucose (IFG) > _____ mg/dL – Dyslipidemia (Fasting TG > 150 mg/dL) – Low HDL-C (

Metabolic Syndrome Central 110

Hypoglycemia ``` • Low blood glucose = Sugar or fruit juices used to relieve emergency condition • Characterized by – Nervousness – Tension – Sweating – Nausea – Headache – Convulsion – Coma – Death ***Symptoms related to: Excessive _________ release. Low brain glucose level = _______ ```

epinephrine Ketosis

Prebiotics & Probiotics Functional Food = Any food or food ingredient that may provide a health benefit BEYOND traditional nutritional function. – Examples: inulin, oligofructose (__________) – Lactobacilli, bifidobacteria, others including both lactic acid and maybe some non-lactic acid bacteria (___________)

prebiotics probiotics

Prebiotics Enhances the colonization of HEALTH promoting bacteria in the ______ intestine. 1--– _____-______ food ingredient that beneficially affects the host’s health by selectively stimulating growth and/or activity of one or a number of bacteria in the colon. 2--– Does NOT depend on administration of a viable microbe. 3--– Inulin, oligofructose preferentially PROMOTE growth of bifidobacteria

large Non-digestable

Prebiotics • Inulin and Oligofructose: polymers of fructose (_______) connected by α2--->1 linkages. –______= 2-60 fructose monomers – Oligofructose

fructan Inulin sucrose

Prebiotics ``` 1 • Inulin and Oligofructose: 2 • Average American diet: – 2.6 grams inulin & 2.5 g oligofructose 3 • MAJOR food sources of FRUCTAN: – ______ (70% total dietary fructan) – Onions (25%) – Bananas and garlic (remainder) 4 • Fructans have NO toxicity, except high intake may cause __________ ```

Wheat flatulence

Prebiotics: As additives 1• Both inulin and oligofructose have been used as FIBER in food products 2• _________ is most SOLUBLE. Its sweetness is about 30-50% of sucrose… used as sugar substitute in dairy products, baking goods and granola bars 3•___________ is less soluble. It has a smooth creamy texture when sheared in water or milk… has a fat-like taste. Used as fat substitute

oligofructose Inulin

Prebiotics: Effects on the body • Limited energy source 1--– Fructans like other soluble fibers, are non-digestible in _________ intestine. 2--– They are ____________ by bacteria in LARGE INTESTINE = short-chain fatty acids, lactic acid, pyruvic acid, ethanol, and others = these CAN be absorbed and metabolized for energy release. 3--– Caloric value of fructans ranges from 0-2.5 kcal / gram ---->______ kcal / gram average

small fermentable 1.5

Prebiotics: Effects on the body * Effects at intestine * Increase fecal bulk (_________ diarrhea) * Prevent bile re-absorption (__________ constipation) * Increase intestinal flora * increase short fatty acids * Increase vitamin B7 and K synthesis * Increase mineral absorption

decrease decrease

Probiotics Definition: “A preparation of, or a product containing, viable defined microorganisms in sufficient numbers which, by implantation or colonization, alter the ________ in a compartment of the host and thereby exert health effects in this host” Unlike commonly thought, NOT limited to the intestine… could be other parts of gut, vagina, or skin.

microflora

Probiotic microbes ``` • Microbes – Lactobacillus –12 species – Bifidobacterium – 7 species – Streptococcus thermophilus – Lactic-acid bacteria – 6 other species – Non-lactic acid bacteria – maybe ? – Yeast – Sacchromyces –proposed • Available as fermented probiotic products – Dairy-based yogurt, cheese, acidophilus milk – Non-dairy: brined olives, sauerkraut, Togwa (cereal/ flour with bacteria) – Commercial lyophilized bacteria OTC ```

KNOW

Probiotics: Criteria 1. Human origin 2. Non-pathogenic 3. Resistance to technological processing and delivery 4. Resistance to gastric _______ 5. Resistance to bile __________ 6. Viability in GI environment 7. Adherence to epithelial tissue 8. Production of antimicrobial substances 9. Ability to modulate host’s immune response 10. Ability to modulate host’s biochemistry A. Absorption of cholesterol and minerals, lactase activity and vitamin production

acidity toxicity

Probiotics: Known Effects ``` 1--Balance of intestinal ______ 2--Reduction of ____________ symptoms 3--Relief from constipation 4--Relief of irritable bowel syndrome 5--Beneficial effects on mineral metabolism, esp. bone density and stability ```

flora allergic

Probiotics: Known Effects 6--Protection against malignancy 7--Reduction in serum cholesterol and TGs 8--Enhanced________ function A. Increased phagocytic activity and ___ cell activity B. Increased INF-α 9. Protection against rotavirus diarrhea 10. Protection against ‘traveler’s diarrhea’ (_______)

immune NK E. coli

Focal Points 1 • The major nutrients with roles in the human body include energy-containing macronutrients (carbohydrates, lipids, protein, and alcohol) as well as the micronutrients (vitamins and minerals.) 2 • The indigestible food component, fiber, is essential for health, especially related to the GI tract and cardiovascular system, but ____% of Americans do NOT get enough fiber. 3 • Changing concepts regarding the structure, function, and utilization of nutrients in the body are important to keep in mind because they determine the impact of _____ _________ or excesses on health and disease management.

80% nutrient deficiencies