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NU FS 305 > Chapter 10 - Nutrients Involved in Energy Metabolism > Flashcards

Chapter 10 - Nutrients Involved in Energy Metabolism Flashcards

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1
Q

How are vitamins different from the macronutrients?

A
  • Individual molecules i.e. not linked together
  • Not a source of energy
  • Co-activity in metabolic enzyme function
  • µg or mg
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2
Q

What are the fat-soluble vitamins?

A

A, D, E, and K

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3
Q

What are the water-soluble vitamins?

A

C, and Bs (thiamin, niacin, riboflavin, B6, folate, B12, pantothenic acid, biotin)

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4
Q

What are the major minerals?

A
  • Sodium
  • Chloride
  • Potassium
  • Phosphorus
  • Calcium
  • Magnesium
  • Sulphur
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5
Q

What are the trace minerals?

A
  • Iodide
  • Manganese
  • Chromium
  • Selenium
  • Fluoride
  • Iron
  • Zinc
  • Copper
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6
Q

What is the difference between vitamins and minerals?

A

Vitamins are organic, while minerals are inorganic

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7
Q

What is the role of micronutrients in energy metabolism?

A

Working with enzymes or hormones to extract the energy found within the bonds of macronutrients

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8
Q

What is the main function of Thiamin?

A

It is the vitamin portion of coenzyme TPP (Thiamin pyrophosphate); it is involved in both glycolysis and TCA

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9
Q

What are some minor functions of thiamin? (2)

A
  • Membrane function of neuronal cells
  • Biosynthesis of lipid and acetyl-CoA
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10
Q

Where is thiamin absorbed?

A

In the SI, directly to the bloodstream

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11
Q

How is thiamin absorbed?

A
  • At low concentrations (<1.5 uM): carrier-mediated transport (ThTr-1 and ThTr-2)
  • At high concentrations (>5mg) : passive diffusion
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12
Q

Thiamin RDA

A
  • Men: 1.2 mg/day
  • Women: 1.1 mg/day
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13
Q

What are significant food sources of Thiamin?

A
  • Whole grain, fortified, or enriched grains
  • Moderate amounts in all nutritious foods (vegetables, milk, soy)
  • Pork
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14
Q

What commonly causes thiamin deficiency?

A
  • Malnutrition/empty kcal foods
  • Consuming milled, non-enriches grains
  • raw fish
  • alcoholism
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15
Q

What does thiamin deficiency result in?

A

Beriberi

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16
Q

What are the clinical symptoms of thiamin deficiency?

A
  • Englarged heart, cardiac failure
  • Muscular weakness
  • Paralysis of motor nerves of eye
  • Apathy, poor short-term memory, confusion, irritability
  • Anorexica, weight loss
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17
Q

What is the difference between wet and dry beriberi?

A
  • Wet involves the cardiovascular and lymphatic systems; results from physical exertion with high CHO intake. Results in edema
  • Dry involves the neural system; results from chronic caloric restriction. Results in neural, muscle wasting and neural effects
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18
Q

What is Wernicke-Korsakoff syndrome?

A
  • A form of dry beriberi
  • Comes from alcoholism or impaired/absorption or excretion of B1
  • Results in neural deficiencies (disorientation, staggering gait, short-term memory loss, jerky eye movements)
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19
Q

What is the toxicity risk of Thiamin?

A

There are none (no TUL) as it’s a water-soluble vitamin

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20
Q

What is the main function of riboflavin?

A

Coenzyme for FMN and FAD; involved in TCA (accept/donate), delivery of H+ and e- to ETC, and fatty acid oxidation

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21
Q

Where is riboflavin absored?

A

In the SI, directly into the bloodstream

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22
Q

How is riboflavin absorbed?

A
  • First it is digested in the SI through proteolysis or hydrolysis via pyrorphosphatase
  • Enterocyte absorbption is done through carrier mediated transport (RCP)
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23
Q

Riboflavin RDA

A
  • Men: 1.3 mg/day
  • Women: 1.1 mg/day
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24
Q

What are significant food source for riboflavin?

