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Nutritional Aspects of Health > Exam 2 - Nutrition > Flashcards

Exam 2 - Nutrition Flashcards

1
Q

Carbohydrates

A
  • consumed in diet as sugar, starch, and fiber
  • plants are main source
  • glucose is a universal energy source for cells, and especially preferred by red blood cells and neurons
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2
Q

Monosaccharides

A
  • have generic formula C6H12O6
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3
Q

Disacchardies

A

two monosaccharides linked by covalent bonds

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4
Q

Polysaccharides

A

many glucose molecules linked together

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5
Q

Glucose

A
  • most abundant monosaccharides
  • linked together with other sugars in our diets
  • blood sugar
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6
Q

Disaccharide are:

A
  • maltose, sucrose, and lactose
  • 2 monosaccharides linked together in a condensation reaction
  • humans have low levels of enzymes capable of hydrolyzing beta bonds
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7
Q

Fructose

A

found in fruits, vegetables, honey, and high-fructose corn syrup

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8
Q

C-O-C alpha bonds form

A

maltose and sucrose

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9
Q

C-O-C beta bond forms

A

lactose

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10
Q

maltose

A
  • glucose-glucose
  • found in seeds and alcoholic beverages
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11
Q

sucrose

A
  • glucose-fructose
  • table sugar
  • sugarcane, sugar beets, maple tree sap
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12
Q

lactose

A
  • glucose-galactose
  • milk and milk products
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13
Q

Oligosaccharides

A
  • 3 to 10 sugar units
  • raffinose and stachyose
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14
Q

Raffinose and stachyose

A
  • plant sources such as broccoli and beans
  • contain beta bonds that humans can’t break
  • metabolized by bacteria in large intestine, which produce gas
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15
Q

Polysaccharides

A
  • complex carbohydrates with more than ten sugar units
  • starch: amylose, amylopectin
  • glycogen
  • fiber: indigestible polysaccharides
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16
Q

Starch

A

amylose and amylopectin

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17
Q

amylose

A

unbranched chain of glucose molecules linked by 1-4 alpha bonds

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18
Q

Amylopectin

A
  • more branches, more sites for enzyme action
  • faster increase in blood glucose levels
  • branches are formed by 1-6 alpha bonds
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19
Q

Dietary Fiber

A
  • a family of carbohydrates that are linked by beta bonds
  • cannot be broken by human enzymes
  • bacteria convert some components of fiber into fatty acids which can be used by cells of large intestine
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20
Q

Soluble fibers

A
  • dissolve in water
  • found inside and around plant cells
  • pectins, gums, mucilages, and some hemicelluloses
  • oat bran, fruits, legumes, and psyllium
  • inside part of fruits and veggies
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21
Q

Insoluble fibers

A
  • do not dissolve in water
  • form strucutral parts of the plant cell
  • cellulose, hemicellulose, ligins
  • seeds and whole grains
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22
Q

Carbohydrates in foods

A

starch: much of carbohydrates in our diets, from plant based foods: legumes, tubers, grains
fibers: found in many of the same foods as starch, but processing often decreases fiber content

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23
Q

Net carbs or impact carbs

A
  • calculated by people on low carbohydrate diets and occasionally advertised on low-carb food products
  • Not FDA regulated
  • Subtract fiber and sugar alcohol from total carbohydrates, since these have less effect on blood glucose
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24
Q

Which form of fiber is associated with decreased blood cholesterol levels?

