Nutrition Flashcards
1
Q
Give a general description of Vitamin A
A
- collectively called retinoids
- Retinol: transport and storage form of vitamin A
- 11-cis retinal is required for vision
- Retinol and retinal can be easily interconverted.
- Retinoic acid: epithelial growth and differentiation. It has steroid hormone like effect.
2
Q
Describes the steps of the absorption and transport of Vitamin A
A
Diet contain Retinol esters -> hydrolysis by intestinal mucosa releasing Retinol and free fatty acids -> re-esterfication and secretion in chylomicrons which are taken up by the liver where it is stored -> plasma Retinol binding protein in the liver transports to extra hepatic tissues -> tissues contain cellular Retinol binding protein that carries Retinol into the cell
3
Q
List the sources of Vitamin A
A
- Liver, kidney, butter and cream products; egg yolks
- Yellow vegetables and fruits ( dietary pro vitamin form: B-carotene)
4
Q
What are the functions of Vitamin A?
A
- Vision: 11 cis retinal is a component of rhodopsin (visual pigment). Visual cycle req isomerization b/w cis and trans-retinal
- Maintenance of specialized epithelia, esp mucus secreting cells (Retinoic acid)
- Growth (Retinoic acid)
- Reproduction (Retinol)
5
Q
Describe the mechanism of action of Retinoic acid in epithelia cells.
A
1) Retinol enters target cell and is oxidized to Retinoic Acid in cytosol
2) Retinoic Acid moves from cytosol into nucleus with help of Retinoid Binding Proteins
3) Retinoic Acid binds to nuclear receptors forming an activated receptor complex
4) Retinoic acid-receptor complex binds to chromatin activating the transcription of specific genes (keratin)
6
Q
Describes the steps in the visual cycle pathway
A
- Retinol (transported in blood in the form of all-trans Retinol) enters retinal pigment epithelium.
- Esterfied to All-trans retinyl ester
- becomes 11-cis Retinol
- oxidized to 11-cis Retinal
- 11-cis retinal enters rod cell where it combines with opsin to form rhodopsin (visual pigment).
- absorption of light photon catalyzes isomerization of 11-cis retinal to all-trans Retinal triggering eventual signal for vision.
- Opsin becomes available again and All-trans retinal eventually becomes all-trans Retinol.
- all trans Retinol goes back to retinal pigment epithelium to renter cycle.
7
Q
What causes Vitamin A deficiency?
A
Dietary deficiency most common - fat free diet
Fat malabsorption
8
Q
What are some signs and symptoms of Vitamin A deficiency?
A
- Night blindness
- Xerophthalmia
- Bitot’s spots
- Keratomalacia
- increased risk of pulmonary infections
- immune deficiency - weakened innate immunity
9
Q
What is Night blindness and what is the cause?
A
Earliest of the symptoms of Vitamin A deficiency.
- inability to see Dim light
- reversible
10
Q
What is Xerophthalmia and what is the cause?
A
Vitamin A deficiency that produces dryness of the conjunctiva and cornea.
Reversible
11
Q
What treatment is Retinoic acid given for?
A
Acne treatment, especially topical form
12
Q
What is all-trans Retinoic acid used in treatment of?
A
Acute promyelocytic leukemia
13
Q
What can hypervitaminosis of Vitamin A cause?
A
- Raised intracranial pressure leading to headaches - may mimic brain rumors
- Dry and pruritic skin
- enlarged liver
- can cause spontaneous abortions and congenital malformations in the fetus during pregnancy.
14
Q
What is the name for vitamin D found in plants?
A
Ergocalciferol (D2)
15
Q
What is the general name for vitamin D found in animals?
A
Cholecalciferol (D3)
16
Q
What is the name of the precursor for Cholecalciferol synthesis in skin?
A
7-Dehydroxycholesterol
(intermediate in cholesterol synthesis)
(Cholecalciferol is Vitamin D3)
17
Q
What are other names for the active form of Vitamin D?
A
- Calcitriol
* 1,25 dihydroxy cholecalciferol
18
Q
In Vitamin D synthesis, what is the first step?
A
7-dehydrocholesterol in the skin is activated by sunlight to form Cholecalciferol.
Or
Cholecalciferol is taken in through diet.
19
Q
Regarding the steps of Vitamin D synthesis, what happens to Cholecalciferol?
A
Goes to liver (from skin or diet) and, through enzyme 25-Hydroxylase, becomes 25-hydroxycholecalciferol. Next goes to kidney.
20
Q
Regarding the steps of Vitamin D synthesis, what happens in the kidney?
