Nutrition Exam 3 Flashcards
(109 cards)
0
Q
Vitamins
A
Vitamins are carbon-containing compounds that regulate a wide range of body processes
1
Q
What are micronutrients?
A
- Vitamins and minerals that are needed in much smaller amounts
- assist body functions such as energy metabolism and the formation and maintenance of healthy cells and tissues
2
Q
Fat soluble vitamins
A
◦Readily stored in the body’s adipose tissue
◦Can be toxic when taken in excess
◦Megadosing: >10 X recommended intake
-used as medicine (pharmacological way)
3
Q
How are vitamins named
A
Named in the order we discover them
4
Q
Water soluble vitamins
A
Water-soluble vitamins:
◦Vitamin C (ascorbic acid) and B-vitamins (thiamin, riboflavin, niacin, vitamin B6, vitamin B12, folate, pantothenic acid, and biotin)
◦Not stored in large amounts: must be consumed on a daily or weekly basis
◦Deficiency symptoms, including diseases or syndromes, can arise fairly quickly
5
Q
Minerals
A
Naturally occurring inorganic (non-carbon-containing) substances
All minerals are elements:
◦already exist in the simplest chemical form possible
◦are not digested or broken down prior to absorption
6
Q
Major vs trace minerals
A
Difference in amounts you take in, but does not mean major is more important than trace
7
Q
Major minerals
A
require at least 100 mg per day ◦Sodium (Na) ◦Potassium (K) ◦Phosphorus (P) ◦Chloride (Cl) ◦Calcium (Ca) ◦Magnesium (Mg) ◦Sulfur (S)
8
Q
Trace minerals
A
require less than 100 mg per day ◦Selenium (Se) ◦Fluoride ◦Iodine ◦Chromium ◦Manganese ◦Iron (Fe) ◦Zinc (Zn) ◦Copper (Cu)
9
Q
What impacts vitamin and mineral absorption
A
Bio availability: How easy is it to get that nutrient from the food into the body
10
Q
Bio availability is impacted by..
A
-chemical form
◦Dietary iron: heme (only in meats, fish, and poultry) and non-heme (in plant and animal foods, iron-fortified foods, supplements)
-Binding factors within the same food
-Other foods within the meal
◦High-fiber foods (whole grains) and oxalic acid (tea, spinach) decrease zinc and iron absorption
11
Q
Chemical transformation of vitamins
A
Many vitamins are modified after they are eaten and absorbed:
◦B-vitamins combine with other substances
◦Combinations activate the vitamin when the compound is needed
12
Q
Chemical transformation of minerals
A
basic natures do not change, but may undergo minor adjustments in their atomic structure
13
Q
Toxic overload
A
- generally more likely to develop from taking supplements than from consuming foods
- Some micronutrient supplements may be harmful to the health of certain groups of people
14
Q
Micronutrient metabolism
A
- Enriching low-nutrient foods with vitamins/minerals does not turn them into healthful foods
- Eating a variety of healthful foods provides more nutrients, phytochemicals, and other dietary benefits than do supplements alone
- A healthful diet built from a variety of foods offers social, emotional, and other benefits absent from supplements
15
Q
Benefits of micronutrient supplementation
A
In certain populations—such as pregnant women—micronutrient supplements can play an important role in promoting health
-folate for pregnant women and women of childbearing age
16
Q
Phytochemicals
A
- Naturally-occurring plant chemicals
- Not considered nutrients (substances necessary for sustaining life)
- Have antioxidant properties that neutralize free radicals
- Antioxidant-rich foods reduce the risk of diseases of aging
17
Q
Phytochemicals and disease
A
- Epidemiologic studies show reduced risk of cardiovascular disease, cancer, diabetes, Alzheimer’s disease, arthritis, cataracts, and age-related functional decline
- Numerous diseases of aging related to oxidative damage may benefit from phytochemicals in foods
- Reduce inflammation
- Protect against cancer (slow its growth)
- Protect against infections (enhance immune function, act as antibacterial agents)
18
Q
Phytochemical research
A
- interact with each other in the body to produce a synergistic effect; may increase the effectiveness of medications
- interact with macronutrients and vitamins and minerals
19
Q
Phytochemical requirements
A
- no RDA; synergistic effects make establishing RDA difficult
- Appear to be beneficial in low doses commonly provided by foods, but may have risky effects as supplements
- Avoid phytochemical supplements
- Consume a plant-based diet consisting of as many whole foods as possible
20
Q
Vitamins and minerals and energy metabolism
A
◦Do not directly provide energy
◦Are needed for generating energy from macronutrients
◦B-vitamins are particularly important in assisting energy metabolism
◦Often function as coenzymes
21
Q
Coenzyme
A
a molecule that combines with an enzyme to activate it
22
Q
Vitamins involved primarily in energy metabolism
A
Thiamin, riboflavin, vitamin B6, niacin, pantothenic acid, and biotin
23
Q
Vitamins that function primarily in cell regeneration and RBC synthesis