A

Soluble

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25
Q

Sweetners

A
  • Nutritive: metabolized to yield energy-contribute calores to diet
  • Non-nutritive: not metabolized to yield energy
  • synthetic vs. natural
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26
Q

Nutritive sweeteners:

A
  • sugar alcohols
  • derivatives of monosaccharides
  • naturlly present in certain foods, used as additive for sugar-free foods
  • example: sorbitol
  • slow metabolism: 1.5-3 kcal/g
  • can cause diarrhea in large amounts
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27
Q

Nutritive Sweeteners: HFCS

A
  • high-fructose corn syrup: treatment of cornstarch with acids and enzymes break starch down into glucose
  • enzymes convert glucose to fructose so that final product is about 55% fructose
  • similar in sweetness to sucrose
  • health effects probably not much different than sucrose
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28
Q

Non-Nutritive (Alternative) Sweetners

A
  • common examples: aspartame, sucralose, stevia, acesulfame-K
  • safety is determined by the FDA and indicated by an Acceptable Daily Intake (ADI) guideline:
  • amount of alternative sweeter considered safe for daily use over one’s lifetime
  • based on animal studies
  • set at 100 times less than the level where no harmful effects were seen
  • does not necessarily evaluate all health effects
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29
Q

Potential problems with non-nutritive sweetners

A
  • diminished ability to appreciate natural sweetness of food
  • lack of association between calories and sweetness
  • mid addictive-like properties
  • alteration of gut microbiome
  • possible effects on insulin and glucose tolerance: daily diet soda consumption associated with increased risk of type 2 diabetes
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30
Q

Carbohydrate nutritional status of Americans

A

we have no problem getting enough carbohydrates, but could improve out diets by getting those carbs from fiber-rich sources with no added sugars (ex: whole grains, fruits, and vegetables)

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31
Q

Digestible Carbohydrates: functions

A
  • provide energy: can be used by essentially all cells, main energy source for red blood cells and brain
  • spares protein from use as an energy source
  • prevents ketosis, a state where fatty acids are used for energy
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32
Q

Functions of fiber - indigestible carbohydrates

A
  • promotes bowel health: adds bulk to feces, prevents: constipation, hemorrhoids, diverticula, causing diverticulosis.diverticulitis
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33
Q

Fiber continued

A
  • reduces obesity risk by promoting fullness
  • enhances blood glucose control: soluble fiber slows glucose absorption, decreases insulin release from pancreas
  • reduces cholesterol absorption
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34
Q

Carbohydrate Digestion and Absorption

A
  • food preparation starts digestion of carbohydrates: cooking softens tough, fibrous tissues, starch granules swell as they soak up water, making them easier to digest
  • in the mouth, salivary amylase begins breaking down starch
  • pancreatic amylase continues the process in the small intestine
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35
Q

Digestion continued

A
  • disaccharides are digest by brush border enzymes in the absorptive cells of the small intestine
  • indigestible carbohydrates cannot be broken down: pass into the large intestine, fermented by bacteria into acids and gases or excreted
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36
Q

Maltose

A

Digested with maltase
Glucose + Glucose

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37
Q

Sucrose

A

Digested with sucrase
Glucose + Fructose

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38
Q

Lactose

A

Glucose + Galactose

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39
Q

Indigestible carbohydrates

A

Raffinose

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40
Q

Absorption

A
  • glucose and galactose: absorbed by active transport, pumped into absorptive cells using energy from sodium gradient
  • fructose: absorbed by facilitated diffusion, slower absorption than glucose or galactose
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41
Q

Absorption continued

A
  • some fructose is converted to glucose in absorptive cells; remainder converted in the liver
  • galactose is converted to glucose in the liver
  • glucose is then sent to cells for use; liver stores extra as glycogen
  • if glycogen storage capacity is exceeded, glucose is converted to fat
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42
Q

Health Concerns Related to Carbohydrate Intake

A
  • very high fiber intake can cause: hard, dry stools if fluid intake is low, decrease in absorption of minerals
  • high sugar intake: empty calories, potential increased risk of weight gain, cardiovascular disease, type 2 diabetes, dental cavities
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43
Q

Lactose intolerance

A
  • lactase production begins to decrease after early childhood
  • primary lactose intolerance: insufficiency of lactase production: symptoms include abdominal pain, bloating, gas, diarrhea, amount of lactose tolerance varies by individuals; some foods such as hard cheese and yogurt may be tolerated
  • secondary lactose intolerance: conditions of the small intestine damage the lactase producing cells, symptoms can cease if intestine recovers
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44
Q