A
25-hydroxycholecalciferol (from liver) is converted into 1,25-dihydroxycholecalciferol/Calcitriol (active form of vitamin D) by the enzyme: 1-Hydroxylase
21
Q
Which is the regulated step in Vitamin D synthesis and how is it regulated?
A
25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol step in kidney.
1-Hydroxylase is activated by:
1) Parathyroid Hormone
2) low calcium levels
1-Hydroxylase is inhibited by:
1) Calcitriol
22
Q
What occurs once 1,25-dihydroxycholecalciferol (Calcitriol) is made?
(Mechanism of action)
A
It binds to intercellular receptor proteins
23
Q
What happens after Calcitrol binds to intracellular receptor proteins of the target cell?
A
Calcitrol-receptor complex interacts with DNA in nucleus and can either stimulate or repress gene expression.
24
Q
What effect does Calcitriol have on the intestine?
A
It stimulates intestinal absorption of calcium and phosphate by increasing synthesis of a specific calcium binding protein.
25
What effect does Calcitriol have on bone?
It stimulates the mobilization of calcium and phosphate from the bone in the presence of parathyroid hormone.
26
What effect does Calcitriol have on the kidneys?
It inhibits calcium excretion by stimulating parathyroid dependent calcium reabsorption.
27
What are the causes of Vitamin D deficiency?
* nutritional deficiency - decreased intake / fat malabsorption
* inadequate exposure to sunlight (common during winter)
* chronic renal disease, chronic liver disease results in decreased hydroxylation of vitamin D
28
What is Rickets?
Vitamin D deficiency in children.
29
How does Rickets effect calcium absorption in the diet?
Calcium absorption is decreased, causing:
- increased parathyroid hormone release which leads to
- demineralization of bone.
30
What are the manifestations of Rickets?
* Soft pliable bones
* Bow- leg deformity
* Rachitic rosary (overgrowth at costochondral jxn)
* Pigeon chest deformity
* frontal bossing
* swelling of wrists
31
What is Osteomalacia?
Vitamin D deficiency in adults
32
What are the manifestations of Osteomalacia?
Bones are demineralized and thus susceptible to fracture.
33
What can cause Osetomalacia?
Dietary deficiency of vitamin D, renal failure or liver disease.
34
What is name for the active form of Vitamin E
Alpha tocopherol
35
What is the primary role of Vitamin E?
Anti-oxidant
36
When is vitamin E deficiency typically seen?
Patients with fat malabsorption.
| rare
37
How is Vitamin E deficiency manifested?
1) Hemolytic Anemia (abnormal cellular membranes)
| 2) Reduced deep tendon reflexes and gait problems due to anoxal degeneration.
38
What is the name for Vitamin K in plants?
Phylloquinone
| -dietary source
39
What is the name for Vitamin K in bacteria?
Menaquinone
| -intestine
40
Which clotting factors are Vitamin K required for?
Hepatic synthesis of the mature clotting factors:
```
Prothrombin (II)
VII
IX
X
Proteins C and S
```
41
Which enzyme does Vitamin K serve as a cofactor for?
Liver microsomal y-carboxylase
42
Which amino acid residues do Vitamin K dependent y-carboxylase act upon?
Glutamic acid residues
(y-carboxylation forms a mature clotting factor that contains y-carboxyglutamate (Gla) and is capable of subsequent activation)
43
Why is y-carboxylation important for the activation of clotting factors?
y-carboxylation allows Ca2+ binding because of two adjacent negatively charged carboxylate groups.
44
What does the clotting factor calcium complex bind to?
Phospholipids in the plasma membrane.
45
How vitamin K deficiency manifested in neonates?
Hemorrhagic disease of the newborn
- Bleeding at various sites in the body including skin, umbilicus and viscera
- Intracranial bleeding
Sterile intestines of the newborn - no synthesis of Vitamin K
46
How is neonatal vitamin K deficiency treated?
Routine intramuscular injection of Vitamin K for all newborns.
47
What is the effect of warfarin administration?
1) Vitamin K antagonist
2) Warfarin blocks the activity of liver epoxide reductase and prevents regeneration of reduced vitamin K (no recycling of Vitamin K)
3) There is reduced y-carboxylation of clotting factors and a delay in clotting (increased prothrombin time or INR)
48
What causes vitamin K deficiency in adults?
Fat malabsorption and prolonged use of broad spectrum antibiotics
49
How is vitamin K deficiency manifested in adults?
Bleeding disorder characterized by:
- Hematuria
- Melena (black tarry stools)
- Ecchymoses (bruises)
- Bleeding from gums
50
What is another name for Vitamin C?