A
  • Milk products
  • Enriched/whole grains
  • Liver
  • Dark leafy greens
  • Yeast
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25
What commonly causes riboflavin deficiency?
* Often accompanies other nutrient deficiencies * Low micronutrient diet * Absorprtion disorder
26
What is riboflavin deficiency?
Ariboflavinosis
27
What are the clinical symptoms of ariboflavinosis?
* Inflamed eyelids * Reddening of cornea * Light sensitivity * Sore throat * Cheilosis * Glottitis * Skin lesions with greasy scales
28
What is the toxicity risk of riboflavin?
There is none as its water soluble
29
What is the main function of niacin?
Part of coenzymes NAD and NADP used in energy metabolism (glycolysis, TCA, ETC, biosynthesis, fatty acid oxidation)
30
Where is niacin absorbed?
In the SI, directly to the blood stream
31
How is niacin absorbed?
* First it is digested in the SI through proteolysis or hydrolysis via pyrorphosphatase * Enterocyte absorbption is done through **carrier mediated transport** (SMCT1, SMTC2, and MCT1) or passive diffusion
32
Niacin RDA
* Men: 16 mg NE/day * Women: 14 mg NE/day
33
How is niacin formed in the body?
* Endogenous synthesis from dietary trptophan * 60 mg tyrptophan to make 1 mg B3
34
What are significant food sources of niacin?
* Milk, eggs, meat, poultry, fish * Whole grains, enriched breads and cereals, nuts * **All protein-containing foods**
35
What is a NE equivalent to?
1mg niacin or 60mg tryptophan
36
What causes niacin deficiency?
* Corn or sorghum diet, which is low protein and low available niacin * Inability to use niacin (genetic/malabsorption disorders, alcoholism, medications)
37
What does a niacin deficiency cause?
Pellagra
38
What are the clinical symptoms of niacin deficiency?
* Diarrhea * Vomiting * Glossitis * Depression, apathy, fatigue, dementia * Bilateral symmetrical dermatitis on areas exposed to sunlight
39
What is the toxicity risk of niacin?
TUL: 35 mg/day
40
What is niacin flush?
When oversupplementation (3-4x DRI) of niacin occurs; causes painful flush, excessive sweating, blurred vision, and gastro sensitivity
41
Why do individuals take pharmacological doses of niacin?
High doses of niacin (~2000mg) can decrease total cholesterol, VLDL, and LDL; increases HDL
42
What is the main function of biotin?
A coenzyme to carboxylases * TCA: recycling of oxaloacetate * Gluconeogenesis * Fatty acid synthesis * Breakdown of some fatty acids and amino acids
43
Where is biotin absorbed?
In the SI, directly into the bloodstream
44
How is biotin absorbed?
* First it is digested through proteolysis (a large fraction of biotin is covalently bonded to lysine) * Absorbed throught the SMVT in SI
45
Biotin RDA
No RDA; AI for adults in 30 mcg/day
46
What are significant food sources for biotin?
Widespread in foods * Liver * Egg yolds * Soy beans * Fish * Whole grains * *Produced by GI bacteria*
47
What is biotin deficiency caused by?
* Raw egg whites; they contain avidin which binds to biotin, preventing absorption * Protein-energy malnutrition
48
What are the symptoms of biotin deficiency?
* Skin rash * Hair loss * Neurological impairment
49
What is the toxicity risk of biotin?
There is no toxicity risk with biotin
50
What is biotinidase deficiency?
Inherited disorder where there is a deficiency of biotinidase, an enzyme that helps recycle biotin to be reused by the body
51
What are the symptoms of bioinidase deficiency?
* Depression, lethargy, hallucinations * Numb or tingling sensation in limbs * Red, scaly rash around the eyes, nose, and mouth * Hair loss
52
How can biotinidase deficiency be corrected?
Supplementing dietary, free biotin
53
What is the main function of panthothenic acid (B5)?
Substrate for Coenzyme A synthesis * CoA is used in energy metabolism * Needed for synthesis of acyl carrier protein which is involved in fatty acid synthesis
54