Regulation of Blood Glucose

A
  • normal fasting blood glucose levels: 70-100mg/dl
  • above 126mg/dl is classified as diabetes: hunger, thirst, frequent urination, weight loss
  • below 50mg/dl is classified as hypoglycemia; hunger, shakiness, irritability, weakness, headache
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45
Q

Regulation of blood glucose continued

A
  • most important organs for blood glucose regulation: liver and pancreas
  • liver determines how much glucose enter the blood after a meal, and how much is stored as glycogen
  • pancreas secretes insulin and glucagon
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46
Q

Diabetes

A

: Inability to control blood glucose levels

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47
Q

Type 1 diabetes

A
  • insulin deficiency
  • usually early-onset
  • autoimmune disorder that tends to run in families
  • pancreatic cells are attacked and pancreas cannot produce insulin
  • need insulin injections
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48
Q

Type 2 diabetes:

A

insulin resistance
- adult-onset
- target cells do not respond to insulin
- usually diet and exercise are important for controlling this and may even prevent type 2

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49
Q

Risk factors (prediabetes)

A
  • apple shaped waistline
  • elevated blood pressure
  • low levels of HDL
  • elevated glucose and triglycerides
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50
Q

Diabetes Treatment

A
  • insulin therapy (always for T1 and sometimes for T2)
  • nutrition therapy: 3 regular meals plus snacks to reduce swings in blood glucose
  • diet low in saturated fats and choloesterol
  • careful and relatively consistent diet
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51
Q

Metabolic Syndrome, 3 or more criteria need to be present to diagnose metabolic syndrome

A
  • waist circumference larger than: 35 inches for women, 40 inches for men
  • fasting triglycerides above 150 mg/dl
  • HDL-cholesterol below: 40 mg/dl for men, 50 mg/dl for women
  • elevated blood pressure
  • fasting blood glucose above 110 mg/dl
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52
Q

Glycemic index and gylcemic load

A
  • indicated how blood glucose responds to various foods
  • glycemic index: ratio of blood glucose response of a food compared with a standard (usually pure glucose)
  • influenced by food’s: starch structure, fiber content, food processing, physical structure, temperature, amount of protein and fat in a meal
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53
Q

Glycemic Load

A
  • takes into account the glycemic index and also the amount of carbs per serving
  • better reflects a food’s effect on blood glucose
  • to calculate: grams of carbohydrate in serving x glycemic index 100
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54
Q

Glycemic index and glycemic load

A
  • foods with a high glycemic load elicit: increased insulin response and sharper rise and drop in blood glucose
  • chronically high insulin output can lead to: increased fat synthesis in liver, more rapid return of hunger after meal
  • limitations of GI/GL: mixed meals
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55
Q

Lipids

A
  • in the diet, lipids come as fats and oils:
  • family include: triglycerides, phospholipids, sterols
  • do not dissolve in water
    triglycerides are the most common type of lipid in food and in the body
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56
Q

Fatty acids

A
  • basic structure: long chains of carbon atoms
  • one individual molecule is a free fatty acid: acid (carboxyl group on 1 end) and methyl group on the other
  • variations in structure: number of carbons, extent of saturation with hydrogen, shape when double bonds are present
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57
Q

Long chain fatty acids

A
  • 12 or more carbons
  • most animal and plant sources
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58
Q

medium chain fatty acids

A
  • 6-10 carbons
  • coconut and palm oil
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59
Q

short chain fatty acids

A
  • fewer than 6 carbons
  • small amounts naturally occurring
  • also produced by gut bacteria
60
Q

Which of these is an omega-6 fatty acid

A

linoleic acid

61
Q

naming fatty acids

A

in nutrition, common names and omega system are used

62
Q

essential fatty acids

A
  • cannot be made in the body
  • alpha-linolenic acid: omega-3 fatty acid
  • linoleic acid: omega-6 fatty acid
63
Q