Ascorbic acid
51
What is vitamin C's role in collagen synthesis and wound healing?
- Required for collagen cross-linking.
| - Acts as a coenzyme for hydroxylation of proline and lysine residues in collagen
52
What is vitamin C's role in iron absorption?
Reduces iron to the ferrous state in the stomach
53
How does vitamin C acts as a water soluble anti-oxidant?
- Scavenger of free radicals
| - Regenerates anti-oxidant form of Vitamin E
54
Vitamin C deficiency leads to?
Scurvy
| - due to decreased hydroxylation of collagen; results in a fewer number of Hydrogen bonds in collagen.
55
What are the symptoms of Scurvey?
1) Perifollicular hemorrhages (fragile blood vessels)
2) Sore, spongy gums - bleeding from gums
3) Loose teeth
4) Bleeding into joints
5) Frequency bruising
6) Impaired wound healing
56
Which vitamin deficiencies cause bleeding from gums?
Vitamins K and C
57
Which are the fat soluble vitamins?
A,D,E,K
58
Which are the energy-releasing vitamins?
1) Thiamine (Vitamin B1)
2) Riboflavin (Vitamin B2)
3) Niacin (Vitamin B3)
4) Biotin
5) Pantothenic acid
59
What is another name for Vitamin B1
Thiamine
60
What is the coenzyme form of Vitamin B1?
Thiamine Pyrophosphate (TPP)
61
Which enzymes are TPP dependent?
Pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, branched chain alpha-keto acid dehydrogenase, and transketolase
62
Which enzyme in the pentose phosphate shunt uses TPP?
Transketolase
| Ribose 5-P to Glyceraldehyde 3-P; vice-versa
63
Which types of foods lack Vitamin B1?
Refined foods such as:
- Polished rice
- White flour
- White sugar
64
Describe the cause of dry Beri Beri
Thiamine deficiency
| - Paralysis due to polyneuropathy resulting from disruption of motor, sensory, and reflex arcs.
65
Describe the cause of wet Beri Beri
Thiamine deficiency leading to cardiac faliure
66
What are the symptoms of Wernicke-Korsakoff?
1) Ophthalmoplegia and nystamus (to and fro movement of eyeballs)
2) Ataxia
3) Confusion
4) Disorientation
5) loss of memory
6) Confabulation
67
What is another name for Vitamin B2?
Riboflavin
68
What are the coenzyme forms of Riboflavin? (Vit B2)
- Flavin mononucleotide (FMN)
| - Flavin dinucleotide (FAD)
69
What is the function of Riboflavin (VitB2)?
Participates in oxidation-reduction reactions of TCA cycle, beta oxidation (Succinate D.H, PDH, Acyl CoA DH...)
70
What are the signs and symptoms of Riboflavin deficiency?
- Cheilosis
- Glossitis
- Facial dermatitis
71
What is Cheilosis?
- Riboflavin deficiency.
| - Pallor, cracks & fissures @ mouth angles
72
What is glossitis?
- Riboflavin deficiency
| - tounge atrophy & inflammation
73
What is another name for Vitamin B3?
Niacin
74
What are the coenzyme forms of Vitamin B3?
- NAD+
| - NADP+
75
How is Vitamin B3 used in treatment of type IIb hyperlipoproteinemia?
Inhibits lypolysis -> adipose tissue = free F.A. reduction
76
What are the manifestations of Niacin deficiency?
- Pellagra (necklace-like skin damage)
| - Death
77
What characterized Pellagra?
3 D's:
1) Dermatitis
2) Diarrhea
3) Dementia
78
What amino acid is used to synthesize NAD+ AND NADP+?
Tryptophan
79
What can corn based diets cause?
Pellagra
| - Corn = no niacin / tryptophan
80
Which disease can cause pellagre-like symptoms?
Hartnup's disease
| - supplement = niacin
81
What else, besides nacin deficiency, can cause Pellagra?
Carcinoid syndrome
82
What is another name for Biotin?
Biocytin
83
What is Biotin a prosthetic group for?
Carboxylation reactions
84
What protein inhibits Biotin absorption?
Avidin
| - found: raw egg whites
85
What is Multiple Carboxylase Deficiency
Inherited deficiency of the incorporation of biotin
86
Which enzymes require Biotin?
1) Pyruvate Carboxylase
2) Acetyl-CoA carboxylase
3) Propionyl-CoA carboxylase
87
Whats another name for Vitamin B6?
Pyridoxine
88
What are precursors for pyridoxal phosphate (PLP)?
