Week 6 (good) Flashcards
What are vitamins?
- organic compounds
- do not yield energy
- micronutrients
- vital to life
- indispensible to bodily functions
What are precursors/provitamins?
transform chemically to one or more active vitamin forms
What does the measure of vitamin of a food usually include?
- vitamin and the vitamin activity potential from its precursors
What is bioavailability?
the rate and extent to which a nutrient is absorbed and used
what is subclinical deficiency?
a deficiency in the early stages, before the outward signs have appeared
What are the fat soluble vitamins?
- A
- D
- E
- K
What are the water soluble vitamins?
- B vitamins
- vitamin C
General characteristics of the fat soluble vitamins?
- absorped into the lymph
- trvel in blood in association with protein carriers
- found in fats and oils of food
- require bile for absorption
- stored in liver and fatty tissues until needed
- body can survive weeks without eating these vitamins (diet as a whole. meets the average amounts needed)
- excess vitamin A and D can easily reach toxic levels
General characteristics of water soluble vitamins?
- absorbed directly into bloodstream
- travel freely in bloodstream
- most are not stored to any great extent
- excess excreted in urine
- lower risk of toxicity than fat soluble vitamins
What are possible causes of deficiency for fat soluble vitamins?
- likely if consistently low in fat soluble vitamins
- fat malabsorption (has trouble digesting/absorbing it)
- mineral oil laxatives can cause vitamin loss
- very low fat diets interfere with absorption
What are the 3 active forms of Vitamin A in the body?
- retinol
- retinal
- retinoic acid
What is the plant derived precursor for vitamin a?
beta carotene
What are the roles of Vitamin A? (general)
- vision
- gene expression
- maintenance of body linings and skin
- immunity
- growth of bones and of the body
- normal development of cells
- critial importance to reproduction
What does the retina contain?
light sensitive nerve cells
what is the vitamin A containing pigment and what does it do?
- rhodopsin
- light bleaches this pigmemt
- this pigment breaks off the vitamin, which intiates an impulse to the optic center in the brain
- the vitamin reuintes with the pigment with very little vitamin a destruction
- Vitamin A must regenerate the supply
What happens if Vitamin A supply runs low
- night blindness
- a lag occurs before the eye can see again after a flash of bright light
What is keratinization and how can it occur?
- kertain accumulation of the cornea can occur with vitamin A deficiency
- can lead to xerosis (drying) then to thickening (xerophthalmia) causing permanent blindness
How can keratinization be prevented if caught early? why is this important
- can be reversed with vitamin A supplementation or regular consumption of vegetables and fruit
- important to prevent permanent blindess
How does Vitamin A play a role in control of gene expression?
retinoic acid activates/deactivates certain genes thereby affecting protein production
How is Vitamin A important for skin and body linings?
- needed by all epithelial tissue (serve as protection)
- this vitamin promotes cell differentations (so it develops to serve a particular function)
How does Vitamin A play a role in immunity?
- regulation of genes that produce immune system proteins
- deficiency can lead to malnutrition and infection
How does Vitamin A play a role in growth?
assists in growth of bones and teeth
Consequences of Vitamin A deficiency?
- cell differentiation and maturation impaired
- can’t produce mucus
- increase in keratin producing cells
- more vulnerable to infection
True or False: supplemental vitamin A cuts childhood death rates
How can vitamin A toxicity occur and consequences?
- can occur from supplements or fortified foods, children who think vitamins are candy
- may weaken bones, bone and joint pain, abdominal pain, stunted growth, liver damage
early symptoms: loss of appetite, blurred vision, growth failure in children, headache, skin itching, irritability
long term symptoms: bone weakening and hip fracture
Connection between vitamin a toxicity and acne?
- teens who take large doses for acne
- acutane is derived from vitamin a
- vitamin a supplements do not help with acne
Will Beta Carotene cause Vitamin A toxicity?
NO
- can turn yellow/orange due to deposition in subcataneous fat
Does eating carrots really promote good vision?
- bright deep orange fruits and veggies and dark green veggies (rich in beta carotene) have a role in healthy eyesight
- does not improve vision if vitamin a intake is already adequate
what does lack of foods rich in beta carotene increase the risk of?
macular degeneration (a disease that affects a person’s central vision)
What is one of the main dietary antioxidants linked to vitamin A?
beta carotene
Good food sources of vitamin A?
- liver and fish oil
- foritifed milk and milk products
- eggs
- beta carotene
As Vitamin D is not essential, how does the body make sufficient amounts of it?
can make it all it needs with the help of sunlight
Roles of Vitamin D?
- regulation of blood calcium and phosphorus levels
- maintains bone integrity
- vitamin D can raise blood calcium levels (promotes absorption, retention by kidneys, draws calcium from bones)
- functions as hormone (brain, heart, stomach, pancreas, skin, reproductive organs, cancer cells, immune cells)
What does deficiency of vitamin D promote?
