Exam 3 - Chpt 9-11 Flashcards
What are the 4 fat-soluble vitamins?
A, D, E, K
What do fat-soluble vitamins require for abspt?
Bile and dietary fat
How are these vitamins transported?
W/ fats through lymphatic system in chylomicrons
Are these vits stored? Where?
Yes, in body fat (adipose tissue)
>Thus intake can vary w/o risk of deficiency
How do fat soluble vitamins compare to water soluble?
Not easily excreted, unlike water soluble vitamins
>Ppl should not take supplements high in these vitamins
What are pre-made/preformed vit A called? Is it active or inactive? Toxic?
Retinoids: retinol, retinal, retinoic acid
Active (usable)
May be toxic
Where are retinoids found?
Animal foods
>Liver, eggs, fortified into dairy, fish
What is the provitamin/precursor form of Vit A? Is it active or inactive? Toxic?
Carotenoids
Inactive
Non-toxic
Where are carotenoids found?
Plants → Yellow, orange, red fruits and veggies
>More color, more carotenoids
• Frozen and canned > retail fresh
> > Carrots, red bell peppers, cantaloupe
What is Retinoid fxn?
> Key role in night vision
Cell differentiation and growth
“needed for vision (retinal), and for growth and differentiation of cells (retinoic acid)”
What is Retinoic Acid used for?
used topically to treat certain skin conditions (e.g. acne)
>Vit A is a key component
>Helps cells divide more rapidly, clearing old cells
What is fxn of Carotenoids?
Decrease cancer risk and prevent macular de-generation
How are preformed and precursor forms of Vit A transformed in digestive tract?
> Preformed → Retinol transformed into Retinal
Precursor → Beta-carotene transformed into Retinal in liver and intestinal mucosa
> > Retinal is converted to Retinoic Acid, can’t covert back
What is Vit A role in Visual Cycle?
> Vit A is a component of Rhodopsin (retinal + opsin)
When light strikes rhodopsin, a nerve impulse is sent to brain so light is perceived.
When Vit A is deficient, there is delay in regeneration of rhodpsin that causes difficulty seeing in dim light (night blindness)
—
When light hits, Retinal molecule changes molecular form
»Bent (cis) → straight (trans)
»Signals to brain that there’s light
> Retinal breaks away from opsin → brain perceives light
»Retinal is lost in cycle
»Need more to form Rhodopsin
»If insufficient Retinal, eyes have difficulty adjusting to dark
What is Vit A role in Gene Expression and Cell Differentiation ?
Vit A has a role in directing which genes are transcribed and translated to create diff kinds of proteins
>Impt in early development and growth
What is relationship btwn Vit A and Keratin?
Vit A helps w/ turnover of cells in eye that help w/ moisture and lubrication
>W/ insufficient Vit A, body creates Keratin, which leads to a hard and dry layer in the eye
Symptoms of Vit A Deficiency?
> Night blindness
If severe: permanent blindness
Xerophathalmia – lack of mucous synthesis
»Keratin on the eye
Causes and symptoms of Vit A Toxicity (each form)?
Retinoids – can increase risk of bone fractures and birth defects
>Vit A supplements linked to hip fractures
Carotenoids – not toxic, but high intake can cause
>Hypercarotenemia: orange hue in skin, benign
>Birth defects
What are dietary and other sources of Vit D? Essential?
Vit D = “sunshine vitamin” → Produced in skin by exposure to UV light
>Found in eggs, fatty fish (salmon), and milk (fortified dairy products)
**Only conditionally essential in diet if you’re not producing enough through skin
What is active form of Vit D?
Vit D3, or Cholecalciferol
Modified in liver and then activated in kidney
Vit D toxicity?
May be toxic at high lvls
>Flynn – toxicity not thought to be issue, even w/ supplementation
Book info:
>High blood and urine Ca2+ concentrations
>Depositing of Ca2+ in blood vessels and kidneys, cardiovascular damage, possibly death
Vit D fxns?
> Bone health–maintains lvls of Ca2+ and P in blood that favor bone mineralization w/ calcium phosphate
Normal fxning of parathyroid gland
Regulation of immune system
How is Vit D synthesized? Where is it activated?