```
Pyridoxine
Pyridoxal
Pyridoxamine
(collectively = Vit B6)
```
89
Which enzyme in heme synthesis needs PLP
ALA Synthase (condensation)
90
Which reactions do PLP act as a co-enzyme for?
1) Transamination (amino acid metabolism)
2) Amino Acid decarboxylation (synthesis of neurotransmitters)
3) Condensation
4) Conversion of homocysteine and cysteine
91
What are children with homocystinuria supplemented with?
Vitamin B6
92
What inactivates pyridoxine?
Isoniazid (Anti-TB drug)
93
What are sign's and symptoms of pyridoxine deficiency?
1) Microcytic anemia
2) Peripheral neuropathy
3) Increased risk of cardiovascular disease (homocysteine = high)
4) Seizures
94
What is another name for Vitamin B12?
Cobalamin
95
Which reactions require Vitamin B12?
1) Homocysteine -> Methionine (Homocysteine methyltransferase)
- Methytetrahydrofolate -> Tetrahydrofolate
2) Methylmalonyl CoA -> Succinyl CoA
(Methylmalonyl CoA mutase) (odd # F.A. degradation)
96
What happens to folate in B12 deficiency?
Folate trap - Methyltetrahydrofolate
| - Result: macrocytic anemia
97
How does B12 deficiency affect methylmalonate?
Methylmalonate accumulation -> neurological manifestations
98
What is given to patients with inherited methylmalonic aciduria?
Vitamin B12
99
Why do vegans have a high risk of developing B12 deficiency?
- Synthesized only by micro-organisms;
| - not present in plants.
100
Which cells produce intrinsic factor?
Gastric Parietal cells
101
Why is intrinsic factor necessary?
B12 absorption.
| - Lack of = pernicious anemia
102
What are signs and symptoms of Vitamin B12 deficiency?
Macrocytic anemia
| Neuropsychiatric symptoms
103
What are signs of macrocytic anemia?
- Macrocytes in peripheral blood film
- Megaloblasts in bone marrow
- occurs due to folate deficiency
104
What neuropsychiatric symptoms stem from B12 deficiency?
- Myelin degen in motor and sensory pathways due to methylmalonyl CoA accum.
- present in absence of anemia
105
What plays a key role in one-Carbon metabolism?
Folic Acid
106
In what form do most cells receive folate?
Methyl THF
| - methyl THF -> THF needs B12.
107
How does Megaloblastic anemia occur?
Diminished synthesis of purines & pyrimidines -> inability of cells to synthesize DNA -> delayed mitosis = larger cells
108
What are causes of Folic acid deficiency?
- Lack of leafy green vegtables
- Impaired absorption
- Increased req as in pregnancy
- Methotrexate
- Folate trapping
109
How should megaloblastic anemia be treated?
Combination of folic acid & Cobalamin
110
What effect does folic acid deficiency during pregnancy cause?
Neural tube defects
111
Tyrosine needs the co-factor Copper for?
Melanin synthesis
112
Dopamin B-hydroxylase needs the co-factor Copper for?
Neurotransmitter synthesis
113
How is ingested copper transported to the liver?
Albumin
114
Aged ceruloplasmin is taken up by the liver from the plasma, endocytosed and degraded and...
Copper is secreted into bile
115
What are signs and symptoms of Copper deficiency?
- Microcytic anemia
- Vascular tissue degredation
- Defects in hair
116
Why does copper deficiency contribute to microcytic anemia?
Ceruloplasmin (ferroxidase) req. 4 iron metabolism
117
Why does copper deficiency contribute to the degradation of vascular tissue?
Dec. lysyl oxidase activity
118
What causes Menke's syndrome?
x-linked GI tract copper absorption defect
119
What is a characteristic of Menke's syndrome?
Hair: Twisted, grayish, kinky
120
What can copper deficiency lead to?
- Aneurysms
| - Cerebral dysfunction
121
What is Wilson's disease?
Autosomal recessive copper metabolism disorder
122
What characterizes Wilson's disease?
Copper accumulation -> toxic
| - liver, brain, eye
123
What chromosome does Wilson's disease affect?
Chromosome 13
124
Where is Wilson's disease found to affect?
Copper transporting ATPase - Liver
125
What is the copper transporting ATPase in liver needed for?
- copper -> ceruloplasmin (attach)
| - Copper excretion into bile
126
What causes Kayser Fleischer (KF) rings?
Deposition of copper in the cornea
127
What is the importance of Iron?
- Heme synthesis
| - Redox rxn
128
What is iron's role in Heme synthesis?1
Incorp into heme of heme containing proteins
129
What happens when your body's iron stores are high?