A
Folate and vitamin B12
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vitamins responsible for protein metabolism
B12
Niacin
B6
Folate
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vitamins responsible for fat metabolism
```
Riboflavin
B12
Thiamin
Niacin
Pantothenic acid
```
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vitamins responsible for carbohydrate metabolism
```
Thiamin
Riboflavin
Niacin
Pantothenic acid
B12
```
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RDA for micronutrients
Mg is correct
| G, kg is NOT
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Thiamin
B1
Coenzyme thiamin pyrophosphate
◦Required for metabolism of carbohydrate and branched-chain amino acids
Assists in production of
◦DNA and RNA
◦Synthesis of neurotransmitters
Food sources: pork products, sunflower seeds, beans, whole or enriched grains
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Riboflavin
B2
Involved in oxidation−reduction reactions
Part of coenzyme that works as an antioxidant
Food sources: milk, enriched foods, meat
Light sensitive (use opaque milk cartons)
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Niacin
B3
Two forms:
◦nicotinic acid and nicotinamide
Required for oxidation–reduction reactions of carbohydrates, proteins, and fats
Can be made from amino acid tryptophan
Food sources: meat, fish, poultry, enriched breads and cereals
Toxicity?
31
Niacin can only be made from tryptophan if..
- meeting tryptophan needs in the body
- corn: niacin bonded to protein, so it is not available to the body
- contains tryptophan, but not enough to synthesize niacin
- created pellagra epidemic
32
Vitamin B6
Pyridoxine
Group of three related compounds
Coenzyme in amino acid metabolism and gluconeogenesis
Central role in transamination
◦Without B6, ALL amino acids become essential(cannot synthesize nonessential aa from essential aa)
Neurotransmitter synthesis
Heme synthesis
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Gluconeogenesis
Good bcuz helps combat low blood pressure
| Bad when it is exclusively used for energy
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Why glucose?
Bcuz nerve cells, RBCs and brain need it
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Transamination
.
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Heme synthesis. ??
Homocysteine is converted to cysteine with help of B6
| If adequate folate and B12, converts homocysteine to methionine
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Folate
```
Works with enzymes critical for
◦DNA synthesis
◦Cell differentiation
◦Plays a special role in embryo development
◦Amino acid metabolism
◦Repair of damaged cells
2 forms
◦Folate (natural)
◦Folic acid (supplements)
Absorb folic acid better than folate
Sources: foliage
```
38
RDA for folate
- 400 ug for adults
- 600 ug for pregnant women
- Women of child-bearing age should ensure intake with supplements and enriched foods
- Deficiency issues include neural tube defects in infants, anemia, and heart disease
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B12
Cyanocobalamin
Includes a number of compounds that have a cobalt center surrounded by a ring structure
Works with coenzymes to
◦assist DNA synthesis
◦essential for nervous system functioning
Food sources are animal products
◦meat, eggs, dairy, and seafood
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Deficiencies for B12
Deficiencies are rare
◦Often related to absorption issues
◦Can be masked by excess folate
◦Macrocytic anemia
Concerned about vegans, babies breast feeding from vegan moms
Over age of 50, decreased stomach acid, thus decreased intrinsic factor, thus B12 absorption issues
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How B12 absorption works
- B12 goes in mouth
- In mouth, B12 combines with protein
- In stomach, acidic environment breaks bind between B12 and protein. Promotes production of intrinsic factor. B12 added to R protein
- in small intestine pancreatic enzymes break B12 and r protein
- B12 ends up with intrinsic factor
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Pantothenic acid
```
Essential for fatty acid metabolism
Required for
◦synthesizing cholesterol, steroids
◦detoxification of drugs
Food sources: chicken, beef, egg yolk, potatoes, oat cereals, tomato products
No adverse effects from excess amounts
Deficiencies are rare
```
43
Biotin
-A component of coenzymes used for fatty acid synthesis, gluconeogenesis
-Also contribute to carbohydrate, fat, and protein metabolism
-Content had been determined for very few foods
Deficiencies
◦large consumption of raw egg whites over time
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Choline
```
Vitamin-like substance:
◦Metabolism
◦Fat and cholesterol metabolism/transport
◦Homocysteine metabolism
◦cell membranes
◦neurotransmission
Widespread in foods
Deficiency: fat accumulation in the liver