- high blood pressure
- some cancers
- Type I diabetes
- heart disease
- arthritis
- inflammatory bowel disease
- MS
What is Rickets?
- vitamin D deficiency disease in children
- abormal bone growth
- bowed legs, outward bowed chest, knobs on ribs
what is the vitamin D deficiency disease in children?
Rickets
What does health canada recommend for breastfed babies in relation to Vitamin D?
all breastfed healthy term infants recieve a 400 IU Vitamin D supplement each day
Why can consuming soft drinks lead to bone loss later in life?
- risk for bone loss later in life due to potential lack of Vitamin D in adolescents who consume soft drinks rathern than vitamin D fortified milk or alternatives
- prefer indoor to outdoor activities
What is osteomalacia?
- the adult form of rickets
- mostly occurs in women who have low calcium levels, little exposure to the sun, who go through many pregnancies and lactation
How can too much Vitamin D become a danger to soft tissues?
- very toxic of all of the other vitamins in excess
- continued overdoses cause dangerously high blood calcium level, forcing calcium to be deposited in soft tissues
- these tissues could be the heart, blood vessels, lungs, or kidneys
Does skin synthesis of vitamin D pose a risk of toxicity?
no, the sun begins breaking down excess vitamin D made in the skin
How can sunscreens actually be negative for vitamin synthesis?
it reduces sun risks, but also prevents vitamin d synthesis
What is osteoporosis Canada’s recommendations for adults with osteoporosis or at high risk for vitamin D supplementation?
800IU-2000IU daily regardless of age
What is osteoporosis Canada’s recommendations for routine supplementation of vitamin D for those with no osteoporosis risk for 19-50 year olds?
400-1000IU daily
Why do recommendations for vitamin D intake increase with age?
since the skins ability to synthesize vitamin D declines with age. Also, as you get old you tend to spend less time outside.
What are sources of Vitamin D?
- sunlight
- some from butter, cream, margarine
- fortified milk
- egg yolks, fatty fish, fish oil
- mushrooms
What does vitamin E consist of?
4 tocopherol compounds
what does oxidative damage result from?
free radicals: could lead to cancer, heart disease, and other diseases
What does the antioxidant activity of vitamin E do?
defends the body against oxidative damage
What are some of vitamim E’s roles?
protect red and white blood cells, immunity, nerve development
Do supplements provide health benefits for Vitamin E?
no unless deficient
How can vitamin E deficiency for infants occur? Why is it bad?
- infants born before the transfer of vitamin E from their mother to the infant
- erthyrocyte hemolysis is a rupruting of the red blood cells which results in anemia
How can vitamin E increase the effects of anticoagulant medication?
can increase the effects
Food sources of vitamin E?
- lots of types
- animal fats almost have no vitamin E
Functions of Vitamin K?
- synthesis of blood clotting proteins (intereferes with certain anticoagulant medications- blood thinners)
- synthesis of normal form of bone proteins that bind minerals to bone
Sources of Vitamin K?
- intestinal bacteria (Cannot meet the body’s need)
- leafy green vegiies
- canola and soybean oils
- eggs and milk
- liver is the only rich animal source
True or False: Newborns are given a dose of vitamin k?
true
Who are at risk for vitamin K deficiency?
- newborns
- those on antibiotic treatment as it kills both the beneficial and harmful bacteria in the intestinal tract
Who are at risk for vitamin K toxicity?
- rare among healthy adults
- infants and pregnant women: from over supplementation
- can lead to jaundice and bilirubin the in the brain of an infant which could cause brain damage or death
How can vitamin B and C be ‘leeched out’ of food?
cooking and washing
What is the general advice for meeting your water soluble vitamin needs?
choose foods daily that are rich in water soluble vitamins to achieve the recommended intakes regularly
how can toxicity for the water soluble vitamins occur?
- not from food
- can occur from the large doses concentrated in some vitamin supplements (expensive urine)
What is scurvy?
- vitamin C (absorbic acid) deficiency
- to avoid scurvy, british sailors were given lime juice
What are the roles of vitamin C?
maintenance of connective tissues:
* component of bone, teeth, skin, etc
* formation and maintenance of collagen
anxtioxidant:
* protect substrances found in foods and the body
* protects iron from oxidation
* protects blood constituents from oxidation
* helps protect vitamin E
**supplements only useuful to treat a deficiency disease, do not help protect against heart disease, cancer, etc
Deficiency symptoms of vitamin C?
- most scurvy symptoms are due to collagen breakdown
- loose teeth, bleeding gums, anemia, etc
- the risk of scurvy is low in North America
- people at risk: elderly, food insecurity, addicted people, infants who are fed cow milk and not breast milk or formula (know this i think)
Vitamin C and the immune system?