Less Fe absorbed by intestines
130
Where is heme iron derived from?
Meat
131
Where is inorganic iron derived from?
Vegtables
132
What state does inorganic iron need to be in in order to be taken up into the intestinal mucosal cells?
Ferrous
133
Which is absorbed more effectively, heme iron or inorganic iron?
Heme (meat) iron
134
Where is ferric iron changed to ferrous iron?
Stomach (low pH and vit C)
135
What is the transport protein for ferric iron in blood plasma?
Transferrin
136
Where is iron stored and in what form?
- Liver & RES
| - Ferritin & hemosiderin (ferric)
137
What is another name for ceruloplasmin?
Ferroxidase
138
What is the role of ceruloplasmin?
- Ferrous ion release from intestinal cells
- forms ferric iron (transport)
- Copper carrying protein
139
Who are typically susceptible to iron deficiency?
Infants
pregnant women
blood donors
140
What are the clinical features of iron deficiency?
1) Hypochromic microcytic anemia
2) Fatigue and pallor
3) Weakness
4) Brittle nails
5) Pica
141
What is pica?
Appetite for soil
| - iron deficiency
142
What is Hereditary Hemochromatosis?
Autosomal recessive
- HFE gene defect
- excessive iron absorption -> accum in liver and pancreas
143
What is the role of HFE gene?
-Protein regulates iron absorption by regulating interaction of transferrin receptor to transferrin.
144
How does excess iron damage tissues?
- DNA damage
| - Lipid peroxidation through free radicals
145
What are the clinical features of Hereditary Hemochromatosis?
- 40 y/o M
- Liver damage: cirrhosis; hepatocellular carcinoma; hepatomegaly
- Diabetes: pancreas destruction
- Cardiac dysfunction
- Acute synovitis (arthritis)
- Bronze skin
- Testicular atrophy (dec FSH/LH sec)
- Hair loss
- Memory loss
- Vertigo
146
What is the cause of microcytic anemia?
-Reduced heme synthesis
-Lead poisoning
-Deficiency of:
Iron
Copper
Pyridoxine
147
What is the cause of macrocytic anemia?
-Reduced cell division
-Deficiency of:
B12
Folate
148
What does Copper form in the liver?
Ceruloplasmin
149
In general, what types of reactions is copper an important cofactor for?
Redox rxns
150
What specific enzymes needs copper as a co-factor?
1) Cytochrome C
2) Superoxide Dismutase
3) Lysyl Oxidase
4) Tyrosinase
5) Dopamine B-Hydroxylase
151
Can essential molecules be synthesized at all or at a rate compatible with need?
No
152
What are the 3 components of the Daily Energy Expenditure (DEE)?
1) Energy for BMR or RMR
2) Physical activity
3) Energy req to process food. (induced thermogenesis)
153
What is RMR?
Resting metabolic rate
| - energy expenditure by individual in resting, post-absorptive state
154
How much of total energy expenditure in a sedentary individual is represented by RMR?
50-70%
155
How does gender play a role in affecting RMR?
Male = 20% higher than female
156
How does body temperature play a role in affecting RMR?
Inc. with temp. inc. (fever)
157
How does environmental temperature play a role in affecting RMR?
Cold temp = High RMR
158
What effect does HYPERthyroidism have on RMR?
Increase
159
How does pregnancy and lactation affect RMR?
Increase
160
How does age affect RMR?
Decrease
161
What is diet-induced thermogenesis (DIT) also known as?
- Thermic effect of food (TEF)
| - Specific dynamic action (SDA)
162
What does diet-induced thermogenesis (DIT) represent?
Req. energy to digest, absorb, distribute and store nutrients
163
What are the three main categories of macronutrients provided by diet?
Fat
Protein
Carbohydrate
(also ethanol if consumed)
164
What are minor or micronutrients?
Vitamins and minerals
165
How much kcal/g does Fat produce?
9 kcal/g
166
How much kcal/g do carbohydrates produce?
4 kcal/g
167
How much kcal/g does protein produces?
4 kcal/g
168
How much kcal/g does alcohol produce?
7 kcal/g
169
How are carbohydrates classified?
- Simple sugars: monosaccharides and disaccharides
- Complex sugars: Polysaccharides
- Fiber
170
What are the principle monosacharides in food?
Glucose and Fructose
171
Which foods are abundant in glucose?
Fruits, sweet corn, corn syrup, honey
172
Where is free fructose found?
together with free glucose and sucrose - honey and fruits
173
Which are the most abundant disaccharides?
Sucrose
Lactose
Maltose
174
What does sucrose consist of and where is it found?
