Nutrition Exam 2 Flashcards
(119 cards)
0
Q
Glucose
A
◦The most abundant carbohydrate
◦Produced by plants through photosynthesis
Good energy source
Monosaccharides
1
Q
Carbohydrates
A
One of the three macronutrients Important source of energy for all cells Preferred energy source for nerve cells Composed of carbon, hydrogen, oxygen Good sources: fruits, vegetables, grains
2
Q
Simple carbohydrates
A
◦Contain one or two molecules
◦Commonly referred to as sugars
Monosaccharides
Disaccharide
3
Q
Monosaccharides
A
contain one molecule
◦Glucose, fructose, and galactose
◦Ribose*
4
Q
Disaccharides
A
contain two molecules
Lactose, maltose, and sucrose
5
Q
Fructose
A
Sweetest natural sugar
Found in fruit
High fructose corn syrup
Monosaccharide
6
Q
Galactose
A
Does not occur alone in foods
Binds with glucose to form lactose
Monosaccharide
7
Q
Lactose
A
Disaccharide
Also called milk sugar
Glucose and galactose
8
Q
Maltose
A
Glucose and glucose
Disaccharide
Maltose molecules join in food to form starch molecules
By product of fermentation
9
Q
Sucrose
A
Disaccharide
Glucose and fructose
Found in Sugar cane, honey, and sugar beets
10
Q
Complex carbohydrates
A
Oligosaccarides
Polysaccharides
11
Q
Oligosaccarides
A
◦ (oligo = few)
◦3 to 10 monosaccharides
◦Glucose, fructose and galactose
◦Sources: cruciferous vegetables, legumes, whole grains
12
Q
Polysaccharides
A
Poly=many
◦Hundreds to thousands of glucose molecules
◦Form starch, glycogen, most fibers
13
Q
Starch
A
Polysaccharide
◦Plants store carbohydrates as starch (storage form of glucose in plants)
◦Amylose—straight chain of glucose
◦Amylopectin—branched chain of glucose
◦Resistant starch (fiber)—glucose molecules linked by beta bonds are largely indigestible
◦Sources: grains, legumes, fruits, vegetables
14
Q
Glycogen
A
◦Storage form of glucose for animals (humans)
◦Not found in food and therefore not a source of dietary carbohydrate
◦Stored in the liver and muscles
15
Q
Fiber
A
◦Composed of long polysaccharide chains
◦Dietary fibers are non-digestible parts of plants
◦Functional fibers
◦Non-digestible forms of carbohydrates
◦Extracted from plants or manufactured in a laboratory
◦Have known health benefits
◦Example: psyllium
◦Total fiber = Dietary fiber + Functional fiber
16
Q
Soluble fibers
A
◦Dissolve in water; viscous and gel-forming
◦Fermentable
◦Digested by intestinal bacteria
◦Associated with risk reduction of CVD & Type II DM
◦Examples: pectin, gum, mucilage
◦Found in citrus fruits, berries, oats, beans
17
Q
Insoluble fiber
A
◦Do not dissolve in water, nonviscous ◦Cannot be fermented by intestinal flora ◦Promote regular bowel movements ◦Alleviate constipation ◦Reduce diverticulosis ◦Examples: lignins, cellulose, hemicelluloses
18
Q
Carbohydrate digestion
A
Digestion breaks down most carbohydrates into monosaccharides
Salivary amylase
Carbohydrate digestion does not occur in the stomach
◦Stomach acids inactivate salivary amylase
19
Q
Salivary amylase
A
◦Enzyme that begins carbohydrate digestion in the mouth
◦Breaks carbohydrates down to maltose
20
Q
Carbohydrate digestion in small intestine
A
-Most chemical digestion of carbohydrates occurs in the small intestine
-Pancreatic amylase
-Additional enzymes in the microvilli digest disaccharides to monosaccharides
◦Maltase
◦Sucrase
◦Lactase
-Monosaccharides are absorbed into the cells lining the small intestine and then enter the bloodstream
21
Q
Pancreatic amylase
A
◦Enzyme produced in the pancreas and secreted into the small intestine
◦Digests carbohydrates to maltose
22
Q
Carbohydrate digestion-liver
A
- All monosaccharides are converted to glucose by the liver
- Glucose circulating in the blood is our primary energy source
- Excess glucose is stored as glycogen in the liver and muscles
23
Q
