Nutrition Flashcards
(127 cards)
1
Q
What is DRI?
A
Dietary Reference Intake
2
Q
How much energy is derived from carbohydrates, lipids/dietary fats, protein, an dalochol?
A
Carbohydrates: 4 kcal/g
Lipids/dietary fats: 9 kcal/g
Protein: 4 kcal/g
Alcohol: 7 kcal/g
3
Q
What are the current national dietary guidelines for fat, protein, and carbohydrates?
A
Fat: <30% kcal from fat (<10% saturated fats, <1% trans fats)
Protein: 15% kcal
Carbohydrate: 55-60%
4
Q
What is energy requirement?
A
Amount of food energy needed to balance energy expenditure in order to maintain body size, body composition, and a level of necessary and desirable physical activity consistent with long-term good health.
5
Q
What are the components of daily energy expenditure for weight-stable adults?
A
- Basal metabolic rate (resting metabolic rate) - 60-70%
- Dietary-induced thermogenesis - 10%
- Physical activity - 20-30%
6
Q
What are the components of daily energy expenditure for special stages of growth?
A
- Growth (tissue development and energy in new tissue)
- Pregnancy (maternal and fetal tissue deposition)
- Lactation (milk production and energy in milk)
7
Q
True or False: overweight and obese individuals have relatively low metabolic rates.
A
False; BMR is comprised of organ mass and tissue - fat mass is relatively inert.
8
Q
True or False: low metabolism contributes significantly to obese individuals’ excess weight gain.
A
False; no association between BMR and weight gain (for most populations)
9
Q
True or False: there are diets available to increase a person’s metabolic rate thereby inducing weight loss.
A
False (unless that diet contains compounds like caffeine or ephedrine - short term); the only way to increase your BMR is to add muscle mass.
10
Q
True or False: a person’s metabolic rate decreases during caloric restriction inhibiting the rate of weight loss.
A
True
11
Q
When does decreased BMR occur?
A
Hypothyroidism
Anorexia nervosa
Individuals with Down syndrome
Very-low-calorie diets and starvation states
12
Q
When does increased BMR occur?
A
Hyperthyroidism
Parkinson’s disease
Asthma
Any type of hypermetabolic state (burns, injury, sepsis)
13
Q
BMR is suppressed in situations of severe ___.
A
Caloric restrictions
14
Q
Energy Intake = ?
A
Energy Expenditure + Change in Energy Stores
15
Q
What are the BMI ranges for Underweight (Chronic Energy Deficiency III, II, I), Healthy Weight, Overweight, and Obese?
A
CED III: <16.0 CED II: 16.0-16.9 CED I: 17.0-18.4 Healthy Weight: 18.5-24.9 Overweight: 25.0-29.9 Obese: 30.0+
16
Q
BMI is highly correlated with ___ in most populations.
A
Adiposity
17
Q
Describe situations in which BMI does not correlate to adiposity.
A
1.
18
Q
What are “normal” levels of body fat? Note that there is no consensus
A
Women: 20-35%
Men: 5-20%
19
Q
What are consequences of low levels of body fat? High levels?
A
Low levels: amenorrhea, cold intolerance, excessive use of protein stores for energy
High levels: Type 2 diabetes, all organ systems affected
20
Q
When energy expenditure exceeds energy intake, what occurs?
A
Protein energy malnutrition and being underweight
21
Q
Chronic mild protein energy malnutrition (PEM) leads to ___.
A
Stunting (linear growth failure)
22
Q
Acute PEM can lead to ___ or ___.
A
Underweight; Wasting (Marasmus)
23
Q
Is severe marasmus reversible?
A
Yes (calories + appropriate micronutrients)
24
Q
What are symptoms of kwashiorkor (linked to low protein intake rather than low calorie intake)?
A
Edema, pigment changes
25
PEM increases risk of death from ___.
Concomitant infections
26
When energy expenditure is excessive (energy expended in metabolic functions), ___ results.