Toxicity from excess supplementation
```
45
Iodine
Mineral
- Component of thyroid hormones
- Regulates body temperature, metabolism
- Important for reproduction and growth
- Food sources: saltwater fish, iodized salt, foods prepared with iodized salt
- Excess interferes with thyroid function
- Goiter (enlarged thyroid gland) occurs with both toxicity and deficiency
46
Iodine deficiency disorders (IDDs)
◦Cretinism: mental retardation, stunted growth
◦Hypothyroidism: low thyroid hormone results in decreased body temperature, cold intolerance, weight gain, fatigue, sluggishness
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Hyperthyroidism
high levels of thyroid hormone caused by Graves' disease
| ◦Weight loss, increased heat production, muscular tremors, nervousness, racing heartbeat, and protrusion of the eyes
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Chromium
-Assists insulin to transport glucose from the bloodstream into the cells
-Important for RNA and DNA metabolism
-Supports immune function and growth
-Dietary adequacy is controversial
◦Widely distributed in foods
◦Not much present
49
Manganese
```
Mineral
A cofactor in
◦Protein, fat, and carbohydrate metabolism
◦Gluconeogenesis
◦Cholesterol synthesis
◦Urea formation
antioxidant properties
Food sources: whole-grain foods
Toxicity (not from supplements)
◦Associated with occupational environments (mines)
◦Impairs the nervous system, causing spasms and tremors
◦Similar to Parkinson’s
```
50
Sulfer
```
A major mineral
Don't get it from food
Component of
◦Vitamins: thiamin and biotin
◦Amino acids: methionine, cysteine
Stabilizes 3-D structure of proteins
Required by liver for alcohol detoxification
Assists in maintaining acid–base balance
Obtained from dietary proteins
```
51
Inadequate B vitamin intake
-Impacts ability to perform physical activity
◦Limited studies show poor work performance: lower intensity and duration
-Diets high in unenriched processed foods provide inadequate levels of B-vitamins
◦Some B-vitamins lost in milling of grains are replaced by the enrichment process
52
Metabolic diet studies
```
◦Carefully controlled
◦Subjects may live in facility
◦All meals prepared for subjects
◦Accurate intake measurements
◦Fluid restriction possible
◦Collect blood, urine and/or feces
◦Depends on nutrient
```
53
PMS and vitamin B6 and folate
```
High doses of B6 and folate in PMS supplements
◦B6 UL – 100 mg/day
◦Neuropathy – numbness, tingling in hands/feet, impaired walking
-folate ul -1000 mg/day
Interference with zinc absorption
Promotion of cancer
Predisposition to allergies
Not enough studies
```
54
Body fluids
Body fluid is the liquid portion of cells and tissues
Characterized by its ability to move freely and changeably, adapting to the shape of the container that holds it
About 50−70% of healthy adult body weight
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Intracellular fluid
within the cell
| ◦2/3 of body fluid
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Extracellular fluid
outside the cell
◦1/3 of body fluid
◦Interstitial fluid flows between cells that make up a particular tissue or organ (muscle, liver)
◦Intravascular fluid is the water in the blood and lymph
◦Plasma transports blood cells within arteries, veins, and capillaries
57
Fluid composition of tissue varies depending on
Tissue type
Gender
Age
58
Tissue type and fluid composition
lean tissues have higher fluid content than fat tissues
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Gender and fluid composition
males have more lean tissue and therefore more body fluid than females
60
Age and fluid composition
- decrease in body water results partly from loss of lean tissue as people age
- maybe get notes from someone
- babies made up like 75% water or something like that
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Electrolytes
Dissolved substances that disassociate in solution into electrically charged particles called ions
◦Positive charge: sodium, potassium
◦Negative charge: chloride, phosphorus
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Predominant electrolytes
◦Extracellular fluid: potassium, phosphorus
| ◦Intracellular fluid: sodium, chloride
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Functions of body fluids
- dissolve and transport substances
- account for blood volume
- help maintain body temperature
- Protect and lubricate tissues
64
Fluids dissolve and transport substances
◦Water is an excellent solvent because it dissolves a variety of substances
◦Water-soluble substances are readily transported in the bloodstream: amino acids, glucose, vitamins, minerals, medications
◦Fatty substances must be attached to or surrounded by water-soluble proteins
65
Fluids account for blood volume
◦Appropriate body fluid levels are essential for maintaining healthful blood volume
◦Blood pressure increases when blood volume rises