Carbohydrate digestion in large intestine
A
- We do not have the enzymes necessary to digest fiber
- Bacteria in the large intestine can break down some fiber
- Most fiber remains undigested and is excreted in the feces
24
Blood Glucose Regulation
```
Blood glucose must be closely regulated
Hormones control blood glucose levels:
◦Insulin
◦Glucagon
◦Epinephrine
◦Norepinephrine
◦Cortisol
◦Growth hormone
```
25
Insulin
- Secreted by beta cells of the pancreas
- Stimulates glucose transporters (carrier proteins) to help take glucose from the blood across the cell membrane
- Stimulates the liver to take up glucose and convert it to glycogen
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Glucagon
-Secreted by alpha cells of the pancreas
-Stimulates the liver to convert glycogen to glucose
-Stimulates gluconeogenesis, the production of glucose from amino acids
(Increases blood glucose levels)
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Epinephrine and norepinephrine
- Secreted by the adrenal glands and nerve endings when blood glucose is low
- Increase glycogen breakdown in the liver, releasing glucose into the blood
- Responsible for our "fight-or-flight" reactions to danger
28
Cortisol and growth hormone
- Secreted by the adrenal glands to act on the liver, muscle, and adipose tissue
- Cortisol increases gluconeogenesis and decreases muscle glucose use
- Growth hormone decreases muscle glucose uptake, increases fatty acid mobilization and use, and increases liver glucose output
29
Glycemic index
- A food's potential to raise blood glucose
- Foods with a high glycemic index cause a sudden surge in blood glucose, triggering a large increase in insulin, which may be followed by a dramatic fall in blood glucose
- Foods with a low glycemic index cause low to moderate fluctuations in blood glucose
- Not always easy to predict
- Food's absorption rate varies with type of carbohydrate, preparation methods, and its fat and fiber content
- Most foods are eaten in combination in a meal
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Value of lower glycemic index
-Less fluctuations in blood glucose
-Risk reduction for heart disease and colon cancer
◦High fiber intake helps to improve fat levels in the blood (higher HDL and lower LDL)
-Foods with lower glycemic index:
◦Beans, fresh vegetables, whole wheat
31
The role of carbohydrates
Energy
◦Each gram of carbohydrate: 4 kcal
◦Red blood cells use only glucose for energy
◦Both carbohydrates and fats supply energy for daily activities
◦Glucose is especially important for energy during exercise
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Ketosis
◦Fat breakdown during fasting forms ketones
◦Excess ketones increase blood acidity and cause ketoacidosis
◦Sufficient energy from carbohydrates prevents ketone production as alternate energy source
(Fats that aren't efficiently metabolized form ketones)
33
Carbohydrates spare proteins
- Gluconeogenesis occurs when a diet is deficient in carbohydrate
- The body will make its own glucose from protein
- Amino acids from these proteins cannot be used to make new cells, repair tissue damage, support the immune system, or perform any of their other functions
34
Health benefits of fiber
- May reduce the risk of colon cancer
- helps prevent constipation, hemorrhoids and other intestinal problems
- may reduce the risk of diverticulosis
- May reduce the risk of heart disease
- may enhance weight loss
- May lower the risk of type 2 diabetes
35
How much carbs should you eat
-Recommended Dietary Allowance (RDA) is
130 grams/day to supply adequate glucose to the brain
-Acceptable Macronutrient Distribution Range (AMDR) is 45% to 65% of daily calories
-Focus on fiber-rich carbohydrate foods
36
Diets high in simple sugars..