Hypermetabolism
27
Lipids and dietary fats are ___ in organic solvents.
Soluble
28
Dietary lipids include ___, ___, and ___.
TAGs, cholesterol, phytosterols
29
What is the majority of lipids consumed by humans?
Triglycerides (>95%)
30
Saturated fatty acids have ___ double bonds.
NO
31
Saturated fatty acids are ___ at room temperature.
Solid
32
Saturated fatty acids are associated with ___.
Hypercholesterolemia
33
Mono-unsaturated fatty acids are at least 12 C long and have one double bond at ___.
n-9
34
Are mono-unsaturated fatty acids associated with hypercholesterolemia or decreased HDL?
NO
35
Polyunsaturated fatty acids have ___ double bonds.
Multiple
36
What are the two essential fatty acids?
Linoleic and alpha-linolenic acid
37
Oils high in polyunsaturated fatty acids are generally ___ at room temperature.
Liquid
38
Essential fatty acid (EFA) deficiency can result from...
...very low fat diets (10-20% of calories coming from fat)
39
Omega-3 fatty acids are likely critical for neural and retinal tissue development. They have also been shown to reduce CVD risk in people at ____.
High risk
40
Hydrogenation turns liquid oils to solid fats and reduces the rotational mobility of the fatty acyl chain in ___.
Trans fats
41
Trans fats are associated with increased ___ levels, CHD, and atherosclerosis (to the same degree or more than saturated fats).
LDL
42
Soluble fibers are implicated in ___ lowering.
Cholesterol
43
What are the dietary sources of soluble fibers?
Legumes, oats, some fruits, some vegetables, nuts
44
What are the dietary sources of insoluble fibers?
Whole grains, wheat bran, some vegetables, potato skins
45
How do soluble fibers help lower cholesterol?
1. Act as a bile-acid sequestering agent
2. Reduce rate of insulin rise by slowing CHO absorption and slowing hepatic cholesterol synthesis
3. Stimulate production of short-chain fatty acids in the gut which inhibit cholesterol synthesis
46
What are the 4 fat-soluble vitamins?
1. A (retinol)
2. D (cholecalciferol)
3. E (tocopherols)
4. K (phylloquinone)
47
Which type of vitamin (fat or water soluble) is stored in the body?
Fat-soluble (water-soluble tend to be excreted)
48
What are the 9 water-soluble vitamins?
1. Thiamin (B1)
2. Riboflavin (B2)
3. Niacin (B3)
4. Pantothenic acid (B5)
5. Pyridoxine (B6)
6. Biotin (B7)
7. Folic acid (B9)
8. B12
9. Vitamin C (ascorbic acid)
49
Beta-carotene is a water-soluble pigment that can be cleaved to ___.
Retinaldehyde
50
Retinaldehyde can then be converted to ___ or ___.
Retinol and retinoic acid
51
What is the primary function of retinal?
Prostethic group of visual pigments
52
What is the primary function of retinoic acid?
Nuclear modulator of gene expression
53
Describe the initiation of nerve impulse by retinol.
Retinol --> retinal --> rhodopsin --> conformational change in opsin --> trans-retinal and initiation of nerve impulse
54
___ is required for normal limb and eye development in the embryo.
Retinoic acid
55
What are precursors to retinoids?
Carotenoids
56
What synthesizes carotenoids?
Plants
57
What is an early sign of Vitamin A deficiency?
Night blindness
58
Vitamin A deficiency leads to...
...dedifferentiation of epithelial cells --> epithelial keratinization, poor appetite, poor growth, and xerophthalmia
59
What is the cardinal sign of Vitamin A deficiency?
Xerophthalmia
60
What are the stages of xerophthalmia?
1. Conjunctival xerosis (dryness)
2. Bitot's spots
3. Keratomalacia (softening of cornea, irreversible damage)
61
What is the cardinal sign of Vitamin A toxicity?