- supports immune system functions, and protects against infection
- not been shown to prevent colds
- a small benefit from vitamin C high dose intake at the onset of a cold
- may shorten duration of cold or reduce the symptoms
How can vitamin C work as a weak antihistamine?
- 2 grams per day for 2 weeks seems to reduce blood histamine
- this is the substrance that is responsible for sneezing, runny/stuffy nose, swollen sinuses
- vitamin C works as a weak antihistamine
*also need to consider the placebo effect
What can overconsumption of vitamin C lead to?
- massive doses may interfere with medications to prevent blood clotting
- may be dangerous for people with an overload of iron
What does smoking do to vitamin C?
smoking introduces oxidants that deplete vitamin C
What is the RDA for smoking and vitamin C?
RDS set high 35 mg higher of vitamin C intake for smokers
Food sources of vitamin C?
- citrus fruits
- dark green vegetaables
- potateos
What do the B vitamins act a part of?
- act as part of coenzymes
- coenzyme combine with and activate an enzyme
What are the B vitamins roles in metabolism?
- metabolism of carbohydrates, lipids, and amino acids
- thiamin, riboflavin, niacin, panthothenic acid, and biotin all help release the energy stores in the energy yielding nutrients
- vitamin B6 helps the body make protein
- folate and vitamin B12 help cells to multiply
What are vitamin B deficiencies?
- every cell affected
- cell renewal depends on energy and protein, which depends on B vitamins
- a thiamin deficiency during growth can cause permanent brain damage
- deficiency of any one B vitamin rarely shows up alone, because people eat foods that contain mixtures of nutrients
What is the role of thiamin?
- energy metabolism
- nerve processes and their responding tissue (muscle)
What is beriberi?
- thiamin deficiency
- loss of sensation in hands and feet, muscular weakness, advancing paralysis, abnormal heart action
- wet beriberi: edema present
- dry beriberi: no edema
What is Wernicke-Korsakoff Syndrome?
- thiamin deficiency?
- alcohol abuse with severe tiamin deficiency
- alcohol displaces food in the diet, impaires thiamin absorption, promotes thiamin excretion in the urine
- symptom: mental confusion, disorientation, loss of memory, jerky eye movements, staggering gait, apathy, irritabilitu
- treatment: thiamin by IV or orally (alcohol withdrawl process in hospitals)
Sources of thiamin?
- one of the B vitamins
- widespread in healthy foods
- pork products, sunflower seeds while grain cereals, legumes are rich sources
Role of riboflavin?
energy metabolism of all cells
What is the deficinecy of riboflavin?
- generally accompanies other vitamin deficiencies
- result of poor diet
- often accompanies thiamin deficiency
What is ariboflavinosis?
- riboflavin deficiency
- inflammation of the membranes of the mouth, skin, eyes an GI tract
- smooth, purplilish red tongue
- may go undetected because thiamin deficiency symptoms more severe
- children who lack milk products and meats are at risk
- treatment: a diet that treats a riboflavin deficiency also resolves a thiamin deficiency
Sources of riboflavin?
- widespread in healthy foods
- milk and milk products
- leaft green vegetables
- whole grain breads
- enriched/fortified grain products
- some meats and eggs
what is the role of niacin?
energy metabolism
What is pellagra?
- niacin deficiency
- called the “4 Ds”
- Diarrhea, dermatitis, dementia, and death
- poorly nourished people living in poverty and especially those with alcohol addiction are at risk
Sources of niacin?
- tryptophan (which is abundant in almost all proteins) can be converted to niacin
- if you eat enough protein, will not be deficient in niacin
- milk ,eggs, meat, poultry, fish, whole grains, fortified and enriched grains, nuts and seeds
What are the impacts of niacin toxicity?
- large doeses can cause niacin flish (painful tingling, flush, hives)
- can injure the liber and cause blurred vision
- large doses of a form of niacin (nicotinic acid) may be prescibed to lower blood lipids
What is the role of folate?
- DNA synthesis
- part of coenzymes for new cell synthesis
What type of deficiency is this line describing: “Because immature red and white bloof cells and cells of the GI tract divide rapidly, they are most vulerable to a deficiency”
folate deficiency
What deficiency can cause anemia?
- folate deficiency
- megaloblastic anemia or macrocytic anemia
- large immature red blood cells
- related to anemia of vitamin B12 deficiency
What can a folate deficient diet increase the risk of?
- CVD
- colon and cervical cancer
What can NTDs (neural tube birth defects be caused with which type of deficiency)?