How is CoA turned into free pantothenic acid during digestion?
Action of alkaline phosphatase in the SI
55
How is pantotheic acid digested?
Through the SMVT in the SI, directly into bloodstream
56
RDA Pantothenic Acid
No RDA; AI is 5 mg/day for adults
57
What are significant food sources for pantothenic acid?
Widespread in plant and animal foods * Organ meats * Mushrooms * Avocados * Broccoli * Whole grains
58
What causes pantothenic acid deficiency?
**Lack of the pantothenate kinase gene (PANK2)**; this is the gene that encodes pantothenate kinase which is a regulatory enzyme in the synthesis of CoA
59
What is the result of pantothenic acid deficiency?
PKAN (Pantothenate kinase-associated neurodegeneration)
60
What are the symptoms of PKAN?
* Insomnia, fatigue, depression, irritability * Hypoglycemia, increased sensitivity to insulin * Vomiting, nausea, stomach cramps
61
what is the toxicity risk of pantothenic acid?
None; possible upset stomach with supplement doses
62
What is the main function of vitamin B6?
Coenzyme; either as PLP (Pyridoxal phosphate) and PNP (Pyridoxamine phosphate) * Transamination reactions * Conversion of tryptophan to niacin * Synthesis of serotonin * Synthesis of heme, nucleic acids, phosphatidycholine * Metabolism of homocysteine
63
How is vitamin B6 digested?
B6 is found bound to glucoside * hydrolysis of the glucoside by action of β- glucosidases PLP/PMP hydrolyzed by a phosphatase
64
How is Vitamin B6 absorbed?
Directly into the bloodstream from the SI through passive diffusion
65
RDA B6
1.3 mg/day for adults
66
What are significant food sources for B6?
* Meats * Potatoes * Legumes * Non-citrus fruits * Fortified cereals * Liver * Soy products
67
What causes B6 deficiency?
Alcoholism and Isoniazid (medication used for TB)
68
What are symptoms of B6 deficiency?
* Scaly dermatitis * Microcytic anemia * Depression, confusion * Abnormal brain wave pattern, convulsions * Elevated homocysteine
69
What is toxicity risk of B6?
TUL: 100mg/day * Depression, fatigue, irritability, headaches * Sensory neuropathy * Skin lesions * neurological damage
70
Why may someone take supplements of B6?
* Reduces plasma homocysteine * Possibly beneficial for carpal tunnel syndrome and PMS
71
What is the main function of folate?
1 Carbon metabolism. It is used in: * DNA synthesis * Amino acid metabolism * Vitamin B12 activation to co-enzyme
72
What are the additional benefits of folate in the diet?
* CVD * folate assists homocysteine catabolism * Cancer * sufficient folate reduces risk of cancer but excess folate may exacerbate progession cancer and cause initiation of cancer * Prevention of neural tube defects (e.g. spina bifia/anencephaly)
73
What is the bioavailability of differing types of folate?
* Naturally found: 50% * Added or synthetic: 100%
74
What are the folate consumption reccommendations for prevention of neural tubes defects?
* Supplements at least 4 weeks prior to conception * All women childbearing age 400 mcg/day
75
How do you calculate dietary folate equivalents?
DFE = mcg good folate = (1.7 x synthetic folate)
76
What are significant food sources for folate?
* Fortified grains, milk, juice * Leafy green vegetables * Legumes * Seeds * Liver | Folate is susceptible to heat loss
77
RDA Folate
400 mcg DFE/day for adults, 600 mcg/day if pregnant
78
What is the toxicity risk of folate?
1000 mcg DFE/day; only applies to synthetic forms or fortified foods * Can mask a B12 deficiency and cause neurological damage
79
What causes folate deficiency?
* Typically a lack of dietary folate; diets lacking fresh vegetables * Malabsroption * Increased metabolic requirement
80
What are the symptoms of folate deficiency?
* Anemia * Smooth, red tongue * Mental confusion * Weakness, fatigue, irritability, headache * Increased homocysteine * Neural tube defects
81

NU FS 305 (13 decks)

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