Bright red margins of gingiva
62
Vitamin D and Parathyroid Hormone Regulate ___ balance.
Calcium
63
What is the primary function of Vitamin D?
Increase intestinal absorption, bone resorption, and renal reabsorption of calcium
64
Vitamin D functions through regulation of ___.
Gene expression
65
There is a significant prevalence of ___ vitamin D deficiency in the US.
Subclinical
66
What is caused by a failure of appropriate deposition of mineral in the matrix of the epiphyseal cartilage?
Rickets (children)
67
Vitamin D can cause ___ by stimulated mobilization of calcium and phosphorus from bone to maintain serum concentrations.
Osteomalacia
68
What are the symptoms of rickets?
1. Bowlegs
2. Frontal bones prominent and bossed
3. Uncalcified osteoid
69
What is the primary function of vitamin E?
Scavenger of free radicals and peroxyl radicals, inhibition of platelet aggregation, and increased vasodilation
70
What is the primary function of vitamin K?
Regulation of blood clotting protein synthesis
71
Vitamin K functions as a coenzyme in ___.
Carboxylation reactions (carboxylases)
72
What is the primary manifestation of vitamin K deficiency?
Bleeding
73
What is the function of thiamin?
Coenzyme for oxidative carboxylation of pyruvate dehydrogenase
74
Thiamin deficiency leads to ___.
Beriberi
75
What are classic signs of a thiamin deficiency (dry beriberi)?
Peripheral neuropathy, calf muscle tenderness, wrist and ankle drop, impairment of sensory, motor, and reflex functions affecting limbs
76
What are classic signs of a thiamin deficiency (wet/cardiac beriberi)?
Edema, tachycardia, cardiomegaly, congestive heart failure, neuropathy
77
What are classic signs of a thiamin deficiency (cerebral beriberi)?
Wernicke's encephalopathy, mental confusion, coma
78
___ impairs absorption of thiamin across basolateral membrane in gut.
Ethanol
79
Wernicke's encephalopathy in alcoholism (thiamin deficiency) must do what when someone comes into the ER?
Administer IV thiamin prior to glucose, otherwise coma and death can result from rapid hyperglycemia
80
What is the primary function of riboflavin?
Redox coenzyme (FAD, FMN) in energy-yielding reactions in citric acid cycle (succinate dehydrogenase) and beta-oxidation (acyl CoA dehydrogenase)
81
What is the key symptom of riboflavin deficiency?
Bilateral oral ulcers
82
Niacin can be synthesized from ___.
Tryptophan
83
What are the functions of niacin?
Coenzyme in redox reactions, ATP synthesis, and ADP-ribose transfer reactions, anti-hyperlipidemic agent in large doses
84
Niacin deficiency disease is known as ___ and is characterized by ___.
Pellegra; photosensitive dermatitis around hands, feet, neck (not necklace); 3 D's: dermatitis, diarrhea, dementia
85
Vitamin C functions...
...as a coenzyme in redox reactions.
86
Vitamin C deficiency can lead to ___.
Scurvy
87
What are the cardinal symptoms of Vitamin C deficiency?
Things resulting from defects in collagen formation (petechiae, perifollicular hemorrhages, bleeding gums, impaired wound healing, depression, etc)
88
What does folic acid do?
Coenzyme for one-carbon transfer reactions (most significantly purine and pyrimidine synthesis and methylation of tRNA - thymidylate synthetase, methionine synthase)
89
What is the only vitamin with a non-organic component and what is this component?
Vitamin B12; cobalt atom
90
What is the function of vitamin B12?
Coenzyme for one-carbon transfers: methionine synthase and methylmalonyl-CoA mutase - methylmalonyl CoA --> succinyl CoA
91
Vitamin B12 deficiency also looks like ___ deficiency. How are they distinguished?
Folate; increased methylmalonic acid in Vitamin B12 deficiency
92
What is the link between Vitamin B12 and folic acid?