Light converts 7-dehydrocholesterol to Vit D3 → activated in liver, then kidney
Is dietary Vit D3 active or inactive?
Inactive
How does Vit D affect Ca2+ Abspt? PTH?
> Increases abspt of dietary Ca2+ through normalizing parathyroid gland
Vit D works w/ parathyroid hormone (PTH) to increase Ca2+ retention at kidney, increase release at bone, and increase abspt at intestine
Symptoms of Vit D deficiency?
> Dietary Ca2+ can’t be absorbed efficiently
Improper bone mineralization
Abnormalities in bone structure
Cancer potential for all ages
Vit D deficiency in CHILDREN?
RICKETS=Bowed legs and abnormal ribs
>Has increased overtime bc children wearing more sunscreen and covered up
Vit D deficiency in ADULTS?
OSTEOMALACIA=Bone pain, muscle aches, increase in bone fractures
How does Vit E exist in food?
In 8 forms/isomers – we can’t absorb all forms
What form of Vit E is the ONLY form we can absorb and USE in the body?
Alpha-tocopherol
Why is Vit E requirement so high?
Req assumes veg oil intake
>Vit E is added to keep veg oils (high in polyunsat fats) from oxidizing
Causes and symptoms of Vit E deficiency in premature infants?
Mother doesn’t transfer Vit E to fetus until 37weeks
>Can result in hemolytic anemia (rupture of RBCs)
>Same symptoms as Fe and Vit B6 deficiency
> Deficiency is rare bc vit E is plentiful in food supply and stored in many body tissues
What are some dietary sources of Vit E?
EVOO, Soybean oil, Nuts and seeds
What are some fxns of Vit E?
> Antioxidant–Protects against cell damage by neutralizing free radicals that cause oxidative damage
»Vit E donates one of its e- to free radical → impairs further Vit E activity → VIT C can restore Vit E by replacing e-
Vit E in supplements vs in food?
> Supplement–no benefit, and some studies show Vit E supplements increase disease and hemorrhagic stroke risk
In food–not toxic
Benefits of Vit E in EVOO?
EVOO is highest in alpha tocophorol and monounsat fat
>More Vit E available to body than in other veg oils bc its low in polyunsat fat
Primary fxn of Vit K?
Blood clotting (“Koagulation”/coagulation)
1st form of Vit K? Dietary sources?
> Phylloquinone
>Plants: Leafy greens (spinach, kale, broccoli)
2nd form of Vit K? Dietary sources?
> Menaquinone
>Animal foods (and synthesized by gut bacteria): Liver, salmon
Symptoms of Vit K deficiency?
Major symptom: Abnormal blood coagulation
>Discovered when cattle were given fat-free diet, cows bleeding to death bc couldn’t absorb Vit K w/o fat
>Almost no Vit K is transferred from mother to fetus → newborns are routinely given Vit K injections at birth to prevent blood clotting disorders
Very rare in US
What is Vit K blood clotting process?
**Vit K is part of clotting cascade→Series of rxns involving clotting factors, several of which require Vit K for formation
Vit K is coenzyme needed for produxn of prothrombin, other blood-clotting factors, and several proteins involved in bone formation and breakdown
>Prothrombin (requires Vit K for its formation and subsequent conversion to Thrombin) → Thrombin → Fibrinogen (requires Thrombin for conversion to Fibrin) → Fibrin
Vit K Toxicity?
problem if you take supplements, less risk in diet
- Bc vit K fxns in blood clotting, high doses can interfere w/ anticoagulant drugs, e.g. Coumadin
What is Vit K impt for, other than coagulation?
Bone health
>Used in laying down healthy, new bone
>Unlike other fat-soluble vitamins, body uses vit K rapidly, so a constant supply is necessary
What is relationship btwn Vit K and Coumadin? Past v now?
> Coumadin (warfarin) =anticoagulation medicine
Vit K interferes (role in clotting)
»In past: patient told not to eat Vit K containing veggies
»Newer thought: Vit K containing veggies daily, adjust med to diet
Why is too much clotting dangerous?