Omega-3 fatty acids

A

alpha-linolenic acid –> eicosapentaenoic acid (EPA) –> Docoahexaenoic acid (DHA) –> eicosanoids

64
Q

omega-6 fatty acids

A

linoleic acid –> dihomo-gamma-linolenic acid –> arachidonic acid –> eicosanoids

65
Q

Food sources of triglycerides

A
  • most foods provide some triglycerides:
  • animal fat and vegetable fat are primarily triglycerides
  • fat-free milk and yogurt, breakfast cereal, and yeast breads contain little or no fat
  • other than coconuts and avocados, fruits and vegetable are low in fat
  • pay attention to nutrition facts: some foods have more fat then you would expect
66
Q

Functions of triglycerides

A
  • essential for optimal health
  • concentrated source of energy
  • insulate and cushion organs
  • help transport nutrients
  • high intakes, especially of saturated and trans fat, and imbalances of essential fatty acids, can cause health issues
67
Q

Fats provide energy

A
  • triglycerides provide 9kcal/g
  • main fuel source for all cells except nervous system and red blood cells
  • when at rest or during light activity 30-70% of energy is supplied by triglycerides
68
Q

Fats provide compact energy storage

A
  • excess calories from carbohydrates, fat, protein, and alcohol can be converted to triglycerides
  • calorie dense
  • expandable storage
69
Q
A
70
Q

Fat insulate and protect the body

A
  • subcutaneous fat is found just bellow the skin: helps keep the body at a constant temperature
  • visceral fat is found around organs: cushions organs, protects organs from injury
71
Q

Fats aid fat-soluble vitamin absorption and transportation

A
  • dietary fats: carry fat-soluble vitamins are transported in the bloodstream with dietary fats
72
Q

phospholipids

A
  • structure is similar to triglycerides except one fatty acid is replaced with a phosphate compound
  • phosphate head is hydrophilic
73
Q

Phospholipid functions

A
  • cell membrane component
74
Q

emulsifiers

A
  • forms a shell around fat droplets and suspend then in watery solution
  • essential for fat digestion and transportation
  • bile and lecithin
  • used in foods such as mayo
75
Q

total dietary fats: IOM recommendations

A

25-35% of calories

76
Q

source of phospholipids

A
  • synthesized by the body
  • found in food: egg yolks, wheat germ, peanuts
  • high does can cause: gas, diarrhea, weight gain
77
Q

sterols

A
  • type of steroid
  • carbons are arrange in multi-ringed structures
  • cholesterol used to make: sex hormones, active form of vitamin D, adrenal hormones, bile, cell membranes, shell-covering chylomicrons
78
Q

sources of sterols

A
  • cholesterol is found in foods of animal origin: meat, fish, poultry, eggs, dairy products
  • plants make other type of sterol (ergosterol)
  • body synthesizes about 3x dietary intake
79
Q

Mediterranean Diet

A
  • Dr. Ancel Keys: 7 countries study
  • lowered risk of heart disease associated with:
  • most fat from olive oil (monounsaturrated)
  • abundant intake of fruit, vegetables, whole grains, beans, nuts and seeds
  • minimally processed and seasonal local food
  • small amounts of cheese and yogurt daily
  • low to moderate fish intake weekly
  • limit eggs and meat
  • exercise
  • moderate intake of wine
80
Q

Fat digestion and absorption

A
  • small amounts of digestion in mouth and stomach
  • lingual lipase: active during infancy, minor role in adults
  • stomach: fat not yet emulsified
  • most digestion in the small intestine: fat in small intestine triggers release of CCK; bile, lipase, and colipase released from pancreas
81
Q

bile emulsifies fat

A
  • breaks down fat into micelles
  • increase the surface are for lipase to work
82
Q

fatty acids and monoglycerides are

A

absorbed by brush border cells

83
Q

chain length of fatty acids determines

A

where they go

84
Q

transporting lipids in the blood: lipoproteins

A
  • lipoprotein structure:
  • composed of a core of lipids
  • covered with a shell of proteins, phospholipids, and cholesterol
  • triglyceride/cholesterol ratio is major difference between lipoprotein types
85
Q