- folate deficiency
- would cause problems with spinal cord, mental delay, severly diminshed brain size or even death after birth
- arise in the first few days or weeks of pregnancy
- most women eat too few fruits and veggies to supply folate need
Where is fortification seen and what does it cause?
- folate fortification is seen in bleached white grain products
- now fortified with folic acid
- since fortification began, folate intakes have increased
What are the seen effects of folate toxicity?
- can mask vitamin B12 deficiency
- excess folate may be antagonostic to the actions of some anticancer drugs
What is DFE?
- dietary folate equivalent
- converts all forms of folate into units that are equivalent to the folate in food
How are DFE calculations done?
- folate from foods is given full credit
- fortified foods and supplements are given extra credit (1.7x more available)
ex. 100 micrograms from food, 100 micrograms from supplements
100+(100* 1.7)
=100+170
==270 micrograms of DFE
Sources of folate?
- leafy green vegetables
- fresh uncooked vegetables and fruits
- heat of cooking destroys
- eggs
- orange juice and legumes
RDA for folate for healthy adults and pregnancy?
healthy adults: 400 mcg DFE/day
pregnancy: 600 mcg DFE/day
What is the role of vitamin B12?
- close relationship with folate
- vitamin B12 is activated by folate
- folate is activated by vitamin B12
- maintenance of the sheaths that surround and protect nerve fibres
Effects of vitamin B12 deficiency?
- damaged nerve sheaths
- creeping paralysis
- general malfunctioning of nerves and muscles
- deficiency results in failure of folate to make red blood cells
- vitamin B12 deficiency same anemia as folate
- folate will clear up anemia, but the vitamin B12 deficiency continues
If you have anemia from a folate deficiency, what should you also take?
give b12 vitamins as well if there are symptoms of folate deficiency incase of b12 deficiency
Who are those at risk for vitamin B12 deficiency?
- the elderly (absorption problems, decreased stomach acidity and decreased intrinsic factor)
- atrophic gastrics (inherited gene defect for intrinsic factor production, mid-adulthood)
- vegans (deficiency symptoms take time, must be sure to use vitamin B12 fortified products or supplements)
What is Vitamin B12 absorption?
- requires intrinsic factor
- a compound made by stomach
- the stomach’s acid liberates vitamin B12 from food, intrinsic factor then binds to the vitamin
- the complex is then abosrbed from the small intestine into the blood
What is prenicious anemia?
- a vitamin B12 deficiency diseases
- caused by lack of intrinsic factor and characterized by large, immature red blood cells
- treatment would be B12 injections
Sources of B12?
- animal sources are the only sig. source
- milk and fish
- fortified plant foods
What are the many roles of vitamin B6?
- 100+ reactions in the tissues
- assist in conversions of one amino acid to another needed amino acid- protein synthesis
- aids in the conversion of tryptophan to niacin
- neurotransmitter synthesis: conversion of tryptophan to serotonin
- hemoglobin synthesis
- assists in release of stored glucose from glycogen, contributing to the regulation of blood glucose
- immune function
- steroid hormonal activity
- fetal brain and nervous system development
General symptoms of Vitamin B6 deficiency?
- weakness
- psychologcial depression
- confusion
- irritability
- insomnia
- anemia
- greasy dermatitis
Advanced cases of vitamin B6 deficiency?
- covulsions
- may weaken the immune system
- evidence that low intakes may be related to increased risk of heart disease
symptoms of vitamin B6 toxicity?
- seen in women who took 2+ grams/day for 2+ months
- numb feet
- lost sensation in their hands
- evetually became unable to walk or work
- recovered after they stopped taking the supplements
where is vitamin B6 extensively stored?
in muscle tissue unlike the other water soluble vitamins
sources of vitamin B6?
- protein rich foods: meat, fish, poultry
- legumes and peanut butter
- potatoes, leafy green vegetables, some fruit
What is homocytesine?
- elevated homocytestine may be an indicator of CVD risk
- deficiencies of folate, vitamin B12 or Vitamin B6 cause excess homocytestine to build up in the blood
- supplements of these vitamins lead to a sig. drop in homocytesine level
- it is unknown how this affects a person’s CVD risk
what is the role of biotin?
- energy metabolism
- cofactor for several enzymes in the metabolism of carbohydrate, fat, protein
Symptoms and cause of biotin deficiency?
- may occur with some rare diseases
- consumption of dozens of raw egg whites per day, which contain a protein that binds biotin (avidin), will result in a defencieny
- cooking eggs denatures this protein
sources of biotin?
widespread in foods
what is the role of pantothenic acid?
- energy metabolism
- coenzyme that plays a role in the release of energy from the energy nutrients
- plays a role in 100+ steps concerned with the synthesis of lipids, neurotransmitters, steroid hormones and hemoglobin
how can deficiency occur for pantothenic acid?
may occur with some rare diseases