Risk of heart disease and stroke
Clots can break off and
>travel to brain → stroke
>travel to heart → heart attack
How much of the blood is composed of water? Blood fxns?
90%
- Transports O2 and nutrients to cells
- Removes CO2 and waste products
What are direct fxns of water in the body?
- *Lubricant, cleanser, cushion against shock
- Tears–wash away dirt in eye
- Synovial fluid–lubricates joints
- Saliva–assists in chewing, tasting, swallowing
- Spinal fluid–protects again shock
> Assists in regulating body temp (e.g. sweat)
Part of metabolic rxns—we make water at end of ETC
Helps maintain acid-base balance
Danger of overhydration? Low vs high water intake?
> Can lead to hyponatremia (low sodium in blood), which can result in abnormal fluid accumulation in body tissues
»Marathon concern
> Low intake—antidiuretic hormone will cause kidney to conserve water
High—more water excreted in urine
Our need for water is dependent on what 3 dietary factors? How?
> Protein, sodium, and fiber
»higher consumption increases water needs
> [Waste product from protein = urea]
What are the 3 principle electrolytes?
Sodium (Na+), potassium (K+), chloride (Cl-)
Positively and negatively charges ions
What is distribution of principle electrolytes relative to cell?
[remember: 3Na out/2K in]
>Na—main mineral OUTSIDE cell
>K—main mineral INSIDE cell
>Cl—exists w/ Na+ outside cell as salt, NaCl
> > > If eat a lot of sodium food (high Na+ outside of cell), you draw water out of cell = raises BP
What are causes of K+ deficiency?
> Related to fluid loss and medications
> “Low levels can occur when water and electrolyte losses are increased due to excessive sweating, chronic diarrhea or vomiting, or kidney disorders.”
Toxicity of K+?
> Caused by supplements
Leads to renal disease
»Can shut down heart
Toxicity of Na+? Dietary sources?
> Leads to high BP (hypertension/HTN)
»Rare (bc fluid usually compensates when you consume too much Na+)
**Main food sources of Na+ in diet:
-Processed food
-Packaged food (canned)
-Fast food
[not adding salt to food]
What is HTN? Dangers?
Increase in the pressure of the blood against the arterial walls (too much pressure on arteries)
>No outward symptoms but can lead to heart and kidney diseases
-
>Can damage arteries
>Atherosclerosis
>Cerebrovascular Accident (CVA) → stroke
Risk factors for HTN?
>Obesity >Aging >Diabetes – (bc insulin affects kidney) >Lack of physical activity >Poor diet (high Na+, low K+) >Genetics, ethnicity, smoking, heavy alcohol consumption, stress
Treatment of HTN?
Decrease Na+ in diet
What is the DASH diet?
DASH=Dietary Approaches to Stop Hypertension
**Increasing K+ intake by eating fruits and vegetables to lower BP
What is 1 serving of fruits or vegetables?
1/2 cup
How many servings of fruits and veg recommended for lowering BP?
9
What would a typical day on DASH diet look like?
> Fruit at breakfast
>Vegetables at lunch and dinner
Definition of minerals
Nutrients needed by the body in small amounts for health and maintenance
Sources of minerals?
unprocessed foods, some processed foods(fortified) and dietary supplements
>Soil and water mineral concentration affects nutrition quality/content of some foods
What is bioavailability?
Amount of minerals in a food that is ABSORBED and AVAILABLE to the body
What influences bioavailability?
Phytates, tannins, oxalates, and fiber ⇒Tend to be high in plant products
>Minerals from plant foods are LESS bioavailable than animal
What are major sources of tannins? How do tannins affect bioavailability?
> Black tea and red wine
>Hinder abspt of Ca++
What are major sources of oxalates? How do oxalates affect bioavailability?
> Tree nuts, soy, chocolate
>Bind Ca++
How does fiber affect bioavailability?
Traps minerals
How does body’s need of a mineral affect abspt?
The more deficient, the greater the abspt of that mineral
What is mineral to mineral competition?
W/ supplements, Ca2+, Mg, Fe, and Cu all complete for same transport mechanisms
What is fxn of minerals?
