Lesson 7: Vitamins Flashcards
What do we call organic essential nutrients required in tiny amount to perform specific functions that promote growth, reproduction or the maintenance of health and life?
Vitamins
What do we call inorganic essential nutrients required in varying amounts that function primarily as structural components or regulators of body processes?
Minerals
Vitamins do not yield usable energy when metabolized. Therefore, what is their role?
Assist the enzymes that participate in the release of energy from carbohydrates, fats and proteins.
Can vitamins be destroyed?
Yes
In what units do we measure vitamins?
Micrograms (pg) or milligrams (mg)
How are vitamins similar to the energy-yielding nutrients?
Vital to life
Organic
Available from foods
Are are minerals different from vitamins?
They have an inorganic chemical nature
They always retain their chemical identity
Can minerals taken in excess be toxic?
Yes
Can vitamins taken in excess be toxic?
Yes, fat-soluble vitamins
What is “the rate at and the extent to which a nutrient is absorbed and used?”
Bioavailability
What does determining bioavailability of vitamins and minerals depend on?
Food preparation
Efficiency of digestion
Previous nutrient intake
Source of the nutrient (synthetic, naturally occurring)
Some of the vitamins are available from foods in inactive forms before entering the body and converted to the active form of the vitamin. This inactive forms are called___________.
Precursors
Name 4 ways to minimize vitamin losses.
- refrigerate most fruits and vegetables
- store fruits and vegetables that have been cut in airtight wrappers
- rinse fruits and vegetables before cutting
- use a microwave oven or steam vegetables during cooking in a small amount of water
How are water-soluble vitamins absorbed?
Move directly into the blood. Once in the blood, they travel freely
How are fat-soluble vitamins absorbed?
They must first enter the lymph, then the blood. Once in the blood they require transport proteins.
Why do large excesses of fat-soluble vitamins overwhelm the system?
They tend to remain in fat storage sites in the body rather than being excreted, so are more likely to reach toxic levels when consumed in excess.
The presence or absence of one vitamin or mineral can affect another’s absorption, metabolism and excretion.Give 3 examples of interactions
- Folate and B12 can mutually enhance absorption and perform metabolic roles
- Sodium and Calcium cause both to be excreted when sodium intakes are high .
- Phosphorus binds to magnesium in the GI tract, so magnesium absorption is limited when phosphorus intakes are high.
What are the water-soluble vitamins?
Thiamin Riboflavin Niacin Pantothenic Acid Biotin B6 B12 Folate Vitamin C
What are the fat-soluble vitamins?
Vitamin A
Vitamin D
Vitamin E
Vitamin K
What are vitamins made up of?
Carbon, Hydrogen, Oxygen, sometimes Nitrogen and Sulphur
Where do natural sources of vitamins come from?
Plants, Animals, fungi and bacteria
What do we mean by “synthetic” sources of vitamins?
Chemists put bacteria/microbes to work in the laboratory to synthesize vitamins. Used in the enrichment and fortification of foods.
What do we call the addition of vitamins and minerals to foods products to replace those lost during processing (refinement) so that the food will meet a specified standard?
Enrichment
What do we call the addition of supplementary nutrients to food that were either not originally present or present in insignificant amount, to reduce risk of disease at the population level?
Fortification
What does the absorption of micronutrients depend on?
your body’s physiological need for it, which is mostly dictated by:
Age, Gender, Diet
What are the 3 forms vitamin A is found as?
Retinol, Retinal, Retinoic acid
Which form does the liver use to convert it into 2 other forms?
Retinol
Plants provide the precursor for vitamin A. This precursor is called _________.
Beta carotene
What is beta carotene?
A carotenoid that is lipid soluble.
How is the amount of vitamin A in foods expressed?
By RAE = retinal activity equivalents
Does cooking increase or decrease the bioavailability of beta-carotene?
Increase
Why is beta-carotene a deep green color in vegetables?
It is masked by chlorophyll
Where is vitamin A stored?
in the liver and fatty tissue
What is a teratogen?
Agent causing deformation in the fetus
What are some important functions of vitamin A?
Cell differentiation
Vision
Antioxidant Function
What is the process by which immature cells develop specific functions different from those of the original that are characteristic of their mature cell type?
Cell differentiation
What does cell differentiation require?