Chymlomicron

A
  • triglyceride
  • carries dietary fat from the small intestine to cells
86
Q

VLDL

A
  • triglycerides
  • carries lipids both taken up and made by the liver to cells
87
Q

LDL

A
  • cholesterol
  • carries cholesterol made by the liver and from other sources to cells
88
Q

HDL

A
  • protein
  • helps remove cholesterol from cells and, in turn, excrete cholesterol from the body
89
Q

transporting dietary lipids: chylomicrons

A

lipoprotein lipase (LPL)
- enzymes attached to inside of cell membranes
- activated by apo C-II
- hydrolyzes triglycerides from chylomicrons
- free fatty acids are taken up by cells, repackaged into triglycerides and used for energy or put into storage
- chylomicron remnant is left

90
Q

transporting lipids mostly made by the body utilizes VLDLs

A
  • liver can make fat and cholesterol from carbohydrates, protein, and free fatty acids
  • these products are packages as very low-density lipoproteins (VLDLs) to be transported in the blood
91
Q

VLDLs

A
  • lipoprotein lipase hydrolyzes triglycerides in VLDLs: allows free fatty acids to enter cells, creates intermediate-density lipoproteins (IDLs) as triglycerides leave
  • IDLs lose more triglycerides in the liver: hepatic triglyceride lipase catalyzes hydrolysis, the resulting lipoproteins become LDL, with cholesterol as the predominant content
92
Q

LDL removal from the blood

A
  • LDL particles taken into cell via receptor- mediated endocytosis
  • B-100 protein on LDL interacts with LDL receptor on body cells
  • inside cell, lipoprotein is broken down to produce free cholesterol
  • if free cholesterol saturates cell, LDL receptor expression decreases
  • LDL not taken into cell can become oxidized: risk factor for CVD and metabolic syndrome
  • excess LDL deposited into blood vessel walls
  • macrophages scavenge excess LDL, contributing to an inflammatory process
93
Q

HDL

A
  • high density lipoproteins (HDLs)
  • highest proportion of protein = higher density
  • picks up cholesterol from dying cells
  • transport cholesterol back to liver for excretion
  • helps to block the oxidation of LDL
  • slows development of cardiovascular disease
94
Q

Dieats High in total fat

A

increase risk of:
- obesity
- some cancers: colon, prostate, breast
- cardiovascular disease
-all of these are more complex than a simple cause-effect relationship

95
Q

Atherosclerosis:

A

chronic inflammatory response to endothelial injury
- injury can occur due to oxidized LDL, smoking, hypertension, some infections
- asymptomatic for many years until/unless rupture or vessel occlusion occurs

96
Q

Cardiovascular Disease: non-modifiable risk factors

A
  • age: over 65
  • sex: males greater chance of developing than women prior to menopause
  • genetics: close relative who died prematurely of CVD increases risk
  • race/ethnicity: African, Hispanic/Latino, Native American, native Hawaiian, and some asian groups
97
Q

Cardiovascular disease: modifiable risk factors

A
  • elevated LDL, total cholesterol, and/or triglycerides
  • hypertension
  • smoking
  • physical inactivity
  • obesity
  • diabetes
  • liver and kidney disease
  • low thyroid levels
98
Q

Preventing cardiovascular disease

A
  • adults over 20 should have fasting blood lipoprotein profile done every 5 years
  • increase soluble fiber intake to 20-30 grams/day
  • moderate sugar intake
  • keep body weight at a healthy level
  • increase physical activity
  • eat fruits, vegetables, nuts, and plant oils
  • antioxidants (vitamin C and E)
99
Q

Summary of cardiovascular disease

A
  • LDL is an indicator of CVC risk, and LDL levels are positively correlated with saturated fat intake
  • the guideline of 10% calories from saturated fat is somewhat arbitrary
  • many other factors involved: significant individual variation, food matrix and level of processing, specific saturated fatty acids in food, LDL subtypes and effects on HDL levels, CVD risk is more complex than just LDL
100
Q

how many nonessential amino acids:

A
  • 11 nonessential amino acids: body can make them in great enough quantities
101
Q

How many essential amino acids

A
  • cannot be made
  • 9
  • make the carbon skeleton
  • attach an amino group to the carbon skeleton
  • make a sufficient quantity
102
Q

Conditionally essential amino acids

A
  • nonessential amino acids may be classified as conditionally essential: infancy, disease, trauma
  • example: person with phenylketonuria (PKU) has limited ability to metabolize phenylalanine and convert it to tyrosine, tyrosine is conditionally essential in people with PKU
103
Q

Complete and Incomplete Proteins

A
  • animal proteins (except gelatin) contain all essential amino acids and are called complete proteins
  • plant proteins (except quinoa and soy) do not contain all 9 essential amino acids or are low in at least one: incomplete, or low quality, proteins
  • can get complete protein from plants by making complementary combination
104
Q

Denaturation of protein

A
  • alteration of protein’s 3- dimensional structure
  • destroys protein’s function
  • caused by: exposure to acid or alkaline solutions, enzymes, heat, agitation
105
Q

Sources of protein

A
  • adults turn over 250-300 g/day of protein
  • consume 65-100 g/day
  • typical North American diet: much of protein comes from animal sources: may include saturated fat, do not include fiber
106
Q

Evaluation of Food protein quality

A
  • several methods exist to evaluate protein quality: all have imperfections
  • most widely used is the protein digestibility corrected amino acid score (PDCASS)
  • takes into account: digestibility of a protein (how much actually get absorbed), amino acid composition (Does it have the essential amino acids, and are they present in a ration that mirror the body’s needs?)
107
Q

Recommended intakes of protein

A
  • adult RDA is 0.8g/kg of healthy body weight
  • AMDR is 10-35% of calories
  • RDA does not address additional protein amounts needed: during recovery from illness or injury, for highly trained athletes
108
Q

Nitrogen balance

A
  • everyone needs to consume protein in amount that replaces what was lost in urine, feces, sweat, skin cells, hair, and nails
  • most adults are in equilibrium
  • positive nitrogen balance: childhood growth, pregnancy, intense athletic training
  • negative balance: serious illness, bed rest, dietary deficiency
109
Q

Protein Digestion ad Absorption

A
  • cooking denatures proteins and softens the connective tissue in meat: makes proteins easier to chew, digest, and be absorbed
  • in the body, digestion starts in the stomach: hydrochloric acid denatures protein, pepsin breaks down long polypeptide chains: can only break certain peptide bonds
  • chyme entering the small intestine triggers the release of secretin and cholecystokinin
  • these hormones stimulate the pancreas to release proteases: trypsin, chymotrypsin, carboxypeptidase
  • amino acids/small peptides are absorbed by active transport and enter the portal circulation
110
Q

Functions of proteins

A
  • major structural component of body: collagen, actin, myosin
  • during periods of growth, new proteins are synthesized
  • during malnutrition or disease, proteins are broken down to supply energy
111
Q

Blood proteins:

A
  • maintain oncotic pressure
  • extreme low protein diet can cause low blood protein levels and subsequent edema
112
Q

Protein energy malnutrition

A
  • in developing countries people may suffer from malnutrition and disease due to protein and/or total energy deficits
113
Q

Kwashiorkor

A

protein deficiency with moderate energy deficit

114
Q

marasmus

A

overall energy deficit

115
Q

High protein diets

A

when excess protein intake is primarily from high intake of animal proteins, plant-based foods are low leading to:
- lower intake of fiber, some vitamins and minerals, and phytochemicals
- higher consumption of saturated fat and cholesterol
other potential risks are controversial:
- may overburden kidneys’ capacity to excrete excess urea
- may increase urinary calcium loss