Glucose + fructose
- table sugar
- molasses
- corn syrup
175
What does lactose consist of and where is it found?
Glucose + Galactose
| - milk
176
What does Maltose consist of and where is it found?
Glucose + Glucose
- beer
- malt liquor
177
Polysaccharides are complex carbohydrates, often polymers of...
Glucose
178
What is starch?
Polysaccharide found in plants
179
What are the sources of polysaccharides?
```
Wheat and other grains
Potatoes
Dried peas
Beans
Vegetables
```
180
What does the glycemic index represent?
Quantitates time course - postprandial blood glucose rise and decline
181
What effect do high glycemic index carbohydrates have?
Faster serum glucose rise/ steeper decline (than low G.I. carbs)
182
What does fiber consist of?
Non-digestible carbohydrates
183
What are some examples of fiber containing compounds?
Cellulose
Lignin
Pectin
184
How does dietary fiber add bulk to diet?
Absorbs 10-15X own weight, drawing water into intestine -> increase in bowl motility.
185
How are the binding properties of dietary fiber beneficial?
Dec. absorption of toxic compounds and certain carcinogens
186
How does dietary fiber effect postprandial blood glucose concentration?
Reduce
187
What effect does dietary fiber have on absorption of dietary fat and cholesterol?
Decrease
| also inc fecal loss of cholesterol
188
What do dietary fibers decrease risk for?
Constipation
Hemorrhoids
Diverticulosis
Colon cancer
189
Why is excess fiber not recommended?
Can dec. absorption of fat-soluble vitamins and bind to some trace elements (Zn2+)
190
What percentage of dietary lipids are made up of TAGs?
>90%
191
How are TAGs obtained from plant sources different from those obtained from animal sources?
Plant = more unsaturated fatty acids
| except coconut oil and palm oil
192
What type of saturation do unsaturated fats in plant dietary lipids contain?
Mono or polyunsaturated
193
Corn oil and soybean oil are rich in what type of fat?
Polyunsaturated
194
Olive oil and canola oil are rich in what type of fat?
Monounsaturated
195
Margarine is described as...
A mixture of vegetable oils with varied composition of unsaturated fats -> hydrogenation for stability
196
When does arachidonic acid become essential?
When Linoleic acid is insufficient
197
Essential fatty acids are required for the synthesis of..
eicosanoids
198
What characterizes a deficiency of essential fatty acids?
- Scaly dermatitis
- Hair loss
- Poor wound healing
199
People should aim to decrease _______ fats while increasing _____ or ______ fatty acids.
Saturated
Mono-unsaturated
Poly-unsaturated
200
When do arginine and histidine become required?
during rapid tissue growth as in childhood or recovering from illness
201
Regarding biological value, how do proteins from animal sources differ from those from plants?
```
Animal = higher value
Plant = lower value
```
202
What is an example given of how combination of plant derived proteins can provide complete protein requirement?
Wheat (Lys-deficient, Met-rich) + kidney beans (Met-rich, Lys-poor) = complete protein
203
What is nitrogen balance?
Amount of N consumed = N excreted in urine, sweat and feces
204
An individual is typically in a state of negative N balance when...
The body has to degrade tissue protein in order to fulfill requirements
205
Serum cholesterol levels have a strong correlation with what?
Vascular disease
206
How does reducing dietary cholesterol effect serum cholesterol levels?
Not much affect
207
How does a person reduce serum cholesterol levels?
Reduce saturated fatty acid intake
| Increase mono and polyunsaturated fatty acids
208
How does one decrease de novo synthesis of cholesterol?
Statins
209
What metabolic effects do mono-unsaturated and poly-unsaturated fatty acids have?
Decrease LDL and HDL
| -Through arachidonic acid
210
Leptin acts upon what part of the brain?
Hypothalamus
211
What does leptin regulate?
Inflammatory response, blood pressure, and bone density
212
Leptin is produced in what tissue?
Adipose
213
Leptin is produced proportionally to what?
Fat cell density
214
Leptin plays a role in what?
Appetite supression
Weight gain
Energy expenditure
215
What part of the brain does Insulin act upon?
Hypothalamus
216
How is insulin similar to leptin?
Dampens appetite by acting on hypothalamaus
217
What is Ghrelin?
A peptide hormone secreted by endocrine cells of stomach
218
What effect does Ghrelin have?
Increases release of neuropeptide Y (NPY) which in turn enhances appetite and food intake.
219
How is Ghrelin regulated?
Activated by fasting and low glucose and inhibited by high glucose
220
What is the effect of Cholecystokinin (CKK)?