- can cause tooth decay
- may increase bad cholesterol
- may decrease good cholesterol
- may contribute to obesity
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Enriched foods
are foods in which nutrients that were lost during processing have been added back so the food meets a specified standard
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Fortified foods
have nutrients added that did not originally exist in the food (or existed in insignificant amounts)
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How much fiber should we eat
-Adequate Intake (AI) for fiber
◦25 g per day for women
◦38 g per day for men, or
◦14 g of fiber for every 1,000 kcal per day
-It is best to get fiber from food (also a source of vitamins and minerals)
-An adequate fluid intake (at least 8 oz/day) with high-fiber diets is recommended
40
Nutritive sweeteners
◦Sucrose, fructose, honey, and brown sugar contain 4 kcal energy per gram
◦Slow-absorbing sugar alcohols: 2−3 kcal/gm
41
Non nutritive (alternative) sweeteners
◦Provide little or no energy because used in small amounts
-have calories but way sweeter
◦Safe for adults, children, people with diabetes
42
Alternative sweeteners
```
Generally recognized as safe (GRAS)
-list of food additives
-do not require review from FDA
Saccharin (sweet n low)
Aspartame (Equal, nutrasweet)
-more protein than carbs
Sucralose (Splenda)
Stevis (Truvia and pure via)
-natural
```
43
Diabetes
- Inability to regulate blood glucose levels
- Type 1 diabetes
- Type 2 diabetes
- Gestational diabetes
- Uncontrolled diabetes can cause nerve damage, kidney damage, blindness, and can be fatal
- Hyperglycemia = higher-than-normal blood glucose levels
44
Type 1 diabetes
- Accounts for 10% of all cases
- Body does not produce enough insulin
- Causes hyperglycemia (high blood glucose)
- Requires insulin injections
- May be an autoimmune disease
45
Type 2 diabetes
-Insulin insensitivity
-metabolic syndrome
-Once known as adult-onset diabetes
-Increasing in children and adolescents
-Cause is unclear, but genetics, obesity, and physical inactivity play a role
-Treat with weight loss, healthy eating, regular exercise, and, if necessary, medications
-Healthy lifestyle choices may prevent or delay the onset of type 2 diabetes
(10% decrease in weight can greatly reduce risk of diabetes)
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-Insulin insensitivity (insulin resistance):
cells become less responsive to insulin
47
Metabolic syndrome:
a cluster of risk factors that increase the risk for type 2 diabetes
48
Hypoglycemia
Low blood glucose may cause shakiness, sweating, anxiety, weakness
49
Reactive hypoglycemia
pancreas secretes too much insulin after a high-carbohydrate meal
50
Fasting hypoglycemia:
pancreas produces too much insulin, even when someone has not eaten
51
Lactose intolerance
- Insufficient enzyme lactase to digest the lactose-containing foods (can't break those beta bonds)
- GI symptoms: gas, cramping, diarrhea
- Variations in extent of intolerance (in GI tract )
- Not to be confused with milk allergy (reaction when you come into contact with it)
- Need alternate sources of calcium
- form of severe lactose maldigestion
52
High fructose corn syrup
```
Made from corn
-abundant and inexpensive
-subsidies for corn production
-easy to transport
Contains 55% fructose
-sucrose contains 50% fructose
-does not stimulate release of appetite regulators
Made by enzymatic process
```
53
High fructose corn syrup and food processing applications
Increased shelf stability
Increased food properties