116
Q

food allergies

A
  • immune reaction against a protein in food
  • the pictured foods account for 90% of food allergies
  • current advice: for most children, introduce allergenic foods starting gradually at 6 months
117
Q

Vegetarian diets

A
  • religious/cultural
  • environmental
  • animal welfare
  • health: diets rich in fruits, vegetables, legumes, and grain result in: antioxidant nutrients, dietary fiber, phytochemicals
  • decreased intakes of: saturated fats and cholesterol
  • possibly reduced obesity
118
Q

Vegetarian diets and micronutrients

A
  • vegetarian diets require greater awareness of micronutrient intake
119
Q

Nutrients of greatest concern in vegetarian diet

A
  • Vitamin B-12: found only in animal sources
  • Calcium: found in green leafy vegetables, but in a form that is not well absorbed
  • Iron: found in whole grains and other plant sources, not absorbed as well as animal sources
  • vitamin D: get from sun
120
Q

Special Concerns for infants and children on vegetarian diets

A
  • bulky, high fiber, low calorie foods can cause fullness without meeting nutrient needs
  • include concentrated sources of energy to meet calorie and nutrient needs: nuts, avocados, juices from whole fruit
121
Q

Sources of Alcohol

A
  • alcoholic beverages vary in alcohol and calorie content
  • Beer: most around 5% but can be 7-8% or higher
  • Wine contains 5-14% alcohol
  • Fortified wines contain 15-22% alcohol
  • Distilled spirits (hard liquor): more than 22% alcohol, alcohol content listed as “proof” (2x the percentage)
122
Q

Standard size for one drink

A
  • provides approximately 14g ethanol: 98 calories from ethanol alone, additional calories primarily from sugars
  • beer: 12 ounces
  • wine 5 ounces
  • hard liquor: 1.5 ounces
  • moderate alcohol intake is defined as one standard drink for women and two for men
123
Q

Production of alcoholic beverages

A
  • fermentation of grains, cereals, fruits, honey, milk, potatoes, or other carbohydrate rich foods: yeast converts carbohydrates to alcohol and carbon dioxide, carbohydrates must be in simple sugar form; if not, they must be malted before fermentation
  • each molecule of fermented glucose yields 2 molecules of ethanol and 2 molecules of carbon dioxide
  • after fermentation, alcohol can be recovered from the product by distilling, whereby alcohol is boiled off and the vapors are collected and condensed
124
Q

Alcohol Absorption and Metabolism

A
  • alcohol require not: digestion or specific transport mechanism
  • absorption: 20% stomach and 80% small intestine: full stomach slows absorption
  • distribution: mixes into body water, disperses throughout body
125
Q

Alcohol Metabolism: ADH

A
  • since ethanol cannot be stored, breaking down for energy is a high priority
  • primary pathway: alcohol dehydrogenase (ADH): active at low to moderate intakes, acetaldehyde is toxic intermediate, acetyl-CoA can be used for energy or fatty acid synthesis
126
Q

Steps of alcohol metabolism

A

alcohol –> (with alcohol dehydrogenase) acetaldehyde –> (with alcohol dehydrogenase) Acetyl-CoA –> energy or fatty acid

127
Q

Alcohol Metabolism: MEOS

A
  • during moderate to excessive alcohol intake, ADH pathway cannot keep up: liver activates microsomal ethanol oxidizing system (MEOS, CYP2E1), produces same intermediates but uses energy
  • induction of MEOS is one factor in tolerance development
128
Q

Factors Affecting Alcohol Metabolism

A
  • ethnicity: low levels of aldehyde dehydrogenase especially common in Asian populations, results in build up of toxic acetaldehyde
  • sex: females produce less alcohol dehydrogenase, females are smaller and have more body fat (less total water)
129
Q

Metabolism facts

A
  • metabolism is approximately 7g/hour (half of a standard drink)
  • consuming more than this will result in a measurable blood alcohol concentration (BAC)
  • breathalyzer works because a small proportion of alcohol is exhaled
130
Q