◦High blood pressure (hypertension) is a risk factor for heart disease and stroke
◦Low blood pressure can cause people to feel tired, confused, or dizzy
◦Kidneys help to regulate blood volume and blood pressure
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Fluids help maintain body temperature
◦Body temperature must be within a safe range
◦Water has a high capacity for heat, which means that only sustained high heat can increase body temperature
◦Sweating releases heat as the evaporation of water from the skin cools the skin and blood
-temperature increased by vasoconstriction
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Fluids Protect and lubricate tissues
◦Cerebrospinal fluid protects the brain and spinal cord
◦Amniotic fluid protects the fetus
◦Synovial fluid lubricates joints
◦Tears cleanse and lubricate eyes
◦Saliva moistens food for swallowing (creates bolus)
68
Kidneys and blood volume
◦Antidiuretic hormone (ADH) stimulates the kidneys to reabsorb water, reducing urine
-high concentration of solutes in the blood, tells kidneys dehydrated, releases ADH
◦Aldosterone signals the kidneys to retain sodium and chloride, thereby retaining water, increasing blood pressure, and decreasing urine output
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Vasoconstriction
Water moves from extremities to core
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Functions of electrolytes
help regulate fluid balance
enable nerves to respond to stimuli
signal muscles to contract
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Electrolytes help regulate fluid balance
◦Cell membranes are permeable to water,
◦Not freely permeable to electrolytes
◦Water moves by osmosis
◦From high concentration to low
◦Control movement of water into and out of the cells
-osmotic pressure: keeps electrolytes in solution from drawing liquid toward them across a semipermeable membrane
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Electrolytes enable nerves to respond to stimuli
◦Nerve impulses are initiated at nerve cell membranes in response to a change in electrical charge across the membrane
◦Depolarization (pull in sodium)—Action Potential(actual message)—Repolarization(pump potassium back out)
◦Na and K ensure that nerve impulses are generated, transmitted, and completed
73
Electrolytes signal muscles to contract
◦Muscles are stimulated to contract in response to stimulation of nerve cells
◦Influx of calcium into the muscle from the extracellular space stimulates contraction
◦Muscles can relax after contraction once the electrical signal is complete and calcium is pumped out of the muscle cell
74
Thirst mechanism
(hypothalamus) prompts us to drink when it is stimulated by
◦Increased concentration of salt and other dissolved substances in the blood
◦A reduction in blood volume and blood pressure, such as during profuse sweating, vomiting, diarrhea, or low fluid intake
ADH signals kidneys to retain water
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Body gains water
◦Water enters the body through beverages
◦Some foods have very high water content
◦Water from metabolic reactions contributes 10−14% of daily water need
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Sensible water loss
◦Kidneys excrete water as urine
| ◦Sweat during exercise or in hot environment
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Insensible water loss
◦Skin (not sweating) people in the desert, or lungs during exhalation
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Significant loss
Illness, injury, exercise, high altitude, pregnancy, breast feeding, diuretics (substances that promote urination)
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Water
◦Essential for life
◦Amount needed varies with gender, age, body size, health status, physical activity level, environment
◦Sources of drinking water: carbonated, mineral, distilled, purified, tap, bottled
80
Nutrients involved in hydration and neuromuscular function
Sodium, potassium, chloride, phosphorous
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Which three micronutrients have an RDA in g/day?
Sodium, potassium, and chloride
82
What happens if we drink too much water?
◦Becoming overhydrated is rare
| ◦Dilution of blood sodium concentration
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What happens if we don't drink enough water?
◦Dehydration is the leading cause of death around the world
84
Sodium
```
◦Major positively charged electrolyte in the extracellular fluid
Functions
◦Blood pressure and acid−base balance
◦Nerve impulse transmission
◦Muscle contraction and relaxation
◦Assists in glucose absorption in SI
◦Sodium-dependent glucose transporters
```
85
High-sodium diets
◦HTN more common
◦May increase urinary Ca excretion in some people
◦Younger females with inadequate Ca intake
◦Not in older women with adequate Ca intake
◦May increase the risk for bone loss
86
What if you consume too much sodium?