Vitamin A
What could be the result of vitamin A deficiency?
Increased rate of infection
Keratinization of the Skin (skin = hard and scaly)
Permanent blindness
How does vitamin A help with vision?
It is required for transforming light into nerve impulses that inform the brain
What are some things that can block UV radiation, preventing us from synthesizing vitamin D?
Sunscreen
Air Pollution
Tall Buildings
Clothing
What are the two major functions of vitamin D?
Bone development
Enhance or suppress activity of genes that regulate cell growth
Explain how the inactive form of vitamin D (vitamin D3) gets converted to its active form?
Vitamin D3 (calcitriol) is derived from cholesterol and is released into your bloodstream, then goes to the liver. The liver converts it to calcidiol & releases it into bloodstream. Goes to kidneys where it is converted to calcitriol, which is the active form of vitamin D.
Does vitamin D increase the bioavailability of calcium?
Yes
Which form of vitamin D is used to fortify milk and other dairy products?
Inactive form…Vitamin D3
What are some factors that contribute to vitamin D deficiency?
Dark skin
Breastfeeding without supplementation
Lack of sunlight
Not using fortified milk
What is rickets?
deficiency disease of vitamin D in children characterized by bowed legs
What happens during rickets?
the bones fail to calcify normally, causing growth retardation and skeletal abnormalities. The bones become so weak that they bend when they have to support the body’s weight.
What is the adult form of rickets and what can it lead to?
Osteomalacia which can lead to osteoporosis
What is osteomalacia?
bones become increasingly soft, flexible and deformed
What is osteoporosis?
condition of greatly reduced bone density.
What does excess vitamin D cause?
Raises blood concentration of calcium which could form kidney stones or harden blood vessels and arteries which could be dangerous.
Can you get too much vitamin D from the sun?
No, it is exclusively caused by an overuse of supplements.
What is the condition in which a person has high blood calcium called?
Hypercalcemia
What is the major fat-soluble antioxidant found in cells?
Vitamin E
How does vitamin E protect against free radicals?
Vitamin E carries extra electrons
What happens to RBCs without vitamin E?
they can break open and spill their contents
What is vitamin K necessary for?
Blood clotting
How are vitamin K requirements met?
Half is met by being synthesized by bacteria living in large intestines. Rest is supplied by diet
Why are infants at risk for Vitamin K deficiency?
Vitamin K is not found in breastmilk and it takes weeks for them to build bacteria capable of synthesizing vitamin K
What is VKDB?
Vitamin K Deficiency Bleeding
What is done to newborns to decrease risk of bleeding to death?
Given a single dose of vitamin K at birth
What is the main role of the B vitamins?
Energy Metabolism
What is energy metabolism?
The sum total of all the chemical reactions that go on in living cells
Why do we say that B vitamins help convert food into energy?
Because they support the generation of energy from macronutrients
Vitamin B works as a coenzyme. What is a coenzyme?
Small molecules that bind to enzymes and activate them.
What is the name of the disease caused by a deficiency in Thiamin?
BeriBeri
What are the symptoms of BeriBeri?
Can cause blood vessels to dilate which can lead to edema
Weakness
Memory loss
Weight loss
Is the deficiency disease for Riboflavin (B2) common? What are the symptoms?
No, it is rare. Deficiency symptoms include:
Weakness
Inflame tongue
Sores on the edge of lips
What is the disease associated with Niacin (B3) deficiency?
Pellagra
What are the 3 D’s of pellagra?
Dementia
Dermatitis
Diarrhea
Which amino acids helps us produce small amounts of Niacin?
Tryptophan
What is the problem with Niacin?
It’s low bioavailability
What is vitamin B6 crucial for?
Energy metabolism
Amino acid metabolism
Heme synthesis
Why is vitamin B6 different from other vitamins?
Unlike most B vitamins, megadoses of B6 are toxic
Why is B6 important for amino acids?
It is necessary for making the non-essential amino acids. Without it, all amino acids would be essential.
What role does B6 play with homocysteine?
It converts toxic homocysteine to cysteine
What is homocysteine?
The intermediate product of methionine being used to synthesize cysteine.
What happens to the body if it lack B6?