Along with PYY, cause satiety during meal & transmit signal to hypothalamus.
221
How can a rough estimate of RMR be obtained?
Assuming it is 24kcal/day/kg of body weight
222
How much additional % of RMR should a person consume if they are sedentary?
30%
223
How much additional % of RMR should a person consume if they are active?
100%
224
How do you calculate total daily energy expenditure (DEE) /day for a sedentary person?
RMR + .3RMR + .1RMR or
| 1.4xRMR
225
How do you calculate total daily energy expenditure (DEE) / day for an active person?
RMR + RMR + .1RMR = 2.1xRMR
226
Calculate the exact weight of nutrients needed to meet DEE req. for a person consuming 2352kcal/day assuming 50 % carb, 30% fat, and 20% protein
Carbs: 0.5(50%) x 2352
Fat: 0.3(30% x 2352
Protein: 0.2.(20%) x 2352
227
What does Albumin tests indicate in regards of nutritional status?
Low levels = malnutrition
228
Tests for serum transferrin levels reflects
Acute protein deficiency
229
What is pre-albumin serum level tests used for?
short-term (3 days) changes in nutritional status, declines rapidly with acute stress or illness
230
What does pre-albumin transport?
Thyroxine
| Retinal-binding protein
231
Which is the most accurate measure for estimating DEE?
```
Indirect Calorimetry test
aka
Respiratory Quotient (RQ)
```
232
What does an RQ test provide information on?
Substate (carbs, fats, proteins) utlization
233
What does the Respiratory Quotient equal?
RQ = Volume of CO2 expired / volume of O2 consumed
234
What does a respiratory quotient (RQ) value less than 0.85 indicate?
Protein and fat oxidation, therefore provide more carbohydrates
235
What does a respiratory quotient (RQ) value greater than 1.0 indicate?
Excess carbohydrate oxidation, provide more lipids
236
What is a general description/definition of obesity in relation to BMI?
More than or equal to 30 kg/m2
237
BMI strongly correlates with
total fat content in adults
238
How do you calculate obesity?
BMI = Weight (kg) / Height (m2)
239
What is a "normal/healthy" BMI range?
18.5 - 24.9
240
What does having a wait to hip ratio greater than 1 in men and women increase?
Health risks
241
What are three methods to assess body fat content?
Skin fold measurements
Bioelectric impedence
Underwater weighing
242
What are 3 metabolic effects of obesity?
Dyslipidimia
Glucose intolerance
Insulin resistance
243
What does obesity increase the risk for?
```
Athlerosclerosis
Cardiovascular disease
stroke
diabetes
cancer
```
244
What do visceral and abdominal fat contribute to higher levels of?
higher VLDL in blood
245
Where do fatty acids released from subcutaneous fat go before they reach the liver?
General circulation -> used up by muscle -> reach liver
246
Apple shaped distribution of fat means higher levels of _____ fat.
Visceral
247
Pear shaped distribution of fat means higher levels of _____ fat.
Subcutaneous
248
How does modest weight gain differ in relation to excessive weight gain in regards to adipose tissue?
Modest gain = inc adipocyte size (hypertrophy)
| Excessive gain = inc in BOTH size and number (hyperplasia)
249
What happens to the the body's TAG content as BMI inc from 20 to 30?
Doubles
250
What percentage of chylomicrons are TAGS?
85%
251
Adipocytes secrete hormones that play a role in what?
Appetite control/ weight gain
Inflammation
Insulin resistance
252
What are the the two hypotheses regarding factors contributing to obesity?
Hypothesis 1: A biologically predetermined "set point" for body weight for most individuals
or
Hypothesis II: A "settling point" that reflects food intake, energy expenditure and other factors
253
What are the major factors that regulate body weight?
Genetic
Environmental
(lifestyle/behavioral)
254
Mutations in is thought to produce hyperphagia and massive obesity?
Leptin gene or
| leptin receptor
255
Ultimately, weight gain results from an ________ bewteen ______ and _______.
inbalance, energy intake, energy expenditure
256
Why is dyslipidimia?
Increase in serum TAGs esp VLDL
| metabolic effect due to obesity
257
Which tissue are affected by obesity?
Liver
Muslce
Adipose
258
Which atherosclerotic cardiovascular disease risk factors define Metabolic syndrome?
Visceral adiposity (obesity)
Insulin resistance
Low levels of HDLs
A systemic proinflammatory state
259
What are several key components leading to metabolic syndrome?
```
Hypertension
Dyslipidemia
Insulin resistance
Chronic inflammation
Impaired fibrinolysis
procoagulation
central obesity (most telling)
```
260
What are the indicators of Metabolic Syndrome?