◦Hypernatremia
◦Abnormally high blood sodium concentration
◦Rare condition (usually from Drinking sea water)
◦Concern for patients with
◦Congestive heart failure
◦Kidney disease
◦Due to inefficient excretion of Na
◦Causes high blood volume, edema (swelling), and high blood pressure
87
What if I don't consume enough sodium?
```
◦Hyponatremia
◦Abnormally low blood sodium level
◦Commonly from prolonged sweating, vomiting, diarrhea
◦More rare - overhydration
◦If untreated: death
```
88
Potassium
◦Major positively charged electrolyte in the intracellular fluid
Works with Na to
◦Maintain fluid balance
◦Regulate the contraction of muscles and transmission of nerve impulses
High potassium intake helps maintain a lower blood pressure
◦DASH diet
89
Recommended intake for potassium
4.7 g
90
Sources of potassium
◦Good sources: fresh fruits, vegetables, legumes, and whole grains
◦Processing foods increases sodium and decreases potassium content
91
RI for sodium
◦AI: 1.5 g
| ◦Most recommend < 2,300 mg/day
92
Sodium sources
Processed foods are high in sodium
◦Tomato juice
-ham
93
What happens if you consume too much potassium?
◦Hyperkalemia
◦High blood potassium levels
◦Can alter normal heart rhythm, resulting in heart attack and death
◦Patients with kidney disease
◦Unable to regulate their blood potassium levels
◦Should avoid consuming potassium-containing salt substitutes
94
What happens if you don't consume enough potassium?
◦Hypokalemia
◦Low blood potassium levels
◦Risks include
◦Taking certain diuretics
◦Speak to MD as some are potassium-sparing
◦Extreme dehydration
◦Vomiting, diarrhea
◦Alcohol abuse
◦Long-term consumption of natural licorice
◦Eating disorder (abnormal heart rhythms)
95
Chloride
```
◦Negative ion in extracellular fluid
Functions
◦Aids digestion
◦Hydrochloric acid (HCl) in the stomach
◦Assists the immune system
◦Role in transmission of nerve impulses
```
96
Too much chloride ?
◦Primary dietary source: table salt
| ◦Hypertension in salt-sensitive individuals
97
Too little chloride?
Rarely occurs, but can with
◦Severe dehydration
◦Frequent vomiting
◦Eating disorders
98
Phosphorous
◦Major intracellular negatively charged electrolyte
Functions
◦Required for fluid balance
◦Critical role in bone formation
◦Regulates biochemical reactions by activating or deactivating enzymes (phosphorylation)
99
Phosphorous is a component of ...
ATP
DNA, RNA.
Phospholipids (cell membranes, lipoproteins)
100
Sources of phosphorous
◦Widespread in many foods
◦High in protein foods (meat, milk, eggs)
◦More readily absorbed from animal sources
Phytic acid: plant storage form (can't break bonds?)
101
Too much phosphorous?
```
Can occur
◦patients with kidney disease
◦When taking too many vitamin D supplements
◦Causes muscle spasms, convulsions
Deficiencies are rare
```
102
Disorders related to fluid and electrolyte imbalance include:
```
◦Dehydration
◦Heatstroke
◦Water intoxication
◦Hypertension
◦Neuromuscular disorders
◦Obesity
```
103
Dehydration
Dehydration occurs when fluid loss exceeds fluid intake
Commonly due to heavy exercise or high environmental temperatures
Elderly and infants are at increased risk
104
Dehydration is determined by % loss of body weight
```
1%-2%
◦Thirst signal
>2%
◦Muscle weakness
◦Significant loss of strength and endurance
10%-12%
◦Heat intolerance
20%
◦Coma and death
```
105
Avoiding dehydration
| Before exercise
◦4 hours before: 5-7 mL/kg fluid
◦Adequate hydration
◦Excretion of excess
106
Avoiding dehydration
| During exercise
◦Measure weight before beginning
| ◦If exercising >30 minutes, hydrate during
107
Avoiding dehydration
| After exercise
◦4-6 hours after: 2-3 cups/pound lost
108
Water intoxication
```
Overhydration
◦Occurrence is rare
Kidneys retain too much water
◦Overhydration
◦Hyponatremia
Documented cases of deaths
-marathon runners (more common among novices who run slower and longer)
-college students (hazing rituals)
-ravers (ecstasy)
```