-doesn't form crystals
-better for freezing
54
High fructose corn syrup and obesity
- increased consumption parallels increased obesity
- soda, energy and sports drinks
- main source
- empty calories don't promote satiety
- fructose is more readily converted to fat
- in presence of excess glucose
- doesn't promote satiety
55
Gestational diabetes
Pregnant women, clears up after baby is born
| More likely to develop type 2
56
Lactose maldigestion/ intolerance causes
- reduction in lactase so lactose is undigested
- undigested lactose draws h2o into SI and causes diarrhea
- undigested lactose metabolized by colonic bacteria and causes gas, bloating cramping
- natural part of aging (decrease in carb enzymes upon cessation of nursing)
57
Primary lactose maldigestion
Symptoms as early as 3-5 yrs
25% of population
Less prone among certain pops (genetic predisposition)
58
Secondary lactose maldigestion
Temporary decrease in lactase production
| Caused by another illness
59
Coping with lactose maldigestion/intolerance
```
Determine amnt you can tolerate
Eat dairy with other foods, especially fats (slows absorption)
Cheese/yogurt usually tolerated
-lost in production
-lactose digested by bacteria
Use lactase pills (lact-aid)
```
60
Alcohol
Recommended in moderation
- 1 drink a day for women
- 2 a day for men
61
Alcohol metabolism
- absorbed directly from the stomach (straight into the bloodstream) and the small intestine
- goes from bloodstream to liver to be metabolized
- most alcohol is oxidized in the liver
- some alcohol is metabolized by both stomach and liver enzymes
- alcohol dehydrogenase (ADH) (women don't produce as much, so absorb more through the stomach causing the liver to do more)
- aldehyde dehydrogenase (ALDH)
62
Things that affect absorption and BAC
- consuming foods with some fat can reduce Blood Alcohol Concentration to up to as much as 50%
- carbonated beverages are absorbed rapidly
- rate of absorption depends on presence or absence of food and type of food, gender
63
Metabolic tolerance
-Liver becomes more efficient in its breakdown of alcohol
64
Functional tolerance
Individuals show few signs of impairment/intoxication even at high BAC
65
Fetal Alcohol Syndrome
Alcohol harms fetal development
The more alcohol a mother consumes, the greater the danger
◦causes malformations of developing fetus's face, limbs, heart, and nervous system
◦child will suffer from emotional, social, learning, and developmental disabilities
66
Narcotic effect of alcohol abuse
alcohol acts as a sedative, depressant
67
Toxicity effect of alcohol abuse
high concentrations destroy cells
68
Alcohol hangover
```
Alcohol Hangover
Lasts up to 24 hours
Symptoms include:
◦headache, fatigue, nausea, vomiting, extreme thirst, light/sound sensitivity, mood disturbances
Consequences include:
◦fluid/electrolyte imbalance
◦stomach and gastric irritation/inflammation
◦metabolic disturbances
◦biological disturbances
```
69
Alcohol poisoning
◦Serious metabolic response to very high intakes
| ◦Reduces oxygen level reaching the brain; can result in death from respiratory or cardiac failure
70
Alcohol abuse
```
Reduced liver function
◦Fatty liver
◦Alcoholic hepatitis
◦Cirrhosis of the liver
Increased risk for chronic diseases
◦Loss of calcium impacts bone health
◦Pancreatic injury and diabetes
◦Cancer (mouth, throat, esophagus, stomach, liver, colon, breast)
```
71
Malnutrition as a result of alcohol abuse
◦Impaired food digestion, nutrient absorption, and nutrient metabolism
-causes direct toxicity to stomach and intestines
-maldigestion and malabsorption