Methionine synthetase
93
In both folic acid and Vitamin B12 deficiencies, you can get ___ and ___.
Megaloblastic anemia
| Hyperhomocysteinemia
94
Hyperhomocysteinemia is ___.
Atherogenic
95
Folate deficiency leads to...
...defective DNA/RNA synthesis, neural tube defects, megaloblastic anemia, and hyperhomocysteinemia
96
Vitamin B12 deficiency leads to...
...defective DNA/RNA synthesis, hyperhomocysteinemia, and pernicous (megaloblastic) anemia
97
Calcium is critical for ___.
Homeostatic regulation
98
In hypocalcemia, what happens?
Plasma calcium concentrations decrease, PTH gene expression increases and secretion activates vitamin D to enhance intestinal calcium absorption, increase renal reabsorption of calcium, and activate bone resorption
99
Vitamin D enhances calcium absorption by upregulating what two things?
Ca-ATPase and calbindin
100
True or false - calcium is poorly absorbed.
True
101
___ is a potent inhibitor of calcium absorption.
Oxalate
102
___, a plant storage form of phosphorus, forms salts with calcium.
Phytate
103
High dietary sodium increases calcium ___.
Excretion
104
What is the most abundant intracellular anion?
Phosphorus
105
What is a major component of bone, phospholipids in cell membranes, and enzymes, required for energy production, and important for acid-base regulation?
Phosphorus
106
What is refeeding syndrome?
Occurs when severely malnourished, dehydrated individuals are given glucose and saline; results from rapid expansion of extracellular fluid (increased sodium intake) and increased insulin secretion (increased carb intake); stimulates rapid glycogen synthesis, depletes plasma phosphorus concentration; may result in cardiac arrhythmias and sudden death
107
What are the two oxidation states of iron?
Fe2+ (ferrous) and Fe3+ (ferric)
108
Which form of iron is more stable?
Fe3+ (ferric), bound to transferrin for plasma transport
109
What is ferrous iron required for?
Gut absorption, cellular storage, heme synthesis
110
Where is heme iron found (exclusively)?
Animal foods
111
Non-heme iron is found in...
...both animal and plant foods.
112
Absorption of ferric iron is increased in the presence of ___, which aids in reduction to ferrous iron.
Vitamin C
113
What is the zinc and copper enzyme that assists in cellular iron uptake?
Ceruloplasmin
114
What is the plasma transport protein of iron?
Transferrin
115
What is the cellular storage protein of iron?
Ferritin
116
What is the hepatocyte storage protein of iron?
Hemosiderin
117
What happens to transferrin and ferritin in iron deficiency?
Upregulation of transferrin and downregulation of ferritin
118
What happens to transferrin and ferritin in iron excess?
Downregulation of transferrin and upregulation of ferritin
119
What are some functions of iron?
Iron-sulfur complexes: mitochondrial aconitase in TCA cycle, cellular energy production via oxidative phosphorylation
Heme-containing proteins: carries oxygen, constitutent of peroxidase enzymes, active site of cytochromes
120
What are the nutrients required for heme formation?
Iron, copper, zinc, vitamin B6, pantothenic acid
121
What happens in iron deficiency?
Microcytic, hypochromic anemia (inhibition of Hb synthesis)
122
Describe the differences in anemia as a result of folic acid or B12 deficiency and iron deficiency.
In folic acid/B12 deficiences, cells are large and immature. In iron deficiency, cells are small and pale.
123
True or false - iron is not formally excreted.
True
124
In adult males, iron deficiency anemia is typically result of ___.
GI bleeding
125
How is iron deficiency defined?
Abnormally low concentration of plasma hemoglobin
126
What are the primary physical signs of iron deficiency?
Fatigue, low energy, pallor, exertional dyspnea
127
Zinc deficiency results in ...
...anemia, hypogonadism, and dwarfism