> Help regulate body processes, often as cofactors
|»_space;>Mineral cofactor combines w/ inactive enzyme to form active enzyme
What is Ca2+? Dietary sources?
> Most abundant mineral in body, 1-2% of adult body weight
Provides structure to bones and teeth and has impt regulatory roles
> Dairy, fish w/ bones, leafy green veggies, fortified foods
How is Ca2+ absorbed?
> Passive diffusion → need high concentration gradient of Ca2+
Active trnspt → w/o gradient, Vit D3 is critical to help transfer Ca2+ across cell membranes
> abspt is highest pre-puberty
What factors increase and decrease bioavailability of Ca2+?
Increase—presence of vit D, acidic foods, lactose, and fat
Decrease—iron, tannins, fiber, phytates, and oxalates
What is role of Ca2+ in the body?
> 99% is found in solid mineral deposits in the bones and teeth
»Pre-puberty is time of greatest Ca2+ deposition
> Remaining 1% is found in intracellular fluid, blood, and extracellular fluid
»Role in cell communication, nerve transmission, mscl contractions, blood pressure regulation and release of hormones
What is osteoporosis? Reversible?
a condition in which LOSS OF BONE mass increases risk of bone fractures
>Not reversible
Risks factors for osteoporosis?
risk is related to lvl of peak bone mass and rate of bone loss
> older age
gender (women greater)
diet—Ca2+ is main mineral in bone, but no data showing that intake after pre-puberty will prevent or treat osteo
low physical activity
What factors increase Ca2+ loss in urine?
> Meat/poultry/seafood metabolism
High Na+ intake
Low plant product intake (K+ prevents loss)
Problems w/ Ca2+ Supplements
> Has been related to kidney stones in women
>Blocks abspt of other minerals: Fe, Mg, Cu
What is Phosphorus (P)? Percentage in body?
> Makes up ~1% of an adult’s body
»85% of P in body is found in bones + teeth
More readily absorbed than Ca2+
Impt component of molecules w/ structural or regulatory roles
Symptoms of phosphorus deficiency?
Bone loss, weakness, and loss of appetite
>Rare bc it’s abundant in most foods and more easily absorbed than other minerals
Phosphorus toxicity?
Toxicity thought to be rare, can lead to bone reabspt
> Daily cola (high soda intake) = increase in bone fractures in adolescent girls, hip fractures in post-menopausal women
What is Magnesium (Mg)? Percentage in body?
> 50-60% in body is found in bone
»Essential for maintenance of structure
> Present INSIDE cells, where it’s 2nd most abundant intracellular ion, after K+
> Cofactor for over 300 enzymes
»Metabolism of energy-yielding nutrients
> affects metabolism of Ca2+, Na+, and K+
Dietary sources of Mg?
> Component of chlorophyll
|»_space;>Leafy greens, nuts, seeds, bran
What are risk factors for Mg deficiency?
Rare, but risk is high w/ high alcohol consumption or general malnourishment
What are symptoms of Mg deficiency?
- Nausea
- Mscl weakness and cramping
- Mental derangement
- Changes in BP and heartbeat
Mg toxicity?
Rare, no adverse effects observed from food
> Some toxicity from supplements observed, esp among elderly
What are sources of sulfur? Recommended daily intake?
> Protein-containing foods and sulfur-containing AAs in vitamins (THYMINE, BIOTIN)
Nonfood additives, e.g. sulfur dioxide, sodium sulfite, and sodium bisulfite
No recommended daily intake
What is sulfur’s role in body?
Sulfur-containing AAs, such as methionine and cysteine, are needed for PROTEIN SYNTHESIS
>need in energy metabolism and in regulation of pH balance
Causes and symptoms of Ca2+ deficiency?
> Causes: Low intake or high loss in urine
»Normal blood lvls are maintained by resorbing Ca2+ from bone, resulting in Ca2+ LOSS FROM BONE
-Deficiency can reduce bone mass and increase risk of osteoporosis
Symptoms of excessive Ca2+?
- Kidney stones,
- constipation,
- raise blood Ca2+ lvls,
- interfere w/ abst of other minerals, like iron