-causes direct toxicity to liver
-impaired utilization of nutrients
-increased degradation of nutrients
-decreased transport of nutrients
Both leads to malnutrition
72
Anorexia
having physiological need to eat but not having the desire to eat
73
Lipids
◦Diverse group of molecules that are insoluble in water
74
Fats
◦The lipid content of diets and foods
75
Three types of lipids are found in foods and in body cells and tissues:
-Triglycerides
◦Phospholipids
◦Sterols
76
Triglycerides
◦a/k/a triacylglycerols (TAG)
◦3 fatty acids
◦Glycerol
77
Fatty acids are classified by
◦Carbon chain length
◦Saturation level
◦Shape
78
Carbons can be numbered
◦Alpha - first
◦Carboxyl group (COOH)
◦Omega - last
◦Methyl end (CH3)
79
Chain length of fatty acids determines:
```
◦Method of digestion and absorption
◦Metabolism and use
Fatty Acid Categories
◦Short- and medium-chain
◦Long-chain
◦Very-long-chain
◦Synthesized
```
80
Saturation of fatty acids
```
Saturated fatty acids (SFA)
◦Have hydrogen atoms surrounding every carbon in the chain
Mono-unsaturated fatty acids (MUFA)
◦-1 hydrogen atom (one double bond)
Poly-unsaturated fatty acids (PUFA)
◦Have more than one double bond
```
81
Shape of fatty acids
Determined by degree of saturation
82
Shape of Saturated fatty acids
◦Pack tightly together
◦Solid at room temperature
◦Animal fats, butter, lard are high in SFA
83
Shape of unsaturated fatty acids
```
◦Do not stack together well
◦Liquid at room temperature
Double bonds
◦Different positions for H atoms around DB
◦Cis: same side of the carbon chain
◦Trans: opposite sides of the chain
```
84
Hydrogenation
◦H atoms added to unsaturated FAs
◦Make oils more solid and more saturated
◦Create trans fats
85
Trans fat
◦Reduce oxidation; resist rancidity
◦In humans
◦Increase risk of CVD
86
Essential fatty acids (EFA)
```
◦Cannot be made by the body
◦Must be obtained from food
Linoleic acid (omega-6)
◦Sources: vegetable and nut oils
Alpha-linolenic acid (omega-3)
◦Sources: vegetables, soy, flaxseeds, walnuts
```
87
Fish Oil
```
◦Rich in Omega-3 FAs
◦Eicosapentaenoic acid (EPA)
◦Docosahexaenoic acid (DHA)
◦Cold water fish
◦Salmon, tuna, cod
◦≈2 servings/week
◦Fish oil supplements
```
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Benefits of fish oil
```
Benefits associated with EPA and DHA
Reduce risk of heart disease
◦Reduce inflammatory response
◦Stimulate prostaglandins and thromboxanes
◦Reduce blood clotting
◦Reduce plasma TAG
May decrease symptoms of
◦Some autoimmune disorders
◦Rheumatoid arthritis, Lupus
◦Behavioral disorders
◦Depression, Schizophrenia
```
89
Phospholipids
```
◦Glycerol
◦2 fatty acids
◦Phosphate
Hydrophillic heads
Hydrophobic tails
```
90
Function of phospholipids
```
Form cell membranes
◦a/k/a phospholipid bilayer
Emulsifiers
◦Make fats soluble in water
◦Many food applications
◦Salad dressing
Used to transport fats in blood
◦Lipoproteins
```
91
Sterols
◦Multiple rings of carbon atoms
Cholesterol
Plant sterols
92
Cholesterol
◦Only from animal sources
◦Made in our bodies
◦Sex hormones, vitamin D, bile
93
Plant sterols
◦Appear to block absorption of cholesterol
94
Digestion of Fats
```
Begins in the small intestine
Cholecystokinin (CCK) and secretin
◦Stimulate gallbladder
Bile
◦Emulsifies fat into small droplets
Pancreatic enzymes
◦Break fat into 2 FAs and a monoglyceride
```
95
The roles of fat
```
9 kcal per gram
Provides EFAs
Allows absorption of fat-soluble vitamins
◦A, D, E & K
Major fuel at rest
Stored energy
◦Adipose tissue
◦Muscles
Endurance exercise
◦Epinephrine
◦Stimulates fat breakdown