```
Elevated fasting blood glucose
Elevated waist circumference
Elevated TAGs
Elevated Blood Pressure
Reduced HDL cholesterol
```
261
Insulin resistance precedes what?
Diabetes type II
262
What is the correlation between weight gain and insulin resistance?
Strong
263
How does insulin affect lipogenesis?
Stimulate
264
How does insulin stimulation effect amino acid uptake?
Increases
265
How does insulin stimulation effect protein synthesis?
Increases
266
How does insulin stimulation effect glycogen storage?
Increases
267
Why do chylomicrons and VLDL's accumulate with insulin resistance?
Decreased lipoprotein lipase
268
What is Sibutramine used for?
Managing obesity
| - An appetite suppressant
269
What is Orlistat used for?
Managing obesity
| - Gastric and pancreatic lipase inhibitor, inhibits digestion of TAGs and therefore reduces TAG absorption.
270
What defines an individual as morbidly obese?
BMI > 35
271
What are two surgical management methods of managing obesity?
Gastric banding
| Ileo gastic bypass
272
What is the difference between gastric banding and ileo gastric bypass?
GB: dec. stomach size -> reduce intake
IGB: dec stomach pouch size -> dec nutrient absorption from intestine
273
How does the liver maintain constant blood glucose levels during a fast?
Gluconeogensis
274
In fat cells, TAGs are degraded to fatty acids and glycerol through activation of what enzyme?
Hormone-sensitive lipase
275
When does hormone-sensitive lipase become activated?
Phosphorylation = activation
276
What is the purpose behind the usage of ketone bodies in prolonged starving?
Spare protein degradation
277
What metabolic adjustments occur during prolonged starving?
- Ketone body usage
- Muscle degradation reduction
- Metabolic rate reduction
- Physcial activity reduction
- Kidney performs gluconeogenesis in addition to liver
- Body fat amount det ultimate survival time
278
How long after a fast has begun are liver glycogen stores depleted?
1 day
279
What is Marasmus?
Chronic dietary restriction of carbs, lipids, proteins and other nutrients.
280
Which diseases are Marasmus associated with?
Anorexia nervosa
GI cancer
Chronic illness (i.e. old age)
281
How does Anorexia Nervosa affect the brain and nerves?
Bad memory, fatigue
282
What affect does anorexia nervosa have on the heart?
Low blood pressure
| Palpitations
283
What affect does anorexia nervosa have on blood?
Anemia
284
What effect does Anorexia Nervosa have on muscles?
Weak
| Swollen joints
285
Once free fatty acids are released from fat cells, what are they used for in the liver?
B-oxidation and Ketone body synthesis
286
During starvation, does the level of free fatty acids in the serum increase?
No. Flatlines.
287
What happens to the level of ketone bodies during starvation?
levels increase
288
What is the role of 3-hydroxybutyrate in the liver?
Formed from acetoacetate at high NADH levels. NAH+ also produced along with 3-hydroxybutyrate, and NAD+ allows for more B-oxidation.
289
What is acetoacetate?
A ketone body
290
How do extra hepatic tissue use 3-hydroxybutyrate?
Break it down to NADH and acetoacetate.
| NADH leads to 2.5 ATP
291
What energy source does muscle prefer during fasting?
Ketone Bodies b/c no ATP is needed for activation
292
How is acetoacetate broken down in muscle?
Thiophorase converts succinyl CoA to Succinate, and takes the CoA and makes Acetoacete into Acetoacyl CoA. Acetoacyl CoA becomes 2 Acetyl CoA.
293
Why can't the liver use ketone bodies
Liver lacks thiophorase.
294
What affect does Anorexia have on the kidneys?
Kidney stones
| kidney failure
295
What affect does anorexia have on body fluids?
Low minerals like potassium, magnesium, and sodium
296
What affect does anorexia have on the intestines?
Constipation
297
What affect does anorexia have on hormones?
Loss of menstrual cycle
298
What is Kwashiorkor?
Deficiency of dietary protein (esp essential amino acids)
299
What are the manifestations of kwashiorkor?
Muscle wasting
stunted growth
Decreased ability to produce digestive enzymes and new intestinal epithelial cells
Edema in legs and abdomen
300
What causes the edema in patients with Kwashiorkor?
Decreased concentrations of albumin
301
Besides deficiency of dietary protein, what else can cause Kwashiorkor?
Partial obstruction of upper GI tract
302
Deficiency of which vitamins cause Macrocytic anemia?
Deficiencies of:
B9
B12