Selected effects of ethanol

A

Molecular and phsiologic

131
Q

Molecular effects of ethanol

A
  • potentiates effects of GABA
  • Blocks effects of glutamate
  • Endogenous opioid release
  • Activates reward pathway
132
Q

Physiological selected effects of ethanol

A
  • decreased inhibition
  • decrease motor control
  • disrupted sleep and memory consolidation
  • at high doses, central nervous system and respiratory depression, can lead to death
133
Q

Risk of excessive alcohol intake

A
  • contributes to 5 of 10 leading causes of death in North America:
  • heat failure
  • cancers: oral cavity, pharynx, larynx, esophagus, liver, breast, colon, rectum
  • cirrhosis of liver
  • motor vehicle and other accidents
  • suicide
134
Q

Health effects of alcohol

A

most current analysis: there is no safe amount of alcohol consumption

135
Q

Historical Context

A
  • 1990s-recently: moderate alcohol consumption reduces mortality
  • J curve: displays the correlation of drinks per day consumed vs. relative risk of mortality, it was thought that 1-2 drinks a day could lower the risk, any more drinks per day would increase it
  • Alcohol does appear to slightly reduce
    risk of cardiovascular disease and
    possibly diabetes, but these effects are
    offset by increased mortality from other
    causes
136
Q

Potential reasons for the original J-curve

A
  • moderate drinkers generally have healthy lifestyles, higher socioeconomic status, and score better on overall indicators of health
  • people in poor health advised not to drink
  • moderate alcohol intake may: reduce stress and anxiety and the risk of CVD
  • red win contains antioxidants, but amounts are fairly small
137
Q

How alcohol reduces the risk of CVD

A
  • lower low-density lipoproteins
  • increase high-density lipoproteins
  • decrease platelet aggregation
138
Q

Cirrhosis of the Liver

A
  • loss of functioning hepatocytes
  • decreased synthesis of plasma proteins, often leading to ascites
  • not reversible and liver failure develops
  • 50% chance of death in 4 years
  • susceptibility varies, but generally associated with drinking >3 drinks per day for 10+ years
  • while nutritious diet may delay or lessen some complications of cirrhosis, it will not prevent
139
Q

Cirrhosis may be due to

A
  • increase concentration of acetaldehyde
  • accumulation of fat in liver resulting in inflammation and cell damage
  • production of free radicals from alcohol metabolism
140
Q

Effects of alcohol abuse on nutritional status

A
  • alcohol abuse can lead to poor nutritional status and development of nutrient deficiencies
  • when alcohol replaces food in the diet: protein-energy malnutrition develops, with symptoms similar to kwashiorkor, deficiencies of vitamins and mineral can also occur: decreased intake, impaired absorption, altered metabolism, alcohol-related tissue damage
141
Q

Vitamin deficiencies - alcohol

A
  • Thiamin: Wenicke-Korsakoff syndrome: severe effects on brain and nervous system, confusion, ataxia, memory impairment
  • Vitamin A: normally stored by liver
  • Vitamin D: liver involved in synthesis of active form
142
Q

Effects on minerals

A
  • if a vitamin D levels are low, what minerals would you expect to be low?
    Iron: bleeding (increased loos and poor absorption)
143
Q

Alcohol Consumption During pregnancy and breastfeeding

A
  • drinking during pregnancy can cause serious harm to developing fetus: slow nutrient and oxygen delivery to the fetus, retards growth and development, may replace nutrient dense food
  • most vulnerable during first 12-16 weeks: fetal alcohol spectrum disorders, fetal alcohol syndrome
144
Q

Alcohol use disorder AUD

A

Alcohol use disorder may include:
- Failure to fulfill major responsibilities
- Drinking when physically dangerous
- Social or relationship problems
- Craving
- Tolerance
- Withdrawal

145
Q

Risk factors for AUD

A
  • 40 to 50% of risk is inherited
  • More common in men, but women more susceptible to health effects
  • More likely in those who start young
  • Socioeconomic factors

Nutritional Aspects of Health (4 decks)

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