◦Stimulates rapid breakdown of glycogen
◦Decreases insulin production
◦Activates hormone-sensitive lipase
◦Adipose tissue
```
96
Functions of fat in the body
◦Regulates cell function
◦Maintains membrane
◦Protects the body: insulation and cushions
97
Functions of fat in foods
◦Provides flavors and textures of foods
| ◦Helps us feel satiated
98
Visible Fats
-fats we add to food
-fats we can see that occur naturally in food
Marbeling: white fat in meat
99
Invisible fats
```
◦Fats hidden within foods
◦Occur naturally or added during processing
◦Emulsifiers
◦Salad dressings
◦Eggs in baked goods
```
100
Beneficial fats
```
◦Omega-3 fatty acids may be low in diets
◦Fish, walnuts, soy, canola, flaxseed
More healthful fats
◦w/out increasing total fat intake
◦Use olive or canola oil in place of butter or margarine
◦Select low-fat or nonfat dairy products
```
101
Cardiovascular disease
◦Dysfunction of Heart and or Blood vessels
◦Heart attack or stroke
Medicines help reduce risk
◦Endogenous cholesterol synthesis inhibitors: statins
◦Bile acid sequestrants
102
Risk factors for CVD
```
◦Overweight/obese
◦Physical inactivity
◦Smoking
◦High blood pressure
◦DM
◦Inflammation
These also contribute to damage to walls of blood vessels
```
103
How does the body repair damage to blood vessels?
Uses LDL to repair damage by depositing cholesterol on damage. As more and more is des posited, blood vessel becomes harder and has plaque buildup
104
Dietary fats increase blood lipids
```
Saturated
◦Decrease removal LDL from blood
◦Increase blood lipids
◦Contribute to plaque formation
Trans fat
◦Raise LDL-cholesterol
◦Abundant in hydrogenated vegetable oils
FDA requires disclosure of trans fat
```
105
Consuming omega-3
◦Reduce inflammation
| ◦Blood TAG
106
Lowering blood TAG
```
Most diet-responsive blood lipid
Avoid overeating
◦Small, frequent meals
Limit
◦Alcohol
◦Simple sugars
Include fish in diet
```
107
Raising HDL
```
Physical activity
◦At least 45 min/day, 4 days a week
Eat regularly
Eat less total fat
Moderate intake of alcohol
Don’t smoke
```
108
How much fat?
AMDR: 20−35% of calories
◦Minimize saturated and trans fat intake
◦To lower risk of heart disease
Active people may need more energy from carbohydrates
◦Reduce their fat intake to 20−25% of total calories
SAFA: <7% of energy
◦Trans fats: reduced to the absolute minimum
109
How much fatty acids?
```
◦Linoleic acid (Omega-6)
◦AMDR: 5−10% of energy
◦Alpha-linolenic acid (Omega-3)
◦AMDR: 0.6−1.2% of energy
◦5:1 to 10:1 ratio of Omega-6:Omega-3
```
110
Lipoprotein
◦Transport mechanism for lipids in the body
◦FAs surrounded by phospholipids and proteins
4 kinds
-chylomicron
-VLDL (very low density lipoprotein)
-LDL (low density lipoprotein)
-HDL (High density lipoprotein)
111
Chylomicron
◦Produced in intestine
◦Transport dietary lipids from gut to body
◦Long-chain FAs*
◦Enter bloodstream via the lymphatic system
Short- and medium-chain FAs
◦Not arranged into chylomicrons
◦Absorbed directly (and more quickly)
112
VLDL
Carry fats from the liver to the body
113
LDL
Carry cholesterol from liver to body(cells)
114
HDL
Carry cholesterol from tissues (body) to liver (which makes bile)
115
Lipoprotein lipase
◦Liberates TAG from chylomicron
| ◦Allows cell uptake
116
In body cells, TAG can b
◦Used immediately for energy
◦Used to make lipid-containing compounds
◦Stored
◦In muscle and adipose tissues
117
What cells cannot metabolize fats for energy
Nerve cells
| Red blood cells (cuz don't have nucleus)
118
When you break down triglycerides what do you end up with
A monoglyceride and 2 free fatty acids
