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