Homocysteine can accumulate in the blood and contribute to CVD
What is heme?
the iron in foods that is bound to the hemoglobin and myoglobin proteins; found only in meat, fish, poultry and eggs
B6 is required for heme synthesis. What happens without B6?
Anemia develops (specifically, small cell anemia)
What is anemia?
any condition in which too few red blood cells are present, or the red blood cells are immature (and therefore large) or too small or contain too little hemoglobin to carry the normal amount of oxygen to the tissues
What are the symptoms to anemia?
General weakness and fatigue
Can even lead to cardiac arrest
What happens if your cells lack oxygen?
your cells cannot break down macronutrients to obtain energy
What are the key roles of folate?
energy metabolism
amino acid metabolism
DNA metabolism
Which role is the most important?
DNA metabolism
What are the two deficiency diseases (neural tube defects) associated with Folate?
Spina Bifida
Anencephaly
What is spina bifida?
one of the most common types of neural tube defects; characterized by the incomplete closure of the spinal cord and it’s bony encasement
What is anencephaly?
an uncommon and always fatal type of neural tube defect; characterized by the absence of a brain
What happens to RBCs in the absence of folate and vitamin B12?
RBC precursor cells that reside in bone marrow enlarge but cannot divide normally because they are unable to form new DNA
What is folic acid?
the synthetic form of folate found in supplements and added to fortify foods
Does folic acid have a higher or lower bioavailability than folate?
higher
What has Canada done since 1998 in order to help with reducing neural tube defects?
all wheat flour is fortified with folic acid
What is vitamin B12 crucial for?
Energy Metabolism
DNA Metabolism
Amino Acid Metabolism
Maintaining myelin sheaths (very important for nerve cells)
What happens to myelin sheaths without B12?
segments of the myelin sheath gradually undergo destruction that can lead to neuropathy - degeneration of spinal cord
What is special about vitamin B12?
Unlike other water-soluble vitamins, we store and recycle vitamin B12 in the body
What could occur in mothers on a vegan diet with no supplementation of B12?
Nerve damage
What is vitamin B12 bound to?
Proteins that prevent its absorption
What releases B12 from the protein in the stomach?
HCL and pepsin
What happens to B12 in the stomach once it is released from the protein?
B12 binds to intrinsic factor (IF)
What is IF?
a protein produced by the stomach cells
Where does the B12/IF complex go to be absorbed?
The Ileum
What happens if theres no IF?
B12 cant be absorbed, even with supplements
What does the absence of IF cause?
Pernicious anemia
What is pernicious anemia?
the result of the protein not being produced, or having the wrong shape because of incorrectly placed amino acids
What other type of anemia can B12 also cause?
megaloblastic anemia
What is a treatment for pernicious anemia?
monthly injections of B12, or nasal gels/sprays containing vitamin B12
Are deficiencies in pantothenic acid and biotin rate?
Yes because they are both abundant in food and the requirements are low
What is biotin synthesized by?
By our gut-friendly microbes
What is the deficiency disease associated with Vitamin C?
Scurvy
What are some symptoms of scurvy?
Profuse bleeding, vision loss and memory loss
What is vitamin C crucial for?
synthesis and proper formation of collagen
what is collagen?
a protein that gives strength to connective tissue like bone, skin and tendons.
What is the foundation of bone? What do bones need to form properly?
Collagen…they need vitamin C
What is vitamin C best known for?
It’s antioxidant power
Is vitamin C a water-soluble or fat-soluble antioxidant?
water-soluble
How does vitamin C act as an antioxidant?
by donating electrons to free radicals to stabilize them
What are the vitamins that play essential roles for energy metabolism?
All B vitamins
What are the vitamins that play essential roles for blood health?
Vitamin B6
Folate
Vitamin B12
Vitamin K
What are the vitamins that play essential roles for bone health?
Vitamin C
Vitamin D
What are the vitamins that play essential roles for vision health?
vitamin A
What are the vitamins that play essential roles for Amino Acid Metabolism?
Folate
B6
B12
What are the vitamins that play essential roles for DNA Metabolism?
Folate
Vitamin B12
What are the vitamins that play essential roles for Growth and Development?
Vitamin A (epithelial health) Vitamin B12 (neural health) Folate (fetal development) Vitamin D (bone health)
What are the vitamins that play essential roles for Antioxidants?
Vitamin C
Vitamin E
Carotenoids
